Another score - Prius battery modules on eBay!

[Sulfuric]

Originally Posted by Christ

Oh - The reason I bought them.. Well, they're NiMH, and 7.2V, and 6Ah... so basically, they're enough to run my TwinStar!

I figure that one of them will run the TwinStar, the other 3, I can use for something else when I get around to playing with stuff... 7.2V won't bother the bike's 6V electrical system, and I can wire in LED's in place of all the lights for 7.2V instead of 6.

The Modules are approx 1/2 of the Ah rating of the flooded lead acid battery that came OEM on the TwinStar, but lighter, smaller, and dry, all of which are huge pluses.

OTOH - I'm still going to see about washing the OEM battery that came on the TwinStar and seeing if I can revive it with new sulfuric... Just for kicks, I guess.

I don't perform CPR on batteries, FYI...

[Christ]

Japanese GenI and GenII/USA GenI have 38 modules, All others have 28, not sure about the '10 model.

[Christ]

Originally Posted by Sulfuric

I don't perform CPR on batteries, FYI...

Tee Hee. LOL. Thanks for that, but I said "NEW sulfuric"... you're getting kinda old, aren't ya?

*Friendly Jest, take no offense*

[MetroMPG]

You probably already know this, but my understanding of these modules is they need to be mechanically constrained or they'll bulge/warp when charging.

The Prius pack is very tightly clamped together.... and then very snugly emboxened.

EDIT: this bulging/warping may have to do with charge current.

[cfg83]

MetroMPG -

Originally Posted by MetroMPG

You probably already know this, but my understanding of these modules is they need to be mechanically constrained or they'll bulge/warp when charging.

The Prius pack is very tightly clamped together.... and then very snugly emboxened.

EDIT: this bulging/warping may have to do with charge current.

Do you mean physically, like a balloon blowing up? Sounds like even more reason for a "trickle charge" type of solution, yes?

CarloSW2

[Christ]

Carlos -
The plastic softens, and they sort of glop into themselves at the bottom.

I'm hoping that it's just a matter of making a plate to lay it on, then bolting another plate on top of it at a fairly tight spec.

[brucey]

If they dont need any BMS and could be charged like lead, this could be a good deal for many many projects!

I could also see these being used as a average battery of sorts. Have cheap lead or thundersky batts charging them at an average rate while the nickel batts could supply huge surges of amperage.

Although they have seemed to have raise their prices since you bought them.

[Christ]

I made an offer. The "normal" price was 19.99 plus 9.99 shipping.

Carlos - I don't have dibs, I've got what I need for now, and they're on there alot, just keep searching around for them. You can feel free to buy him out, if you like. So far, I think I've figured out the idea behind charging them.

I'm fairly certain you can charge them "normally", like with a car's alternator, as long as they're clamped tight enough to maintain their shape. They have their own form of overheat protection, in the pressure vent. Temperature monitoring should be used if you plan on charging them with high current, though, or at least an inductive load cell to check pressure while charging/discharging the pack.

What I'm going to do is make myself a pair of plates, one that I can put the battery against, and the other that will bolt to the first, compressing the battery module. I'm probably going to shoot for something like 20PSI across the whole of the module, using aluminum plates of approx 3mm thickness. Hopefully, the aluminum will help dissipate any excess heat.

In the case of the bike, and with cars (that still have their alternators), the cells will probably not see high current draw anyway, other than with starter use, so this shouldn't be too much of an issue.

If you look at the modules, each one has a single molded nut in it to mount with. Using more than one module side by side, each one interlocks with the previous/next one, and they bolt to a frame, so they hold each other down when you lay them in opposite directions. Once they're all bolted down, plates on each end should be sufficient to mechanically clamp them together, to prevent breakdown of the module wall and eventual internal shorting.

Anyone agree/disagree?