Sunday, December 26, 2021

Rurui XT10 Electric Mountain Bike 150 mile review


I like bike riding for exercise and fun.  I have began riding much more off-road where a fat-tire full-suspension bike is really needed.  I started shopping for one and ended up with this Rurui XT10.  It was on sale through Amazon for $1899 with a $300 coupon making the price $1599.  Given all the features this bike has, that seems like a good price for what you get.  I call this my Cheat-O-Cycle since the electric power on a bike is sort of cheating.

The bike came shipped in one box.

It took me about 30 minutes to complete the assembly.  It was pretty intuitive which is good given there was no documentation, manuals, or instructions at all.  I later emailed Rurui and got the manual for the display.  I also found out later that one of the videos in the Amazon listing is an assembly video.  

The bike feels very solid and inspires confidence.  The hydraulic disc brakes are fantastic.  This is my first disc brake bike and this has been a huge upgrade.  The improvement is comparable with the difference between my 1968 Ford Mustang with 4-wheel no-assist drum brakes and my 2006 Porsche Cayman S.  The rear suspension is a bit too soft for me when you are off-road in rough terrain at speed.  The front can be adjusted so I set the preload to the maximum, and the damping about half which works well.  I plan to upgrade the rear shock soon. The headlight as great, although I have not ridden much at all in the dark.  I wish they would have included a wired taillight as well.  They included a battery powered taillight but that is a bit inconvenient.  The controller does have outputs for brake and tail lights and I may add that in the future. I really like the clamp-on grips as they feel great and stay put.  All my previous bikes had slip-on grips and they were always moving around.  The seat is really great too.  This is the best bike seat I have ever had, by far.  The shifter is great.  Button click upshifts, and you can downshift multiple gears at once.  

I wanted electric assist as a heavy, fat-tire- full-suspension bike like this takes more pedal power to ride.  The electric assist is fantastic to help with that.  I pedal pretty much all the time and let the electric power assist.  I still get plenty of exercise but my range is at least triple what I would have without electric assist, probably even more. So far my longest ride has been 30 miles and that used about half the battery.  Only having 7 speeds means you don't have the lower gears you would with a mountain bike that has a front derailleur.  The electric assist fills most of this gap but in very tight technical bits, I do miss the lower gears.  The electric assist does not work as well at speeds below about 5mph. I have considered changing the gear set to have a lower first gear to help with low speed riding.  You tend to ride much faster off-road than you would without electric assist.  I found myself going up loamy grades at over 15mph where I would be going more like 5mph without electric assist.  I also noticed my rides work my arms much more than before because I am riding much faster off-road.  

Fat tires make a huge difference in soft loamy conditions.  My other mountain bike has 2.2" tires and they just sink in and you stop.  The 4" wide fat tires float over most of that.  You also retain steering control much better in soft conditions.  It enables riding in places I just would not with narrow tires.    

I had some strange issues with the display.  It would only read speed when the motor was engaged, and even then it was way off, only reading about one third actual speed.  I emailed them back and forth for a while until finally fixing one of the parameters.  The display has settings you can change in a programming mode.  My parameter P07 was somehow set to 255 when it should have been 1.  I have heard others having parameters being off on bikes like this.  If you get one, and you have issues, check these settings.  My speedometer now works correctly.  You can also calibrate it to ensure accurate speed.  They have a wheel size setting as well as a fine tuning speed adjustment.

The color display is very hard to read in the sunlight, especially when wearing sunglasses.  It is very important to make sure your sunglasses are not polarized!  Even with non-polarized sunglasses, and on the brightest display setting, it is very hard to read.  

I would prefer a high-contrast black and white display that is focused on easy reading in direct sunlight.  Color is really just a gimmick.  Sure it looks pretty but it is much less functional.

The rear shock is not properly mounted to allow for proper rotation in the joints.  I noticed creaking when riding.  When I removed one end of the mounting, I found the other end to be clamped very tight.  

I replaced the front bolt with a longer 8mm shoulder bolt that I cut and added a locking nut.  I also greased the inside of the shock mounting hole and the bolt as this surface will be moving.  I was able to file down the rear shock enough to prevent the binding.  I also lubricated this.  Now the suspension moves freely with no binding or creaking.  

My first off-road ride was great, but I did have issues with how low the crank is to the ground, especially when the suspension is compressed over bumps.  My pedals took a beating.  I adjusted the front preload to the maximum and that helped.  The rear could really use a preload adjustment, and a longer shock.  See the "upgrades" section below.

When riding fast over very bumpy terrain the chain sometimes comes off.  This is a common problem with mountain bikes when you ride them aggressively off-road.  See "upgrades" section below. Mountain bikes with a front derailleur don't tend to have as much of a problem with this as the derailleur guides the chain back on the sprocket. 

