When Smarter is not always better..

It's not total amps - see your PCS operator manual. The PCS system is supposed to make intelligent decisions about load shedding, even considering what is on L1 vs L2.  It could well be that it was originally set up with the knowledge that two a/cs are acting as one (single zone) and making decisions accordingly. On the other hand, it could be controlling the a/c's though the power supply rather than via thermostat, in which case the zone configuration won't make any difference.

Ok, I think I understand how this Precision Circuits PCS system works.  I spoke to Winnebago Technical support and George Cepynsky at Precision Circuit, I think he is the owner ? a very nice guy.  Winnebago?s knowledge on this system is only superficial, George designed it.

First you have to define a load as understood by this system; there are loads which can be shed and there are user loads.  Loads that can be shed are factory defined and there can be a maximum of 7.  In order of first shed loads in my coach they are, 1)Engine Heater 2) Water Heater-AquaHot  3)Front A/C 4)Rear A/C  5)Middle A/C  6)Dryer  7)Washer.  These shed-able loads can only be changed by the factory.

User loads are all the other stuff, in my coach they are RR, Dishwasher, Microwave, Fake Fireplace/heater and of course the Inerter/Charger.  User loads are never ?shed?, as George said, we don?t want to prevent you from popping your microwave popcorn.  If I am on a 30amp service running 2 a/c units at 28amps and I turn on the microwave, 20amps, my 2 a/c units will be shed.  George said the ?bad guy? in this 30amp situation is the RR, it is normally drawing 6amps leaving only 24amps to run the 2 a/c?s.

Enter the ?Inverter-Assit? feature of the PCS, its purpose is to ?provide additional power from the battery bank to smooth high peak demands?.  Here is where things get tricky.  The Precision Circuits PCS works closely with the Magnum Energy MS Series Pure Sine Wave Inverter/Charger and the Magnum Energy Inverter Remote Control.  The PCS will draw additional current from the Inverter/Charger as long as the ?Low Battery CutOut? setting, established by the Magnum Remote control, has not been met.

So here is how it works; I am running on a 30amp service, I am drawing 28amps to run my 2 a/c units.  Suddenly the RR cuts on drawing 6amps, I am now at 34amps.  The PCS system immediately directs the Inverter/Charger to supply the additional current so the 30amp threshold will not be met.  The PCS will continue receiving the additional amps from the Inverter/Charger until it senses the ?Low Battery CutOut? voltage has been reached.  When this LBCO has been reached the PCS will begin a battery charging operation and shed loads (my second a/c) until the 30amp threshold has been reestablished.

The LBCO can be set at 9, 10, and 11 volts, my coach is set at 11 volts.  Next time I have this problem I am going to set the LBCO to 10 volts and see if that helps.  If not, I know where the RR circuit breaker is located.

Good write-up Tom, thanks for taking the time to document the energy management system characteristics.  I think I'll copy/paste that to the Winnebago Resources sticky.  I really like the concept of using the inverter during peak AC demand on an as-needed basis to take care of transitory power loads.  Ingenious idea.

So the way I read it, two of your ACs should have remained running since the inverter can supply the necessary current to run the fridge which begs the question of why that didn't work.  Your experience closely parallels the issue my buddy in our Winnie club was having with only roof air running on 30 amp shore supply at the GNR.

10 volts is pretty low - I set our low voltage cut-off at 11.0 volts, but you could give it a try, that would be an interesting test.

John Canfield said:

Good write-up Tom, thanks for taking the time to document the energy management system characteristics.  I think I'll copy/paste that to the Winnebago Resources sticky.  I really like the concept of using the inverter during peak AC demand on an as-needed basis to take care of transitory power loads.  Ingenious idea.

So the way I read it, two of your ACs should have remained running since the inverter can supply the necessary current to run the fridge which begs the question of why that didn't work.  Your experience closely parallels the issue my buddy in our Winnie club was having with only roof air running on 30 amp shore supply at the GNR.

10 volts is pretty low - I set our low voltage cut-off at 11.0 volts, but you could give it a try, that would be an interesting test.

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John - here is what I think was going on, this from a very nontechnical person.  I have 30 amps to play with, but 2 major bad actors, non-shedable, plus other house battery drains  were the problem.  The non-shedable drains were the RR and the Inverter Charger, the house battery drains were the TV and DVR.  Assume the 2 a/c's draw around 28 amps.  The RR is going to take 6amps, the Inverter/Charger is going to take amps, not sure how many, because it is being drained by the TV and DVR, plus lights, etc.  So just the RR, non-shedable coming on will shut down 1 a/c, shedable.  The PCS system may have sensed an LCBO or the inverter/charger and may have initiated a bulk, absorb or float charge. I'm not really sure how those decisions are made by the "system".  So this system is very marginal to sustain a constant 28amps, too many other things want to suck some amps. 

