twin battery to leisure battery - a quick conversion?

[tom wharf]

I have just bought a northern japanese van with twin batteries. in three weeks I go on my honeymoon in it, highlands and islands. I am a bit short on time (and cash) what with the wedding and all.

Is there an easy way of sacrificing one of the twin batteries as a leisure battery when we stop on a secluded beach somewhere (i know that deep cycling a 'regular' automotive battery will trash it) whilst making sure we always have enough charge on the other one to get our self going?

Is it as simple as physically disconnecting the chosen "starter" battery when we park up? does it matter which one of the pair we choose?

Cheers all,
Tom

[francophile1947]

You can do it by fitting an isolating switch to the positive terminal of the passenger side battery http://cgi.ebay.co.uk/Battery-Disconnec ... 35a86a4554
You then need to modify the fuse box wiring so that interior lights, radio etc work from this battery. I used that method for quite a while with no problems - just follow Pippin's instructions that I posted on this thread http://www.igmaynard.co.uk/bongo/forum/ ... in#p304148.

[tom wharf]

Thanks John

[dave_aber]

Why not just disconnect the negative lead from the 'starter' battery when you park up?

No danger of things going spark in the night, and the S/B will stay full overnight. If the 'leisure' battery is flat in the morning, disconnect its earth lead and reconnect the S/B one. Once the engine is running, reconnect the L/B earth to make sure it charges as you drive.

[Simon Jones]

Bear in mind that two batteries connected together, effectively provide twice the current, so assuming they're both in good condition, you should have a bit more power in reserve once the voltage has started to drop after a few hours of use. Another thing to factor in is that (as far as I know) the starter motors are more beefy on the winter pack version, so require more current to start the engine. By disconnecting the second battery, it may make it harder to start.

[tom wharf]

I noticed that the starter motor is quite shiny, i am assuming replaced recently; How would I tell if it is a winter pack starter motor, or just a plain old everyday one?

T-wharf

(ps - thanks all for your responses!)

[scanner]

. Another thing to factor in is that (as far as I know) the starter motors are more beefy on the winter pack version, so require more current to start the engine. By disconnecting the second battery, it may make it harder to start.

But not by enough to make any serious difference.

[mikeonb4c]

. Another thing to factor in is that (as far as I know) the starter motors are more beefy on the winter pack version, so require more current to start the engine. By disconnecting the second battery, it may make it harder to start.

But not by enough to make any serious difference.

I reckon that right as its the load the engine puts on the starter motor that more than anything determines the current it draws. The bigger motor is simply capable of drawing more current to produce more power if needed by e.g. a stiffer to turn (think 'cold weather, thick engine oil') engine.