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Ivan Ivan is offline
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Default Battery charger shorts out?


"redwood" wrote in message
...
The brother-in-law has an old car that he wanted to take to the breakers
yard and asked if I could charge the battery. It had been stood for
several months without starting so was flatter than a witches tit. I
measured the voltage at the terminals and it read 1.6volts. I said it
may be too far knackered but would give it a try. I have 2 battery
chargers, one is a new 3 phase charger from Lidl and the other a donkeys
years old basic 6amp charger with switchable 6 or 12 volts.

I tried to charge using the new 3 phase charger but it would not even
come out of standby mode. I then tried the old 6amp charger and when I
switched it on the needle on the amp meter started to rise & rise and
went completely off the scale. It was only connected for a few moments
and when I measured the battery voltage it now read over 13v so I
disconnected the old charger and reconnected the new 3 phase charger and
it now went into charge mode and was fully charged about 15 hours later.

I think this has damaged the old charger as when I now try and connect
the charger leads to a battery it causes a short with loads of sparks
(this is before the charger is switched on). If I switch on the charger
without the leads connected the charger makes a clicking sound as though
it's continually cutting on & off. I'm guessing that trying to charge a
battery so flat has forced more current from the charger than it was
designed to give? Before I take a look inside (or bin the thing) I just
wondered if anyone had an idea what might have gone kaput.

Older battery chargers are usually very basic, generally consisting of a
mains transformer, rectifier, ammeter, and a fuse... I'd guess by the sound
of it that the rectifier has gone short circuit.