Split charge relay fuses melting

[ncmcdonald]

I have setup a split charge relay using a 30a voltage sensitive relay between the starter battery and the relay isa 25a fuse and the same with the leisure battery.The problem is these fuses seem to be getting hot and melting the plastic on top but not actually breaking so it is actually working still but not ideal.

Has anyone got any suggestions.

Thanks

[moonshine]

In my opinion those ratings are way too low, and it is this that is causing the overheating. Your alternator is capable of pushing out way in excess of 30 amps, and if one of the batteries is well down, the output from the alternator is going to be high, initially at least.

I personally would not use a relay of less than 60 amps (preferrably 100 amps), and battery fuses of 50 amps. That way they should not run hot.

[Aethelric]

I agree with moonshine. There is slso the possibility that your relay has welded closed and the leisure battery is supplementing the starter battery when you start the engine. The current would be well over 25A, but not on long enough to blow the fuse.