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- MilkyWay Galaxy
My 87 Renix, 4.0, Waggy is back on the road (AW4 swap finally done). It has been in my shop for about 6 months now. I put a 20 minute head light load, followed by a full re-charge on the battery about every 6-8 weeks, then disconnected the battery posts in between during the 6 month down time. It starts the jeep fine, but at idle, with headlights on, brake lights, back up lights and AC on max, and radiator e-fan on, it starts draining the battery, reading about 12.6 V after 10 seconds of peak load.:rattle:
At first the battery was reading 12.25 V this morning, No load engine off, before running it again. Started up fine, got up to about 14.05 V peak with no loads (it is usually about 14.7 V peak, no load). Cranking voltage has stayed above 10.1 volts at all times in about 8 restarts, even with the head lights and radiator e-fan running while cranking.
I cycled the battery several times today, load, crank, run recharge and the final engine off no load battery voltage was 12.75 V (.50 volts higher), but It still drops to 12.6 volts at idle in gear, brakes on, in reverse, back up lights on, head lights on and radiator efan on with AC at Max AC, so at that point it is discharging the battery. Note the idle is at about 550 rpm at that point, in gear, but running smoothly.
When the voltage was only 12.25 at the beginning today, when I started all this testing, I figured the battery was weak, on its last legs (Autozone Red top, about 2-2.5 years old) and that maybe it was not giving the alternator enough juice at full load for the alternator to put out max power.
Not sure if the alternator is a 60/65 amp, or 100 amp. It is OEM stock, but this Waggy has electric windows, locks, seats, etc.
IIRC, I found out last year that the 100 amp and 60-65 amp look almost exactly alike? So with spares floating around, hard to tell what I have. One question I have, is what should it have stock, 87 Wagoneer, 4x4, with trailer tow package, D44 rear....the works, what size alternator was stock?
How can I pin down the problem?
At first the battery was reading 12.25 V this morning, No load engine off, before running it again. Started up fine, got up to about 14.05 V peak with no loads (it is usually about 14.7 V peak, no load). Cranking voltage has stayed above 10.1 volts at all times in about 8 restarts, even with the head lights and radiator e-fan running while cranking.
I cycled the battery several times today, load, crank, run recharge and the final engine off no load battery voltage was 12.75 V (.50 volts higher), but It still drops to 12.6 volts at idle in gear, brakes on, in reverse, back up lights on, head lights on and radiator efan on with AC at Max AC, so at that point it is discharging the battery. Note the idle is at about 550 rpm at that point, in gear, but running smoothly.
When the voltage was only 12.25 at the beginning today, when I started all this testing, I figured the battery was weak, on its last legs (Autozone Red top, about 2-2.5 years old) and that maybe it was not giving the alternator enough juice at full load for the alternator to put out max power.
Not sure if the alternator is a 60/65 amp, or 100 amp. It is OEM stock, but this Waggy has electric windows, locks, seats, etc.
IIRC, I found out last year that the 100 amp and 60-65 amp look almost exactly alike? So with spares floating around, hard to tell what I have. One question I have, is what should it have stock, 87 Wagoneer, 4x4, with trailer tow package, D44 rear....the works, what size alternator was stock?
How can I pin down the problem?