The manual seems to have no problem with setting the LCBO at 9, 10, or 11 volts, personally I don't want to go below 10 volts.

This is a great write up. Very informative. I have a View with a 30 amp service. I would like to shed loads when hooked up to residential power. 15 amps is normal and occasionally 20 amp circuit is available. Any suggestions?

We do it quite often. Just be cognizant of your loads. Warn the wife about microwave, hair dryer, coffee pot, electric frying pan, AC and etc. Only use one of those at a time and every thing should be fine.

Tom, how long, if at all, are you able to run both a/c's on 30 amp? Did lowering your voltage cutoff help? Did turning the RR off help in running 2 a/c's and how long is it safe to do this. We are trying to decide between the RR and the ac/gas fridge on a new Winnie so any info would be much appreciated.

Brent

Brent - I am a recent convert philosophically and out of cost savings to having a residential fridge.  I was resistant because I liked the idea of being able to run a fridge on LP but after all of the trouble we've had with ours, I would never, ever have a gas fridge again.

When they break (and they will break), they are expensive to fix and not everybody can work on them.  There is an element of inherent risk due to the problematic heaters (can you spell recall after recall which didn't address the problem but only shut the fridge down in an overheat situation.)  They take a long time to cool down and I don't think they are very efficient.  Our residential fridge is simple, extremely energy efficient and it doesn't care what angle it operates on.

Energy management shouldn't be a big issue on 30 amp but I can't speak for the newer power management system.  With our 290 watts of solar power and a gen set, we're good for boondocking.

Thanks for the perspective John, I feel the same about the reliability issue. I think we will go with the residential fridge and figure out how to deal with the power issue on 30 amp, either with solar or perhaps a trickle charger plugged into the campground 15 amp outlet (if it has a separate breaker). In any event 75% of the time we will have 50 amp and we will only require 2 air conditioners a portion of the remaining 25%.

Soaringeagle said:

Tom, how long, if at all, are you able to run both a/c's on 30 amp? Did lowering your voltage cutoff help? Did turning the RR off help in running 2 a/c's and how long is it safe to do this. We are trying to decide between the RR and the ac/gas fridge on a new Winnie so any info would be much appreciated.

Brent

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Brent - since starting that post, seems like it was so long ago, we have never again run into a 30amp shore power issue.  But if, when, it happens again I will first try turning off the RR, next will be lowering the cut off voltage, then TV's and all the rest of the stuff .  Cutting off the inverter/charger is probably not an option, these batteries are way to expensive to risk damage.

One of the reason we purchased the new coach was to dump the Norcold unit.  Love the new RR, the contiuned 6 amp draw could be an issue if you do much boondocking.  The 2 extra house batteries, in our limited experience will give you about a day worth of RR run time..

Hey thanks for the response Tom, sounds like the RR is the way to go. I feel confident we will be able to deal with the power issues using some of the strategies you mentioned and maybe some external charging. Gonna decide between the Journey 42e and the Tour 42qd in the next day or so and put our order in. 

Soaringeagle said:

Hey thanks for the response Tom, sounds like the RR is the way to go. I feel confident we will be able to deal with the power issues using some of the strategies you mentioned and maybe some external charging. Gonna decide between the Journey 42e and the Tour 42qd in the next day or so and put our order in. 

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Both are great coaches, let us know which one you choose..

Ordered the 42e today with the residential refrigerator. I have a few days to get back to them on the factory solar option, 100 watt panel and charger for $900. Wondering if the factory option is worthwhile or is aftermarket the way to go, any thoughts appreciated.

Soaringeagle said:

Ordered the 42e today with the residential refrigerator. I have a few days to get back to them on the factory solar option, 100 watt panel and charger for $900. Wondering if the factory option is worthwhile or is aftermarket the way to go, any thoughts appreciated.

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The 42e is a great coach, congrats...  John, one of the Winny forum monitors, would be able to assist re: solar power options.

Soaringeagle said:

Ordered the 42e today with the residential refrigerator. I have a few days to get back to them on the factory solar option, 100 watt panel and charger for $900. Wondering if the factory option is worthwhile or is aftermarket the way to go, any thoughts appreciated.

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Congratulations!!  Good move on the fridge - you won't regret that decision.

100 watts for $900 - Hmmm.  From a parts/DIY perspective you can do a little better but to have it factory installed is worth the extra ~$300.  It is my understanding Winnie is using Zamp panels (I would ask who makes the panels) which are very high quality, here's their 95 watt panel.  If you want more panels, add three 150 watt Zamp panels and you are all set for boondocking with minimum gen time required.

I would like the specifics of the factory installed option, especially wire sizes and controller type and size. Here in Quartzsite you can get a 190 watt panel for $200.