Range extender !

olagon said:

Is this cost effective for storage? Looks like an interesting option.

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No. $300 for 1/2 a kWh worth of storage. I only went this route because I didn't want the worry of frying lithiums and I couldn't keep lead fully charged. From what I've read about NiMH, they don't care what SoC they are kept at, don't suffer from memory like NiCad's do, can handle being overcharged (at least at the amps I'm pushing), and last forever. If it didn't work, I would have batteries for every remote, clock, and RC car that we have. :lol: :mrgreen:

Those original RAV4-EVs are still going on their factory NiMHs, with near zero degradation with over 100,000 miles on them. One could only wonder where NiMH would be if they stuck with EVs up to now.

SO, the first road test of my pusher trailer has come, with success! (Towing only, not pushing.)
https://www.dropbox.com/s/v0h6envbukmmxxq/IMG_6887%5B1%5D.JPG
As you can see, much remains to be done, but the engine is balanced nicely by the battery. The trailer tracks and corners beautifully and had no problems following the car behind some at-the-limit maneuvering.
Next imagineering tasks are to fab up the clutch engagement actuator, mount the fuel tank and come up with fenders and a rear bumper to mount lights on and satisfy state inspection. Also planning to delete the battery and run a straight connection to the iMiEV's 'starting battery'. For now, I've disabled the pusher's generator since it was toasty and the onboard dc-dc converter is adequate. Might EVen be more efficient to put all fuel into forward progress and then use some of that regen current for 12V production in the DC-DC rather than a generator (yup, the doner was a '67) or even a modern alternator. The generator is now just a bearing for the engine cooling fan pulley.

Congrats. I've been thinking about a generator to feed directly into the high voltage system. This would sit on a hitch-mounted cargo tray. Hardest part about it is getting a 360 volt generator.

jray3 said:

SO, the first road test of my pusher trailer has come, with success! (Towing only, not pushing.)
https://www.dropbox.com/s/v0h6envbukmmxxq/IMG_6887%5B1%5D.JPG

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Jray, thanks for sharing. Looks funny, though.

Looks funny, though.

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If you think that looks funny, just wait 'till the roof top tent camper is installed (on the trailer). If that works out, it'll probably just have flat sides enclosing the engine, but without the square tent on top, I'm leaning towards a streamlined, tensioned fabric cover over curved bows. That style would be called the iSlug. :roll:

PV1 said:

Congrats. I've been thinking about a generator to feed directly into the high voltage system. This would sit on a hitch-mounted cargo tray. Hardest part about it is getting a 360 volt generator.

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Indeed- it's relatively easy to rectify a consumer genset 240V alternator, but the 350+VDC that we need to charge gets expensive. I'd prefer to install a second J1772 inlet on the rear bumper for genset input, and use the onboard charger or a secondary charger. A local electric utility installed rear-bumper J1772 inlets on their fleet LEAFs to enable back-in parking! Said it was relatively simple to splice in, but of course they don't want to charge while underway.

Of course our 3.3 kW onboard charger is only worth about 15 mph of charging, so it's a range extender that would turn 60 miles of range into 75. Not worthwhile for most mievers. I figure we'd need real charging output of nearly 20 kW for highway cruising that's limited only by the gasoline tank. That kind of electrical generation gets heavy, and hazardous to hack, which is what pushed me into a pusher. With the pusher, you don't hack the OEM electronics, and actually unload the stock drivetrain rather than putting a lot more current through the components. With our strong regen, I expect to turn any long flat stretch into a nice downhill run that can bring up the SOC.

jray3 said:

PV1 said:

Indeed- it's relatively easy to rectify a consumer genset 240V alternator,

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Military gensets off liquidation sites are very cheap and they happen to come in configurations up to 440v and even in DC configurations.

jray3 said:

Of course our 3.3 kW onboard charger is only worth about 15 mph of charging

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I drive an electric minivan called a miles ZX40, it takes 3.3kw to drive it 25mph. I don't think the MIEV would be any less efficient than that box but who knows? You would have to plot energy consumption at different speeds like they did on the leaf.

So I think the effect of 3.3kw would really depend on your driving speed, faster would mean less effect, slower or stopped more effect.

Ah well.

