Lion charger high current

[unblockgames]

@eevblog I am attempting to make a very large lion battery backpack somewhere between 60 to 120 ah. I don't want it to take a week to charge, haha. So I'd like to design my own charger circuit. I have watches your videos on lion charging but they don't go into the details of the charging module and I would like to redesign the inner workings of a charging modules so as to handle my very high current needs. I understand the genre concepts of op amp current limiting but I need a bit of .... reinforcement if you will. Please help.

[senso]

All the cell will be in parallel?
If not, you will need cell balancing..
And some/lots of temperature sensors if you pack the cells together.

[unblockgames]

10 cells parallel per pack, 3 packs in series for 12v for discharge, circuit will put packs back in parallel for charging (essentially balancing every charge cycle)

[chota.sanjiv]

First of all you will need to add some balancing circuit so that the cells connected in series can be protected from overcharge and over discharge. Depending on your application you can used active balancing (using energy from fully charged cell to charger others) or passive (dissipate the extra charge as heat) you can check solution from TI and LT for these. For charging unfortunately there is no ready made chip that can do that job, at max the li-ion charger chips can give a 10A current but not more, you will have to use off the shelf li-ion chargers or design a new one yourself.   The below link may help

http://liionbms.com/

[james_s]

I recommend against designing your own charger. There are good high power off the shelf balancing chargers available for RC aircraft and other toys. Look at Revolectrix products http://www.revolectrix.com/cat.chargers.htm They are highly regarded chargers. Most guys use a pair of converted hot swap server power supplies in series to power them. The LiPo packs typically don't have any sort of internal protection or balancing, they have a balance tap that the charger uses to monitor the cells.