Charging system failure - maybe.

[Monty]

Hi guys,

Pretty new here but I'm the proud new owner of a black 01 curvy, previously owned by BigBadDad. Unfortunately I'm having some problems with starting it, and I'm fairly sure it's the battery that's gone but thought I'd seek some expert advice first ;).

Basically it wouldn't start by itself - it kept nearly catching but the starter motor just couldn't quite do it. Jump leads from the car solved the problem, but I'd like to find a slightly more permanent solution... I measured these voltages (unfortunately only an analogue meter so these are a little rough) from across the battery terminals.

After being left for about 24 hours: 12-12.5ish (didn't start)
While running after the jump start: 14
About 5 mins after a half an hour ride: 13-13.5ish (did start again)

So, new battery needed? Or is it a problem with charging the battery? The fact that it does start straight after a ride but doesn't 24 hours later makes me think it's more likely to be the battery than the alternator or reg/rec.

Cheers for the advice :)

Monty

[Biker Biggles]

Those readings look ok.Did you check it with the lights on and reving to about 5000?
Battery looks most likely culprit though.

[Sid Squid]

Those numbers are not accurate enough to make a confident diagnosis - a more accurate meter will be needed, and more information on how the charging system performs will need to be gained.

[Monty]

Ok, I'll beg/borrow/steal one and do them again when I get the chance. What information on the charging system would be needed and how would I gather it?

Thanks for the replies

[yorkie_chris]

Readings at 5000 rpm with and without the lights on with a charged battery.

[Monty]

Great, thanks, I'll get back to you with the readings. Unfortunately I'm in Yorkshire for the next few days so won't be back to test things til later this week but I'll resurect this thread then.

[Monty]

Right so I had a chance to check things out again today, and at 5000rpm the readings were:
lights off: 18.5V
lights on: 17.0V

This strikes me as pretty reasonable so hopefully the charging system is ok, but I'm no expert. Cheers for the advice, much appreciated.

[Biker Biggles]

Too high.Id be looking for a new reg/rec and checking the battery out to see if it was cooked.

[Monty]

hehe shows how useful a newbie's opinion is. Yeah I just looked through some of the other threads and those voltages are obviously way off. New reg/rec it is...