Lister 16/1 48VDC Battery Charging

[Revolutionary]

Greetings all,
 I just finished installing/making work a MARS 0709 Electric Motor as a Generator to charge my forklift batteries. My batts are 48VDC @ 1105AH, so pretty large, about 5,000 pounds in (2) batteries.
 The MARS Motor is a DC motor used to run electric vehicles, like a golf cart of a electric motorcycle. When powered, it's about 90% efficient.
The motor used as generator makes around 125 amps at 48-58VDC. It's nothing short of awesome, and I also use it as a starter for my Lister, a GM-90 16/1, running at about 750 RPM.
 The motor cost a little under $500, is build like a tank, and is a cheap alternative to buying a direct DC generator at the same amperage/voltage. I saw it charge this morning at almost 7KW, and keep in mind that that's CONSISTENT 7KW, not on & off.
Anyway, I'm pretty happy about all of this, and I'll be writing an article on it on my website at some point in the future, (yes I'll stick up a link if you guys want it), just thought I'd share it up with some of you guys now. Like I said, it's the least expensive & most efficient way I've seen to charge large batteries at real amperage. A DC generator that is diesel & runs at the same current wil cost (new) between 11 & 14 thousand dollars.

Chris

[dnix71]

How long are the brushes supposed to last and how much work is it to change them? At 38 pounds you could make a pretty fast ebike if you could find batteries to fit.

I'm not sure it would make an efficient e-motor, though. There is a forum post about a guy who smoked the brushes and holders at idle speed because a contactor connection was loose. That kind of power may mean you need to keep the rpms up for cooling even under light load.

On a Lister genset, that's no problem as long as you have it geared up to spin maybe 3:1. Do you run your house off the forklift batteries?

[Revolutionary]

Brushes are suposed to go 2,000 hours, I have an extra set of brushes and and extra motor. The guy that designed these said the casing could go up to 250 degrees and does regularly as a motor, I've been keeping an eye on it & the highest I've seen the outside casing was/is about 160.
 They tested the motor as a generator at teh manufacturing facility by connecting a motor directly to the shaft of another one, and checked the ooutgoing current versus incoming, it ran at about 90% efficiency.
As to RPM's, The Lister is running at 750 or so when the voltage is down, and colser to 820 when it's up. the (23 inch) pulley on the Lister is connected to about a 6 inch (or so) pulley on the Motor/Generator. It's spinning around 2800-3200 RPM.
 Changing the brushes is easy, the brushes come on a holder, so you unbolt it & remove the first (old) set, and set the new set on, tighten down. Even I can do it.

Yes, I've been on the batteries (totally off-grid, although I have grid power) since August, last year. Installed 100 panels & an old Jacobs Wind Electric Head & 50 foot tower. I actually have (2) sets of batteries; my old one is an 875 AH & the new one is an 1105.

[dave ames]

Nice set up Revolutionary,

Was checking out that brush holder change over system they use..Eight big brushes on a bolt up assembly. That's well made, ..spread them amps out!

Curious how you went about switching between the starting function and generator mode?

Any pics  ..and the link to the write up when you go live with it, please!

Thanks.
Cheers, Dave

[Revolutionary]

Thanks Dave, it was a long time in coming....

The switch between Motor (starting) mode & generator mode ended up coming out pretty simple.
Initially, I wanted to use the 48V batteries as a source for starting. IF I did that, though, the switching got pretty complicated from the perspective that I would need to use double pole double throw switches, and on top of that, at 48VDC it MIGHT spin the engine too fast; I.E. without it slow starting, this beat of a motor might just spin the belt really badly, out of pure torque. Like you said, that MARS Motor IS a beast, no doubt.
So....I was sitting there looking at it, and I had a car battery sitting there in my shop, too. I grabbed the battery (which was low at the time) and put a set of jumper cables on it, and tried to start the Lister with it with the cables hooked onto the (2) posts on the MARS & on the positive post on the battery, & touching the negative to see how it'd do.
 The result:
It spins up the Lister slow enough to where there's no bad torque issues, easily fast enough to start, voila!
 On wiring, we start out w/ (2) #1 cables coming from the batteries, the positive goes through a set of diodes (to stop the MARS motor from "running" on battery power, and the negative goes through a 150A fuse. Downrange from that, right at the motor, I set a battery, and ran the cables the same you would in a car, I.E. the negative is run direct battery to MARS, and the positive goes through a solenoid that is fired by a switch (that I can tap my foot on).
To start:
(A) Turn on Fuel on Lister
(B) Put foot on switch, MARS Motor runs, Lister spins
(C) Once the Lister spins a few times, release intake valve for compression
(D) Take foot off of switch, machine running!
It's really simple, in the end. The Lister gets started by a 12V car battery, via solenoid. once running, the power made is driven STRAIGHT at the batteries, at nice BIG current.
That's about it; the MARS is held by a frame & a regular alternator bracket.
The guy that owns EV Drives, Carl, was very helpful in getting this done.