400/4 Battery not charging

[THUNDERDOWNUNDER]

Ideas needed for fix . At the moment I have to charge my battery off the bike . Fully Charged it lasts about Half an hour . Starts on the button then looses power fast no starter and indicators stop . If I fully charge and leave it over night it drains . So what’s wrong Guys ?

[Bryanj]

Most likely is corroded connectors then regulator then rectifier.
You need a decent multimeter and a methodical approch to sort out electrical problems

[SteveD CB500K0]

Good place to start:

Place voltmeter on battery terminals and start engine. Run up to 4000 revs.

What voltage do you see?

[THUNDERDOWNUNDER]

At 4000 rpm it’s readin 12.41.  At tic over it’s 12.34  .

[Johnwebley]

How old is the battery?
Get it load tested

Sent from my SM-A750FN using Tapatalk

[SteveD CB500K0]

That’s nowhere near enough.

When you charge it off the bike, is it the same?


Sent from my iPhone using Tapatalk

[THUNDERDOWNUNDER]

The battery is only a few months old . So don’t think it’s that . When I bought the bike a few years ago the owner said there was a short somewhere . I have put a new wiring loom on . So it’s down to the generator or regulator/ rectifier

[cooleronthecoast]

It does sound like the charging system is at fault, as Steve says you should be seeing a much higher voltage than you are at 4000 rpm

[THUNDERDOWNUNDER]

With the battery loosing power over night where is the short ?

[Bryanj]

Disconnect the 3 wires from the regulator, with ignition on check voltage at black reg wire with ignition on it should be same as battery voltage.
No more instructions till that andwer posted

[Moorey]

What kind of battery is it. If your battery has been deeply discharged several times it could well be knackered now. Remove it from the bike and fully charge it. Remove charger and leave it to stand for a couple of hours to settle out.  Then check voltage. Leave it to stand for at least a further 24hrs and check again the battery voltage. It should be between 12.7 to 12.5 this is for lead acid and gel type. Batteries can collapse inside and take on any charge given but not store it and at the same time will cause low voltage readings at the posts when checking with the engine running. Also decent voltage readings alone do not always mean a healthy charging circuit as you can have good volts but may only be getting milliamps to the battery.

[THUNDERDOWNUNDER]

Thanks BryanJ  I will give it a go latter today if I can get a chance . I will be away for the next week so will get back to you as soon as . Rob .

[Bryanj]

No problem, i work nights so you get answers at odd times! Easier to give you 1 test at a time even though it will take longer

[THUNDERDOWNUNDER]

Great stuff thanks for the help !

[THUNDERDOWNUNDER]

Back now . Tested as recommended . Wires off regulator . ignition on .  test came out at 0.07 volts Battery was 13.10 volts . That was testing black wire only Black wire from multimeter to black wire from regulator and red wire from multimeter .
to positive on battery .