It looks like the alternator is working but the current is not getting to
the battery. The battery voltage should go up when the alternator voltage
goes up. The most likely problem is the wire from the alternator to the
battery. If it goes through the amp gauge then the gauge may be bad. The gauge
is the first thing to burn out if the system is overloaded, a very expensive
fuse.
keith w
In a message dated 6/22/2011 2:41:33 P.M. Pacific Daylight Time,
tputland@charter.net writes:
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@autox.team.net
> [mailto:datsun-roadsters-bounces@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
> ________________________________________
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