Battery / Charging problem.

[gerbrox]

Wandering if someone can give me a bit of advise.

I've had a battery / charging problem for a while omnths on and off to be exact. I managed last night to get the bike jumped, when the battery wouldn't start the bike, the battery was 12.4 volts across the terminals before, when the bike started it was down at 9.6v, that was as I had the generator coupler disconnected at the time, when I connected up the coupler the battery read 14.5v.

The question is, is this enough info for someone well more experienced than me to advise if the generator is trying to charge the battery or not?

[yorkie_chris]

Yes if it's showing 14.5v then it's alright. Rev it to 5krpm with the lights on and tell us what voltage is then.

Silly pointies draw quite a bit due to fuel pump etc. so voltage will be low running it without generator. Not sure it would be as low as 9.6v though.

[gerbrox]

It was 14.5v at 5,000rpm or very close to it.

[hovis]

I connected up the coupler the battery read 14.5v.



It was 14.5v at 5,000rpm or very close to it.

so.........

did the volts go up when you revved the bike?

[gerbrox]

I'd probably need to run it again later tonight but I think it did flicker up to around 14.6v.

I get the impression to establish if charging the volts should go up and be noticible very quickly when at 5,000rpm.

[yorkie_chris]

No. Should be a relatively constant 14.5ish ... you tend to find the volts actually drop as you rev it. Like the regulation gets more accurate with higher frequency. Kinda. Above 15.5v is a problem though.

[thefallenangel]

sounds like the battery isn't holding charge to me or am i missing something?

Battery without it being connected to a generator should still give out 12.6vish because it's the charge that drops. Am i missing something?

[Sid Squid]

Not sure it would be as low as 9.6v though.
Can be when the alternator is out of circuit and the battery is a bit low - pointies ain't got no light switch.

OP: Info given thus far suggests charging is good. You need to do a leak test to ascertain the charge is staying in the battery when the motor isn't running. Turn off the ignition and take the key out - this test must be done with the bike turned off. Disconnect the battery negative terminal and connect an ammeter between the battery terminal and the negative lead, ideally there should be no current flow but in reality it's not unusual to find a few milliamps, but only a few - it really should be very low.
If there's no significant reading then the battery is your prime suspect. If there is a reading do you have any additions to the electrical system - heated grips or suchlike? Disconnect them and try again. If no remedy then disconnect the regulator/rectifier, does the reading reduce significantly? If yes, then the rectifier diodes are leaking. If no then a wiring fault is possible.

[gerbrox]

UPdate: Couldn't get the bike jumped last night!!!!!

I have set the battery on charge and will try tonight to start and get teh reading posted tonight all going well.

Sid,

I have tested the leak and the readings were low if anything, again I'l try again tonight just to be absolutely certain.

[gerbrox]

Okay battery charged via mains, following data.

13.46v before connecting up to bike.
12.06v Bike started without the generator coupler connected.
13.43v av, With generator connected, the readings does fluctuate.
14.48v recorded at 5,000 RPM does not move at all.

Tested the battery for leaks and the reading was 0.

[Sid Squid]

Did you get that battery reading immediately after disconnecting from the charger? If yes then it won't be a reliable reading - the voltage will be a bit high and to get a realistic reading you need to let it settle for an hour or two, or you can connect a headlamp bulb to it for 5-10 mins to get you a more real world reading.
If you didn't then the charging isn't good at very low revs, it may not be a great reading at tickover, but it should be a dab higher than battery voltage alone if all is well.
That said, the rest of your figures suggest the charging is good, and the leak test result certainly points at the battery being the weak link.
All the above assumes, as I must from a distance, that your testing and test equipment is accurate, I'm sure it is but obviously I don't know what meter you've got and how good it is for instance.

[gerbrox]

Cheers sid,

Just wandering on a couple of things, if there is a 0 leak does that not mean theres no earth fault?

The battery seems to chage off of mains okay.

If the batterry is completely dead woudl have it charged at all from the generator?

[gerbrox]

I have now managed to check the generator laod performace and accross all points I get in excess of 60v DC which suggests it definately is the battery andnow ordered new one!!