The motor power is great from about 8mph to over 27mph.  However, when running full power for long periods sometimes the motor cuts out.  I suspect this is either the controller overheating or battery voltage at the controller dropping intermittently below the 39V cut-out.  The first time it happened I was going up a soft loamy grade that was at least 6% and very long.  After about 20 minutes on assist level 2, and moving fairly slow, the power assist surged a few times and then dropped out.  I felt the motor temperature and it was not that warm.  I was tired anyway so I rested for a few minutes.  After that the assist was fine again.  I have found on very long steep hills you need to use assist level 1.  I had the power drop out like that one other time.  This time it was at the end of a 30 mile ride where I had been using full power for a long time and the battery was about 1/2.  This was all in December so it was cool out.  In all my riding so far this issue has been rare and temporary.  If you are wanting a off-road bike that you don't have to pedal, just get a dirt bike.  This bike is great for my use case though.

One thing you will notice when shopping for bikes like this is that many of the components can be found on competitors bikes.  Most of these bikes are a collection of components assembled into a complete bike.  This is of course true with many things today but it seems even more so with these ebikes.  Some are so similar you may not be able to tell them apart except for the labels.  I found other bikes which appear to even have the same frame.  

Overall I am very happy with my purchase especially given what I paid for this bike compared to the alternatives.  The bike is a blast to ride and I ride more often, and go places I never did before.  The first 150 miles have been great.  Sure, there are a few things I will change but even making those changes I am well under $2,000 for a well featured electric mountain bike.  The 150 miles I have ridden so far has been a mix of pavement and off-road but mostly off-road.  It has enabled rides I would just not be able to do on my other mountain bikes.  


As I mentioned above, there were a few things that I wanted to improve.  I made the following modifications to the bike at 150 miles.

Rear Shock Upgrade

In order to keep the pedals from hitting the ground so much I needed to raise the bike.  While I was at it, I also wanted more aggressive damping and preload.  The original shock on this bike was 165mm (mount-to-mount) and most of these shocks have 35mm travel (at the shock).  I wanted a 190mm shock at least.  Given the space in this frame, I needed an air shock rather than a coil spring type.  The front fork has a lockout so when you are riding on pavement you can reduce your energy consumption that is absorbed into the suspension when pedaling.  It is even more important on the rear.  You can easily spend $400 or much more on a rear shock with these features.  I found a DNM AO-38RL-190 that looked like it would work well and was only $99 on Amazon. It is 190mm long and has 55mm travel.  

It was tricky getting the remote cable routed.  I was not able to use the routing they intended because the cable would interfere with the suspension.  If I rotated the shock 180 degrees, then the air port was not accessible.  Instead I routed the cable the opposite direction and added a cable clamp I made from a simple screw, nut, and washer that I drilled a hole through.

Now the cable housing is what locks the shock.  Leave the original cable set screw loose in this orientation.  It actually works quite well like this.  The cable has a nice long loop to prevent fatigue with suspension movement.

I took it for a good hard run off-road over very bumpy, rocky, rutted trails and it works great.  Much more controlled overall.  It no longer sacked the suspension even over the very rough stuff.  My pedals never hit anything either.  Before this was a common issue and an issue I had on this same trail.  I found myself riding faster and with more confidence.  The feel of the bike really improved. 

I tried the shock lock on the road while I was pedaling hard.  It worked well.  The suspension did not move while pedaling when locked.  The lock is not a full lock but it makes it enough stiffer that the suspension acts pretty solid.  Over real hard bumps it may move some though.  Perfect actually.   I like having the remote cable instead of having to stop and fiddle with a shock valve.

Front Sprocket/Chain Guard

A problem with mountain bikes is that the chain will come off when traveling fast over very rough terrain.  Not having a front derailleur makes it much worse.  The problem generally happens when going downhill where you don't have tension on the chain.  Riding in 3rd gear really helps as the chain is straight between the sprockets in that gear.  Also, make sure you don't rotate the crank backwards at all on rough terrain.  I had this issue pretty bad.  First I tried this chain guide, after significant modification.

It really helps.  I had it come of once or twice but far less than before.  I noticed that I tended to roll the pedals back at time while riding downhill over rough terrain and that would cause the issues too.  I was careful to stop doing that and it worked pretty well.   I was not thrilled with this approach though.

I noticed another electric mountain bike that solved this by adding an inner sprocket guard such as the Cyrusher XF900. I decided this was a better approach to solve this issue.  I bought this one from Amazon. It is made of plastic which is what I wanted so it would not get bent or wear with chain contact.  It was intended to be used on the outside but I just bolted it to the inside.

It worked fantastic!  I took the bike on a good rough off-road ride and never had an issue.  It retains the chain on the sprocket great.  In first gear the chain actually touches it a bit but it is silent.  Even if you pedal back a bit the chain stays on the sprocket.  Since installing this the chain has never come off again. 

Here is a short video discussing these upgrades

Sunday, December 12, 2021

Mountain Bikes

 My favorite form of exercise is biking.  I really prefer to ride on designated bike paths or off-road versus on the street.  I currently have 3 bikes.  

Hybrid Mountain Bike

My oldest is a 2013 Specialized Crossroads Sport hybrid (mountain/road) rigid frame, no suspension. I bought this bike in 2014.  At the time of this post my Garmin watch recorded 830 miles but I did not get the watch until 5 years after I bought the bike.  I would guess I have closer to 4,500 miles on this bike.

