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Discussion Starter #1
Hiya folks,
Apparently I joined this forum 6 years ago and never posted anything!

But I'm back and ready to give it a go.
So I have a short school bus/skoolie turned RV. It's basically a Ford E350.

I'm pondering ways to make this more environmentally friendly drive. I've got some ideas on how to increase the MPGs, but then I get to thinking about converting to an electric drivetrain.

So I'm hoping you kind folks can help me figure out if this is even feasible or if it should remain as a dream project for now.

Here's what I am thinking:
-100-200 mile range on electric.
-On board generator for emergencies and for days when I need to cover a bit more miles
-Two motors, one on the rear axle and one on the front axle.
-48v batteries, this will allow me to use off the shelf electronics to tie in the PV array and also use commonly available generator.

I've never done an EV conversion before, but I've done all sorts of automotive work and I'm comfortable with electrical work too.

I work for a solar PV installation company so I'll be able to get Lithium batteries at whole sale cost as well as the related PV equipment.

I'm trying to figure out what kind of battery pack I'd need to squeeze into this thing to make this a reality.
I'm not sure of the calculations required but with the old diesel engine I'm getting about 13-14 mpg.

Any advice or help would be appreciated!
 

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About once a season on average, someone shows up here wanting to do an electric RV to save money.

No one ever has. I suspect, because the case against doing so is very poor.

You could be an exception, but probably not.

Here's a thread from a week ago: https://www.diyelectriccar.com/forums/showthread.php?t=202713

Same logic applies to you.

In short: Large, heavy vehicles that move long distances infrequently (RVs) are the worst circumstances to justify RV. Especially for cost savings.

But do search for RVs on the forums and read the old threads, there's longer discussions of why, no matter what you try, it just doesn't make sense.

If you want to do it for the sake of doing it, go ahead, but you will be paying thousands to get everything worse.
 

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Discussion Starter #3
Yeah fair enough.
I figured that would be the case right now.

So here is my next plan then:

1) Run engine electrical loads off solar.
I have my coash battery connected to the engine battery already to charge the coash battery from the alternator if need be. Now I just need to wire the alternator to a relay and switch. The idea is to eliminate the load on the engine from the alternator.

2) Power other engine loads w/ coach battery.
The next goal is to move as many mechanical belt driven loads from the engine to electric and run them off the coach battery/solar. Best case the ICE only has one job, to power the rear wheels.
Electric cooling fans should be easy. Electric power steering pump might be a bit more work but doable. Electric water pump is kind of scary but might be an option. Electric fuel pump would be easy too. Ideally the serpentine belt goes only to the crank and alternator.

3) Aerodynamics. This I need to look into more for sure. I'd like to have some kind of wind screens and an air dam in front to help with Aerodynamics like a semi truck. I'd want them to be able to shift up out of the way for the dirt roads. This is the part I have no idea on.

4) Front axle w/ electric motor. This is probably back to the dream stage but might be more realistic. Id keep the whole diesel drivetrain powering the rear wheels. But attach an electric motor straight to the front axle, turn it on as much as possible to decrease load on the ICE. This might be an on-off type situation unless I can find a way to throttle both the ICE and electric motor together.

5) Electric motor running in parallel with the ICE. If I can mount an electric motor onto the ICE and have a belt connecting the electric motor to the crank shaft. Best case I can have a motor/generator in one instead of a motor and alternator.
Is there such a motor? I have to look into how brake Regen systems work.

This way I always have a complete ICE drivetrain to rely on!

The first stage is almost done, I just need the relay.
Stage 2 will probably happen at some point.
Stage 3, I have no idea there.
Stages 4 & 5 are likely to remain in the idea stage but its interesting to think about.
 

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4) Front axle w/ electric motor. This is probably back to the dream stage but might be more realistic. Id keep the whole diesel drivetrain powering the rear wheels. But attach an electric motor straight to the front axle, turn it on as much as possible to decrease load on the ICE. This might be an on-off type situation unless I can find a way to throttle both the ICE and electric motor together.
The biggest technical issue with this is that the only way to recharge the hybrid system battery from engine power is "through the road" (engine drives rear wheels and front wheels drive motor as generator), which is very inefficient.

