Venturing into the world of inexpensive LiCo batteries...

[BrandonB]

Just bought five of these for a total of $52 shipped:

http://www.legendmicro.com/store/more_info.asp?Product_ID=6019&OpenTreeBranches=0&SortBy=0

A 12 cell pack @ 5.4Ah and 14.8V tells me that there are 1.8Ah cells inside the pack, in a 4S3P configuration. 5 packs at 12 cells each gives me 60 cells, which I plan to plan to reconfigure into a 10.8Ah 37V pack. The batteries are quoted to have a charge rate of 2.5A (Safe charge rate of around 0.5C) and to have a Wh rating of somewhere in the ballpark of 90-100Wh. These cells are old stock (8 years old or so), but they're inside of Dell packs made in Japan, so they should be of a reasonable quality. The batteries have a 90 day warranty on them, so I'm almost tempted to buy an Inspiron 7500 just to test them and see if any of them are bad. Anyone have any ideas or suggestions?

Thanks,
Brandon

 

[texaspyro]

Be careful... the cells may have self-discharged below their Minimum Lethal Level. If so, you can't recharge the pack in the computer because of the protection circuit. You would have to open the pack and individually charge the cells. Also 8 years is pushing the viable shelf life of a lithium cell by quite a bit. Whatever... don't charge them around anything you don't want incinerated.

 

[liveforphysics]

8 years ago, LiCo formulas were dangerous to build the reputation that has stuck with them to present time.

More danger than Lipo with none of the advantages.

But the price is nice.

 

[BrandonB]

The infamous Dell power indicator on the battery will help me out a lot, if it still works. I am hoping they are still holding enough of a charge for it to...even though that's a far stretch. Just so I've got my bases covered here...These batteries like to be charged at 3.7 volts, and a safe rate is about 0.5C...how many cycles could I expect out of the pack if it works as I want it? Calculated, the finished pack will have just under .5 kwh, which will suit my needs. I don't (THINK) I'll be overtaxing it at all...anyone got any good suggestions?

Thanks again,
Brandon

 

[amberwolf]

If they are low voltage, I'd charge them at far less than 0.5C; more like a tenth or less of that. Slower is safer, at least until you are sure they are going to work and not blow up.

Read the advice I got in this thread:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=14892&start=0
it's probably good.

 

[BrandonB]

GREENIES! All 2.4V or more, most 3+! All tested good! The Dell BMS did it's job!

 

[DAND214]

LiCo, what are the limits for them,HVC & LVC?
What charger will you use? LiPo charger I would guess.
Hope they work for you.
Keep us informed.
I am always looking for something to spend the money, I don't have, on.
Dan

 

[kZs0lt]

Hi Brandon,

How did these batteries turned out for you?
Did you have a chance to test them capacity, and internal resistance wise? Do they keep in balance?

 

[DrkAngel]

Just bought five of these for a total of $52 shipped:

http://www.legendmicro.com/store/more_info.asp?Product_ID=6019&OpenTreeBranches=0&SortBy=0

A 12 cell pack @ 5.4Ah and 14.8V tells me that there are 1.8Ah cells inside the pack, in a 4S3P configuration. 5 packs at 12 cells each gives me 60 cells, which I plan to plan to reconfigure into a 10.8Ah 37V pack. The batteries are quoted to have a charge rate of 2.5A (Safe charge rate of around 0.5C) and to have a Wh rating of somewhere in the ballpark of 90-100Wh. These cells are old stock (8 years old or so), but they're inside of Dell packs made in Japan, so they should be of a reasonable quality. The batteries have a 90 day warranty on them, so I'm almost tempted to buy an Inspiron 7500 just to test them and see if any of them are bad. Anyone have any ideas or suggestions?

Thanks,
Brandon

I've built several packs using "used" 2600mah cells.
Tips:
(2600mah cell results)
Minimum of 20ah pack with 650w motor, 30ah highly recommended.
1.5C output, 1C sustainable, .5C recommended.
(1800mah cells, with a lesser energy density, should have a better surge - sustainable, capability.)
Pre-charge batteries to full capacity - 4.2v, before "pack" assembly.

dual - 3 packs, of cells can be charged simultaneously. Multiple of these cheap chargers recommended.(Safe, but slow, charge rate.)
18650 Li-ion charger

A PCB (Protect & Charge Board) is highly recommended, $40 - $ 60, and be sure to use a 37v Li-ion charger. SLA charger NOT recommended.
Alternative is a pair of iMax B6 chargers. (ebay available <$30 each.) Provides charge - equalization to banks of 5-6 cells each. Also designed for Lipo, LiFe, Nimh, SLA etc. (Titan, Mystery, Tenergy, and more, also produce similar)


If used in cold weather, keep the pack warm, performance is greatly reduced by low temperature.

Tips on building packs and acquiring cells, available here: Homemade Battery Packs