DIY Volt Hybrid - Open ReVolt style

[bennelson]

In general, fuses are there to keep wires from melting.

Cabling is rated for various amperage, above which, it gets hot.

I took a 3-credit college course on energy a while back, and the teacher had all sorts of great stories. He pointed out how many amps you could put through 14ga copper wire IF it were completely UNINSULATED and strung up outside on a cold day - it was a lot.

On top of that, yeah, motors and engines are designed for a certain range of power, so the cabling, motor, and engine are all roughly matched.

My main thought is that you need a generator that can put out in direct current the same as the AVERAGE energy use of your electric motor while cruising. I had some issues with my battery charger, and some battery chargers are particularly picky about the AC they get. I always thought a bridge rectifier and a battery pack of close to the same voltage would be a simple way to go about it.

[MPaulHolmes]

Hi Ben! You know when you feel like a new project is coming on? I'm feeling that charger/controller combo that talks about their day over canbus. The BMS may not be necessary in the Lead Acid case. A person could buy an off the shelf generator using any fuel they wanted. I've gotten a 6kW charger working already before. It bucked down 220v to 'x', where 'x' is whatever the battery pack was. It didn't care what voltage the pack was at. It just figured it out. It was a constant current mode version used in a Thundersky bank. It was all chassis mounted components, so around $500, but I could do it for maybe $300 in parts I bet. The controller parts aren't much either.

[bennelson]

Ideas.... bubbling...... in ..... back....of .......... brain....

[rmay635703]

Originally Posted by bwilson4web

You might want to look-up synchronous rectifiers:

Method provides self-timing for synchronous rectifiers - 2002-05-16 07:00:00 | EDN

They have lower, forward losses, and coupled with a feedback circuit, provides voltage regulation.

Bob Wilson

Are there any "off the shelf" 240v 100amp synchronous rectifiers?

If a simple oscillator would control PWM one could build a simple dial in your current device with an ammeter a sr and a variable oscillator.

[MPaulHolmes]

I have most of the components picked out for a buck converter. 35 amps at 144v should be enough for 35 mph travel I think, if I understood that link that Ben posted earlier in the thread. Heck, the controller doesn't even need to tell the charger to turn on. We could save that for later. It could just be a basic good heavy duty constant current charger that you turn on whenever you feel like it. Flip a switch turning on the charger, and it will take care of turning on the electric start generator. It can ramp up the load at any rate you want, or do whatever the code says to. I think that would be a good option at first since then I wouldn't have to do a new control board for the controller.

Ben, do you have a student ID card? There's a place that has a special for $33 for making a new PCB, with no setup fees. I could afford that. Get a dang charger going! Just imagine a $2000 Chevy volt that doesn't catch on fire. hahaha.

[bennelson]

I've got a student ID. Send me a link.

[MPaulHolmes]

33 Each-2-Layer PCBs

[MPaulHolmes]

I got some of the power electronics ordered for the charger. hurray! I'm just trying to figure out a few details about which input and output caps to pick. But the rectifier, 600v mosfet, and diode are ordered. The control board will be easy.

[JethroBodine]

One thing I would like to bring to your attention. As a generator tech(military and civilian), I have worked with those rotating magnet generators, Generac and Onan. They have been known to throw their magnets due to glue failure and/or impacts from jostling where the magnets contact the windings/housings. I've replaced a couple rotors and still have some of the balls of broken magnets I brought home for my son. I'm not trying to put you off the generator, you got it at a great price, just letting you know that is one possible failure point.