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SmokChsr
Who let the magic smoke out?
Premium Member
join:2006-03-17
Saint Augustine, FL

SmokChsr to lutful

Premium Member

to lutful

Re: PSU's and DC-DC convters or Is There An EE In The House!?

said by lutful:

The exact time when charger needs to move a particular battery pack from constant current mode (CC) to constant voltage mode (CV) will gradually drift apart.

The packs I'm working with the protection circuit in the battery pack does all the decision making for the pack. All the pack wants from the charger is the proper voltage to charge with. After that the circuit will do all the cell balancing and even cut the charger off if it allows the voltage to get too high. Since my charger doesn't even approach 1C, I don't know if they will regulate the charging current to keep it from getting to high.

With a 40A charger that should put him a bit above a 2C charge with 6 packs connected. Even worse it could try to go above 10C if only one pack is connected.

PS I'm using 8cell 10AH packs for ENG lighting. Replacing the old standard 24 cell 4000mAh NiCad battery belt. Ahh so nice 3X the run time and half the weight.
lutful
... of ideas
Premium Member
join:2005-06-16
Ottawa, ON

lutful

Premium Member

said by SmokChsr:

The packs I'm working with the protection circuit in the battery pack does all the decision making for the pack ... don't know if they will regulate the charging current

Yes. Since I usually quote Linear Tech, let me try Texas Instruments this time ... bqSWITCHER™ series are highly integrated Li-ion and Li-polymer switch-mode charge management devices ... high-accuracy current and voltage regulation, charge preconditioning, charge status, and charge termination, in a small, thermally enhanced QFN package

»www.ti.com/product/bq24100

Of course, RC li-poly packs do not incorporate such ICs and brute-force parallel chargers can't adjust the charge current for each pack.