Today, roughly 20 minutes after we fired up the engine
and right after we pulled up the anchor
, our Balmar alternator
(Balmar-AT-DF-165-K6) got on fire with flames coming out of the grills. We noticed a smell and checked the engine
compartment to see the flames coming out of the alternator
. We stopped the engine immediately, dropped the hook back and then I pulled the alternator fuse. After testing the temperature a bit after firing up the engine, we continued and dropped the hook in our destination
. Needless to say, this was very worrisome.
We have 7x100Ah 12V LiFePO4 batteries
that are connected in parallel. I also have a Balmar
MC-614 controller and I have configured it with the following settings: Field reduction is 70%. High voltage/bulk limit is 14V. Absorption voltage is 13.9V and float voltage is 13.8V. There is a temperature sensor
and max alternator temp is set to 100 degrees celsius. I also have a Starlink alternator protector device. I think these were relatively conservative settings.
Alternator charges the lithium batteries
. Starter battery
(AGM) is charged by a DC-DC charger
from the lithium
We fired the engine at 16:30 and incident happened in less than 20 minutes after that. At that point battery
bank was about 80% charged and solar panels
were pumping in ~40A. Net current
draw from the batteries was between +30A and -10A during this window. Attaching screenshots from Victron MPPT
and Shunt. Looking at the output of the shunt, doesn't look like alternator ever produced anything, all power
was coming from the solar panels
So all in all, I struggle to explain this. I don't think there was a surge from the alternator. Also there was really no possibility of a BMS shutdown of any of the batteries.
This was an alternator that was installed brand new when we purchased the boat
1.5 years ago, as the original one burned during the survey
and was replaced as part of the purchase
. Since then, we changed the batteries, added solar
etc etc and it has been running without any issues close to a year with this new setup.
Is this common? Alternator failing is one thing but it going into flames is another thing, presenting a fire hazard. Any relevant experiences?