Alternator Replacement

[Don Bradner]

My batteries are AGM, total 660AH, combined house and starting. Alternators
don't do Bulk/Absorption/Float three-stage charging, they are constant voltage.
In this case, 14.2. That does not mean that they would measure 14.2 across the
terminals, as they are pulled down by the current flow/low resistance when the
batteries are not fully charged.

When my batteries are fully charged, starting will still pull them down to about
12.7 volts (and that's only if there are just a few turns to start). The 100 amp
pull is immediately after that, and I mentioned that the amps dropped quickly as
the start drop was replaced and the voltage rose. I did not go to fully charged,
as I was just idling in the driveway.

On 3/6/2007 at 2:34 AM ronmarabito2002 wrote:

>Not sure why you are pulling 100 amps, unless your batteries are
>really low. After driving it a bit, it should go down to maybe 10 to
>15 amps max. What kind of batteries do you have and how many for the
>house and starting? If GEL cells, they should be at least 14.1 volts
>during absorption and then drop to 13.5 volts for float voltage. The
>"Ample Power Regulator" folks recommend 14.4 volts for absorption and
>have not found this to cause gassing.

Don Bradner
90 PT40 "Blue Thunder"
Eureka, CA