"Dave Plowman (News)" wrote in message
...
In article ,
Eddie wrote:
My car battery is oversized for the car. The battery is a bit old
but usually works fine. The battery is flat (I left the lights
on).

My fancy new modern charger senses a poor battery and only puts in
very little charge.

I used to use a really old charger to charge this battery
successfully. I opened up the old charger and saw it was only a
transformer and a big rectifier. That's it. No soothing.

Is this ok for a car battery or is it way too crude?

An ancient crude charger is actually quite good at recovering a flat and
possibly sulphated battery - it will output quite a high voltage with a
high impedance load, which is needed to help combat the sulphation.
However, after the battery has started to take a reasonable charge rate,
ditch it and use your modern one.

I keep one just for that purpose & then connect the new fangled smart
charger soon as the batt can take it. From experience though, if connecting
a totally flat batt get ready to switch off the old charger before the
needle goes off the scale followed by a big bang as the bridge rectifier
decides its had enough!!