After receiving my first EarthX battery, I immediately noticed the large amount of current produced by the alternator to recharge the battery right after cranking the engine.
This is normal & expected behavior for LiFePo+ batteries.
What I couldn't explain was how the current reported by the EFIS exceeded that which the Alternator was supposed to be capable. I had rationalized that a few amps over the rating was within spec, but I was seeing more than 10% on occasion.
Turns out that the Plane Power Alternator that I have, model #99-1012, which is included in the AL12-60B/C kits, is in actuality a 70 amp model. This is documented on the data sheet/test report (attached).
Note the output curve; this alternator is capable of 60A at 3100RPM, 70A at 4100RPM and so on. This means it is capable of 70A at engine idle, and ~80A at cruise RPM, assuming you are using relatively stock pulley arrangement.
So, is >60A ok to dump into an EarthX battery rated for 60A? Is a 60A CB or 60A ANL sufficient to protect this Alternator? Should we resize the CB / ANL to a larger value? Should we keep the engine < 700RPM right after start to keep the output below 60A?
Time for more coffee...
This is normal & expected behavior for LiFePo+ batteries.
What I couldn't explain was how the current reported by the EFIS exceeded that which the Alternator was supposed to be capable. I had rationalized that a few amps over the rating was within spec, but I was seeing more than 10% on occasion.
Turns out that the Plane Power Alternator that I have, model #99-1012, which is included in the AL12-60B/C kits, is in actuality a 70 amp model. This is documented on the data sheet/test report (attached).
Note the output curve; this alternator is capable of 60A at 3100RPM, 70A at 4100RPM and so on. This means it is capable of 70A at engine idle, and ~80A at cruise RPM, assuming you are using relatively stock pulley arrangement.
So, is >60A ok to dump into an EarthX battery rated for 60A? Is a 60A CB or 60A ANL sufficient to protect this Alternator? Should we resize the CB / ANL to a larger value? Should we keep the engine < 700RPM right after start to keep the output below 60A?
Time for more coffee...