At 09:01 AM 4/9/2005, John J. Riddell wrote:
>I'd agree with Royce, W3IF. I too had a power supply across my
>battery bank for my
>sump pump. It was a really nice Hewlett-Packard 6264B adjustable 0 -
>20 volts @ 20 amps.
>
>One day after switching off the AC, the power supply started to smoke !
>
>Upon investigation, it was repairable since only a 5 watt resistor
>burned up in the
>crowbar circuit. I soon added a large diode in series with this
>supply in the positive
>lead feeding the battery bank.
Now think about that for a minute. The supply is designed to output
20V, yet it's crowbar triggered on 14.5V?
Something else went wrong there, you had some transient on the bus.
>Never again will I use a power supply directly across batteries
>without a series diode.
Well, I agree the crowbar needs to be set to something reasonable,
and have enough delay to allow for switching noise not to trigger it.
The diode is fine by me, but I wouldn't give up the fuse. I would
also move the voltage regulation input to the battery, and let the
supply remote sense it, rather than dialing it out. You loose load
regulation that way.
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