Wiring push start button

[tony1969]

Hello
I’m currently wiring a small fishing boat

It will have two batteries one just for cranking and one for auxiliaries

I’m fitting a push start button for the outboard engine

My question is should I get the positive feed from the fuse board supplied by the aux battery

Or should I get the positive feed direct from the cranking battery

Thanks Tony

 

[simonfraser]

i'd keep it 'simple' & wire all that is required to start the motor from the cranking battery

 

[tony1969]

Thank you for the reply

is there any technical reason for using the cranking battery and not the aux battery for the push start button
(Just learning as I go )

That’s a shame as the positive feed I was going to use from the fuse board which is supplied by the aux battery is inches from the start push button

Ok I will wire the push start button back to the battery with inline fuse

Thanks Tony

 

[simonfraser]

if all your electrical system is totally sound you can of course use the aux battery
but any fault chasing by a future owner is going to be more difficult that it needs to be

 

[tony1969]

Thanks again for your help

I’ve completely re wired the boat I’ve coloured coded with coloured heat shrink the positive wire at the fuse board ring terminal connection point and also the positive connection at switch or horn button etc and negative

So tracing any problem will be very easy

Thanks Tony

 

[Commercial Dave]

I also don't think any starter motor should be wired from a fuse board should it? I'm not sure what sort of current an outboard engine starter motor pulls but on a large one I imagine it could be over 100 amps?

I think even our 90hp outboards use 25mm² cable...whereas the fuse board is supplied by a 10mm² cable and is only capable of 60A total for all circuits

 

[simonfraser]

I also don't think any starter motor should be wired from a fuse board should it? I'm not sure what sort of current an outboard engine starter motor pulls but on a large one I imagine it could be over 100 amps?

I think even our 90hp outboards use 25mm² cable...whereas the fuse board is supplied by a 10mm² cable and is only capable of 60A total for all circuits

indeed, we're hopefully discussing the power feed to the starter button and not to the starter motor ...

 

[tony1969]

Hello
I m talking about taking a live feed from the fuse board to the push start button which goes to the solenoid on the outboard engine ,which opens the solenoid like a switch. this doesn’t start the engine the cranking battery does ? which is connected to the starter motor with 25mm cable

Thanks Tony

 

[simonfraser]

Yes that's what we assumed

Run your aux battery down with the fridge fishfinder etc and now you can't start your motor

 

[ChromeDome]

Best practice is to keep the crucial engine start isolated from other consumption.

How are your batteries charged? If they are connected full time anyway, you can take the push button power from any. The wire supposedly is notably thinner (as the solenoid doesn't need a lot to work) than the heavy wire that supplies the very high amp to the starter.

Both should dimensioned according to their length an the amount of power that is drawn though it. You can fit a fuse to solenoid control wire but I don't really see why?

 

[tony1969]

Thank you very much

The outboard doesn’t charge the batteries at the moment

It’s an old engine I’m looking into getting a charging kit for it

I suppose it makes more sense as the engine doesn’t charge any batteries to use the aux battery for the push start button

The batteries are connected like this picture but without the neutral bar and I have a switch panel from the fuse board

I did used an online calculator for sizing the cable based on length and amp draw

Thank you

 

[ChromeDome]

Start button not in the drawing, but at least yu have the otino to combine batteries in an emergency.

I don't see the need for a 30a breaker to solenoid though?

I guess you a planning on a cherge regime aand for that may want to revisit the drawing

 

[PaulRainbow]

Start button not in the drawing, but at least yu have the otino to combine batteries in an emergency.

I don't see the need for a 30a breaker to solenoid though?

I guess you a planning on a cherge regime aand for that may want to revisit the drawing

The 30a breaker is protecting the cable from the fuse board, which supplies all systems, it's an appropriate rating for the cable.

 

[Commercial Dave]

I would wire the start button to whatever battery is used to actually start the engines. Ideally this battery should be isolated from all other loads while it is not being charged, so that if you leave a fridge or something on accidentally, you can still start the engine later. Wire the start button with 1.0mm² cable and put a 5A fuse in it

 

[ChromeDome]

The 30a breaker is protecting the cable from the fuse board, which supplies all systems, it's an appropriate rating for the cable.

You're right - missed that angle.

 

[tony1969]

Great information thank you, Very much !

Ok so the consensus is wire push start to start battery ok I will do that with inline 5amp fuse


Thank you very much
Tony