[Anaerin]

Looking around eBay, I found a few interesting things:

• http://www.ebay.ca/itm/Belt-Driven-9...item5ae3bb8dab
• http://www.ebay.ca/itm/10-200-watt-g...item35ae0a6f89
• http://www.ebay.ca/itm/PTO-Driven-Me...item5ae3083129 (albeit having removed that step-down gearbox)
• http://www.ebay.ca/itm/Tapered-Cone-...item588cd4bc6d

These all have a generation speed (apart from the PTO one) of 3600RPM, which is nicely in the power band for most small ICEs.

So, if you took one of these, and a small engine (Say, the 3-cylinder diesel motor from a Smart car, or a 30hp+ motorcycle engine, so probably 500cc or higher), mounted the pair on a small trailer, and hooked it up to a reasonably sized charger (probably on-board the vehicle), you'd have a cheap, fuel-sipping (usable with SVO or Biodiesel if you go for the Smart engine), and adequately-sized range extender.

If you're doing a pickup conversion, and used Direct Drive with the motor in place of the gearbox (or even shortened the drive shaft and moved the gearbox back), this would easily fit in place of the large V6 or V8 lump they put in there with room to spare for a few batteries and the controller/electronics.

It seems that most people, if they're talking of range extenders, advocate pusher trailers. I'm unconvinced, especially in conditions like we get here in Canada with ice and snow leading to poor grip, and the potential for jackknifing. It also means that in case of power outage you have a long-lasting power backup unit available (As, probably most of the time, it'd be at home, only brought out for long journeys, when you wouldn't be home anyway).

It certainly seems cheaper (and smaller) than buying an aircraft APU (not that I can find many/any on eBay) and a lot cheaper than buying a pre-built generator for the kinds of capacities an EV needs to stay on the road (10kw+ for a medium-sized vehicle maintaining 110KPH/70MPH on a level road).

And if you wanted a cheap, headless version to use as an (AC?) drive motor, one of these (http://www.ebay.ca/itm/6500-watt-rep...item483efdb27b http://www.ebay.ca/itm/3000-watt-rep...item48371ad3f9) would probably do the job.

[piotrsko]

actually you could save tons of equipment by just selecting the battery pack voltage properly and regulating the genset output appropriately. This however might lead to requiring a 'Zilla or Soliton or some other Hi-voltage controller. Most of the "purists" here will degrade you for the thought, but from one standpoint, it does work. I have the capacity in the ranger and room to provide a small generator for boonies recharge, but it won't be elegant (another sticking point on the forum). BTW 3600 is the magic 60 hz typical line frequency of an American home. You really don't need 3600 rpm, anything from 3000 to 4000 would work for a transformer isolated power supply. Switching power supplies could generally care less about frequency. If you have a DC output genset, anything above, say, 1500 rpm would be fine.

[ChristianThomas]

What you're talking about is getting closer to a series hybrid (as opposed to a parallel hybrid, like the Pruis).
I'm not advocating either the pure EV path or the series hybrid path. But if a series hybrid is what you're looking for, tossing the big battery pack and using that space/weight for a better gen-set, and then using high duty cycle capacitor banks to handle surge demand, will get you farther/faster/cheaper than trying to build both an EV and a hybrid in the same vehicle.

Just food for thought.

As to their functional worth, all of the old diesel submarines worked this way. If the system was reliable enough to put in a submarine, it might just work for your car too. :-P

[Anaerin]

Originally Posted by ChristianThomas

But if a series hybrid is what you're looking for, tossing the big battery pack and using that space/weight for a better gen-set, and then using high duty cycle capacitor banks to handle surge demand, will get you farther/faster/cheaper than trying to build both an EV and a hybrid in the same vehicle.

