Balmar Regulator blowing 10A fuse

[Mark65]

Originally Posted by s/v Jedi

You have two problems: blowing the fuse and overheating the alternator. Don’t try a fix that only addresses one of the two

The overheating alternator is great for finding the blown fuse problem. Did you try another alternator already?

Not so easy for me - I am not mechanic enough to remove the alternator from the van. I have not researched how hot alternators should be expected to get - I will dig into that some and see if I can assess whether I have realistic expectations given the ventilation I have.

[smac999]

Turn the belt manager all the way down and see what happens. It will limit charging and heat. See if the fuse blows.

It’s possible the 280a alt is simply too big for the mc614 and requires more then 10a of feild current?

[Mark65]

Originally Posted by smac999

Turn the belt manager all the way down and see what happens. It will limit charging and heat. See if the fuse blows.

It’s possible the 280a alt is simply too big for the mc614 and requires more then 10a of feild current?

I do plan to check behavior with different belt manager settings. I expect I can find a setting that doesn't overheat or blow a fuse even at low idle, I am wanting to see where that setting is.


Regarding your second question -



I have never seen more than 170A coming out of the alternator. How much field current this requires depends on the shaft speed of the alternator. Double the shaft speed takes half the field current for the same power generation from the alternator, so getting to 280A is a question of making sure the RPM's are high enough to not need more than 10A and also putting a high enough load on the bus that the regulator will need to push enough field current to maintain the target voltage that the output current does get to 280A. I suspect There are RPM's at which 10A would not be enough. But as I said, the loading my battery puts on the alternator has never exceeded 170A, that has always been the max I have seen so far for the regulator to hit the target voltage.

[Bycrick]

You might also very carefully check the fuse holder. Once upon a time I had a bilge pump that would blow the fuse if it ran for "a while." Replaced lots of fuses. Checked wires. Measured current draws; OK. Still blows fuses. Problem finally turned out to be and improperly soldered connection between the fuse-holder clip and the original wire. That connection would get warm at normal current and the elevated temperature would cause the fuse to open at less than rated load. It took me months to find it.

[Bycrick]

If the alternator really requires more than 10 amps of field current, you might check with Balmar about swapping the 614 for the 612Dual. It’s designed to drive two alternators and has a 15 amp output limit. And if that isn’t enough, the Panbo forum recently had a write up on a fancy-new, whiz bang alternator regulator that he’s using. I think I remember something about 30 amps field maximum.