HotGrips Relay question.

Benihana · 26 Oct 2010 at 14:16

So now the icy winds are upon us, i've stumped up for some Hotgrips and on my lunch went to allparts to get the relay, inline fuse holders and some terminal blocks so I could be sure I wont leave the grips on by accident.

The only 4 pin relay the guy could find was one with an in-built blade fuse (15 amps) my question is does this negate the need for having inline fuses?

Benihana · 26 Oct 2010 at 14:24

Also mini rant for Halfords, just rang them to cancel some of the same bits I ordered last night, and they're telling me once an order is placed it can't be cancelled....errr

MatteH Oxford · 26 Oct 2010 at 20:08

15 amps is mega high! :eek:

Check the manual for your grips, modern grips use very low current & I'd fit a 5 amp fusemaximum! ( my last grips ran @ 2 amps, 3 amp fuse).

As for the relay, check to see which side is fused, i take it just the one side which should be the 'switched' high current side. If so, it can't hurt having a 3 amp inline on the switch side for extra protection.

Lumeycom · 26 Oct 2010 at 20:20

agreed 15amp is way ott. my current R+G heated grips run off 4amp.

Benihana · 26 Oct 2010 at 23:04

I think the 4 pin automotive relays are usually rated for 40amps, hence the need for an in-line fuse. The (Oxford Hotgrip Sport) grips will pull 4 amps max so I can put a 5 amp fuse directly in the relay, and upgrade later when I add a GPS charger.

The 4 pin relay has the pin layout of:

30 (has the fuse) and 87 form one circuit, and 85 and 86 make the other. I guess which ever takes the positive feed should get the fuse?

Flukester · 27 Oct 2010 at 07:51

The hotgrips come with a inline 5A blade fuse in the wiring... so even if your relay has a built in 15A fuse you are protected (short circuit / high current fault will pop the 5A). If you just had the 15A fuse, there is a possibility that in a short condition the wiring would just heat / melt and still stay under 15A... meaning risk of fire.

Rather than wire direct to battery I powered mine from the headlight loom... downside is that with both my 55w HID on and 55w main on it just about tips the circuit over it's 10A rating. (which I found out on a dark b road doh)

To cure this I took 10A fuse out of headlight circuit and put a 15A in. The extra load will easily be handled by the bikes wiring.

The above method means you can't forget to switch off hotgrips, and you don't need to faff about with a relay as you are using the existing headlight relay to do all the work

edit: I wish I had bought heated grips years back.. I don't think I'd ride without them now through winter

Flukester · 27 Oct 2010 at 08:00

nvmind