18650 based battery packs...

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This topic has 5 replies, 4 voices, and was last updated 10 years ago by Doh1Nut.

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18650 based battery packs…
vincienup
Free Member

I’ve been doing a bit of digging around and headscratching and concluded that probably it would be as cheap/cheaper to buy decent packs from Smudge or someone similar by the time I’ve bought cells and got some form of CD welder in operation (even a cheap Chinese readymade is over £100 – can put something together with an SCR, a big Bass cap, a car battery charged and some chewing gum etc…) and from what I understand taking a regular soldering iron to Lion cells is a bit of a gamble.

So this is more of a theory question than a ‘how do i…’

Protected cells in battery packs for lights. Yay or nay?

I understand that if the cells get overly discharged they’re ruined. Would a protection circuit in the cells userd for this purpose lead to a light battery that shut down too early?

Posted 10 years ago

Doh1Nut
Full Member

I always put in a protection circuit for a few dollars its too easy not to. not just from discharge but also when charging as a charger can only monitor the pack voltage, a protection circuit will monitor individual cells.

It is pretty easy to get hold of cells with tabs that can easily soldered to each other / wire.
The over discharge voltage is usually set low enough for it not to interfere with the lights.

I would spend my money on a decent charger like an accucel-6 and fit some balance leads too so you will

Posted 10 years ago

vincienup
Free Member

Hm. I’d been discounting based on weld more than anything.

Maybe I’ll have a play then. Cheers for the heads up on the protection circuit staying out of the way. I’d been planning to rely on protected charger but if i can have both then as you say it’s a no brainer.

Posted 10 years ago

FGF 701 The Hydrate Or Die Edition

forzafkawi
Free Member

I used to solder up my own multi-cell battery packs including a balance lead but don’t bother now. I use DX twin cell cases and individual protected cells to make up twin and quad cell battery packs.

I’ve been doing that for several years now with lights that I built myself and have never had any problems either charging (with a Turnigy Accucell-6 charger) or discharging with the lights. If you are worried about individual cells getting out of balance then you can charge them individually periodically but again, I’ve never bothered.

I’ve built similar battery packs for friends and they have had no problems either even using cheap DX TrustFire cells.

Posted 10 years ago

cookeaa
Full Member

I’ve been looking more at ways of packaging individual cells together so I can Balance charge them individually and bin knackered ones without having to constantly disassemble a pack…

Not keen on having to weld or solder cells if I don’t have to…

I thought most LED drivers have cut off points to prevent them from over discharging the cells, I suppose that only works if all the cells iin the pack are balanced.

Posted 10 years ago

Doh1Nut
Full Member

Just realized I missed that last bit – monitor what is going on. were the missing words.
I have some packs built without balance leads and some have been fine, and some started to show connection break on the charger when a single cell tripped out often a balance charge has pulled them back into line and they have been fine since.

Posted 10 years ago