Thoughts on plug-in hybrid conversion

[Skookum]

I fully expect to be dead in 10-15 years.

Well, this took a dark turn...

 

[Onyrlef]

Well, this took a dark turn...

Remember debbie downer on SNL?

 

[BlueDotTom]

Man, you guys are a fun crowd.

Just a couple of point/opinions. We're really trying to make this product for the highly budget constrained customer. For a good number of daily pickup drivers, the fuel savings will exceed the finance payment, so you can get one and instantly have a bit more money in your pocket than you did before. Then once it's paid off, you'll have a lot more money in your pocket.

Now that EVs have been on the road for a while, we finally have some good data on battery life. Looks like 15-17 years of typical usage is about what can be expected from a pure EV. We're planning on a lifecycle for our product of 10-12 years. We have the advantage of using lithium-iron-phosphate batteries, which last longer than typical EV batteries, but the disadvantage of being more sensitive to degradation because we are PHEV. Right now, the battery accounts for about 1/2 the cost of the system. That will come down over time, so 10-12 years in the future, replacing the battery shouldn't be too painful.

On weight: With current batteries, it will be something like 300 lbs for a midsize, 350 lbs for a full size, 400 lbs for an HD. We're hoping LMFP batteries are available by the time we launch, which should cut at least 50 lbs from each system. Before everyone jumps on me...I know that quite a few people already operate at close to their payload limit. This wouldn't be for them.

 

[Lou Schneider]

So right now you're either only engine, only motor, or using the engine to spin the motor without turning the wheels (generator). We haven't determine the power we will make available in generator mode, but certainly at least 10 kW.

An interesting concept, but how do you operate engine driven accessories like power steering, air conditioning and brake boosters when you're in engine-off, electric only mode? Seems to me having to idle the gas engine to run them would seriously reduce any fuel savings.

 

[BlueDotTom]

If there's hydraulic power steering, we add an electric pump in parallel with the engine-driven pump. If there is no electric vacuum pump for the brakes (most diesels and turbos already have one), we add one. Our prototype has both of these systems, and they work well. For now, AC is done by idling the engine. We will follow up with an electric compressor kit.

 

[Lou Schneider]

If there's hydraulic power steering, we add an electric pump in parallel with the engine-driven pump. If there is no electric vacuum pump for the brakes (most diesels and turbos already have one), we add one. Our prototype has both of these systems, and they work well. For now, AC is done by idling the engine. We will follow up with an electric compressor kit.

I live in the desert, being able to remote start the a/c and get the interior comfortable on battery power before I get to the car would be a major selling point for me.

 

[BlueDotTom]

Yes, I could see that being nice! Because our system will require the rest of the climate control system to be active, the car would need to be remote started as well. At that point, you don't really need us in the equation. Unless of course you're trying to avoid burning fuel idling, in which case we would be able to design the system to work with remote start. That's an area where we haven't focused yet, but definitely will.

 

[Onyrlef]

Seems to me you’re adding to the load on the battery without increasing the capacity which in turn equals less range. Increasing the capacity of the battery means increasing costs. Determining the point at which rapidly diminishing returns outweigh the benefit could be key to success, I’d imagine.

 

[BlueDotTom]

The advantage of "remote start" with aircon is that you can do that initial energy-intensive cool down of the vehicle while it's plugged into the wall, so you save that range hit.

 

[Ex-Calif]

This is really getting confusing for me. If the system is suppsed to be charged at a station and then at some point activated such that the ICE engine can be shut down then all the vehicle systems need to be able to be run on electricity. Power Steering, Air conditioning, transmissions are predominantly electro/hydraulic as well, lighting, cruise control etc. etc. etc. This would require a level of integration that I am sure cannot be done cheaply.

I can see it as an assist to ICE (as I mentioned before) but I don't see the ICE engine being shut down.

Then, if the only way to regen the batteries is to plug in I am pretty much subject to the same limitations of all electric.

If I can regen on downgrades and use the electric selectively then the "magic (free energy) comes from something the vehicle does naturally - go downhill and brake.

 

[Steven UK]

The advantage of "remote start" with aircon is that you can do that initial energy-intensive cool down of the vehicle while it's plugged into the wall, so you save that range hit.

Hybrid cars work very well when you have pets and need to keep the AC on all the time. you can lock the car and walk away and the engine will start and stop as needed to keep the battery charged. I think the AC Compressor in the Honda is 400v but you can buy 12 and 24v units easily enough. I have been thinking about DC AirCon recently about this recently for an RV project. It would also be easy to control it remotely with a Wemos D1 Mini...

