Always good advice there, but the OP asked for simple and cheap. He didn't mention "accurate" or optimal. Depending on the details of his adapter, it might in fact be ideal for the simple and cheap criteria. A strategy taking a nominal 12v battery to 12v, as you noted, doesn't give a full charge, but it's close and unlikely to overcharge. That may be good enough. On the other hand, his adapter might be 12v at rated current and more like 16v or so at open circuit. Devil in the details....and come back with more questions.
I assume that the battery is 10 cells so the maximum voltage for charging would be 10 x 1.5V or 15V. If you use the 24vdc adapter, us a LM317 as a constant current charger @ AH x .095(1.5 x.095=0.142A) you would not have to disconnect the charger as the battery would not overcharge.hello
is there any way to build a charger to charge a 12v 1.5AH battery?
i have a 24vdc @ 0.417A ac/dc adapter and a 12vac @ 0.4A adapter.
please and thank you
Yeah, your right, I got the chemistry wrong and suggested a float charger voltage regulator for a Lead-Acid Battery! Thus the sulfation issue is not present and 14V - 15V is fine.He's charging a Ni-cad. Taking a Ni-cad cell to 1.2v or ten of them to 12v, is not so ridiculous, IMHO, if the charger is "typical" (unregulated) and actually gives something a bit more than 12v at low current.
Electric drill batteries generally incorporate a thermal switch that indicates to the charger when the battery pack is getting too warm. The switch connection is generally separate from the battery terminals; there are 3 terminal connections to the battery.will the constant current LM317 charger work for a drill battery?
Charge time depends on the AH rating of the battery, the charge current, and how deeply the battery was discharged.is this charger a 10 hours charge?
Schematic of the battery? Or the current regulator?is there a schematic? i'm not really sure how to wire it..
The output current can be affected by a number of factors. One is the input output differiential, another is the temperature of the 7815. Although it is classed as a 1A regulator there are conditions when the output current can be greater. The way you have it wired the output voltage will be somewhere around 9V as the there will be about 15V dropped across the resistor connected between the adjust terminal and the output terminal. There will also be a voltage drop between the input and the adjust terminal.With this configuration, 1.83A from a 1.0A regulator???
Perhaps R should be 100 ohms....!
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by Luke James
by Luke James