Full-Suspension Mountain Bike

In December 2020 bikes were scarce.  Most bike shops had very little available and even used bikes were hard to find.  I found myself looking for a full-suspension mountain bike at a very bad time.  I happened to be shopping at Walmart one day and they had a Kent Flexor in stock for $148 so I bought it.  

I was surprised how inexpensive this bike was, but it is also cheap.  I call it my Cheap-O-Cycle.  At the time of this post I have accumulated 676 miles.  I would say about half the hours I have put on this bike have been off-road.  I did have trouble with the freewheeling hub.  It fell apart on one of the early rides. 

Kent sent me a set of replacement wheels (which included the freewheeling hub).  The new one did it as well and I learned how to tighten it.  It appears they do not seat the bearings or torque the unit properly when assembling it.  I tightened it very tight and the issue seems to have been corrected now.  I did buy a replacement on Amazon for $16 and that was much better.  Overall though I did get my $148 worth.  

Electric Fat-Tire Mountain Bike

Riding the Kent Flexor made me realize that I needed a fat tire bike for off-road.  The narrow tires on the Flexor would sink it too much.  A fat-tire full suspension bike takes more energy to ride.  I also found steep or long hills to be not fun on the Flexor.  When riding downhill on rough terrain, the Flexor did not feel substantial enough either.  It does not have actual shocks, just springs.  The brakes are just rim brakes and I wanted hydraulic disc.  These things led to to wanting to upgrade to an electric assisted mountain bike.  

I ended up with a Rurui XT10.  Since it has electric assist, I call it my Cheat-O-Cycle.  This bike has a much more substantial frame, full suspension with real shocks, hydraulic brakes, and 4" wide fat tires.  

My first ride on this bike was great. I was able to ride a trail that previously took about 2 hours in 20 minutes.  This particular ride has about 1000' elevation gain and is mostly loamy sand and gravel.  I made about a 14 mile loop which also included some paved bike path.  Most of that 14 miles was rugged off-road riding.  I was in PAS mode 1 for most of the ride.  PAS mode 1 provides electric assist up to about 10mph.  I took it on a paved bike path for a bit as well and tested the top speed in mode 5.  I was able to get over 27mph which is plenty fast for me on a bike. The maximum assist speed in user configurable through the display. In high gear the pedaling cadence is the limiting factor.

It took a bit to get used to how the electric drive worked.  This bike uses a rear hub-motor.  Some other electric bikes used a motor at the crank.  Each have pros and cons.  The hub motor is simple and does not impact the chain or gears.  However, it lacks the multiple gear ratios of the gears too.  This limits the speed range where it is most efficient.  I am happy with my choice of bike having a hub motor.  One upgrade I may consider it going with wider gear ratios, mostly for first gear.

I am happy with the battery range versus weight.  My first ride was not many miles for the effort as it was mostly off-road with many hills and loamy terrain.  Since these bikes don't have regenerative braking, that really consumes battery.  Garmin reported the ride at 13.9 miles and I used less than half the battery. This will really vary based on the specific ride and how much the rider puts into it.  I ride for enjoyment but a main goal is also exercise. I plan to always pedal. The first ride was much more intense than off-road rides on the Flexor since the speed was so much higher going up in elevation, and through loamy terrain.  

The hydraulic brakes and actual shocks were big upgrades from the Flexor.  One issue I did have is the pedals hit the ground when riding in ruts or when there are rocks.  I measured the distance from the bottom of the pedals to the ground on this and the Flexor and found the Flexor had at least 1" more ground clearance.  I may look into raising the back suspension on this bike a bit.  The fat tire made a huge difference off-road.  I was able to easily go through stuff I would have to get off and walk the Flexor through.  Same with hills.  The fat tires also soak up some of the bumpiness.  

I had dirt bikes back in the day.  My favorite was  KTM 500MX.  Riding the Rurui was somewhere between a mountain bike and a dirt bike, but more towards the mountain bike.  Obviously the 1HP this Rurui generates is tiny compared to my KTM that had 55HP.  Of course the KTM was also at least 100lbs heavier.  I was able to push the Rurui up super steep hills which was not really possible with dirt bikes.



Saturday, November 6, 2021

SEMA 2021


The SEMA Show

The Specialty Equipment Manufacturers Association (SEMA) offered a new Friday Experience where they sold a limited number of tickets to the public to attend SEMA Friday.  I bought one of those tickets and attended.  I have wanted to attend SEMA ever since I first heard about it from Hot Rod magazine writeups back in the 1970's.  This years event was the largest convention in Las Vegas for 2021.  I have been to MINExpo in 2021, and CONEXPO in 2020, both at the Las Vegas Convention Center as well and SEMA is a bigger show using all of the convention center halls as well as most of the parking lots.  My Garmin watch reported over 19,000 steps and almost 11 miles of walking for the day.  It's nice the LVCC Loop helps get you between some of it without as much walking. I did not get to most of the stuff in the parking lots which took up all of the Central Hall lots, and likely more. It is a huge show to cover in one day.  

