[Roadsters] battery not charging

[Keith0alan at aol.com]

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 at 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 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
>  ________________________________________
________________________________________

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