wiring diagram

Stemar

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I reckon you'd be better off using a relay. Diodes usually drop the voltage a bit so your batteries won't charge as much unless you do clever things with the alternator. If you use a voltage sensitive relay, the system will charge your engine start battery until it reaches a good state, then start work on the domestics. I use an ordinary relay on Jissel, 'cos that's what I had left over from the dynastart system when I re-engined, and I've never had a problem. It just means the flatter battery gets the lion's share until it catches up with the other one

PM me an email address and I'll send you a circuit diagram.

Doubtless someone will be along in a while to explain why you need some Adverc or Stirling kit for loadsamoney, but my simple system works for my simple needs.
 

William_H

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As said a Voltage sensing relay is best. Diodes will drop so much voltage that no battery will get a decent charge.
Essentially the engine battery is wired up for just the engine and accessories.
The service battery is wired up for all the other services.
The negative terminals are connected together with heavy cable. ie for start current.
The positive terminals are connected together via the VSR. Both systems remain isolated except when enhgine is running and charge voltage has risen then service battery is connected to be charged.
Emergency start can be done with jump lead, via the VSR(if so rated) or via an extra switch for jump start. good lcuk olewill
 

john_morris_uk

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[ QUOTE ]
As said a Voltage sensing relay is best. Diodes will drop so much voltage that no battery will get a decent charge.

[/ QUOTE ] Whilst that is true, we circumvent this problem by having a sensing wire direct from the battery to the alternator controller. The alternator is forced to make up for the voltage drop across the diodes and we have no mechanical relays to go wrong. (And we carry a spare diode splitter in case that blows up!)

I know lots of people swear by Voltage sensing relays, but there is more than one way to skin a cat. Splitter diodes got a bad name through people ignoring the voltage drop problem. Allow for it (there are other ways than the method we use) and either system is fine. I am not sure that anyone can say which one is BEST.
 

lw395

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I would tend to vote for a diode solution on the ground of no moving parts. But a VSR can be a good solution.
Its more important to have whichever it is properly sorted for the boat's needs than to choose VSR or diodes.
 
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