SEMA is about more than just aftermarket vehicles and equipment.  It also focuses on shops that service or modify vehicles.  SEMA has many vendors of tools, shop equipment, training, software, and pretty much everything a shop would need to service or modify vehicles.  

SEMA had an area they called SEMA Electrified.  This area showcased mostly BEV performance.  

At the end of the show they have an event called SEMA Ignite where a parade of vehicles from the show drive through the parking lot of the West Hall past a bunch of bleachers.  They have live music and beer too.  They block off Convention Center Drive from the LVCC Central Hall to the parking lot of the West Hall where SEMA Ignite is.  They also block off Paradise Road for a block in each direction.  This made it a challenge to get an Uber home.    

Cat had some products there, in 2 different areas.

There were of course plenty of press there so you can find many great photos, articles, and videos online from SEMA.  The pro's obviously have far better equipment and skill than me with my 2.5 year old smartphone.  Below are some videos I captured.

Here is a playlist of 360-degree videos I took

Aftermarket Performance Future

Another thing that attracted me to SEMA was to see where industry was with electrification.  I wrote this article earlier about what I see as a likely path for future aftermarket performance.  While full battery electric (BEV) conversions are happening, I have only found Vonnen doing hybrid conversions so far.  There are retailers selling Tesla motors and systems.  GM and Ford have both advertised "crate" electric motors. Ford did show off their Eluminator truck built on their e-crate motor that does have a part number and the article claims you can order it now. 

There were other companies offering BEV components at SEMA such as Blacmotor and Torque Trends

I can see a real future for full BEV conversions, but I also see a market for hybrids conversions which appears pretty much unserved except for Vonnen.

Many look at the trends and see the bigger leap direct to BEV in all cases.  I see it a bit differently.  I agree there is a market for BEV conversions and they are compelling in many ways but I also see a market for enhancements to internal combustion engine (ICE) vehicles.  This market is larger than some think in my opinion.  There is something about hearing the sound of an engine that really matters to some.  I am one of those it matters to.  Maybe that desire runs stronger in older folks. I wrote an article about this earlier in this blog.  For those people (which includes me), hybrid really makes sense.  The use case for performance hybrid is very different than hybrid focused on fuel economy, as all the mainstream hybrids are.  Hybrid has been in racing for years now.  Look at F1 KERS for instance, or recent LeMans race cars.  Hybrid powertains are everywhere.  Sports cars often look to racing to adopt those approaches to enhance the performance of street/track sports cars.  Supercars are already well down this path too.  Some of the first were the Porsche 918, Ferrari LaFerrari, and the McLaren P1 which came out years ago.  Many more have followed.

The other issue to consider is the increasing focus and regulation around emissions. The California Bureau of Auto Repair (BAR) has increased focus on going after modified vehicles.  The days of modifying flash files and tunes are nearing an end. Other aftermarket equipment that negatively impacts emissions will face increased scrutiny and eventual ban going forward as well.  Hybrid retrofits do not suffer these risks since they will result in neutral or decreased emissions, and they do not negatively impact emissions control or OBD. 

The performance benefits of electric and hybrid are clear.  Electric motors give a very different powerband than ICE engines.  Their performance peaks in the RPM range are opposites. Combining the 2 together give a much flatter performance curve and really fill in the low end power gaps that ICE engines have, particularly naturally aspirated ICE engines.  Adding hybrid has no effect on the engine sound, other than to allow it to rev even quicker.  The driver experience is enhanced with no downside.  

Some may look at the hybrid retrofit and claim the extra weight will be a bug downside.  That would be true if the net weight gain was significant, or worse, poorly placed in the vehicle.  They would also look at BEV and plug-in hybrids and claim those batteries are heavy and expensive, which is true.  However, the battery capacity needed for performance enhancement is much smaller than what you need for BEV and plug-in hybrid where you are trying to save fuel.  Vonnen's system uses a 1kWh battery.  Most BEVs require more like 80kWh or larger.  Vonnen's system also adds a total of 170lbs but places is lower in the chassis.  The only real downside of Vonnen's system I can see if the cost.  I believe as BEV and hybrids go more mainstream, we will see these costs go down.  I really like what Vonnen has done here and I think they are only the first of many to come.  

