158 volts of 30ahr NiMH what to do?

[rmay635703]

I am looking for suggestions on what to do with NiMH cells I picked up.

The top few things I would like to do are

1. Mini Hybrid (aka boost my Volts and Insights 12v system to 15.6 volts and keep the inverter shut off for a while) But then I need a charger and a disconnect system so the car can't "see" the charging voltage.

2. Insight PHEV project, this one although #2 on the list is probably #1 for ease and also would motivate me to get a MIMA or IMAC setup, Heck a good anderson connector, a charger (already have a dumb glacial 1.2 amp 170v unit (which charges 144v NiMH OK) would make this easy and best of all the batteries fit right in and even have a fiberglass carrying case that can replace my trunk.

3. Get some high amp diodes and run either my C-car or my Fathers Miles zx40 on paralleled strings (separately charged) for a 48v, 60v or 72 volt pack
60-90 ahr might be good enough, would be better if I could parallel them with lead or lithium but NiMH just has too much charge and discharge range to cooperate with them well. I tried figuring out how to match up the right number of cells and also use the old don't charge above 75% so you stay out of the knee crap but can't figure it out, looks impossible as the amount of discharge you would get would be poor, though the batteries would last forever.

Anyway

I don't think NiMH cares if it discharges in parallel too much its just the charging that has to be done separately and then link up when you are ready to rock.

So what do you think I should do with the real deal in terms of low temperature capable batteries?

Replacing the 12v systems I think would require a method again of paralleling and charging separately.

144v insight is cool but the insight can't run strictly EV (though I have often wondered why no one didn't just put an output shaft on the main cog of a MT transaxle so you could hook up an AC motor to the final drive while the gasser stayed clutched and geared)

Also understand I only have stupid chargers and garbage I have built, I can build anything to charge very slowly and stupidly but am limited to smart 48v chargers and obviously smart 12v lead chargers along with dumb 12v, 72v, 144v chargers.

The main limitation will be the charging method for me, I have a way figured out but it won't be elegant. If you know of any cheap methods I am all ears.

Ah well

Cheers
Ryan

[P-hack]

nimh is tricky. Charging Nickel-Metal-Hydride Batteries

You are probably gonna need a 240v outlet just to charge 'em hard enough to see the peak/termination hint. Do they have a specified charge profile?

[rmay635703]

Originally Posted by P-hack

nimh is tricky. Charging Nickel-Metal-Hydride Batteries

Do they have a specified charge profile?

Yes they do but its not very well specified, in my case I plan on doing 2 stage.

http://www.gpina.com/pdf/GP30EVH_DS.pdf

These aren't the most terrific brand but cost was very low so no complaints.

Charging to the point just before the "knee" would occur on a bulk charger that craps out at too low of a voltage to get past the knee on any of the cells, then a slow dumb charger would trickle them after that point at a low enough current with a moderately low voltage limit as well so that no significant damage could occur if I managed to overcharge, more than likely though these aren't going to get fully charged most of the time anyway.

Cheers
Ryan

[P-hack]

yah, 60 amps continuous discharge, thats like 12hp, and a PITA to charge. Would be a good fit for the citi car if you can sort out charging (and ~48v is going to be easier to sort out nicely for nimh). According to this, the problem with parallel charging is the different resistances How to charge Nickel Metal Hydride Batteries tutorial for design engineers.

So maybe you can measure the resistances and match them up 3 wide for the c-car? or live with a 10 hour charge?

Hope you beat the $2.50/cell price by a decent margin

[Cobb]

Id say #2. The Enginer kit gave the gen 2 at least a 15 mpg boost, Im sure the gen 1 was easily able to exceed 100 mpg before all the fancy doodahs were added.

[rmay635703]

Originally Posted by P-hack

yah, 60 amps continuous discharge, thats like 12hp, and a PITA to charge. Would be a good fit for the citi car if you can sort out charging (and ~48v is going to be easier to sort out nicely for nimh). According to this, the problem with parallel charging is the different resistances How to charge Nickel Metal Hydride Batteries tutorial for design engineers.

So maybe you can measure the resistances and match them up 3 wide for the c-car? or live with a 10 hour charge?

Lol, if I can achieve a full charge in 10 hours I would be happy, my current dumb 144v charger that could taper nickle would take more like 30 hours if I don't suppliment it with something else

Originally Posted by P-hack

Hope you beat the $2.50/cell price by a decent margin

Where could I buy a 30ahr NiMH cell for $2.50? (cough no I didn't pay that much but I am curious)

[samwichse]

I vote insight PHEV! You can actually use the stock electronics (BCM, MCM) without any buddy pack or lossy kludges like charging the small pack from the large.

You'd just need an IMAC&C and an OBDIIC&C to full use the capacity. Heck, they're so "fat," you can probably also do the current hack to get more juice to the IMA motor. Sounds awesome to me!

IIRC 40A output in the IMA is enough to keep you moving about 35mph. That would be enough with the Peukert effect and say... a 75%DOD to do 15 miles using almost no gas. Assuming you have 30AH to play with.

You didn't get these from the guy advertising on DIYelectriccar did you? I think he said those were rated for 30AH, but had 20-24AH capacity.

Sam