Detailed alternator based regenerative braking in a conversion - Fuel Economy, Hypermiling, EcoModding News and Forum

MetroMPG · 05-30-2009, 10:08 AM

Further to this thread .... http://ecomodder.com/forum/showthrea...king-8091.html

This is really good stuff.

Found an insanely well done conversion that is using an alternator to regen 150+ volts at over 10 amps back into the pack.

The basic setup: electromagnetic air conditioning clutch activates/deactivates a pulley on the motor tail shaft that spins the alternator, controlled by a brake light switch or manual activation (switch on the gear shift).

Alternator coils were re-wired to get the extra-high voltage for his vehicle.

There's an amazing level of detail in his explanation:

Regen details: Regeneration Braking!

Main web page: 1987 Chevrolet S10 to Total Electric Operation

YouTube vids that explain the regen & show development:

Finished regen demonstration:

http://www.youtube.com/watch?v=KzKI45XS360

Overall show & tell of his truck (incl. regen components):

http://www.youtube.com/watch?v=R9dKqekvXhk

Testing alternator @ 45v output

http://www.youtube.com/watch?v=IWCO5...e=channel_page

Youtube channel for this vehicle: http://www.youtube.com/user/ws64play

Daox · 05-30-2009, 11:49 AM

Nice, but wow that is no small task to achieve... rewinding an alternator, not my idea of fun.

MetroMPG · 05-30-2009, 11:55 AM

No small task. He definitely didn't slap this together. A lot of thought, design & building went into it.

But he only had to re-wind the alternator because of his high pack voltage.

For those of us with lower voltage vehicles, that step wouldn't be necessary. A normal alternator can be modded (through field control & RPM being the issues) to output up to 120v without re-winding.

Alternator Secrets

ev59rag · 06-03-2009, 04:30 PM

Maybe you dont need to rewind????

Maybe I can point you to another source. I also mentioned this from the other thread. But here it goes. I have a ES-31C double shaft motor (not installed yet). The main reason is to do the same alternator/regen configuration (hoping)...

I have this unit that i use for my wind turbine. Im not selling or even connected with the company. Some people says its no good but I want to try it myself anyway. I cant say its good or bad since my wind source from where I live is not really consistent thats why I moved to solar. Now its just collecting dust from my garage.

Back to the subject... Since I have the alternator already, the only thing left form me is to use it. As you can see on the graph, that it can provide 15 amps at more that 100 volts (open) depending on the rpm.

And if your going to check their website, they have 4 alternators that are designed for different situations. Whats also interesting is that you can also buy just the stator if thats what you need if you already have a matching alternator from junk shop i suppose. I think the best alternator for our use is the DC-500... If mine does not work then I might try to buy just the stator to convert it to DC-500. They claim that it can produce 150 amps and 100 open volts @ 1000 rpm. So maybe we need to do a ratio pulley or something like the old aircooled vw configuration. I believe that these are perfect fit from a Delco 10si alternator.

I hope i dont sound selling or promoting. Just to give you another source of info... There are so many sellers out there on ebay claiming this and that. So no guarantee from me that my theory will work... But we will find out soon.

Cesar

Intrigued · 06-03-2009, 11:19 PM

One of the tests we used to do at the GM dealership was what we called "full-fielding" an alternator to check output. To do that, we simply stuck a small metal object such as a nail into a small hole built into the back of the alternator. The "nail", when touching the side of the hole, and what I'm thinking was a spot on the regulator, would cause the alternator to go to full output, dragging down the car engine considerably.

This was to be done only for a couple of seconds, to prevent damage to the alternator or car's electrical circuits. We did this to help diagnose if a problem in charging was internal to the alternator, or somewhere else.

What I'm wondering now is if this was causing the generator to go to a higher voltage or full amperage. I never did do it with a meter attached to find out for sure, as I can remember. I'll have to play with my son's GMC to find out what it was...

MetroMPG · 06-03-2009, 11:32 PM

I bet you were probably going to full amperage. Full voltage might have damaged voltage sensitive components (computer?) and I can't see a dealership risking that kind of test.

If you do this on the GMC, I'd be interested to find out what readings you get.

dcb · 06-03-2009, 11:46 PM

The two are closely related, but bypassing the voltage regulator puts the alternator in "full voltage", but you are not doing it at a high rpm so the full voltage isn't terribly high. The electrical components will draw a bit more current at the higher voltage, but should not be near the max current output of the alternator.

P.S. Alternator secrets = good find

Intrigued · 06-04-2009, 10:11 AM

Yes, after looking at the Alternator Secrets site (REALLY good catch

) and thinking about what we did at the dealership (only full-field at idle) then it would be doing full voltage at a low RPM. It's been over 10 years ago...

As soon as I can capture my son and his Money Pi... I mean GMC (He works for a tree-trimming contractor... 10 hour days...), I'll dig out the camera, load tester, and a non-rusty nail, and play!

Funny · 06-04-2009, 01:59 PM

I wish I could see these videos at work, but no dice. I have always been interested something similar to this. Subscribed.

Intrigued · 09-09-2009, 01:47 PM

First off, I need to apologize for the delay. I've had an 8-week break from classes, and have been doing a lot of catch-up.

ANYwayyy... I load-tested young Skylifter's (I am his father!) GMC alternator while full-fielding it a while back. (Okay, maybe TWO whiles back...

)

The hardest part was capturing young Skylifter:

After suitable negotiations (Protein Powder!!!) Skylifter was coaxed out of the Money Pi - I mean GMC...:

After that the handy-dandy load tester was retrieved and properly connected:

Hmmm... 14 volts at idle as per above pic... Since the Money Pi - I mean GMC was cranking slow, I put a load on the alternator down to 12.6 volts and held it there until the load tester started beeping:

Yep, sucking amps from all available sources...

Hmmm... alternator seems to be doing okay, so there are other issues. At this point, I couldn't take any more pictures because I needed at least one more arm.

Anyway, I conned Skylifter into more motor revvings (...yep, CHOCOLATE protein powder...) and stuck a nail in the test hole in the back of the alternator while I checked voltage and load a couple of times.

At 1500 RPMs voltage was close to 15, and held over 13.2 under rated (100 amp) load.

At 2000 RPMs I decided that the nail shouldn't go in the back of the alternator any more, as the voltage needle was almost pegged at 16, and the load tester was beginning to smell funny, besides emitting that annoying beep.

The load on the accessory belt/engine was noticably higher at the higher RPMs.

dcb seems to have the idea about full-fielding pretty well in-hand. The regulator is taking all of whatever voltage is being created, and sending it out through the rectifier bridge (do they still call them that???). Volts and amps are both increased as the speed of the stator through the magnetic field increases, and as the magnetic field itself increases.

At the lower RPMs not enough voltage is created to be of concern, and at idle the thing does seem to be pretty close to full-field on its own. 2K engine speed would mean something like 6-8K alternator speed, IIRC, so if a person was wanting to use an alternator for regen on a higher-voltage pack, you would most likely want to step up its RPMs for better efficiency...