I believe that hybrid and electric offer many benefits over an ICE powertain.  Those include:

  • The energy storage (batteries, ultra-caps) can be more strategically placed around the vehicle in more optimum places for the weight.  You can also have multiple smaller battery packs to optimize weight location.
  • Energy storage can use a combination of batteries and ultra-capacitors based on optimizing for the use cases of the vehicle. Other future energy storage devices can also be used.
  • Multiple motor/generators can be used.  This allows for better active torque vectoring without the use of the brakes.
  • Electric motor/generators are not only used for propulsion, but also play a part in braking. I like track days and brakes take a real beating on track days.  Absorbing some of that braking energy with the electric system can be a real advantage.
  • Multiple motor/generators can be placed to drive each wheel independently.  This will allow for torque vectoring to optimize deceleration in and acceleration out of corners on the track.  It is also a better way to manage traction control overall.
  • Electric motor/generator control is very fast.  There is very little time lag between a command and the actual torque application.  This response is far better than any ICE powertrain and give a new level of control.
  • When using multiple motor/generators, a single failure will not leave the vehicle incapacitated.  It is like having multiple engines on a airplane.  You can limp home even if one or more fail as long as you have enough for the job.
  • You can enhance a hybrid system to also drive an electric supercharger.  When used with a Roots or screw supercharger, a motor/generator driving the supercharger can be used in place of the traditional throttle.  This can recover some otherwise wasted energy from the Otto-cycle engines during light loads.  You can also create custom tuned boost curves to optimize for the ICE engine.   
  • You can dispense with all the ICE belt driven accessories like alternator, HVAC, and power steering.  Even the water pump can go electric drive.  This can also eliminate most or all of the related hoses from those systems.  The HVAC can be all hard lines instead of hoses since the compressor can now be body mounted.  Electric assist power steering already exists.  Eliminating all this belt driven stuff lets the engine rev quicker too.
  • Engine attached motor/generators like the Vonnen system allows for the removal of the alternator and starter.  No longer do you have that noisy starter to start the engine.  This can also be used for anti-stall and stall recovery where the motor/generator are used to maintain idle speed even if the engine dies.
  • In the case of highly modified engines, the engine attached motor/generator can by used to stabilize the idle.  The Aston Martin Valkyrie is a great example of this where the hybrid system is used to make the car more drivable. 
  • It is possible, especially in off-road vehicles, to recover energy from the suspension using electro-magnetic suspension dampers (shocks).  These can be used to actively control vehicle ride.  Electro-magnetic suspension control can be used to eliminate the sway bars and instead have the ride height actively controlled.  This will allow the off-road vehicle to rock climb and keep all the wheels in contact with the ground while also preventing body roll at high speeds.  Body roll can be actively eliminated completely improving performance of all vehicles.  In fact, negative body roll can be implemented.  Since some of the energy is being recovered rather than generating waste heat, the devices would not have as much of a heat problem as shocks do in off-road racing.  Their performance can be temperature compensated too, whereas tradition shocks change performance when hot versus cold. 
  • Optionally, auto start/stop could be implemented for street cars.  When combined with moving the belt driven accessories to electric drive, you can sit in comfort with the HVAC ON and engine off for some time.  This would be great for a daily driver in town.  Like many hybrids today, the motors can both start the engine and start the vehicle moving at the same time giving good response to accelerate from a stop (unlike non-hybrid start/stop systems).  
  • The ICE can be electrically warmed up.  ICE engine wear is much higher on a cold engine.  The less cold operation the better.  Using the hybrid generator to drive an electric engine heater will both worm the engine faster, and heat the coolant faster.  
  • An electric heater can be used for cab heat and windshield defrosting until the engine warms up. This is safer as well as more comfortable.
  • Trailers can also be equipped with motor/generators.  This can allow for all the wheels to be driven in poor traction conditions so you don't get stuck.  It also allows for regenerative braking.  The trailer can have its own battery, or connect into the vehicles electrical system.
  • Electric winches can be smaller and much more powerful using the high-voltage electrical system.  
  • Electric PTO accessories can by used to drive various things that tradition PTO systems did.
  • The list goes on and on.
The main point is to not think of electric drive as a replacement for a traditional powertrain but rather a whole new way of managing energy and power.  Think of solving the various use case challenges from scratch, rather than just evolving from traditional approaches.  

I would really like a BEV for my daily driver but I want a hybrid for my sports car.  BEV just makes so much more sense for a daily driver as I discussed in this blog post.  Longer term I do hope the ICE can live on in a carbon free fuel form using future fuels.  It will be a niche though as BEV really makes the most sense for the vast majority of people in most use cases. Getting the vast majority of people out of ICE vehicles will leave the remaining niche with little overall emissions impact even if we keep using petroleum to power them.

I am an optimist and I do believe the future of performance vehicles and vehicle customization is bright, even in the face of BEV and autonomous revolution.  I still remember the 1970's, the dark ages of the automobile in many way.  Many predicted the end of high-performance vehicles completely.  They said performance is just not possible with all the new emissions regulations.  I have to laugh at that now as todays performance cars are far better then the old muscle cars prior to the 1970's when it comes to performance.  Things got far better, not worse during the 1980's once the OEMs changed their mindset.  Aftermarket performance will of course remain a niche market, not the mainstream.  But that is really the point anyway.  SEMA is a fantastic display of this niche market, and just how big it really is.  Most of the folks in this business are passionate about performance first, and running a profitable business comes after that.  

Saturday, June 19, 2021

Mercedes GL450 100k miles


I bought a 2013 Mercedes GL450 back in 2018.  It had 64k miles at the time.  It is a fantastic trip vehicle and we have used it for many long road trips.  It hit 100k miles the other day.

