A123

[Doozie870]

During my hobby table clean up I found a complete dewalt 36 volt pack and some loose a123 cells, much to my surprise the voltage is still good after sitting for a year lol, so I am going to build a pack with all of these. Two 7 cell packs paralled. heres what where starting with.

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[NorthernBoater]

I am very interested to see how they work. I would like to build a cat that runs 6s2p with the a123 cells and I am still unsure if it is a good idea.

[Doozie870]

Broke the cheapo tabs off and wrapped each cell with electrical tape for good measure.
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Threw a few rolls of tape around to hold the cells together and soldered on deans bars (soldering not recommended by 123 BTW) Topping off each cell to 3.6 volts individually before use as a pack. at this point after 4 cells they are ranging between 300-396 mah to reach this point (3.6volts) not bad for all the sitting.

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[NorthernBoater]

I thought the a123 cells were 3.3 volts.

[avengersteve]

its amazing what we find when we clean our work areas. i found a hole sv27

[saleens7]

thats nothin, after i cleaned out my workshop, i found out i had a whole bedroom bueried in there..:D

[Diegoboy]

That sounds familiar.
I cleaned my work area, to find that I actually have an area to work in. :)

[Doozie870]

Having a hard time linking the data from the first load test,(seven cells in series) so I just took a pic of the screen lol.

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[Doozie870]

Second pack made up, will do some parallel testing tonight,appears that the recommended range of the cells is 3.6 with a 2 volt cut off.

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[Doozie870]

Heres the first parallel test,

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[Doozie870]

I had wanted to run it to the voltage cutoff, i.e. 14 in this case, but the 50 amp recorder was getting pretty toasty!!

[Doozie870]

If the graphs were at all legible, you would see there is still a pretty good voltage drop, I think 3 paralled sets of 5 in series would be the ticket, unfortunatly I only have 14 cells. The next step to running these in a boat is to figure how long they can be run as I still do not have any voltage cutoff device. So what will do is put em under the 50 amp load with a timer and shut it off at 14 volts, this will give me a general timeframe, as my boats pull slightly less than that. :rolleyes:

[Doozie870]

Well the smoke has cleared from my harbor tool load tester, it looked like 3 arc welders going at one time inside the case, as I attempted to keep the amp draw at a steady 50 amps with the dial, there were some brief surges to 125 amps. after 5 minutes the voltage was at 18, batts hot! put them in the chest freezer for a while.

[Doozie870]

Batts OK, these cool down much quicker than sub-c's do. I feel pretty safe with a five minute run time for starters.

[seabassturd]

i'm still running the a123 as well dooz, ive got a 18 inch mono, with brushed 540, that runs on a 2 cell pack. and my miss timex on 3 cell packs, and the brushless 24 inch mono, on a 4 cell 13.2 volt. these batteries are awesome, and i've been running them for well over a year, i dont find any need to parralell them for the amp draw, they will deliver lots of amps without getting to hot. that mono pulls a continous 60 amps easy. i cooked a mgm 160 amp, with 200 amp surge. thats with a 8xl on a 5 cell. running 56.4 mph. my best mono speed so far., and that was the hottest ive seen one get. which is just flat out abuse