Trickle Charge main battery

[Mini Men]

Hello

Should I disconnect the main/started battery if hooking it up to a trickle starter or can I just clip on the terminals and leave the thing hooked up for a while.

I have a Streetwise Plastic Cased 12 Volt 4 Amp Battery Charger with 2.7 Amp DC (4 Amp RMS). Suitable for lead acid batteries only.

Van lives in the garage (lucky bugger) and I can't easily reach the battery on that side when parked up.

Cheers

[bongojoe]

Yes, you can charge your battery without disconnecting from the vehicle electrics.

[jimmo62]

A related question - I have a leisure battery with smart relay. If I want to charge the leisure battery do I need to pull the fuse between the output of the smart relay and the battery to avoid damaging the smart relay or will it be OK?


Or am I just better off connecting the charger to the main battery and then will that charge both (I assume so because the smart relay should then turn on allowing the charger to charge both batteries)

[bongojoe]

Sticking my neck out as a battery expert here... (I'm not)

I don't know what type of split charger you have, but you won't damage anything by connecting a charger to the S/B. When the engine's running, the alternator is providing around 14v to the starter battery, which will feed over to the L/B - the mains charger will do the same thing.

Depending on how your split charger works, it may or may not also charge the leisure battery at the same time. Mine are only connected together when the ignition is on. It sounds like you have a voltage sensing split charger, which will only start charging the L/B when the S/B reaches a certain voltage.

The other thing to consider is that if it's a trickle charge, it could take a very long time to charge both batteries.

[g8dhe]

It will depend on how "smart" your relay and charger are, but in some cases you will find that charging the S/B will cause the relay to operate and both batteries will be charged, however NO guarantee and it may even vary between charging sessions! Smart Chargers of the mtce. variety have 3 or more states, provided one or other of the states allows the S/B to reach over 14 volts then the smart relay should operate and put both batteries in parallel to be charged but not all will do this if the S/B is pretty full then the charger may switch to mtce. mode which is about 13.6 volts and this may not be sufficient to operate the relay.