JRay, I guess your pusher is from VW beetle, right? I was googling for the HP rating but beetle engines had various ratings up to 80 kW depending on production year etc. Perhaps, as you stated, we need an average output of 20 kW so, we can use a pusher with small motorcycle engine at 20 kW constant power and use the electric motor to either run as a regen or as power boost as needed. The battery would be the buffer. No need for generator. That way, you can use more efficient gas engine and have the emission system in place (as long as the powertrain is not too early production year). The Beetle pusher looks like it has no emission control.

Great job jray3.

Thank you Malm. Jaracz and Rmay, you got around to my intent. Referring to 3.3 kW as "15 mph charging" is based upon average consumption per mile, not 15 mph steady-state driving. When cruising on the highway, my car consumes anywhere between 10 kW on the flats to 40 kW on sustained high speed climbs in this hilly part of the world. The pusher is intended only for highway cruising, and my first iteration will be to lock the carburetor at nearly Wide Open Throttle, enough for 70+ mph cruising without any power from the battery. That's more power than needed for 65 mph cruising (though less than 80 kW on this salvaged engine), but is still the most efficient spot on the engine's powerband from a power/fuel consumption standpoint. I'll scrub off any excess speed with regen, and turn the engine off entirely and disengage the clutch when the battery is at high SOC, has enough charge to make the next charging point, or we're facing a long downhill section or an off ramp. If I'm facing a long downhill at high SOC, I can leave the pusher engaged with the engine switched off, for good old-fashioned engine compression braking (not wasting fuel due to a fuel shutoff solenoid on the ignition wire, which is also running through a reed switch on the clutch arm to prevent the engine from revving when disengaged).

I don't intend to use the original drum brakes, but that's an option to add back in, as well as a remote throttle control. I have a catalytic converter waiting to be included in a future custom exhaust, but would prefer to run the pusher on propane. For this project, simplicity and low cost/salvaged parts rule the day, with plenty of tinkering possibilities left for future iterations.

PV1 said:

olagon said:

One could only wonder where NiMH would be if they stuck with EVs up to now.

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Yes. I was wondering about that also. My 2002 Prius has 270,000+ miles on the original NiMh battery.

-Barry

If it wasn't for Chevron (slimes) the NiMH battery would be a lot farther on in development. The large format EV-95 Panasonic battery was about to be re-released as a EV-110 (same size, weight) before the Chevron (ex-Texaco) lawsuit that doomed the batteries until the Ovanic patents expire. You need to look at the lawsuit to see what a $*#@$ Chevron is. That patent end date is coming soon and possibly there will be another look at the NiMH battery. It is far more tolerant of heat, self-balancing, can be taken down to a zero state of charge without permanent damage. The calendar life and cycle life of the battery makes a Lithium battery look like yesterday's news with one exception---energy density. I put a lot of miles on a RAV4-EV with Panasonic EV-95 NiMH batteries in it. I really never gave them much thought. 100 mile range under normal conditions. Air cooled and never a problem even when I lived in the Florida Keys. When I sold it, it was eight years old and had no range degradation. The internal resistances of the cells was near new levels. The thing is back in California and is still running fine on its original 2002 batteries. I'd be glad to take the weight hit for the reliability of the Panasonic EV series NiMH. Before the RAV4, I owned a couple of Chevrolet S10-EV pickups with the first design Ovanic NiMH cells in them. The guy I sold them to is still running the trucks with the original 1998 batteries in them. Although not anywhere near as good as the Panasonics, they are still out there working. BTW---it's still fun to drive by Chevron gas stations and give them a one finger salute :lol: .

It didn't help that GM sold them the battery patents, and Chevron turned around and sued Toyota since they were still producing them (GM was filling the last couple EV1 leases out of spare parts).

I honestly think they were scared of what the NiMH battery is capable of, and stopped it before it developed too far.

For a battery range-extender (BRE), how about a pack built out of these cells?

http://www.etvenergy.com/index.htm

Anybody heard of this?

PV1 said:

http://www.etvenergy.com/index.htm
Anybody heard of this?

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Nope, they're a newby to me. I was instantly skeptical of the pictured sample, which has a very poorly-sealed pouch around the cell, and it's the same photo they've had online since January 2011, but the photo of their lab re-established credibility. No Getty Image of beautiful rainbow people in a clean room, instead it's crammed to the rafters with obsolete gear and staffed by rumpled scientific types. They've gotta be real!

