Scooterotica

hi ive got a 7 amp acid battery fitted and I have got a 7.5amp fuse on positive side and a 10 amp on negative side
does that sound right
cheers steve

Only need a fuse on the + side. You are not gaining anything by having it on the - side.

been told that its better to be fused on negative side and to go belt and braces to do both but
the negative needs to be slightly bigger than the positive
I don't know why lol just wondered on size of fuses

here you go

http://www.oznium.com/forum/topic15761


And a little ohm's law

http://www.tecks.co.uk/technicians/heal ... /calc.html

As I said on the other site, just fuse the + side just as automobile manufacturers do. I shouldn't lose sleep over it but if you feel the need and it gives you peace of mind then spend the extra money and do it. Can't see any advantage myself.
Don't use too large a fuse. The ohms law link is your guide.

Chris in Margate wrote:As I said on the other site, just fuse the + side just as automobile manufacturers do. I shouldn't lose sleep over it but if you feel the need and it gives you peace of mind then spend the extra money and do it. Can't see any advantage myself.
Don't use too large a fuse. The ohms law link is your guide.

I tend to agree with your view Chris but I can now see the logic in fusing the negative side. If the positive terminal of the battery is accidentally shorted to earth (battery side of the fuse) the fuse won't blow if it's in the positive feed but one in the negative side would. Car manufacturers ignore this potential problem I guess because it is relatively unlikely to happen with batteries safely mounted. With a Lambretta or Vespa on the other hand, the chances of the positive terminal on the battery coming into accidental contact with earth is considerably more likely and given the usual location close to the petrol tank/carb/fuel lines the potential for a large scale fire is considerable. That said, I have had a fair bit of trouble with my inline fuse holders developing high resistance with the connections for the blade type fuses so adding an additional fuse to negative side is not that appealing so I will probably move my main fuse to the negative side.

Colin