Question Emergency starting

I have a leisure battery with a split charge device fitted. My main battery is fine but it is just a thought. If my main battery failed to start the engine could you put jump leads across the batteries if you disconnected the positive connection from the split charge unit?

yes
better to use both jump leads and leave for a while for LB to charge SB. Preferably Don't start with LB connected They are not designed for high current draw of starting. Other advice may differ. Start the car but don't fry the LB, waiting is better.

the1andonly wrote: yes
better to use both jump leads and leave for a while for LB to charge SB. ..........................

One of the problems with that approach is, if the starter battery is really knackered then it may, probably will, drag the leisure battery down when you leave it connected " ... for a while ...". or even a short while, with jump leads.

I have a 2 starter battery set up and have found if one goes, more often than not, it drags the other down, rather than the good one bringing the bad one up to a reasonable voltage, so it can start the van.

As you pointed out, leisure batteries are not designed for a instantaneous/continuous high current drain. After saying that, in an emergency situation, if I couldn't get a jump start from a passing friendee (pun intended) motorist, then I would be tempted to disconnect both leisure battery connections, jump it to the starter battery and give it one or possibly two goes. If it starts, it starts. Then remove the jump leads and let the alternator do its job on a high tickover for at least 15 minutes before you start to move off.

Rooster, correct me if I'm wrong
Is there any reason why the leisure battery cannot be the same as the starter one, with both rated at the same capacity? 85/95/100 or other high Ah that will physically fit in the trays, so you may swop them over if the need arises? Seems, to me anyway, to be a simple emergency precaution.


Regards,

Peter

You can purchase dual purpose batteries with quite high cranking CCA, then you have the best of both worlds.

PS, you are stranded simply use the leisure battery as suggested, IE connect both batteries leave for 5 minutes then start.

Thanks for the replies - very informative (for me) things I didn't realise.