Reg/Rec or dodge Bat? How do I confirm which is Knackered?
 

The SP battery has been failing to hold its charge since the winter break when installed and run on the bike.

I have had the battery on charge all winter on an optimate type charger, and when first installed on the bike all is well...it turns it over real quick as expected.

However, within a 30 minute ride (even with the lights off) the bat is flat, with not enough juice to turn the engine over to start it again.

So...how do I figure out if the problem is with the battery that may be just plain 'ol knackered, or the reg/rec that is shagged and not providing the charge needed...or A N Other reason?

I have a Digimultimeter and I'm ready to investigate...so what should I be measuring and where/when to identify the culprit?

Cheers

Hello Harv748.

I found this post very helpful.

http://www.ducatisportingclub.com/xm...d.php?tid=2042

regards

TopiToo

Cheers Steve...

I have already replaced the wires for heavier guage stuff, and I know the connecting block etc is all fine, they have been replaced with better bullet type connectors...so I know its not a wiring issue.

I'm interested in what voltage reading I should be getting from the baterry/connectors with the engine on/off/revving etc., and how this will help me identify what component is buggered, rather than splashing out on a new reg or bat if one or the other is OK.

14Volts @ 3K - I think

Anywhere between about 13.8 and 14.4v is generally ok. The easiest test is to turn your lights on at idle and rev the motor. they should get brighter.

If you can get your hands on a clamp-on ammeter you will be able to measure whether or not the battery is receiving a charge or discharging when running. Don't try connecting a normal meter inline and then starting the bike - you'll knacker the meter.

if the battery is receiving a charge from the optimate and can start the bike without too much trouble then the chances are that it is ok. it seems like that it's not receiving a charge from the regulator/rectifier when the bike is being ridden.

What's the reading across the battery terminals with the engine off? Should be well over 12V. Ideally 12.5-12.8. Engine running around 14V as Jools says. Even at idle it should be getting up over 13V.

But never more than 14.5V at any engine speed.

Harv, I finally changed my Reg/Rec after suffering from drained battery trouble. I would go out on a 40 miler and find battery flat. Convinced when I put a meter across the battery and found 13.25v at 3000rmp put the lights on and found it dropped to 12.20v ,that not enough to charge the battery. On fitting new reg it then showed 13.60v even when the lights were on. I have the newer three yellow wired reg/rec 2001 with the newer Altonator my bike is originally a 1998 model. Just under £80 from On Yer Bike Aylesbury. 4D

I bought one of these a little while back:

http://cgi.ebay.co.uk/Regulator-Rect...temZ7985706995

£69.33

OK...fited new reg/rec today as I was convinced mine had packed up...not so apparently, still no charge when the engine is running.

So the story so far is:

Battery seems to be OK as it will quite happily charge on the optimate and once charged will crank the bike over no problem at all.

Reading accross the terminals when fully charged is about 12.5V.

Start the bike and the reading stays at about 12V, but does drop on turning on the lights etc, and will continue to drop if the bike is stopped and started a few times.

Clearly it is not being charged when the bike is running, the highest reading I get is the 12.5 when itys fully charged...certainly not getting anywhere near 13+V

Checked the fuse in the fuse box...OK...are there any others?

Checked the wiring back from the reg/rec to the other side of the bike...all appears OK.

Any other ideas...I'm starting to get a bit peeved with it now...I wanna go ride!!!

[Edited on 15-4-2006 by Harv748]

are you sure nothing is amiss under the crank case cover ?