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Discussion Starter · #1 ·
Hello, I'd like to be able to convert my truck to a hybrid. Having upgraded from my old truck to this one was a huge bump in fuel economy, as much as 30% better while pulling a trailer. Now I'd like to think about making another step to get even more efficiency out of it.

Currently it is a stock 2018 Ram 1500 5.7L Tradesman 2x4. I wasn't looking into installing an inline motor, to replace part of the shaft, but was thinking more along the lines of adding either the front differential or by adding hub motors and make it a 4x4. But I'm not sure if these are the best way to go.

An inline setup, I think that's called the P4 Hybrid, is still an option though. If This is the best way to go, possibly financially, ease of installation, etc, then I'd go that route.

So at this point I'm looking for pointers on which path to go. Pros/Cons of each setup, and maybe some links to existing builds to get ideas of the layout. I'm not wanting to make major modifications to make the truck less functional, ie replace the bed of the truck with a battery skid or take away space for the equipment. I still need 100% usability of the bed.
There's plenty of room between the frame and the outer body to put electronics/batteries.

Just knowing some of the keywords to use to help in searching criteria would help a lot, too. I did try looking up the Azure Dynamics Balance system, but I didn't get very far with that. Maybe there's some other keywords I need included to help narrow down the results or such.

Thanks in advance
 

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Discussion Starter · #7 ·
I did some calculations about fuel economy. While I'm pulling the trailer, I get around 12.5mpg. I have a 23gallon tank. This gives me approximately 288 mile range.
When I am not using the trailer, I average about 24mpg. This would be about 550 mile range.

If the electric assist (regardless if it is on the trailer or somewhere on the truck) were to give me a hauling average mileage of 17mpg, then I would get about 390 miles. This is about 27% increase in fuel economy. Fuel prices right now have risen to $4.55/gallon. With the extra 100 miles I could gain, at 17mpg, that would be a consumption of 5.8 gallons, or $26. Multiply that for the year and that's a savings of $1376.

If the non-hauling average went from 24 to 32mpg, this would be an increase 25%. I think this is pretty conservative, tbh. When driving at 55mph the instant fuel usage meter often goes above the 30mpg mark, which is beyond the gauge. So the average could easily be closer to 35mpg or higher. At 35mpg that's an increase of 32%. So figuring with a 28% (average between the two figures) I would go from 552 miles to 715 miles. This is an increase in 163 miles. At 32mpg this would equate to 5 gallons.

So with these maths calculated, I would estimate a yearly savings of over $1500. And that's if the efficiency is increased by the little amount I was guessing. So if the hybrid system install costs $4k, then roi is just over 2 years. I plan on keeping the truck for quite some time. Plus, this is calculating the costs at $4.50/gallon. If fuel continues to rise and reaches $5/g, or $5.5/g, then my savings goes up even faster!

The above math and fuel usage, and fuel gain, is very much guess work. But I am pretty confident that those values would be achievable. If my math is wrong, I am definitely open to correction.

So, in summary, you're looking to spend $5000+ on components, spend 1000 hours of your time, and have your truck in pieces for two years while you sort it out to save $400 a year in gas?
Why would the truck be in pieces for 2 years? This doesn't make sense. I'm not replacing the engine/transmission. I'm adding assistive power to the existing system.
Hours of time is not an issue for me.
And $400/year is very low guess. Even the Dodge eTorque saves more fuel than that, and it only assists in starting the engine at stops.

The thing I'm looking for achieving is assisting the IC. Not replacing it. Not overpowering it. Not matching its output. If the engine load can be reduced during acceleration, which is where most fuel is consumed, then this alone would boost fuel savings.

Fuel prices are not going down. They will continue to rise. As they rise, the fuel cost savings will go up as well.

The correct response is showing your math vs trolling for yes-men.
I am not trolling for yes-men. I'm asking for assistance. I asked to be pointed in the correct direction, and possible even give me suggestions for key words to search for. I am not adverse to searching on my own. But when I do not know the wording/terminology to search for to begin with, it makes it very hard to find the information relevant to this topic. For example, I search for Electric Assist Trailer, and got pages of "bike trailers", not vehicle trailers. Kinda makes sifting through the results difficult when the words are unknown.

Frankly hybrid conversions aren't viable. Full EV or bust!
At this point in time, Full EV is out of the question. I can't drop $50+ on an EV truck that has the requirements I need for my job. And it's not just "pulling a trailer". Even finding a truck with the proper sized bed is difficult because manufacturers think that most ppl only need a 5.5Ft bed. My previous truck was a "true" full sized 8ft bed, and dropping down to 6.5ft bed made my job a bit more difficult as I lost a lot of working space.
 

