Larger Inverter loads while travelling.

I read an earlier post by Tanglewood, concerning settings on his Balmar charger controller and running inverter loads while travelling and I started to ruminate about my own particular situation. Should I be concerned about overloading my alternator?

Equipment particulars:

Amptech 125 amp alternator
Controlled by Balmar MC 612 controller with temperature monitor. Uncertain about settings. Haven't changed them since purchase of the boat.
1125 amp-hour house bank, seldom under 90% SOC.
Mastervolt battery mate 1603, distributing alternator charging to house and starter banks.
Balmar digital duo charge for thruster bank.
Magnum 2812 inverter charger.

435 watts of solar panels with Bluesky MPPT controller, switched off while travelling.

We sometimes run the microwave for 30-45 seconds while travelling (~120 amps load at 12 VDC). At other times we may use the vacuum for up to 5-6 minutes while travelling (~80 amps load at 12 VDC).

Should I be worried about damage to the alternator...
a) when the bank has 90% SOC.?
b) when the bank has 100% SOC?

I've noticed no issues so far.

Jim

Should not be a problem.
If your alternator is rated for a specific output that's what it should maintain.
Worst case is does not keep up with the load and depletes battteries some, but thats what batteries are for.
Check for excessive heat on connections and wiring.

I don't think you will have a problem. When the battery back is at 90% it isn't charging very fast with the alternator and I doubt if you are anywhere near the alternator's 125 amp rating.

But make sure that the temperature probe is working. It cuts the charging rate in half when the alternator case temp gets up to 200 deg F to protect the alternator from damage due to long term high output charging. If you let your battery bank drop to 50% then you could do some damage to the alternator without the temperature probe's cutting output.

And FWIW, the loads you described are not large in amp hour terms.

But why shut off your solar panel while cruising? 435 watts should bring your battery bank up from 90% to full in a few hours even with no alternator output. Both should do it even less.

David

Agreed, especially for short duration loads. The only real risk is that your alternator will heat up at higher load levels. The really big heavy duty units can run continuously at full load, but not your typical alternator which expects a big load for a little while as it recharges the battery, and then dropping off. So not a lot of time to really heat up. And with the temp sensor installed, the charge rate will back off if the alternator gets too hot.

djmarchand said:

I But why shut off your solar panel while cruising? 435 watts should bring your battery bank up from 90% to full in a few hours even with no alternator output. Both should do it even less.

David

Click to expand...

Chuckle! Because...when the bank gets to 100% SOC, the alternator shuts off and the tachometer shuts down as well. I was warned about this by another boater. There is probably a setting somewhere, but I haven't figured that one out yet.

I will take some temperature readings on the alternator case with the IR gun whilst underway.

Jim

I agree with bank above 85% even such a large bank should not be demanding too many amps, and as long as you're sure the VR derates properly as alt temps climb, you should be OK

But personally I would actually test this, by doing some higher load testing in hot weather using both kinds of temp sensors.

Not just the alt but all the relevant wiring connectors fuses etc while I was at it.

Also measuring the Amps flow real-time.

Because if for some reason that big bank gets below 60%, depending on the bank's CAR (what make/model batts?) they will be asking for everything the alt can produce and more, for a pretty long time.

Tach should not shut down, your alternator even at 100% charge should not "shut down" but go into "float" or whatever the voltage regulator is set for,
Alt regulator maybe set for "example" 14.2v once 100% state of charge maybe only putting out 5-10 amps but keeping at 14.2v. If your tach is shutting down that's a separate issue.
Agree with not shutting off solar, mine is on 24/7 except while at dock when at full charge and on board charger is on. No need to go into absorption mode on solar uses more water then needed.

Panacea123 said:

Tach should not shut down, your alternator even at 100% charge should not "shut down" but go into "float" or whatever the voltage regulator is set for,

Alt regulator maybe set for "example" 14.2v once 100% state of charge maybe only putting out 5-10 amps but keeping at 14.2v. If your tach is shutting down that's a separate issue.

Agree with not shutting off solar, mine is on 24/7 except while at dock when at full charge and on board charger is on. No need to go into absorption mode on solar uses more water then needed.

Click to expand...

Wouldn't that be a setting on the Balmar regulator? Not sure what you mean by "it's a separate issue" because as soon as I turn off the panels, the tach starts right back up again.

I identified the amps on the microwave and vacuum loads by checking the Magnum remote display while on Inverter and no charging.

I agree about the demands on the alternator at 60% SOC, but as I have mentioned, I don't let the bank get down that low. This morning the house bank deficit was -67 amp hours (94% SOC) when I got up, dropping to -79 (93% SOC) with overcast and drizzle. Currently it's at -75, 11:30 am at high latitude, cloudy-bright with 7-10 amps going into the bank, unless the,fridge and freezer come on. If the bank gets below 80% SOC, the genny goes on for an hour or so.

Jim

I just meant doing sufficient testing to ensure the system's safety, verifying hands-on that it can handle unintended even very unlikely edge cases.

I guess your solar controller is set to a higher voltage than the balmar reg.
That could "shut it down" just seems strange.does it happen when both are on in a lower state of charge? If the voltage is lower than the balmar setting tach should then work.

I seem to recall a setting in the Balmar to address exactly this issue. I didn't pay a lot of attention because my tach doesn't come off the alternator, but I think it keeps the alt on enough to maintain tach.

JDCAVE said:

Chuckle! Because...when the bank gets to 100% SOC, the alternator shuts off and the tachometer shuts down as well. I was warned about this by another boater. There is probably a setting somewhere, but I haven't figured that one out yet.

I will take some temperature readings on the alternator case with the IR gun whilst underway.

Jim

Click to expand...

Jim, I'm wondering if the Balmar High Voltage limit is set way too low, but I am not sure if that cuts the field completely, which it may be doing if the alt shuts off. Give Balmar a call. They are incredibly helpful and Tom Pusateri there will answer any question.

http://www.balmar.net/wp-content/uploads/2015/11/PDS-MC-614-H.pdf