SOLVED - CBF500 - Battery issue - Draining 0.16A

sebwin · L Plate Warrior Joined: 10 Aug 2016 Karma :

Hi,

I have a 2006 Honda CBF 500 ABS bike.
I use it about once every 2 weeks.

After 4 weeks of no use, battery was unusually dead (dashboard lights didn't even come on).
Battery removed = 7V !!!

Replaced with new, charged, battery. Bike started fine first time, but I did not ride it.

1 week later went for a ride and starter motor wouldn't fire (dashboard lights did come on).
Battery removed = 8V Sad

I've trickle charged the new battery = stable at 12.9V and re-fitted.

I've removed the positive lead and using a multimeter read a draw of 0.16Amp = too high.

I've sequentially removed all the 10A fuses from the main fuse box (indicators etc), with no effect on the draw.

I've removed the two 10A ABS related fuses near the starter solenoid with no effect on the draw.

I've removed the 30A fuse on the starter solenoid, which causes the draw to drop to 0 Amp.

I'm a little unsure where to go next... would you be able to kindly help, I'm beyond the edge of my knowledge with this!!!

Thanks a lot for your help Smile

fast wooly · Two Stroke Sniffer Joined: 06 Feb 2013 Karma :

Unplug the reg/rectifier and see what happens to the current draw,sounds like you have a diode in the regulator that has failed.

sebwin · L Plate Warrior Joined: 10 Aug 2016 Karma :

Great, thanks for the advice I'll give it a go.

sebwin · L Plate Warrior Joined: 10 Aug 2016 Karma :

Just thought I'd post the outcome incase it's of use in the future.

As "fast wooly" suggested, I unplugged the regulator/rectifier (a very easy job), and the draw dropped to zero.

I bought a replacement one off ebay. There were a lot of new OEM ones for around £15, but I didn't really trust them so bought a second hand £10 one which came off a cbf500 someone was stripping down.

Replaced and still zero draw.

Turned the engine on and volts across the battery went up to 14, reducing to 13 when revved (i.e. the rectifier is correctly charging the battery and the regulator is correctly stopping it over charging).

Very happy!

Out of mild interest, there are a few videos showing how to test a regulator/rectifier to check if it's faulty. Essentially you use the diode test function on your multimeter to check all of the metal contacts give the same value.
My old (something wrong with it) regulator/rectifier passed this test when I tried it = I'm not sure you can always be sure from this test yours isn't faulty.

Many thanks to "fast wooly" and hope this post helps someone else in the future.

davebike · World Chat Champion Joined: 15 Nov 2013 Karma :

That is why most pro's like me check the battery and stator to sort charging issues not the rec/reg the test is just not reliable

A current draw test with bike of can as you have proved be useful
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fast wooly · Two Stroke Sniffer Joined: 06 Feb 2013 Karma :

Glad I could help,have seen this happen so many times!now dont bother with the diode test as I have so many that have passed and are later proven to be faulty.
I'm always happy to help out with electrical problems as I build motorcycle race looms and so electrics are my area.

Wooly

jjdugen · World Chat Champion Joined: 03 Jun 2011 Karma :

Excellent diagnosis that man.
Can I be suggestive? You can pick up an LED charge indicator off the 'Bay for around £16. Wire it into a switched live and then you can keep an eye of your electrical health on the move. One of these things saved me draining my battery and getting stranded the other weekend when... my reg/rec decided to go all Honda on me.
____________________
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Try Soi 23 on Amazon for a good read.... Self promotion? Moi?