Hi Chuck,
Have you had a chance to stop by Coburg to discuss this with Marathon? It's an interesting setup. I wonder how inverter charging works when on generator power with all of your AC's running. It looks to me like only one charger would be working. It'd be interesting to hear Marathon's rationale for their approach.
(07-31-2017 02:05)davidbrady Wrote: [ -> ]Hi Chuck,
Have you had a chance to stop by Coburg to discuss this with Marathon? It's an interesting setup. I wonder how inverter charging works when on generator power with all of your AC's running. It looks to me like only one charger would be working. It'd be interesting to hear Marathon's rationale for their approach.
David,
I have been there and gone. I was in such a daze after receiving the bill that I forgot to ask them about it.
(07-31-2017 12:35)cmillsap Wrote: [ -> ] (07-31-2017 02:05)davidbrady Wrote: [ -> ]Hi Chuck,
Have you had a chance to stop by Coburg to discuss this with Marathon? It's an interesting setup. I wonder how inverter charging works when on generator power with all of your AC's running. It looks to me like only one charger would be working. It'd be interesting to hear Marathon's rationale for their approach.
David,
I have been there and gone. I was in such a daze after receiving the bill that I forgot to ask them about it.
Yikes, must'a been a pricey! I know how you feel; sometimes you just want to get the bus out the door so the clock stops!
Someone told me the Marathon chooses whether to power the two AC's via the inverter or pass-thru via the generator based on discharge level of the battery bank. That would probably require an external shunt to keep track of state of charge or a way to parse the remote control user interface for the Trace SW to extract battery state info.
Here's another thought.
Your alternator is putting out voltage that is too high or your charger is configured for too low of a charge voltage. If you have battery temperature sensors, they too could contribute to the problem if the batteries are getting warm.
There's simply no logic that would have someone spend engineering time and added complexity to force the inverters to stay in inverter mode when they were supplied a good AC input.
CC_Guy,
This is the Marathon approach by design, it's not a bug or a failure, and judging from a recent thread on PC it's news to even the most seasoned owners. There's obviously a sound rationale behind it but not knowing the full details it's lost on me. Not saying it's good or bad, just interested in learning more. Who knows, a Marathon could be in my future.
If the AC2 (Generator) indicator is lit on the Trace remote, then the bypass relay should be passing generator power through the inverter rather than producing inverted power. Although I don't see specific mention of the AC2 indicator being lit I assume it was given the charger is showing bulk charge.
If the AC2 indicator is not lit then the only thing I can think of is that Marathon is triggering a contactor to remove the generator's AC to the inverter when the ignition is on or the alternator is operating. The only rationale I can think of for such an approach is to limit house battery charging sources to one, either the inverter's AC charger or the alternator output. Of course, with 2 chargers this rationale is already flawed. If this is what they did and you have a dedicated house alternator, I would defeat this "feature".
Same here CC_Guy, not knowing more I'd also defeat it. I have a theory. Maybe this setup predates Marathon's use of the Trace SW. Perhaps it was designed for an inverter that didn't have two AC inputs with priority given to AC2.
Chuck, I noticed on this last trip that my inverters also power my ACs when the S60 and genny are running. It's because the 50DN is charging the house bank at 14VDC and the inverters are attempting to bring the voltage level down to float, 26.6VDC, by powering available loads. It's a feature of the SW4024 and they're working as intended. One way around it would be to install a multistage regulator on the 50DN.
And the rest of the story is if the inverters are in Bulk/Absorption charge then the generator is powering the loads, whether air conditioners or other. If the inverters are in Float charge then as I said earlier they supply power to the loads in an attempt to lower the battery voltage which is held at 14V by the 50DN. If you tend to travel with your generator running, as I do, and if you'd like your generator to power your loads while traveling, then one solution is to disconnect AC1 and AC2 prior to departure, which will put your inverters in Bulk charge, and increase the SW4024 Absorption time. As long as the SW4024's are in Bulk/Absorption they're happy with the 14V put out by the 50DN alternator and they won't try to supplement loads.