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So, you're planning on replacing 30% of the energy from the ICE with energy from a presumably precharged battery, since you are looking for highway mileage gains which are close to zero from a start/stop system on a truck that already maximizes pumping efficiency with DoD.

That puts you, roughly back at 3 miles/kWh or having to carry a 130kWh pack for 390 miles of range, which is roughly a ton of extra weight, or a 30% increase in rolling resistance (loss of range).

If this is the case, the battery will set you back around $26,000. If you're going to build a hybrid, and not precharge the assist system, why not just buy a truck with eTorque?
 

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Discussion Starter · #10 ·
I can purchase lithium batteries from a Tesla or other EV for pretty cheap, a whole pack for <$3k. The electric motor won't "always" be being used. And obviously the battery would be charged while I'm at home, primarily using solar.

First, I didn't know about eTorque until a few days ago. Secondly, the eTorque only delivers a very tiny amount of assist and to help start the engine when the truck resumes from a stopped position. From the stats that I've read the eTorque would only save about 50 gallons a year. Not worth the savings considering the added cost it adds to the cost of the truck.

I don't drive 390 miles in one trip. That's over a weeks worth of travel, actually about 8 days. So the battery doesn't need to be "that" large. Only enough to get through 100 miles max per day. My average daily trips is about 40-50 miles.
 

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Where are you getting a Tesla pack for $3k? They're at least $16k for Model S and >$8000 for Model 3.

The motor has to be used all the time to get that 30% increase, or provide an even greater proprtional contribution if cycled in. Where's the magic coming from if not from the electric motor?

I'd also argue you could operate the truck as fully electric only at 100 miles per day...if it had a stick vs automatic in it.
 

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Discussion Starter · #12 ·
Where are you getting a Tesla pack for $3k? They're at least $16k for Model S and >$8000 for Model 3.
I just realized that this is 8 packs minimum. But here's another site that sells them:

The motor has to be used all the time to get that 30% increase, or provide an even greater proprtional contribution if cycled in.
True, I can agree with that. 🤔 Definitely would need to play with when and how much power is applied.

I'd also argue you could operate the truck as fully electric only at 100 miles per day...if it had a stick vs automatic in it.
Interesting thought. This is a possibility, depending on how the system is built and configured. It is an automatic, so that it is a consideration as well. I know that the IC would need to be running at all times reguardless if it's running in Hybrid mode or EV only mode as the trans needs to have fluid pumping at all times. The power steering is electrically driven, so no external power from the IC is needed for that. But the aircon is definitely belt driven, tho.
 

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Discussion Starter · #14 ·
Well I would need a certain number of packs to match the voltage of the motor. Would only need a few modules to get the minimum range I'm after. But I get what you mean, pack vs module. Big difference.
 

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Not merely the trans pumping all the time. My daughter took out the trans by coasting down a 5 mile hill in neutral, engine running, daily. So, the lore of merely running the pump may not be good enough....but maybe a coincidence in her case. Who knows?

Neutral in a transfer case allows you to put the trans in Park and engine off, though, so nothing internally spins. Done that lots of times as have flat towers behind RV's.
 

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You're a little bit all over the map, so, probably best to slow down and make some plans or decisions.

The motor isn't going to be too big of a deal, you can manage that with minimal expense. Ditto for speed controller/inverter.

But batteries is where you're going to have to make some smart decisions.

Batteries are:
  • Expensive - Kills a cost-saving project right then and there.
  • Heavy - Might hurt more fuel mileage and utility than it helps.
  • Bulky - Might not even have room to put them in.

So, obviously, to keep costs, weight, and bulk down to a minimum, you need to get away with the smallest battery pack you can manage.

The math on this is pretty simple, you just need to figure out and then decide how many kilowatthours you need to carry, for the project to be worthwhile.

Don't get stuck in the wishywashy "Well, it'll be partially electric...", because then you can't figure anything out or, you could justify anything. So, while yes you will have a mix of power, and while the motor might not be able to push the truck and pull the trailer, decide on what amount of pure electric range you want to have. You don't have to use it all electric, but you should know how much range you want out of pure electric equivalent.

Then once you have range, look at your gas mileage, and start to ballpark convert that to how many kilowatthours that will be. On a vehicle that size, you'll need perhaps 350-500 kwh per mile at highway speeds, and, double that towing a trailer (because towing a trailer cuts your fuel economy in half, expect it to do the same with electric). That will be how much battery you need to buy. Then there's the issue of, how easily can you divide them up to get a small enough pack to a high enough voltage. For example, if you're using Tesla modules, forget it. They're so large, you'll have to use most of a Tesla pack just to reach a useful voltage. You won't have money, weight, or room to fit them.

