Do I really need to disconnect my battery before charging it?

The instructions that came with the battery charger I bought from Argos yesterday say 'disconnect the battery from the vehicle before charging, to avoid possible damage to the alternator'. That could have quite interesting results without a slave battery. Is this normal?

Asked on 27 September 2013 by MD, Ringwood, Hants

Answered by Honest John
Yes. You bought the wrong type of charger. You should have bought a 'Battery Conditioning Trickle Charger'. Nothing needs to be disconnected when using one of them.
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