Help-AC/Gen issue

[Interstate65]

Originally Posted by Alex AVI

UPDATE -
MIKE , GMILLEROK1, RMKRUM, INTERSTATE65

On units using the PCS MINI, the shed relay is ONLY for the A/C compressor. This solves the mystery of why compressor sheds while fan stays running awhile.
MINI 600 - shed relay 3 compressor only
MINI 610 - shed relay 4 compressor only
MINI 611 - shed relay 3 compressor only

On PCS MIDI (mine) per install spec sheet for Airstream Interstate :
02-10-2018 - shed relay 2 is fan, shed relay 3 is compressor (I assume prior dates inclusive)
02-12-2018 - shed relay 3 is compressor (I assume later dates inclusive)



Dates are per PCS, not AS build dates.

So as you can see, there's many multitudes of combo shed hierarchy that has been implemented by PCS & AS along the way, making us all constantly guess WTF is this not making sense?

I choose option 3!! Storing all this info-in case I have to re-visit-ya’ll are a great resource!

[TayaraTravel]

Here is one more thought: what is your battery state of charge when you turn on the generator for the A/C?

We sometimes stop while driving, turn on generator, wait a minute, turn on A/C and use microwave. All run OK. But since we were recently driving, the house batteries are 100% charged.

On the other hand, after a night of dry camping we might start the generator to run the microwave. If we take no further action, the Microwave will not run, because all the amps from the generator are going to recharge the partly discharged house batteries. After 10-20 minutes, the batteries are soaking up fewer amps and the microwave will run.

If we temporarily set our Magnum "rate of charge" to 50%, we can immediately run the microwave. Maybe the same trick will let you run the A/C without throwing breakers.

[Alex AVI]

Originally Posted by TayaraTravel

If we temporarily set our Magnum "rate of charge" to 50%, we can immediately run the microwave. Maybe the same trick will let you run the A/C without throwing breakers.

TAYARATRAVEL - I believe the PCS MINI does not have option to change ROC to (10, 50, 100%) as the MIDI does, so won't work. And if Max Current was set by factory PCI to 18A as in MIKE's case (which should be 20 or 22A), then won't work either

[Interstate65]

Originally Posted by Interstate65

Just had the Onan service center install new 2500LP gen-everything works great except when the compressor kicks in- it will run for 10 seconds to 4-5 minutes then the compressor cycles off-fan on Ac still runs- plugged into shore power Ac runs fine. BTW-also I stalled new inverter at the same time-same as what was in it.
Thanks for any insight-can’t Get it into service at Airstream dealer until Sept 16!!

Thanks for all the suggestions-several said to turn off breakers to coffee pot and microwave-worked like a charm (currently in 100 degree weather I. MO and inside temp is 72!!!!

[Boxster1971]

Originally Posted by Interstate65

Thanks for all the suggestions-several said to turn off breakers to coffee pot and microwave-worked like a charm (currently in 100 degree weather I. MO and inside temp is 72!!!!

Good to know the work around with breakers works for you too. The generator is more than capable of running the A/C on these Interstates, but then Airstream adds a system that limits the use. Strange - I’m wondering if I could get a better PCS that would avoid the problem. I’ll have to look into the MAXI PCS suggested by Alex. Although I don’t run the A/C off the generator that often - so it might not be worth the trouble and expense.

Stay cool!

[sajohnson]

Originally Posted by TayaraTravel

Here is one more thought: what is your battery state of charge when you turn on the generator for the A/C?

We sometimes stop while driving, turn on generator, wait a minute, turn on A/C and use microwave. All run OK. But since we were recently driving, the house batteries are 100% charged.

On the other hand, after a night of dry camping we might start the generator to run the microwave. If we take no further action, the Microwave will not run, because all the amps from the generator are going to recharge the partly discharged house batteries. After 10-20 minutes, the batteries are soaking up fewer amps and the microwave will run.

If we temporarily set our Magnum "rate of charge" to 50%, we can immediately run the microwave. Maybe the same trick will let you run the A/C without throwing breakers.

Great suggestion!

It's easy to forget that the inverter/charger (or converter on many rigs) can take a significant amount of power.

Most inverter/chargers see battery charging as priority #1. The assumption is that if power has been lost, it may go out again at any time -- so it's best to charge the batteries as quickly as possible (without harming them).

I installed a MS2000 inverter/charger in our rig. We have 2 oversize Crown 260 Ah GC batteries, so the bulk charge rate is dialed back to ~50A. When the charger is in bulk mode it pulls 7-8 amps all by itself -- or close to 1,000 watts! If we had 2 more batteries I could set it for 100A and it would take almost 2,000 watts!

We have a Progressive Industries HW30C so I can keep an eye on the current, but with no display it's out of sight, out of mind.

The 7-8 amps hasn't been a problem, and I do like to charge the batteries quickly, within reason (the "C/5 rate") but if need be the charge rate can be decreased, or the charger can be turned off.