 

[Steven UK]

what is the current state of Electric Power steering, I know its used on cars extensively but HD trucks, probably not... the hydraulic belt driven system on cars always seemed overly complicated and expensive. but I guess necessary.

 

[Ex-Calif]

what is the current state of Electric Power steering, I know its used on cars extensively but HD trucks, probably not... the hydraulic belt driven system on cars always seemed overly complicated and expensive. but I guess necessary.

Somewhere I have bookmarked a system for MGs. Basically inserts a motor & gear system under the dash attached to the steering column. Not sure how the brain works but I remember there being simply a "calibration" on how much assist one wanted. The key with PS is reducing sensitivity at speed and having maximum assist at parking speeds.

(Rich) Guys who've installed it say it's great. The MGB had like a 16 inch steering wheel. My GT has like a 10 inch wheel and it can be a brute to park.

 

[BlueDotTom]

Ok, I see that I should have provided my context up front. I apologize in advance if this is all understood. Conceptually, a plug-in hybrid (PHEV) is an electric car with a relatively small battery, that also has an internal combustion engine that gets called into action when the battery is depleted. The battery gets charged from the grid like an EV. For the way the majority of people drive, this enables most of their driving to be done under electric power, with no sacrifice in capability. And it gives you that benefit using about 20% of the battery of a pure EV. Most OEMs offer PHEV versions of at least some of their models.

Our system adds the electrical side of the equation (battery, electric motor, motor driver, charger, DC-DC converter) to an existing ICE car . The generic use case is to charge at home or work (from a standard wall outlet overnight, or from a level 2 charger in a few hours), commute and do other daily driving on electric power, and then be able to use the engine for longer trips or for things like towing, pulling stumps out of the ground, etc.

To be able to drive around under electric power without the engine on, some vehicles will need a few additional accessories. If the car has hydraulic power steering, we add an electric power steering pump in parallel with the existing pump. This gives you electrohydraulic steering, which some vehicles have from the factory. If the car doesn't already have a brake vacuum pump (most diesels and turbo gas engines already do because engine vacuum isn't abundant), we put in an electric vacuum pump that maintains the proper vacuum level in the booster. All the 12V functions of the car are provided by the car's 12V battery, and our DC-DC converter steps down the hybrid battery to 14V to keep it fully charged. All of these systems are running on our current prototype, and to be honest are not really novel because the DIY EV conversion crowd has been doing them for decades.

We're still working out the details of how to best run the aircon on electric power. If we don't have that implemented by the time we launch, idling the engine when AC is needed will be the way to go until we can follow up with a kit.

At some point in the future, we hope to be able to use the electric motor and the vehicle's gas engine at the same time, but at this point we're not planning on launching with that capability because CARB/EPA/etc. get real fussy when something affects how the cars emissions control systems operate. So for now you're either running on electric power OR engine power, and you can shift-on-the-fly between the two.

Clear as mud?

 

[TheBar]

As an insider what are your thoughts about the new LMFP batteries? They supposedly have a 620 mile range, weigh 32% less, recharge in 18 minutes, and last 2.4 million miles? If true and practical that eliminates my doubts about EV.

 

[Old_Crow]

what is the current state of Electric Power steering, I know its used on cars extensively but HD trucks, probably not... the hydraulic belt driven system on cars always seemed overly complicated and expensive. but I guess necessary.

I was watching a video on You Tube yesterday, apparently the new Bronco has an electric rack and pinion steering system.

 

[penman39]

Hello!

I am the founder of a Seattle-based startup. We are developing a family of universal retrofit kits that convert existing vehicles into plug-in hybrids. Our first product will be for pickup trucks, and I am hoping to get some thoughts from this and other RV communities on what features may be desirable, what the major concerns would be, etc. My thinking is that for people who use their trucks for daily driving but also frequent towing, our product could be very attractive, especially because it can be used as a generator.

In a nutshell, the kits add an electric propulsion system good for 30-45 miles of range without removing the engine. The battery pack and power electronics get mounted in the bed like a small bed toolbox. We remove a section of the tubular part of the driveshaft and install a “coaxial drive unit” that has an electric motor stack, a planetary transmission, and a multi-mode clutch that can shift-on-the-fly. The clutch allows EV operation while disconnecting the engine/tranny, engine operation while disconnecting the electric motors, and generator mode which uses the engine to spin the electric motors without turning the wheels. A linkage that connects to the axle tubes provides reaction torque. We’ve prototyped a simplified version of the system and tested in on real roads.

