High amperage lithium ion charger?

BatteryCharger

Flashlight Enthusiast
Joined
Jun 5, 2003
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The crazy guy next door
I'm planning on stuffing 11.2 amp hours of lithium ion batteries into a lantern of some sort. I made my own charger out of a cell phone charger for other lithium ion batteries, but it only charges at about 400ma. That would take 28 hours to recharge this pack. /ubbthreads/images/graemlins/icon15.gif

Anyway, does anybody know of a charger for something else I can hack apart, or a charging chip that's *SIMPLE* to use that will allow me to charge at a few amps?
 

VidPro

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Joined
Apr 7, 2004
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5,441
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Lost In Space
well yes and no as usual.
i learned THIS, if you regulate the power going to LI-ION batteries to 4.25 , you can charge them without causing venting (all US li-ions disconnect Permafuncktly when they vent bisturds)
So IF your just packing 3.6 single cells in parellel, here is one way you might accomplish it.
get a 6V 3A transformer about 10-12$ max
get a Kit version of a adjustable power regulator 12$
adjust the Pot so its the correct (exact voltage) then replace the pot with a resister of the same, or just leave the pot on and hope nobody messes with it.

that is the simplistic methods i would use, because my electronics skill is not so great, and also i am a cheapskate.

http://www.web-tronics.com/powsupkit.html
i get the kit here
and use kit 38 , MAX 1.5A with a good sync on the regulator.
if you put a higherpower regulator on that board, you can get to the desired 5A for the 6V 3A transformer. the regulator is another 4$

other kits there are better and cleaner, like if you get a centertap -6 +6 (12v centertap) you can get cleaner power, and mabey more.

regulating is much more simple than i though, and my next one will probably just use the chip and a few other parts, but these kits are a good way to learn, and versitile, and will take a AC current, and do all the nessisary conversion.

there is a 1.25 volt drop for the power regulator itself, and a 1.25v drop for the diodes on the bridge rectifyer, so the 6V RMS AC transformer should just pull it off?? i usually use a 12, but am outputting 10.6-8

IF your Li-ION batteries are in SERIES, then your screwed without a circuit thing in there, because if one battery goes over the 4.25, because the other part of the pack is at 3.75 , then it will vent and you lose :-(
but i assume you have a mondo 3.6, which is what i am working on, to run lotsa leds with no bs.

other notes:
the 4.25 was told to me here, after i burned out a few at 4.5, some had no problems, some died, then i learned what it is REALLY supposed to be this 4.25, and 4.3 worked fine on all of them too. just depends on the manufacturer and stuff.

anyways i hope some of that helps.
 
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