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Dec 03, 2003, 05:43 PM
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brian2kgt's Avatar
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PC power supply amperage for Apache charger??

I ordered an Apache 1215 1-2 cell charger to charge my E-tec 1200 2s1p pack. The charger requires a source that can supply 1.5 amps at 12V. And I would be charging at 1200mah (1.2A), correct?

My question is, would a PC power supply that is rated for 2A at 12V be sufficent? I thought so until I read this response to someone asking about an Apache 1500 1-4 cell which also requires 1.5A at 12v...

"What's more important is the 12V amperage rating. The absolute minimum you need is 6 if you're charging at 1 amp."

If the above is correct, why is this? What am I missing here?
Last edited by brian2kgt; Dec 03, 2003 at 05:46 PM.
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Dec 03, 2003, 08:22 PM
Nimble with Gimbals
You're cutting it very close. I threw out a ballpark figure according to my voltmeter readings indicating that there was a fairly large overhead on my particular charger. Simply put an ampmeter between the charger and the PSU to see how much it's taking from it. I imagine you could go about an amp over without doing any damage to the PSU.

FWIW, there are $10 PSU's available that will do at least 5A off the 12V rail.
Dec 03, 2003, 08:40 PM

I bought two and love them.

Dec 03, 2003, 11:59 PM
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brian2kgt's Avatar
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So what happens if the charger pulls more amps then the PS can supply? fire?

Also, do I have to connect a 5V to power good? This PS seems to be running fine with just a ground connected to the PS-on.

Here's my contraption. I was hoping I could use it so all the work wasn't for nothing. I guess I'll just have to wait until my charger gets here and see what happens.
Last edited by brian2kgt; Dec 04, 2003 at 12:07 AM.
Dec 04, 2003, 03:37 AM
Nimble with Gimbals
Neat setup. If the power supply runs under load with Power_Good not connected to anything then you're fine. One less wire to connect. If it pulls over the rated amperage on the 12V keep an eye on the heat output. If the fan exhaust feels very hot it's time to replace that with a slightly better unit. They're a dime a dozen

Neat contraption!
Dec 04, 2003, 04:41 AM
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Citrorob's Avatar
I do this for a few years now with full satisfaction.
I use one which can supply 8 Amp's on the 12v rail.
This is allowing me to charge my 7 cells Nicad's at 2,5 Amp on a Delta peak charger without heaving false peaks. I can go to the full 5 Amp capability of the charger but at the risk of false peaks. If you realise that itís not a problem because I can see how many mA Iíve charged and I just restart the charger at 2,5 Amp to finish the job. I can charge up to 30 cells but then I need to turn down the amps to approx. 0,5 amp to prevent false peaks.
Iíve seen 500w PC power supplies of which the 12v is about 50%. This means an output of about 20Ampís. With that you should be able to charge 7-8 cells at 5Ampís up to 30 cells at 1 Amp.


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