However, the technical info is vague, with no patent references or white papers, and there's apparently no new content on the website in the last three years beyond a change of address.... In January 2011 their address was a university lab in Israel, and now it is in a vibrant commercial district (thank you Google Street View!)....

So color me skeptical...

Not sure if this should be here or one of the towing-related threads, but I'm designing a solar trailer that I hope the i-MiEV can handle. It has 4 SolarWorld 275 watt panels, a 2.4 kWh LiFePO4 battery, and a 1,500 watt power inverter. This could be used for gatherings where the drive there is at or just past the round-trip range point. The panels can generate almost 1,000 watts, and the car consumes 1,350 watts on level 1, 12 amps. Drawing around 400 watts from the battery pack in full sun, this can last for up to 5 hours, which is enough to regain almost 1/2 charge.

The trailer would weigh a little less than 700 pounds and is pretty well balanced over the trailer axle, so there's not a ton of weight pulling down on the back of the i-MiEV. Per the thread i-MiEV Towable, 1,700 lbs. is definitely too much, but a smaller trailer like the 450 lb. "i-Pod" would work. I'm wondering if even 700 lbs. is too much. 4 people in the i-MiEV could total that! :lol:

PV1 said:

Not sure if this should be here or one of the towing-related threads, but I'm designing a solar trailer that ..... up to 5 hours, which is enough to regain almost 1/2 charge.
I'm wondering if even 700 lbs. is too much. :lol:

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I'm not following what the mission is unless it's multi-day off-grid camping. I'm betting for the 700 pound trailer your break even on a 100 mile round-trip is close to half of charge/ 4 kWh, and that range would be no more than 50 miles at most when pulling such a load, since it adds no power while underway. In short I think you'd spend most of the first day simply recovering the extra energy you spent to get there with a heavy trailer. I think that a battery range trailer's most effective like an airplane drop tank; get halfway to your destination on the battery trailer, then drop it and finish the journey on your pristine main battery and do the reverse on the way home. I have a friend who used to do this with his electric motorcycle conversion on a daily commute. He dropped the secondary battery at a friends house halfway to work and picked it up fool on the way home!
I would certainly drag around a 700 pound trailer of dead weight for a while to know for sure how much it will affect your range and performance before building it out. My pusher trailer is almost ready to be licensed and I'll be dragging it around for a while before applying any power.
Best of luck

I was thinking it could be used at events and gatherings to either supply power for the event or grab some charge for the i-MiEV. Like way back when I first joined the forum and my commute was just outside the round-trip range of the i-MiEV. I could let the trailer sit at my destination and charge from it while there, for example. Not so much a true range-extender, but a mobile power supply.

While the trailer's parked and not in use, it can offload power to the grid with a grid-tied inverter.

I have a smaller trailer, I'll see how much it weighs. Thanks.

I agree that it sounds like your trailer may be a 'break even' exercise, at best - You'll end up with about the same range as you get without using the trailer

To get anywhere near 1Kw from the panels you'll need a pretty cloudless day and some way to aim the panels so they can be kept perpendicular to the suns rays. Otherwise, I'd count on about 60% of the panel's max rated output - Then you'll have charger and inverter losses to factor in

The added weight, rolling resistance and wind drag will lower your car's range probably by about the same amount you'll regain by parking and recharging for 4 or 5 hours - I think you'll find it's a losing proposition unless you A.) Have 4 or 5 hours to recharge, and B.) you have a way to keep the panels perpendicular to the suns rays. On a cloudy or rainy day, it's a lose/lose proposition for sure

Don

I think this trailer's utility as a mobile power supply (and not necessarily as a towable range extender) has some merit, and would make an interesting hobby project. Summarizing some of its applications -

1. Leave it at work to recharge the car where the commute is > 60 miles round-trip and the workplace doesn't provide even L1 charging.
2. A home backup emergency power source when storms, earthquakes, etc. knock out the grid.
3. When not otherwise being used, just tie into the grid to supplement the existing home PV solar system, and (very slowly) recoup its cost.

PV1, seems to me this is an extension of the extensive discussions we had prior to your getting your i-MiEV in the first place.
http://myimiev.com/forum/viewtopic.php?p=3435#p3435