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Best way of charging Li-Ion batteries in series? Answered

Hello. I've been working on a speaker project for the last couple of days, but I've now ran into a problem with the speakers battery. I have 4, 3.7 volt 9900mAh batteries, that I want to connect in series to achieve 14.8 V. What is the best way of charging these batteries in series, while still being able to draw power directly from the batteries? Also what amp should I use to charge the batteries as safe as possible? Would something like this be good for that?

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Downunder35m
Downunder35m

Answer 3 years ago

But I like to charge my phone and tablet under my pillow before I go to bed.
This way I only have to turn the pillow around and have a "hotpack pillow".
;)
Did see some Lipo's go up while charging using cheap chargers and battery packs with no protection.
Let's just say that once you notice a problem it is already too late unless you really keep one eye on them all the time.
Once they start to produce gas it is time to pull the plug, if you don't it withing these few minutes of opportunity the battery will seriously overheat causing a breakdown of the insulating layers.
Now you created a dead short and the battery acts like a self feeding heating element.
Considering the amoung of hydrogen produced, the high temperature and the fact that lithium burns really well in just air you really don't want to take any shortcuts when it comes to charging or discharging them.

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-max-
-max-

3 years ago

There are chargers on the market designed to charge lithium ion cells in series. Really you would never bother to DIY something like that because lithium batteries can be a bit dodgy [nemo reference] when it comes to charging / discharging. Amazon sells chargers for the RC battery packs, get one that has good reviews and reputable name and watch out for the knockoffs.

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iceng
iceng

Answer 3 years ago

Do you have an RC pack that you regularly recharge ?

If I wanted the same RC toy what would I need to buy ?

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-max-
-max-

Answer 3 years ago

I personally use the imax B6. I never had a problem with it in normal operation. While attempting to measure how well it maintains a ballenced charge, accidentally shorted a cell, and vaporized some PCB tracks inside. I repaired that and everything was good again. However while investigating the fualt I discovered mine was a fake / knockoff, and there are apperantly a lot of fakes going around.

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iceng
iceng

Answer 3 years ago

Thanks.

Hate knockoffs, they like to fault when you need them most...

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iceng
iceng

3 years ago

No safe way, unless your skill set includes individual uP application to protect each Lion batttery.

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1000Reasons
1000Reasons

Answer 3 years ago

What is the ost safe way, except that? Application of individual uP's is possible, what size should they be? What other kind of battery "system" would you recommend instead?

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iceng
iceng

Answer 3 years ago

Four pin uP ICs are low cost watch temp, voltage and limit current with some FETs or stop and signal a string of batteries to replace...

That is what the electric car Tesla is doing except they also liquid cool the batteries..