To get the most out of your battery pack, I recommend not planning electric to go more than your daily average. Every day you haul around extra battery capacity that you didn't need is extra cost you spent and lower efficiency. Since you're keeping the engine you have zero range anxiety, so, be super efficient with the smallest pack that you'd be about guaranteed to use up in a day. You said 40-50 miles average, and at most 100, so I say plan on 30-40 miles electric. Any extra is less and less efficient. You're keen on 100 miles, but, I think that's foolish.

Let's say best case scenario you're hoping for 30 miles, and you could get away with 400 watt-hours per mile without the trailer. That's a 12kwh battery pack. Or, a 24kwh battery pack if you're towing the trailer pretty much daily.

Let's say you're using Tesla modules, just because you've already looked at them. A module is $3000 you say, weighs 55lbs, and has 5.3kwh. So, to reach you minimal needs, something in the ballpark of 2-5 of them makes sense. That would be 110-275lbs (not bad, you could manage that), $6,000-15,000, and be, well, the size of 2-5 of them (probably something you could hide around the frame somewhere). Let's ignore that the voltage is uselessly low for now.

Just for giggles, let's say you want that 100 mile range. Now you're looking at 40-80kwh pack. 8-16 modules (where would they go?), 440-880lbs, and $24,000-$48,000. And according to you, most days you won't even use it. See why 100 mile goal is foolish?

Let's just stop right there at 30 miles. Do you want to spend $6000-$15000 to get 30 miles of range a day out of electric power?

Well, you say you get 24mpg without the trailer, and about half that with the trailer. You pay $4.55/gallon. So that's $0.19/mile without the trailer, or $0.38/mile with the trailer.

You're avoiding 30 miles of range by installing electric, so, that saves you every day: $5.70 - $11.40.

With just a battery cost (let alone motor/inverter/all other systems and time spent installing it) for $6,000-$15000, how long would it take you to pay that off? 1052-1315 days. 3-4 years.

Let's be silly and go back to that 100 mile range again for a moment. You'd be carrying 100 miles worth of batteries, but only using 40-50 miles of them per day (let's say 50 to be generous). So, $9.50-$19/day. 2526 days. 7 years. Oh, and all that extra weight would probably hurt your gas mileage so much by increasing your rolling resistance (and hurt your suspension and require other truck repairs sooner), that you might not even break even, ever. The same money just invested in an index fund would probably gain you more every day, and you wouldn't have to do any mechanical work.

...

Since you were basing this whole build on getting an entire Tesla battery pack for $3000... does this new reality slow your enthusiasm for a hybrid conversion?

As a basic observation, almost no one has done this before. So either you have a revolutionary idea, or, there are practical, reality-based reasons no one does this even in a community of people who like to goof off and tinker and make stupid projects.

...

Also, this being your only vehicle, which you plan to convert... overnight? On a weekend and be rolling for Monday? ... I know nothing of your mechanical abilities so I won't say it can't be done, but, I'd say even for a very well planned install that is highly ambitious of you. Car projects are highly ambitious enough for people who are doing an extra vehicle.

...

Anyway, that should ground your expectations a bit and help steer any advice anyone could give you here on out. What kinds of choices do you want to make based on what you now know?
 

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If you want to save money while towing then switch to E85 fuel. Your MPG will drop but it's still cheaper in the end. And bonus points you get maximum horsepower. Also cleaner for the environment.

Just put an A.P.E. flexfuel kit on my 300C Hemi 5.7L and picked up some HP and fill up at $2.79/gal
 

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Discussion Starter · #18 ·
Anyway, that should ground your expectations a bit and help steer any advice anyone could give you here on out. What kinds of choices do you want to make based on what you now know?
Wow, that's a lot to take in. Thanks for the reality check on the numbers. 100 miles was just the absolute max I'd drive maybe once a week. Most days is <40 miles. I figured there was some numbers/math I was missing, and I appreciate the explanation making it nice and clearly laid out. Definitely gives me a bit to think about how I want to proceed.

If you want to save money while towing then switch to E85 fuel. Your MPG will drop but it's still cheaper in the end. And bonus points you get maximum horsepower. Also cleaner for the environment.

Just put an A.P.E. flexfuel kit on my 300C Hemi 5.7L and picked up some HP and fill up at $2.79/gal
E85 fuel is not available in my area. Closest station that carries it is almost an hr drive away, one way, and it costs $3.99/g at the time of posting. So that's not an option. But thanks for the suggestion.
 
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