The fundamental question is... where does the electrical energy come from? The overall load on the engine is only decreased if the energy comes from somewhere else.

5) Electric motor running in parallel with the ICE. If I can mount an electric motor onto the ICE and have a belt connecting the electric motor to the crank shaft. Best case I can have a motor/generator in one instead of a motor and alternator.
Is there such a motor? I have to look into how brake Regen systems work.
That is a well-established design for a "mild" hybrid system, often called the BAS (Belt-drive Alternator/Starter) type (that one motor-generator replaces the usual alternator and starter motor, as well as being the electric part of the hybrid system including regenerative braking). It is currently available from FCA under the Ram and Jeep brands in trucks and SUVs under the trade name "eTorque".
 

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Discussion Starter #5
4) Front axle w/ electric motor.
The biggest technical issue with this is that the only way to recharge the hybrid system battery from engine power is "through the road" (engine drives rear wheels and front wheels drive motor as generator), which is very inefficient.

The fundamental question is... where does the electrical energy come from? The overall load on the engine is only decreased if the energy comes from somewhere else.
Mainly I would not want the electrical energy to come from the diesel engine. Like you said that would defeat the purpose.
I'd power the fwd electric motor with the house battery which gets recharged with solar, grid power or the alternator in case of emergencies.
The plan would be only use the fwd electric motor when I have spare energy in the house battery.

5) Electric motor running in parallel with the ICE.
That is a well-established design for a "mild" hybrid system, often called the BAS (Belt-drive Alternator/Starter) type (that one motor-generator replaces the usual alternator and starter motor, as well as being the electric part of the hybrid system including regenerative braking). It is currently available from FCA under the Ram and Jeep brands in trucks and SUVs under the trade name "eTorque".
Thanks for that. Have you seen any DIY builds like that incorporate a motor-generator like this?
I don't have the electronics skills to be the first person to figure out to make it work on a DIY project with an OEM motor-generator.
Anything after market that could work?
 

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Mainly I would not want the electrical energy to come from the diesel engine. Like you said that would defeat the purpose.
I'd power the fwd electric motor with the house battery which gets recharged with solar, grid power or the alternator in case of emergencies.
The plan would be only use the fwd electric motor when I have spare energy in the house battery.
That's a huge expense and mass of hardware to go a very short distance, unless your "house battery" is actually an EV-sized battery, which means tens of kilowatt-hours (for a few miles) to hundreds of kilowatt-hours (for the target range of 100 miles or more). And with rooftop solar as the energy source, accumulating enough energy to move the vehicle would be a rare occurrence.
 

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BAS mild hybrid systems

Have you seen any DIY builds like that incorporate a motor-generator like this?
I don't have the electronics skills to be the first person to figure out to make it work on a DIY project with an OEM motor-generator.
Anything after market that could work?
I'm sure someone has done it DIY, but the effort is large for a small benefit so it won't be common. At least one company was promoting an aftermarket system, apparently for old muscle cars as a performance booster... maybe someone else remembers the vendor.
 

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Discussion Starter #8 (Edited)
That's a huge expense and mass of hardware to go a very short distance, unless your "house battery" is actually an EV-sized battery, which means tens of kilowatt-hours (for a few miles) to hundreds of kilowatt-hours (for the target range of 100 miles or more). And with rooftop solar as the energy source, accumulating enough energy to move the vehicle would be a rare occurrence.
Yeah I agree its a big project that wouldn't make financial sense.

I should focus on turning the engine alternator off, and running the engine electrical loads off my lithium house battery & PV.
And then focus on converting mechanical engine loads to electric and running those on the PV battery too.

What is a common solution for Power steering on the EV's people convert?
I've looked at the MR2 electric/hydraulic power steering, and that does not sound like a difficult solution to electrify the power steering load.
 
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