I just installed 360 Ah Winston cells. More on this adventure later.
My question is regarding alternator not charging. I have a Volvo
B2-40 with 105A Mitsubishi alternator.
After install the installing was about 50 Ah down, started the engine
at the dock
out of gear
running about 1200-1400 RpM
. From memory the alt started charging at 100 amps going quickly to 90+A. With the voltage coming up and probably temperature protection coming in it dropped to 70-80 A. There it stayed until voltage when to 13.88V. This is where my note begin.
+ 10m 13.99 V 48A
+15m. 14.09V 33A
+25m. 14.20V 10A
+30m. 14.21V 6A
I stopped and know that I should install a high voltage cut off solenoid or switch to prevent long term plating damage.
Next day I went on a trip to test under real condition. Morning about 90 Ah down ( had fridges on high with shore charger
Motored about 45 min then sailed for 4-5 hours. Started engine as no wind
. After 30 minutes initially at 2200 RPM
then at 1800 Rpm I get a battery alarm
on the engine control panel
. The BMS shows 8 amps flowing out of the battery, Ah's are -5 at 13.3V clears the alt is not producing output. I feared I fried it or the split diode overheated, which I had replaced 2 years ago for the same reason. I had increased my LA capacity from 440 to 710 about 12 months before the split diode died.
Next morning I went to check. Started the engine and the BMS shows 78A going in with about 90Ah down.
Does the Mitsubishi 105 A alt have a temperature protection that switches it completely off?
Why does it output 'only' 78A and not 100A as it was cold now? It did before. Any change I fried one of the 3 rectifying diodes in the Alt? But that should cut down even more to around 65A.
I am now about 1.5 hours into today's trip running 2200 RPM.
14.1V at 30 A , BMS showing 0.1 A down. It is a Xantrex LinkLite and I have not gone through the parameters to adjust to the different batteries, except for capacity.