[digitaltroy]

Hey all, am hoping to get a quick gut-check on a project I’ve been mulling for many moons. No one makes the pickup I need, so I suppose it’s time to build one!

I’ve researched DIY EV builds for several years now and have a moderate understanding of the requirements, but have a hunch that my goals might still be out of reach.

Platform will be on a 4x4 3500 or 4500 service body, at least with an 8’ bed, although going to a larger ≥10’ isn’t out of the question.

My ideal goal is to travel 400ish miles at highway speeds without needing to stop at a charging station. I run through rural America and British Columbia, as well as remote off-highway travel.

I have been googling to no avail, but my question is: has anyone fitted an on-board generator to act as a backup power supply unit? I’ve seen mentions from several years back that personal generators do not have enough power output to handle peak demand; however, it looks like newer compact diesel generators might be able to handle full power?

I’m already planning to stuff a considerable amount of batteries onboard, but am not sure if an onboard battery generator is within the realm of feasibility yet.

Thanks all!

 

[brian_]

This would be a plug-in series hybrid, presumably with a relatively large battery (for long battery-only range) and low generator power (so not attempting to meet peak demand with the generator).

The problem with series hybrids is that the energy losses in the generator and electric motor are much higher than in a mechanical transmission, so it's difficult to build one which is any more efficient in highway conditions than a conventional non-hybrid engine-driven vehicle. The BMW i3 REX is a series hybrid, but it gets lousy fuel economy. The Honda Accord and Mitsubishi Outlander PHEV run as series hybrids much of the time, but they also have a gear transmission with the single ratio chosen for common highway conditions for better efficiency. There are commercially built series hybrid buses and medium-duty trucks, but they don't use off-the-shelf generator sets, and they struggle to justify their cost.

Generator sets are usually heavy for their power output. Large commercial units are very heavy, and portable home and light commercial sets are not very efficient. Also, if you use an available generator set as-is, you will get 240 V AC power from it which you will need to put through a charger, so you will have another power conversion step and more inefficiency.

 

[remy_martian]

Look at the Via Motors Vtrux. Basically what you want to do, without the battery you want to add. But that was only a half ton truck, iirc.

400 miles range on a 4500 is pretty unrealistic. The reason you have a 4500 is to have a combined vehicle weight of 20,000 to 35,000 pounds. That gets you in the 1~2kW per mile consumption range. You going to buy $160,000 in used batteries for it to get 400 miles of range? And haul 4 tons of battery everywhere when empty? What about charging? Even with the fastest chargers out there, assuming you build a battery cooling system large enough, it'll take three to four hours to charge and cost you $300 a fillup of electrons.

Carrying around all that engine/generator vs battery, and vice versa doesn't make much sense to me. Either make it a hybrid or make it an EV. If you need a range extender, make it part of something you pull, anyway.

The whole thing falls apart at around 150 to 200 miles of range, despite what Saint Elon has been claiming on his Semi for the past 4 years (and still hasn't shipped any. Nikola is another sack of bullshitting, imo, though their gravity-drive Semi is pretty innovative). Which is why sensible companies electrifying their medium duty trucks are doing it for local runs.

 

[brian_]

Look at the Via Motors Vtrux. Basically what you want to do, without the battery you want to add. But that was only a half ton truck, iirc.

The VTrux plug-in hybrid models circa 2013 were based on Express 2500 ("3/4 ton") vans and Silverado 1500 ("1/2 ton") pickups. They had a battery range typical of plug-in hybrids (which is very short compared to the desired 400 mile range, so they would be operating as a gas-engine vehicle most of the time) and Via Motors has since abandoned the hybrid approach. The engines were those that GM provided stock with the trucks, so they were too large to make sense in a series hybrid configuration.

The VTrux hybrid was interesting, because it was clearly inferior to what the earlier GM Two-Mode Hybrid trucks would be with the addition of battery capacity to make it a plug-in.

Consumer Reports: Plug-in hybrid trucks coming soon / All the juice you need for the job-site, plus 40-mile electric range


My suggestion would be to instead emulate the Azure Dynamics Balance hybrid, which was a parallel (instead of series) hybrid built from a Ford F-450 (but could be done with any brand of Class 4 truck), if you want a plug-in hybrid medium-duty.

 

[brian_]

My ideal goal is to travel 400ish miles at highway speeds without needing to stop at a charging station.

