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MG MGB Technical - charging batterys

whats the quickest way of charging the twin 6 volt batterys?

is it possible to charge them while still fitted to the car with a 12 volt charger?

if you can how do i connet the leads?
s truman

You can do it with the batteries still in the car. Connect a 12 volt charger's negative to the negative lead of one of the batteries and the positive to the positive lead of the other battery. It never hurts to disconnect the ground cable, at the battery, to prevent a surge from damaging the charging system. RAY
rjm RAY

mavuless thanks for the quick reply
s truman

If you have an alternator, especially the bigger ones like the 18ACR, take it for a drive.
Many car sales just run the engine to charge batteries.
c cummins

Ray's answer could be misinterpreted.

If the car is negative earth, connect the negative lead of the battery charger to the negative battery terminal which is connected to the chassis/ground. Connect the charger's positive lead to the positive battery terminal which is connected to the long cable that goes to the starter solenoid.

If it is positive earth, connect the charger's positive lead to the grounded positive terminal and the negative lead to the negative terminal which is connected to the long cable.

Hope that helps.
Dave O'Neill 2

its a 1970 so that would be positive?
s truman

A '70 would have negative ground and use an alternator. RAY
rjm RAY

Rather than fiddling with the batteries and possibly getting the connections wrong use the purple fuse and a convenient earth point in the engine compartment. From 1967 all MGBs were originally negative earth, so positive goes to the fuse.

It's only boost or high-voltage charging with a special rapid charger where you might want to unplug the alternator.
PaulH Solihull

... and keep the hood down, or the tailgate open on a GT to venttilate the off gases (mostly hydrogen)...

The cage is open to atmosphere, unless you have fitted one of those seriously misnamed 'battery boxes'! The rubber seal on the cover should keep fumes out of the car if you use the fusebox connections for charging.
PaulH Solihull

Oh yes, for a 73 and later all you have to do is put a cigar lighter plug on the end of the charger wires! Fused, and easily accessible.
PaulH Solihull

This thread was discussed between 04/08/2010 and 06/08/2010

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