As I said this is a fantastic road trip vehicle.  We have taken it on numerous long road trips from 500 miles to 1800 miles each way.  I have made several trips over 1700 miles in 2 days and with me behind the wheel the whole time.  This has the lowest driver fatigue of any vehicle I have ever owned.  For a large SUV it actually handles pretty well.  The fuel economy is not bad either for an SUV this size.  It has done 21MPG on road trips and I generally get about 17MPG in town.  The twin-turbo 4.7L V8 has a nice wide powerband and good power.  I have towed a car on a trailer up steep hills out West with little effort.  

The utility of this vehicle is also very good.  It can tow 7500lbs and has great interior space.  The air suspension keeps it level at all times too.

The vehicle did have one annoying sound that was very intermittent when we bought it.  Accelerating from a stop while turning left cold the clunking sound would intermittently happen.  It was under warranty so we took it to the dealer.  They replaced a bunch of parts at 80k miles and it seemed to go away for a while.  At about 95k miles it came back and was much worse.  Finally we had the left front axle replaced and it was fixed.  One of the CV joints was bad causing this noise.  

The factory equipment tires do not last long at all.  There were not many tire choices for this vehicle either.  It has higher load and higher recommended pressure than most tires this size.  The first set I replaced I used the factory Continental tires at 76k miles.  They were down to the wear bars by 96k.  Now there are better tire options so I upgraded to Michelin tires.

Sunday, June 6, 2021

Energy Efficiency

 It's interesting to see how big of an effect mindset can be on society. Here I will share a few of my thoughts on the subject of energy efficiencies and management.  I do believe in reducing or eliminating waste.  As an engineer, it is my job.  If we focus on waste elimination we will positively impact costs as well as reduce energy needs.  If we just rethink how we acquire and use energy, I believe there are substantial wastes that can be reduced or eliminated.

The views expressed below are just my personal thoughts on opportunities for more efficient use of energy.


Personal commuting

Commuting is the task of moving people (and related cargo) from one place to another.  I see this is a bit different from driving but it certainly includes that. I will focus on energy here rather than get into autonomous commuting.  A typical petroleum powered vehicle is less that 40% efficient use of fuel energy for propelling the vehicle.  At least 60% goes to waste, mostly in the form of heat.  Then when we want to decelerate (brake) we dump all that kinetic energy into even more waste heat. That is very significant energy waste.  Also consider how much time is spent idling at a stop.  Integrate this waste over a typical drive cycle and very little of the total energy consumed is used for propelling the car.  Extremely wasteful.  Hybrid powertrains can really help especially in city traffic.  However a hybrid still lugs around a very heavy inefficient powertrain that requires significant maintenance.  I believe that the best powertrain for nearly all commuters is pure electric.  Here are some of my reasons:
  • Nearly zero maintenance.  No oil/filter changes, no coolant flush, no trans service, no spark plugs, etc.  This is beyond the schedule maintenance as the electric powertrain is far simpler with less moving parts to maintain or fail.
  • Longer service life.  While engines and transmissions have improved in durability, they still pale in comparison to an electric powertrain.  There is of course the battery which is the biggest challenge for electric vehicle durability.  However, battery technology continues to improve and with the increased focus more recently, I believe we can solve this problem and have energy storage that lasts for decades soon.
  • Regenerative braking.  Instead of just wasting the kinetic energy slowing the vehicle down with brakes, a well design electric car recovers most of it, storing it back in the batter to be used on the next acceleration.  This is a huge deal!  Not only does this drastically reduce brake wear and dust pollution, it saves energy.  You get to recover a portion of the kinetic energy and use it to accelerate back to speed. This is a clear win-win no brainier.  
  • No idling, ever.  Electric vehicles do not use propulsion motors to power anything but moving the vehicle.  All accessories are electric so they can run independent from an engine.  No more wasteful idling ever.
  • No need to waste a trip to "refuel".  Unlike petroleum, electricity is already available at our homes, businesses, hotels, stores, etc.  Because of this you don't have to make a special trip, or add a wasteful stop in your commute to refuel.  Instead, the vast majority of daily commuters can simply plug in at home, work, the store, restaurants, etc.  You don't need a special charging place but rather just charge at the places you already go.  No sitting and waiting to refuel.  The refueling happens wherever you stop. This is a big paradigm shift I don't feel many people really grasp.  When electric cars are discussed, people always go right to lack of charging stations as the reason they are not ready for an electric car.  Those should only be needed for long distance drives.  You should never need this for our daily commuting.  I think people get stuck in current mindsets and struggle to adapt to this new approach.  I believe we will get over this. If we all went to electric vehicles we would not need anywhere near the dedicated charging stations that we have gas stations.  We would only need them along interstate highways.  In town any building can have charging ports at parking spaces but even these would not get near the use that gas stations do today.  All hotels, restaurants, work places, grocery stores, etc., can have charging stations and some already do today. Inductive charging is coming too.  This will allow wireless charging like some cellular phones have today.  Just pull into a parking spot and charging will happen automatically.
  • Ability to heat and cool the vehicle while it is parked and even while sitting in the garage.  Instead of hoping into a cold or hot car, or having to start and warm up the car (more waste) you can run the heated seats and HVAC before you even get in the car.  You can even do it (for short periods) while it is in the garage with the doors closed.  This actually help maintain your range as well since you can do this while it is plugged in and not use the battery.  Another benefit is safety since you can warm the windows and prevent fogging before you drive away.

