pianotuna wrote:
Phil,
Are you using a dc to DC charger to get those rates?
Don,
No ... The stock OEM (Motorcraft?) 130 amp alternator puts out these levels into my 230 AH AGM coach battery bank - starting out - whenever the 2 paralled 12 vot Group 31 batteries get discharged down to around a terminal reading of ~12.1 volts.
I believe it is a Motorcraft 3G 130 amp alternator on our 2005 E450 and that the 3G alternator design was noted for it's low RPM output. The pulleys overdrive it relative to engine RPM - if I remember correctly about at a 1.72:1 ratio on the E450 V10.
I used to have the performance curves for this alternator, but can't seem to locate a link to them anymore. When the alternator is cold, it's output voltage into the coach battery bank is around 14.2-14.4 volts. As the batteries charge and the alternator warms up, the voltage drops down into the 13.7-13-9 volt range. When traveling in very high ambient air temperature conditions and with the coach battery bank fully charged, I've seen the alternator's output voltage read only 12.9 volts - which is about right for my fully charged AGM batteries when on "float" in high ambient temperatures. It's as if the alternator somehow treats the AGM batteries perfectly.