Because the systems are universal, we can mass-produce them, have them installed by third-parties, and hit a much lower price point than other conversions (approximately $7k-10K covering the range from midsize to ¾ ton). I’d love to get the group’s thoughts and gage the level of interest.

I have a little twist to your idea. I have a Subaru Crosstrek toad w/manual transmission that I flat tow behind my motorhome. Could you do a driveshaft drive unit that would provide propulsion or regenerative braking to the rear axle that could be set-up via bluetooth with my phone? A system like that would enable the toad to help with ascending or descending hills. The battery pack could be mounted via my 2" receiver hitch.

 

[Mark_K5LXP]

As someone that built and drove a conversion EV I don't see what problem this solves. The concept of putting a drive motor inline with the driveshaft neatly solves the motor coupling question but it all falls apart after that. Pickup trucks are heavy, in EV only mode the drive would need to be at least a couple hundred peak HP just to be drivable. A 400lb battery pack of any contemporary form will not supply that for long. Start throwing in the not trivial to implement power accessories like steering, A/C and 12V chassis supply and now you have a vehicle that's hundreds of pounds heavier, more complex, and pretty expensive all to spend a little less on fuel. As a mild hybrid where the motor supplements the engine but leaves the ICE components intact would seem to make more sense, if enough fuel savings could be realized to offset the motor drive. But I think when you run those numbers you can't get there from here - even under the best of circumstances many thousands of miles and years of trouble free operation are required to reach the break even point, which in practical terms is highly unlikely. Another way to look at it is if it were commercially viable, there'd be a rush of these kits to market. Spending dollars to save pennies only works for a limited few that have a niche interest. Maybe there's enough out there to support a small custom conversion company (as there is for conversion BEV's) but I don't see any widespread interest.

Mark B.
Albuquerque, NM

 

[Onyrlef]

As someone that built and drove a conversion EV I don't see what problem this solves. The concept of putting a drive motor inline with the driveshaft neatly solves the motor coupling question but it all falls apart after that. Pickup trucks are heavy, in EV only mode the drive would need to be at least a couple hundred peak HP just to be drivable. A 400lb battery pack of any contemporary form will not supply that for long. Start throwing in the not trivial to implement power accessories like steering, A/C and 12V chassis supply and now you have a vehicle that's hundreds of pounds heavier, more complex, and pretty expensive all to spend a little less on fuel. As a mild hybrid where the motor supplements the engine but leaves the ICE components intact would seem to make more sense, if enough fuel savings could be realized to offset the motor drive. But I think when you run those numbers you can't get there from here - even under the best of circumstances many thousands of miles and years of trouble free operation are required to reach the break even point, which in practical terms is highly unlikely. Another way to look at it is if it were commercially viable, there'd be a rush of these kits to market. Spending dollars to save pennies only works for a limited few that have a niche interest. Maybe there's enough out there to support a small custom conversion company (as there is for conversion BEV's) but I don't see any widespread interest.

Mark B.
Albuquerque, NM

It really boils down to Einstein's theory of relativity. An abstraction of his theory applied to ordinary mechanics in propulsion, energy equals mass x light squared, ie., in order for anything with mass to achieve a speed in excess of 186,000 mps the amount of energy it would require and thus the mass would exceed that in the known universe. In reduction to everyday mechanics the amount of energy his hybrid propulsion system would need to move the weight of the truck forward for any practical length of time means he'll have to keep adding mass (energy/battery) and keep adding weight, which in turn requires additional energy (mass).
Formula1 solves the conundrum by augmenting the ICE with electric assist. The "Sky" racing team at the TDF some 8 or 10 years ago cheated ( although they deny the allegation,... so sue me) by having a small ev servo motor installed in the lower part of the seat tube which applied only a few extra watts of energy to the crank. The bikes were weighed before the Team and individual Time Trials and the additional weight was to the gram exactly what the servo drive system weighed. Just a few additional watts of energy when all other things are equal with riders is a game changer.

 

[Lou Schneider]

As someone that built and drove a conversion EV I don't see what problem this solves. The concept of putting a drive motor inline with the driveshaft neatly solves the motor coupling question but it all falls apart after that.

Unless you decouple from the ICE engine when you're in electric mode you're also fighting the parasitic losses and friction involved in spinning the engine. This is a significant amount of energy as shown by the power drawn by the electric starting motor.