Electrical output

[Austin]

Any idea what sort of spare output I should have from the alternator?

The reason i ask is that when running with my heated vest on the low voltage warning lights on my heated grips switch comes on. It's a bit weird though: when I first start the bike, when you would expect the battery to be slightly discharged everything is fine and the warning lights don't come on even with every electrical item going. Once it warms up though the warning lights will come on intermittently at any revs and at low revs or with any other item on the switch detects low enough voltage to switch the heated grips off altogether. It could be the switch I suppose. I also suppose this hints at R/R but it was supposedly replaced last year when I was having other electrical problems.

How do I check R/R output? Is it just a case of putting a voltmeter across the battery? I assume I should get 14 volts or so all the time no matter what load is on???

[Austin]

Just got off my arse and looked it up n the Haynes manual. The charging system checks look to be pretty straightforward so will have a go one evening this week.

FWIW the alternator output is 0.315Kw at 5,000rpm.

Regulated output is 13.5 to 15.5 volts at 5,000rpm.

I think this means that with the ignition off I should about 13.2v at the battery. With engine running I should get 13.5 at low revs rising to 15.5 max at 5,000rpm.

The only fix for the R/R is to clean the connections and I assume also clean the heat sink.

I think this also means the bike has about 100watts spare for accessories - based on say 120watts for head and tail lights, plus say another 100watts for fuel pump, fuel injection, ABS pump, ignition, speedo, tacho, etc etc. It's not a lot spare really.... Heated jacket = 50watt, grips 25watts. Add in the wife's heated vest and I am discharging the battery. Hmmmm

[africajim]

Austin mate, with that kind of load you're going to be spending a lot of money between R/R and alternator windings, the max output of the alternator isn't the usable amount of power it's the max!
I personally wouldn't be loading mine to the max with gadgets, if it's that cold just stay at home mate, or take the car!

[Austin]

Austin mate, with that kind of load you're going to be spending a lot of money between R/R and alternator windings, the max output of the alternator isn't the usable amount of power it's the max!
I personally wouldn't be loading mine to the max with gadgets, if it's that cold just stay at home mate, or take the car!

I know, but a heated vest and heated grips ain't exactly an extensive set og gadgets.

Just a thought, if I put my ammeter between the earth lead and battery earth I should a read out of actual power consumption shouldn't I? Is this safe to do? I don't really know about this electric stuff.

[africajim]

With the lights and the vests taking over 200w of power I think the alternator will be struggling to maintian the electrics of the bike, yes a meter set on amps will tell you the bikes power use.
One vest maybe but two? Too much I thinks. This will also put the bikes petrol consumption up as well, the alternator will drain power from the engine. I would have thought you could have ECU problems as well when the voltage starts to go down? Tigers suffer from that, they run like dogs with low voltage.
I recall Robster having a heap of gadgets on his Varadero over in Spain, in the morning he had to get a jump start from a fellow camper to get going! Lucky he wasn't middle of nowhere with nobody to jump start him eh? Just pointing out the pitfalls of battery abuse! Sorry!

[StumpyFingers]

I think you will find the lights using about 140 watts, add to that the grips, 40 watts, FI and pump another 20 watts, that is 200 watts and the vests ?

To work out the wattage check the fuse size and multiply by 12.
Headlights use a maximum of 60 watts each x2 = 120 / 12 =10, fuse therefore 10 amps. this can be used to calculate the maximum usable wattage and also the fuse size needed for a particular circuit.

[Austin]

Here's a link to a brilliant guide on fault finding in the charging system. http://www.offwidth.co.uk/bike/gener...lt_finding.pdf

[Lutin]

I know, but a heated vest and heated grips ain't exactly an extensive set og gadgets.

Just a thought, if I put my ammeter between the earth lead and battery earth I should a read out of actual power consumption shouldn't I? Is this safe to do? I don't really know about this electric stuff.

Hmmm, you'd need a fairly big ammeter capable of measuring in the region of 30 Amps. Not your usual household variety multimeter, I'm afraid. I have one that tops out at 20 Amps.

Going from your figures, alternator output 315 Watts / 12 Volts gives just over 26 Amps.

Even if you take the voltage as higher than 12, say 14 Volts, this will still be 22.5 Amps.

Just a word of warning.

[Austin]

Hmmm, you'd need a fairly big ammeter capable of measuring in the region of 30 Amps. Not your usual household variety multimeter, I'm afraid. I have one that tops out at 20 Amps.

Going from your figures, alternator output 315 Watts / 12 Volts gives just over 26 Amps.

Even if you take the voltage as higher than 12, say 14 Volts, this will still be 22.5 Amps.

Just a word of warning.

Yeah I had thought about that, mainly though about how do I start it with the ammeter attached coz that will be a damn sight more than 30amps.

My multimeter is a B&Q special so probably very average in performance.

[Lutin]

Yeah I had thought about that, mainly though about how do I start it with the ammeter attached coz that will be a damn sight more than 30amps.

My multimeter is a B&Q special so probably very average in performance.

Very good point. Will have to think about that one.