Charging Issue or Not
 

I spent the afternoon chasing a parasitic drain on the battery since I had a dead battery, charged and it was dead again 2 days later. I disconnected the offending circuit and retest battery voltage and circuit draw..voltage 12.6 and 0.01 MA draw..ok, may have addressed that gremlin..will know in a day or two when I got to start again...if it fails then the battery has an issue holding the charge

BUT

While doing this I decided to test the charging and started the car to see what voltage was read

at 1000RPM 12.7
at 2500 14.4

this is without any additional draws like lights or radio...

it strikes me that the 14.4 should be consistent or am I assuming incorrectly?

thanks

I am with you.

14.4 indicates a battery that needs some juice for a recharge for starters and the alt/v-reg should be pumping that 14.4 range out full stop regardless of RPM's.

How is the steadiness of the voltage? When I replaced the V reg it was within one or two one hundredths of a volt. Charging voltage would vary with load I placed on it but it was steady as a rock.

the voltage is steady at both RPMs..just low on the 1000 and "normal" on the 2500...

I will check the belt as well to make sure there isnt any slippage.

i have looked through the various manuals to see if there is a different pulley size between the original 77s 2.7 engine and the 83 sc 3.0 engine..a difference would explain why at 2500 i get the full charging voltage of 14.4 versus low idle only getting 12.7...bring rpm up makes up for lower spin rate?

any thoughts on this?

well, she's dead again...no parasitic loss found anywhere but one day later..it turns over a couple of times and then nothing...readings at terminals of battery started as 12.5 and dropped to 12 after one attempt to start....i would think that would be enough so makes me think the battery just doesnt have real juice...i ve order a load tester but at this point..i am thinking the battery is toast and will take it to local shop to test and get a new one...now which one to get becomes the issue..i would like to stay close to original group 49...

well,,,all that testing and internet research and in the end, the battery had finally died..after charging it showed less than 200 amps and less then 10 V under load...it just got old and died

put the new one is, fired up without hesitation. Even seems to idle better. Idle charging now at 14.5. Even retested for parasitic loss...0.01 amp (clock) is the only draw...

Easy fix but I did get to learn about battery testing, loads, alternators, so to me, a good exercise

If I may suggest, get a Battery Tender, like the C-tek 3300 with maintenance cycle.

Yes, I do use one and that was masking the real issue...it would work fine for extended periods of non use...but because the battery could not get fully charged...it was going to be hit or miss (likely miss) whether it started.

Have you put the battery on a charger since you fixed the drain.
How old is the battery.
The battery may just be going bad.

yes, i charged the old one but it never would get to 12.6..and then load test failed completely..replaced with a new battery and no it charges at a full rate and even the electric windows work perfect...so that was another side effect of bad battery..what I thought was binding windows was a lack of power to power them even with the car running..I was lucky I never got stranded!