Hybrid Fiero- Need genset help - Fuel Economy, Hypermiling, EcoModding News and Forum

Hondo · 01-02-2013, 03:13 PM

Hi guys, it's been a long time since I have posted here, but some of you will remember me as they guy who broke one of Paul's first contollers by mounting it directly to a transmission that had an out of balance flywheel. Anyway, I now have a little time to re-work the fiero and wanted to make it a hybrid. I came back to this forum and found that Ben is doing the same thing, good job Ben!

What I need help on is what type of genset to use. I have a 4kw generator with an 8 horse briggs, and I thought of just using a full wave bridge rectifier on the 110v ac output to go directly into my 96v battery pack. Any thoughts on this idea? How big of rectifier would I need? Any help would be appreciated as I want to get the fiero back on the road as soon as possible.

Thanks in advance,
Hondo

FieroChris · 01-02-2013, 07:35 PM

I will be interested in seeing what advice comes up... have you given a thought to a fuel cell?? I have no idea how much one costs but it would take the ICE out of the loop... feed it propane for a source of electrons..

Hondo · 01-03-2013, 11:07 AM

Quote:

Originally Posted by FieroChris

I will be interested in seeing what advice comes up... have you given a thought to a fuel cell?? I have no idea how much one costs but it would take the ICE out of the loop... feed it propane for a source of electrons..

I like the idea of a fuel cell, but I just don't know enough about them to attempt it. I talked to an electrical engineer last night and he said the ac generator with a full wave bridge would work, but not as efficient as a dc generator. I think I might try this out as it won't cost much since I already have the ac generator. The voltage (110v) should be right for charging a 96v pack and with the generator I should be able to put 40 amps into the batteries. I see on ebay that I can get a 1000 volt, 40 amp full wave bridge for less than 10 bucks. Anyone know if that will be big enough?

Hondo

Daox · 01-03-2013, 11:49 AM

You can't just rectify 110V AC power and feed it into a battery, you'll destroy the battery. Rectified 110V AC power will actually vary from 0-162V! The normal black line is regular 110V AC power. The top of the graph (black/red/black/red) is what you get when you rectify 110V AC power. In order to get the 110V RMS, you would need to create some additional circuitry to smooth the power output out. Unfortunately, I can't help you with that because I don't know how.

Hondo · 01-03-2013, 01:06 PM

Thanks Doax, perhaps something like this?

Bonn Charger

Daox · 01-03-2013, 01:29 PM

That might work. I don't know how well, or how efficient. As I said, the specifics are over my head.

FieroChris · 01-03-2013, 02:17 PM

you will need some sort of charger between the generator and the batteries...
voltage will vary with RPM of ICE and the RPM will vary based on how much charge the batteries are taking...

better to have some regulation with is what a battery charger does... with several phases of charge. and if you have LIPO batteries... well they need special balancing chargers...

Hondo · 01-03-2013, 02:50 PM

Quote:

Originally Posted by FieroChris

you will need some sort of charger between the generator and the batteries...
voltage will vary with RPM of ICE and the RPM will vary based on how much charge the batteries are taking...

better to have some regulation with is what a battery charger does... with several phases of charge. and if you have LIPO batteries... well they need special balancing chargers...

The generator motor runs at a fixed 3600 rpm and you're right,I will have to run the output through some kind of charger if I use this set up.

I wish I had LIPO batteries, just too much $ right now. I am just running eight 12v leads for now with my home made resistive/voltage controller. This controller gave great performance when I had it set up at 108v/54v with 18 six volt leads, and I thought I could get even better performance if I switched to 12v bats and replaced 620 lbs of lead with a 150 lb genset.

Hondo · 01-04-2013, 10:37 AM

OK, I am re thinking this idea because I don't like the loss of efficiency when converting the ac to dc. I did a little looking on ebay and found that used treadmill motors might be a better idea. They are perm. magnet motors rated at around 2.5 hp at 110 volts (1800 watts) and are being sold a lot to use as windmill generators. They are also cheap ($25-$45 each). I also found a 10 hp diesel motor (new) for around $620. My idea is to use the diesel to turn 3 of the treadmill motors to give me around 50 amps of charging. What do you guys think?

mechman600 · 01-04-2013, 10:45 AM

The Inverter series generators from Honda use a DC generator but I am not sure what voltage they output to the inverter.

Your treadmill motor idea sounds good, but I am not sure how you can properly size it. Does input power as a motor = input power as a generator? I really don't know.

You are also going to need to throttle the engine to avoid over charging.
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The guy in there made a bio-diesel series-hybrid Miata and managed to do exactly what you are attempting, but I forget how....