Voltage Sensitive Relay (VSR) position

[warrenpfo]

Does it matter where in the system i place my VSR. Is it best to have it on the other side of the fuse straight after the battery in the engine bay or can i put it just before the Aux fuse box under the dash and so out of the elements.

It cuts out at 12.8 volts to stop the aux fuse box running the battery down.

 

[Gary Stockton]

As long as the cable is a decent size to prevent excessive voltage drop (the thin cable to the VSR, not the power cable) you should be ok either way. I've got mine wrapped in heat-shrink against the firewall in the engine bay and its been happy for a few years now.

Cheers


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[warrenpfo]

Cheers Garry. I'm using 200amp jumper cable no more than 1.5m from battery to aux fuse box. The fuse box has a max draw of 100amps but can't see me pulling much more than 50amp at any one time.

With the VSR cutting off at 12.8v my only concern with it at the end of the cable is that it might not enough volts to even come on but will connect the cables and turn the engine on and check the voltage and see what we have to work with.

If not enough then I might be forced to have it closer to the battery to get it to switch over.

 

[Gary Stockton]

Warren - it's only the sensor wire you need to worry about over that distance (and that should be a tiny little thing, just checking voltage and not carrying a load) - but if it's too piddly you may get enough drop-off to fool the VSR into not opening up when it should.

The load-carrying cable you should have at 25mm or more, I guess, depending on distance / drop-off and current draw. There was a calculator somewhere ...

Cheers

 

[warrenpfo]

Quick question.

Would i be ok using cable rated to 16 amps to run from my carling switch to a solenoid or does it need to carry more load?

 

[Chris]

Warren, I'd think it unlikely you need 16 amp cable to switch a relay. It won't hurt, but 16 amps is a lot. Not sure what a Carling switch says it's capable of handling.



Chris

 

[warrenpfo]

Switch can handle up to 20 amps and the cable is thin wall so its only 1mm thick.