[Roadsters] battery not charging

[Tim]

OK....

Fully charged battery was at 13.20 right after the little green light 
came on so the charge could not get any fresher.

Cold engine (if it matters) @ 550 rpm the battery was 12.74 and the alt 
was 12.20-12.50

Warm engine (again, if it matters) @ 1000 rpm battery was 12.58, alt was 
16.2-16.4
                                                   @ 3000 rpm battery 
was 12.56, alt was 15.7 ish
                       after returning service screw to idle: @ 600rpm 
battery was 12.60, alt was 12.6-13.10

Do these numbers look correct?

I will check the grounds this weekend and also have the battery load 
tested.

Thoughts please?

Thanks!

Tim





On Wed, Jun 22, 2011 at 10:57 AM, Pete Peters wrote:

> Sounds like several issues:
>
> 1. Battery only gets fully charged by external battery charger, not by
> alternator.
>
> 2. Ammeter never goes positive with headlights on.
>
> 3. Car will not start unless battery at full charge.
>
> Troubleshooting is same for all three: Test alternator, battery, and
> double-check wiring & grounds (always check those pesky grounds). The 
> GM alt
> has an internal voltage regulator. You can have it tested at your 
> FLAPS or
> an automotive electrical repair place. Got a known, good spare 
> battery? Swap
> 'em out.
>
> More exact voltages would help, i.e. at idle (800-1000 rpm) the output 
> is
> 12.43v, at 3500 rpm it's 14.5v, etc.
> What does battery read fully charged?
>
> How old is the battery?
>
>
> Pete
>
> -----Original Message-----
> From: datsun-roadsters-bounces at autox.team.net
> [mailto:datsun-roadsters-bounces at autox.team.net] On Behalf Of Tim
> Sent: Tuesday, June 21, 2011 6:07 PM
> To: datsun-roadsters: autox.team.net
> Subject: [Roadsters] battery not charging
>
> First off: I am an electrickery novice. Big time.
>
> This is a new condition this spring: 70 1600 w/ gm alternator upgrade 
> done three or four years ago. Alt is putting out over 12 volts at 600 
> rpm idle; more at higher rpm. Battery is over 12 volts once charged 
> with battery charger. But car won't start if battery does not have 
> most of a fresh charge from the charger. Amp meter will go into the 
> negative if I turn on the head lights but never goes into the positive 
> any more.
>
> Is this my regulator going (gone) bad? How do I test it?
>
> Thanks
>
> Tim
> ________________________________________