Mass Transit

City bussed and local trains can and all go electric.  The same comments for cars apply here.  The use cycle is of course much larger as busses operate all day long.  They do spend a significant amount of time idling at stops.  They also make short acceleration/deceleration cycles constantly.  Here the savings switching to electric is big.  Not to mention the emissions from petroleum powered vehicles in some of the more confined inner cities, tunnels, and drop-off zones in large venues can be a problem. Then there is the noise reduction as well.

Delivery, garbage, mail, etc.

All of these vehicles have even more start-stop and idling periods than the mass transit category above.  Same concepts apply but with even bigger energy savings.

Where does battery electric maybe not make sense?  

I believe there are several categories where hybrid powertrains are likely the best instead of pure battery electric:
  • Sports cars.  While you can make very high-performing electric sports cars, many drivers would miss having the engine as part of this experience.  The Porsche 918, Ferrari LaFerrari, and McLaren P1 were some earlier examples showcasing what hybrid powertrains can do for performance.  These applications do not need much energy storage since the car depends mostly on the engine to supply most the power, only using hybrid to enhance performance and braking.  This approach should make it's way across most sports cars, not just these supercars.  It can be enhanced to provide better active torque vectoring and traction control too. This is a small market share and collectively does not add up to much energy waste in the big picture.
  • Long-haul trucks.  Hybrid makes the most sense here to give the truck a long range and keep the weight reasonable.  The hybrid power can be used to downsize the engine to optimize it for Brake Specific Fuel Consumption (BSFC) while at steady speeds under typical loads.  Use hybrid power to add acceleration and hill climbing power and for regenerative braking.  It could even be possible to make smart mountain passes where trucks going up can take power harvested from trucks going down.  This would improve safety by keeping the brakes cooler as well.  

What about the waste and environmental impact of all those batteries?

Many electric car opponents discuss the cost, energy use, and waste of the batteries for electric vehicles.  It is certainly true that there is a real cost and we need to manage how we handle batteries at the end-of-life.  Todays batteries are hazardous waste.  However, these batteries are getting better and lasting much longer than they once did.  We can also develop recycling programs to recover the materials from the expired batteries.  Of course that is not cheap either.  Energy storage is an engineering problem to solve and as demand increases, the motivation to solve this will also increase research and development. With a world of smart people working on this, I believe we will see breakthrough invention and innovation make step-change improvements as well as continuous improvements in this area.  New electric energy storage can be relatively easily retrofitted to existing electric cars too.  I believe if you buy an electric car now, by the time you need to replace your battery there will be cheaper and better options available than there are today.  These better options can also increase the range of the vehicle, and potentially the charging rate.

Electric Power

Our traditional mindset has a grid with large centralized power generation facilities generating the electricity and distributing it with weather prone ugly powerlines.  It seems most still look at this mindset when applying solar power.  Why?  Instead of making large solar power projects that cover acres of land and then having to send it over these powerlines, why not generate it at the point of use?  Every roof can be used to generate solar power.  Picture every large building having an optimized solar grip on the roof.  Not enough space?  OK, cover the parking lots too. Everyone would get nice shady parking and no land is wasted.  Parking lots are not exactly a view anyone will miss.  

Homes are starting to get more solar power and this makers sense, especially in places like the desert where sun is abundant and air conditioning is one of the highest power consumers that happens to coincide with the most solar power generation.  This can also be used to charge the electric car in your garage.  

I see a continuing need for the power grid but only to fill in the gaps where/when solar cannot be generated, and to move power around from producers and consumers.  Every building can be both a producer and a consumer.  

I think there are places for wind power generation.  Like solar, you are dependent on mother nature to provide the right conditions.  In both cases, alternative power will be needed at times.  I believe natural gas cogen plants can fill this need well in cases where the power is needed for longer periods.  Nuclear power can also be used here.

Electric energy storage can also be used to make better use of solar and wind energy.  

Hydroelectric power is one of the best power sources and we should of course continue to maintain and utilize our dams.  

I still believe there is a place for coal power, primarily as standby power.  This can be started for cases like the Texas deep freeze of 2021.  Keep this electric generation capacity available but use it as a last resort.  

Thermal Energy

We heat and cool our homes and other buildings.  We also convert energy to heat for things like hot water, drying our clothes, etc., and move heat for air conditioning  There are many inefficiencies here where we can make better use of the thermal energy and reduce the need of gas, coal, oil, and electricity.  Take for instance a typical home on a hot summer day.  We run the air conditioning to pump heat to the outside while we use other energy such as gas or electricity to heat the water and dry our clothes in a dryer.  Why do we take the air conditioned air from inside our home only to heat it to dry the clothes?  Why can't the dryer take the heat you are already pumping out of the house to heat the clothes in the dryer?  In fact, why can't it take the hot air from outside to start with already hotter air on warm days?  These things can easily be done actually.  To start with we need dryers that have both intake and exhaust pipes instead of just exhaust.  Then we can bring pre-conditioned air into it and optimize this energy.  

