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recharging a custom-made battery pack

Is it possible to recharge a custom-made battery pack?

Details:

I've used a four-AA batter case from radio shack to build a battery pack for electronic devices (walkmans, MP3 players, digital cameras, etc.)

Every time I need to reacharge the batteries, I must unscrew the batter case, remove the four AA Energizer 2500mah batteries, place them in a charger, and then reassemble everything several hours later.

I would like to be able to find a way simply to connect the battery pack to a standard 5-hour battery charger. I figured I could do this by creating some kind of dummy battery with leads connected to the battery pack. The dummy battery could be placed in one chamber of any good quality battery charger that senses when to turn off oro trickle charge.

My big question:

Is this possible without creating any special circuitry?

Thanks for the help.

Edward

Reply to
esantoro
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You won't need any special circuitry, but you have to get the right charger. You have a 4.8 volt 2500 mAH battery that you need to charge. Is it Ni-Cad or NiMH? Find a charger for the same kind of battery.

Reply to
kell

if you can find a charger that will charge the 4 cells while they're connected in series it is,

many chargers only charge pairs of cells.

Bye. Jasen

Reply to
Jasen Betts

Thanks for your replies.

I've got a good battery charger that will charge AA, D, C, and AAA of any mah. It charges pairs in series, but I don't see why it wouldn't charge 4 batteries in series; it will just take double the time.

ES

Reply to
esantoro

The problem is the 5 hour spec. If you are willing to go for

14 hours, you can make a charger with 4 parts: an LM317 IC, R1 a 5 ohm 1 watt (or higher) resistor, D1, a 1N400x diode and a heat sink for the LM317, plus a 12 V wall wart.

in ------- out

+12 -------| LM317 |-----+ ------- | |adj [R1] | | D1 +---------+--->|--- To Battery plus

Gnd ------------------------------ To Battery negative

You can add a mechanical timer and plug the wall wart into it if you want, to set the charge time to

14 hours. The charger is designed for 2500 maH cells. Do not use it for cells of a lower rating.

Ed

Reply to
ehsjr

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