Battery 3 position isolator switch

[dualin]

I am trying to find a wiring diagram for a 4 position battery switch as mine has BATT1 BOTH BATT2 OFF . I have 2 batterys 1 for domestic and another for starting but i can start my engine in all possitions except OFF. Is this right ? thanks for the help

 

[halcyon]

Yes.

It is only a selector switch, allowing you to use either battery or both. Your engine and domestic power come from the common switch output.

Brian

 

[LadyInBed]

If you are not sure which is which, disconnect one battery (+) connector and see which switch positions allow the electrics to work.

 

[MoodySabre]

Most are the same. Just a question of discipline - I use Batt 1 for starting only and Batt2 for domestic. In the event that Batt 1 gave up then at least you can use batt 2 for starting. The selector also controls which battery is being charged when the engine is running.

 

[tomainsley]

yes its normal. You'll find that your battery for starting the engine will have rather higher cranking amps than your service battery, and that you really don't want to run it down by using the fridge or something (or else you might not be able to start). So find out which number does which battery and try to avoid running household loads off your engine battery.

 

[FullCircle]

 

[dualin]

Thanks All for a speedy reply and thanks to Mr FC for the diagram
straight away from the diagram i can see what the muppit before me has done they have wired the batteries together +to+ and -to - i now know what i am doing tomorrow. Again thank you all /forums/images/graemlins/grin.gif

 

[pikeyrm]

only use both for charging

 

[Gaz22]

hi, Halcyon

fitting a new selector switch myself this weekend, you say its just a switch can you switch between the batterys when the engine is running?? you also say to take your domestic power from the common pole along with the starter cable could this not cause problems, if instruments are being used when sailing and you need to start your engine?

/forums/images/graemlins/confused.gif

 

[halcyon]

It is only a switch, it allows you to connect to battery 1, battery 2 or both.

So you have to have both engine and domestic loads on the output pin.

You can select say battery 1 for start, but both are supplied from battery 1. You cannot supply domestic from say battery 2, while at the same time starting the engine from battery 1.

This is one of the reasons we started making split charge relays. You have engine and domestic loads supplied from different batteries at the same time. So engine starting has no effect on nav equipment.

Does this make sense ?

Brian

 

[LadyInBed]

Normally yes because the contacts in the switch are 'make before break' (going from 1 to Both, the Both contact is made before the 1 contact is broken), ( same with Both to 2).
You should NEVER go from 1 to 2 via Off when the engine is running as it can knacker your alternator.

 

[Gaz22]

Halcyon thanks for replying, get the general idea from your post with a little help from your website, will see my local marine sparky for split charge relays on monday, if he has nothing will order from yourself.

thanks Garry