Today you can buy heat pump hot water heaters and these really make sense in certain hot climates.  Geothermal systems also make sense and can be used to also heat the hot water.  In the summer heating your hot water will actually save energy versus just cooling the house.  Hot water heat can and should be added to heat pump systems in hot climates.  You take the heat from where you don't want it (the house) and pump it to where you do (the hot water tank).

There are times when you can simply bring in outside air to heat or cool the home.  If you have a smart thermostat and air handling system, you can monitor the temperature and humidity inside and outside.  If conditions outside become more desirable, just pump that air into the building.  This also brings fresher healthier air into the house.  In some case you may want to add better filtration systems to the air coming in from outside but that is cheap and easy.  Active duct valves are also needed to make each room in the building comfortable.  This becomes especially important in multi-story buildings.  In buildings with a basement, you may be able to cool the top floor simply by bringing colder air from the basement and pumping it to the top floor.  This will make both spaces more comfortable.

In the winter we take warm air from inside our homes, heat it more in the clothes dryer, and then pump it all outside while our heating system runs trying to heat the house.  Often people will also run a humidifier to add humidity to the house.  Instead, you can simply us the hot humid air your just produced in the dryer.  You would still want to condense some of that humidity out and you may want to employ a heat exchanger for most the air as you can add too much humidity but the current state is very wasteful.    

Thanks goodness we are finally replacing wasteful incandescent and halogen light with LED.  This really makes sense in hot seasons and climates.  Back in the day we would run incandescent bulbs which used over 80% of the energy they consumed to produce heat, only to have to run the air conditioning more to pump all that waste heat back outside.  That is very wasteful.  

Sunday, January 17, 2021

Garage parking indicator

 I shopped around for various parking assistance devices for tight garages, or any garage really.  There are various types but most require that you park a specific vehicle in a specific way to work.  For instance, the old tennis ball on a string really only works for the vehicle you set it up for, parked the direction you set it up for.  I wanted a system that would allow me to park any of my vehicles either direction while minimizing the distance to the garage door.  This way you maximize the space at the front of the garage.

Years ago in another garage I built a simple system using standard garage door sensors, some LEDs, and an old cell phone charger.  It works but this time I wanted something a bit better.  I searched again on the internet for a kit or system I could just buy and install but to my surprise there really is not one like the system I made.  

Here are the components I made the system using.  

I mounted the alarm sensors 18" high and the distance away from the door opening that I wanted.  This was about right for most bumpers or license brackets to interrupt the beams.  I wired one power supply to the sensor that does not have the alarm relay (less terminals).  The other power supply supplies the main sensor and the LEDs.  The sensor has a normally open (NO) and normally closed (NC) contact which is used to switch between the green and red LED strips.  
Main sensor

Terminal block above main sensor. Wire pair on right is power supply.  Wires going up go to the LED strips. Wires heading down connect to the main sensor.

Front LED strips (wall with garage doors)

Back LED strips

My system spans both doors as in this case there are on the same wall.  Other garages stagger the doors so you may need 2 systems.  I had the aim the sensors a bit into the garage to get the performance I wanted.  I had also planned to add some reed switches and a relay to disable the LEDs when the doors were both closed but after I got it working I decided it was not necessary. The extra wires were for that.  There are many variations to this approach.  I like not having anything to trip over on the floor, or things hanging in the garage.  I like that I can pull the vehicles in either direction, and move vehicles to different stalls and it still works.  

These doors do have sensors already to prevent closing the doors on things.  However, those don't indicate if you are parked in the right spot or not.  You can only guess and try to close the door.  I also found the sensors are mounted much too low to prevent closing the door in your car.  

Monday, December 28, 2020

Fixing Home Speaker

 I have a set of Polk Monitor series speakers from the late 1980's.  These are fantastic speakers in my opinion, even now.  However, in one of the speakers (each has 2 drivers) both drivers started crackling very bad.  Upon inspection I found the coils dragging on the magnets.  The drivers in the other speaker were fine.  You can hear the dragging when you press in on the passive bass radiator which pushes the drivers out.  

I looked into these drivers with are part number MW 6503 and have been discontinued.  There are copies available for $35 to $70 range each.

I experimented with pressing on the cone in various places to find a place where it would not drag.  It seemed to be an alignment issue.  Maybe they creped a bit over time? I decided I would try to align them back.  Nothing to lose here right?  Either I fix them or I needed to replace them anyway.  I took a piece of plywood and a vise and began carefully pinching an edge of the magnet where the dragging was gone.  This basically bends the driver frame a bit to realign the coil with the magnet.  To my amazement it actually worked.  Here is the after video.
This is tricky to get right.  The metal has significant spring back and you want to bend in small increments. You have to carefully get it to yield just a bit at a time and retest.