Just so I can understand the intent, what would you want the battery-only range to be?

 

[digitaltroy]

Look at the Via Motors Vtrux. Basically what you want to do, without the battery you want to add. But that was only a half ton truck, iirc.

400 miles range on a 4500 is pretty unrealistic. The reason you have a 4500 is to have a combined vehicle weight of 20,000 to 35,000 pounds. That gets you in the 1~2kW per mile consumption range. You going to buy $160,000 in used batteries for it to get 400 miles of range? And haul 4 tons of battery everywhere when empty? What about charging? Even with the fastest chargers out there, assuming you build a battery cooling system large enough, it'll take three to four hours to charge and cost you $300 a fillup of electrons.

Carrying around all that engine/generator vs battery, and vice versa doesn't make much sense to me. Either make it a hybrid or make it an EV. If you need a range extender, make it part of something you pull, anyway.

Via Motors are local to me, I've had my eye on them for quite some time! I've tried getting in touch with them a few times over the years, but they don't seem to have much appetite working with the general public

I hear you on the 4500 element, likely a 3500 will suffice without the extra weight and can be found in cab+chassis. My goal is to primarily run the truck as an EV; however, I run through rural Idaho, Montana, and Wyoming where chargers (especially late at night in the middle of winter) aren't a sure-fire bet.

I considered a range-extender trailer; however, a handful of mountain passes don't allow trailers in the winter, or I'm pulling my sled-trailer.

 

[digitaltroy]

My suggestion would be to instead emulate the Azure Dynamics Balance hybrid, which was a parallel (instead of series) hybrid built from a Ford F-450 (but could be done with any brand of Class 4 truck), if you want a plug-in hybrid medium-duty.

Let me see if I can dig stuff on them in the Wayback Machine, it looks like their website has been defunct for a minute.

Just so I can understand the intent, what would you want the battery-only range to be?

I'd be quite content with a 150-250 range on battery-only.

 

[brian_]

Let me see if I can dig stuff on them in the Wayback Machine, it looks like their website has been defunct for a minute.

Yes, Azure Dynamics went bankrupt years ago... and some resellers still show component inventory from their liquidation.

This post of mine from an earlier topic describes the Balance hybrid:

... Azure Dynamics adaptation of Ford's E-450 stripped commercial chassis to become a parallel hybrid, which they branded as "Balance Hybrid Electric". Apparently AZD mounted a 280 volt 130 hp AC (induction) motor in parallel with the stock transmission's output. From the diagram and some descriptions, it that is was a motor with a double-ended shaft, forming part of the propeller shaft (driveshaft) and so running at transmission output / final drive input speed. The final drive ratio (in at least some of them) was 4.56:1.

This illustration was taken from the manual (linked below), which also provides system weights and dimensioned drawings of the component layout, as well as many photographs of the system installed on the E-450 chassis.

In the Balance E-450, the electric motor only handled propulsion by itself at low speeds; above a set speed (20 to 35 mph depending on report), or when the accelerator is pressed enough, the engine ran as well. It's unlikely that this motor could handle a six-ton motorhome by itself. About a thousand of these were built, with over half being Purolator delivery vans.

References:

• Wikipedia: Azure Dynamics; Balance Hybrid Electric
• Azure Dynamics Hybrid Delivery-Truck Test Drive: Gas/Electric Hybrid Offers 30 Percent MPG Improvement
• Azure Dynamics' Balance(TM) Hybrid Electric shuttle bus completes rigorous "Altoona" durability testing
• Azure Dynamics and Utilimaster converting Ford E-Series into hybrid commercial vehicles
• Azure Dynamics Parallel Hybrid Electric Vehicle; 2008 Ford E-450 Body Builders Layout Book Supplement
• Azure Dynamics delivers Its 1,000th Balance hybrid electric truck

The problems with this specific hybrid system are that it is intended to be fully functional on engine power (so the engine is large), it is only intended to have limited electric-only performance (so the motor would be too small for the purpose of this discussion), and it doesn't carry enough battery for the desired electric-only range. The same approach could work, with a larger battery and electric motor but smaller engine, but it's a space, weight, and complexity challenge.

I'd be quite content with a 150-250 range on battery-only.

Miles? That's a lot. With the battery required, there will be little room left for the fuel, engine, and generator of series hybrid system, or fuel, engine, transmission, and smaller motor/generator of a parallel hybrid system.