Connecting a battery isolator to battery banks

[Miker]

I have a starter battery and a services battery pair, with each set of batteries switcheable between the starter motor and services. The system is managed by an Adverc system with a Powerline battery isolator. One of the two outlets from the battery isolator is connected directly to the services battery pair. The other outlet is connected to the starter motor and normally to the starter battery by the existing cable.

I have now realised that if I run the engine from the services batteries with the starter battery switched to services, or to Off, the starter battery will not be connected to the battery isolator. To avoid this, can I break the connection between the battery isolator and the starter motor and, instead, take the lead directly to the starter battery?


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[andyball]

If your powerline battery isolator is one of here & <A target="_blank" HREF=http://www.adverc.co.uk/technical/technical-twin.asp>here</A> which may help, but note that by "isolator" adverc & many others mean a battery switch & call something like the powerline isolator mentioned above a diode splitter or diode block.


There's a number of ways to achieve the required result....I presume you're concerned about charging the starter battery having started the engine with the domestic bank?. In many cases you'd switch back to normal after starting (assuming the switch is a make before break model) so the situation shouldn't arise for long.

Some sources recommend an isolator(switch) for each batteryso that any battery bank can be easily disconnected from everything in the event of battery failure or short circuit. Lockable switches are avilable so this isn't done by inexp. crew....& switches can be bought that won't damage the alternator even if switched off with the engine running.

If you've got broadband or you're patient? the 12V bible free download mentioned a few posts down may help too.

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[Miker]

Re: Thanks for the detailed advice

Yes, the Powerline isolator is as you describe. My wiring is a bit like the Adverc Ideal 2, and I want to take the + lead from the isolator direct to the engine battery instead of to the starter motor.
From their construction, I don't think that the battery switches are "make before break" so I don't change the switch position once the engine has started. Just a thought, would it damage the alternator if I switched the batteries around while the engine was running, given that the service battery bank is directly wired to the isolator?
I can't get Broadband yet. It's due in March so I will wait awhile to download the 12V Bible.

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[andyball]

Re: Thanks for the detailed advice

Can't imagine there'd be a problem reconnecting the starter battery once running.

Usual fear with battery switches & running engines is dis connecting the battery + frying alternator electronics

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