Oh, I know that. For the most part, I'm suggesting building a trailer for most EVs. Then if you don't need the genset, you don't have to take it with you, or it could be used by "recovery services" to get stuck EVs back on the road quickly, or even something like u-haul or avis (Rent-a-genset). I believe most EVs (commercial and otherwise) explicitly disallow using the charger and driving at the same time, so a commercial venture making towable gensets for range extending would be a real problem. But if there could be a way of making a towable, on-the-road usable genset with a J1172 connector, and an on-board charger that supports J1172, and provides enough power to run the EV at medium loads (Cruising at highway speeds, for example) with a little bit extra, we'd have something really worth going for.

Originally Posted by ChristianThomas

As to their functional worth, all of the old diesel submarines worked this way. If the system was reliable enough to put in a submarine, it might just work for your car too. :-P

Oh, I know. And most diesel-electric trains still work the same way too.

[HYPRDRV]

I have a similar set up on an Electric Catamaran. 15kw genset that charges the batteries at the same time I'm running the props (2). The motors are eating 50A and the rest (20A to 30A) goes to the batteries. Since it's a sail boat I don't have to do it much but it has come in handy. Some guys are using the small Honda Gensets to do the same thing.

Steve

[charliehorse55]

Mahle makes an amazing EV genset - it produces 30kW of power and only weighs 70kg (including generator). It's very small and therefore quite easy to fit into an existing EV build.

http://www.mahle-powertrain.com/C125..._Engine_EN.pdf

[bjfreeman]

The design I implemented is similar in principle.
I have a power processing board the takes all forms of external power and applies it as DC to the Raw DC bus. the Charger takes the Raw dC to charge the Batteries that all Controllers run off.,

This is Canbus controlled, and monitored.

One of the first EV in the 90's had a pull behind power source.

Now if you think of a Genset, with some tinkering, as a alternator, then all you have to do is regulate the output for max voltage and current.
Also the engine can be variable speed for fuel economy.

the one factor not talked about is the extra weight that would effect the need for more power to pull the trailer, especially up a 15% grade (mountain passes)

[enp13]

Originally Posted by charliehorse55

Mahle makes an amazing EV genset - it produces 30kW of power and only weighs 70kg (including generator). It's very small and therefore quite easy to fit into an existing EV build.

http://www.mahle-powertrain.com/C125..._Engine_EN.pdf

I am very excited about this. I've just begun building my own with very similar specs using a Rotron 294 engine but buying one of these would same heaps of time. Do you know any more about them? Can you actually buy them yet? I've sent them an email so will report back if they reply.

[enp13]

Originally Posted by Anaerin

Looking around eBay, I found a few interesting things:

• http://www.ebay.ca/itm/Belt-Driven-9...item5ae3bb8dab
• http://www.ebay.ca/itm/10-200-watt-g...item35ae0a6f89
• http://www.ebay.ca/itm/PTO-Driven-Me...item5ae3083129 (albeit having removed that step-down gearbox)
• http://www.ebay.ca/itm/Tapered-Cone-...item588cd4bc6d

These all have a generation speed (apart from the PTO one) of 3600RPM, which is nicely in the power band for most small ICEs.

.

Presumably these generators are all permanent magnet types so the voltage and frequency they output are proportional to the speed of the shaft? So it would be quite important to choose an engine that couldn't overspeed or there would be a risk of over-voltaging whatever charger the generator was connected to? There would also be a practical limit to how slow the engine could turn while still producing enough output voltage (and a high enough frequency) to run the charger.

I am also presuming that these are single phase so for large powers (say 30kW like the Mahle unit produces), 3 would be used to output to a 3 phase charger (or output to a 3 phase rectifier to charge the battery bus directly if an overcharging detection system is present)?

[charliehorse55]

Originally Posted by enp13

I am very excited about this. I've just begun building my own with very similar specs using a Rotron 294 engine but buying one of these would same heaps of time. Do you know any more about them? Can you actually buy them yet? I've sent them an email so will report back if they reply.

Alas, I sent them an email and discovered that they are currently at the prototype stage and a single one of these would cost $120,000 (as they would have to make it special order)