Capacity testing new cells required?

[gaisom]

Should I do capacity testing on new unused cells from HP 12cell laptop batteries that have never had the blister pack opened before building my battery packs?

 

[dnmun]

you can test capacity after you build the pack. you should balance them all to the same voltage before assembling the pack. then let the BMS handle the final balancing after you assemble the pack.

 

[gaisom]

Sounds good.

 

[Punx0r]

If there's a weak cell I'd rather find and eliminate it before building it into a pack...

 

[wb9k]

If you're using reclaimed cells, I would definitely test each cell BEFORE building your pack. Capacity and cell impedances should be matched as well as possible--both have big impact. Even new cells can have lot variation....I would test, but that's me.

 

[friendly1uk]

Check they're voltage's all match. They should of all been charged to the same level at factory. If any stand out from the norm then don't use them. Perhaps in another appliance, but not in with the good ones. They have no excuse to be out of balance, and building with unbalanced cells is a bad start for too many reasons.

I think it is good practice to bed your virgin batteries in gently. Leaving the deep discharge events till after a few cycles.

 

[eva-michael]

The best will be check the capacity after build pack.
Factory will charge them full before send out from Factory.
For EV batteries, factory will send cells which are matching voltage, capacity and internal resistance.
Otherwise, we can consider they are not professional totally.

 

[gaisom]

Every single cell has been in the 3.8 voltage range. I looked up the Sanyo cells on the website and I found where it stated that the new batteries were always sent out with a 3.80 volt charge. Leaves me kind of wondering how they stayed at that voltage while hanging in the blister packs for who knows how long. Hmm, I think I will look at one of the blister packs and see if there is a date of manufacture anywhere on it.

I suspect my brother can tell me when he got them in stock to sell, but that won't tell me when they were manufactured.

 

[1KW]

just check the voltage to double check when ya get em.

How are you going to parallel them...copper strip?

 

[gaisom]

I haven't decided yet, I like the tinned woven strap that Drkangel used but I worry it might short across the top of the batts if I used it there.

I suspect I am going to search for some fine strand copper with a tough insulation and use that on the Pos connections.

You have a suggestion?