A/C Soft Start Surprise... in a good way

[creativepart]

We live in South Texas. It.s ~100 every day. When RVing in 100 degree temps you want both A/Cs running. No ifs, ands, or buts. But not every place you camp can supply 50amp to your RV.

Our favorite State Park, is South Llano River SP in Junction, TX which is 100 mi west of our home. But, it's a 30-amp SP. So, we generally do not go there when temps are mid-80's and up. So, a few weeks ago I had an A/C soft start installed on both A/Cs. And now, next week we'll put that to the test for 4-nights at that SP in Junction. Temps are forecasted to be HOT 90's plus.

I brought the RV home today to do a little work on it and to begin loading for Sunday's trip. We have a 30-amp outlet installed in our Garage so this is the first time to try out the two A/Cs on 30-amp.

I waited until the batteries were fully charged and the residential fridge cooled to regular temps and then turned on the front A/C. I let that run for an hour or so and turned on the inverter. Why the inverter when on shore power? I'll get to that in a minute.

I noticed it was pretty hot in the bedroom area even though the front was cool so I looked over the Precision Circuits EMS to see what the status of things was. All was good and no loads shed. So, I fired up the bedroom A/C. I saw the load ramping up but slowly and kept my eye on the EMS power display. What happened then was very satisfying.

The way Winnebago outfitted this Adventurer with a 2000w Magnum inverter and connected it to the EMS is working really smart. The first thing the EMS did when I started the 2nd A/C unit was it turned off the battery charger, put it on standby. The next thing it did was it took 2-amps from the inverter to help with the 2nd A/C startup. Then once that 2nd AC was running strong and cool it stopped taking amps from the inverter and turned the battery charger back on.

How cool is that? Very cool in my book. With the EMS and the Inverter it's like having a Victron Hybrid inverter charger that adds power when needed. But it came stock with my RV.

OK, this if the first test. Let's see how 4 nights in 90 degree weather really does.

 

[Morich]

The newer electronics can be great if it doesn't get over into some of the "fuzzy" side items that cause me to wonder if it is just too much added to make it too complex to last long!
Sounds like it is a good start on great for what you are needing?

I noticed how much smaller and neater the spacecraft they launched this morning and thought some of that might be better electronics!

 

[RayIN]

Morich has a thread here somewhere about the whole RV soft start unit. A retired electrician gave his view of soft-start units, which is very interesting.

 

[Scotty B]

I like that my coach is smarter than me, too!
What would have happened without the soft start? Would it have shed the other AC?
We did not have any issues running two at the same time in Canada last year on 30 amps. Would just have to turn one off to run an appliance.
Only shed something when we forgot to do that...
The two ACs together run 22 amps. Maybe some improvements made there, too

 

[creativepart]

Before the soft starts you could start one and get it's compressor running and then wait a minute and start another but sometimes the front would drop back to fan only while the compressor started on the 2nd A/C. From that point on it would go back and forth between the two, running the fan all the time and the compressor switching back and forth.

It will be interesting to see if I can run both A/Cs and use the microwave via the boost from the inverter. I'll guess that's a bridge too far.

 

[CrispyBones]

Some great info. Thanks, Creative.

 

[bigb56]

I may have missed it in another thread but which soft start kit did you go with? I have this one: https://www.amazon.com/dp/B09WHDXDYG?psc=1&ref=ppx_yo2ov_dt_b_product_details sitting on my workbench right now, we don't really need a soft start and I wasn't going to spend the money but this one gets good reviews and is only $150. I understand it doesn't do anything for the fan motor, it's a compressor only 3 wire model.

The reasons I have for trying one is
1. possibly easier on my AC unit
2. eliminate the loud thump every time the compressor cycles when we are sleeping
3. The remote possibility that I may be able to power our 13.5K unit with my old Honda EU2000i inverter generator.

I plan to install it this weekend before our next trip to the Pacific Coast.

 

[Americanrascal-WO]

I have got to do some practicing on my new Softstartup plug unit. My RV is set up very similar to Creativepart's. First attempt on a 30 amp plug in it started the 2 heat pumps fine. But as soon as I turned on the residential fridge it didn't like it and threw the power management system into a brown out warning and shut down when it apparently shot over 30 amps??.Had to be the compressors making the draw as it was only showing about 24 - 28 amps total on the panel.

I am going to give it a real work out over the next couple of weeks as we are sitting in Biloxi (hotter n' blazes) on our way to the Hill Country in TX (twice as hot as blazes) for a few weeks at the kids place. They have offered dear old dad their 30 amp connection in Dripping Springs. I hope we get more out of the Sorftstartup than I did on my test run. Otherwise we may bake in the rig?

Fingers crossed or the new Softstartup may be my new wheel chock.

 

[creativepart]

I may have missed it in another thread but which soft start kit did you go with?

I got the Coleman-Mach soft starts that are made by the A/C manufacturer.
https://www.amazon.com/dp/B0CF41ZW4W

 

[creativepart]

Not so fast!

OK, day two of camping in 97 degree temps with 30-amp service.

Here’s what I’ve learned… first, even with installing soft starts on both A/Cs there is only so much running both A/Cs can do in an motorhome when it’s over 95 degrees outside. It would be worse if I couldn’t run both A/Cs but even with two it is currently 78 degrees inside because it’s almost 98 degrees outside.

Next, whatever made my inverter chip in a few amps that first day has gone back to fairy tale land. I’ve never seen it do that again. I’m keeping the inverter off to prevent it from using power while idling.

The Precision Circuits EMS does a great job of letting you run the microwave, the toaster oven and the coffee maker. It sheds the bedroom A/C while the appliance is running and quickly switches back to zero loads shed when done. I had hoped that with the inverter running it would take power from the inverter, but no.

Guess I need to pull out the 2000w Magnum inverter and install a Victron Multiplus II to get that kind of result. Maybe one day…

 

[bigb56]

What size are your units, and have you figured out what the running amps are on each one? My Progressive EMS is reporting 15-16 amps on my 13.5K unit for about a minute then it drops to 14-15 amps. I'm just curious since my Honda is rated at 16.6A max and 13.3 A continuous. Could be the EMS is not that accurate, will have to try my Amprobe. (I realize the soft start doesn't affect running amps)

There's a lot of guys on the Sprinter forum that have that setup you are working on where the inverter kicks in automatically to help out but I'm not sure how that works.

I also have a dark brown roof over the cab area which I meant to paint white this past winter but didn't get around to it, I think if you have a dark cap it soaks up a lot of heat.

 

[creativepart]

I have 13.5k btu A/C unit in the bedroom an 15k btu in the lounge. The EMS shows both units using 28 amps, 13 + 15.

The Magnum manual says it can supply extra amps via the inverter, but it seems the EMS doesn’t ask for it to do so. It knows the inverter is there and shows it on the panel display- shows it on or off. But that’s about all except for that first time when I started this thread. I have a vague memory of seeing it add inverted amps one other time, but I don’t know how to repeat that performance.

 

[bigb56]

I have 13.5k btu A/C unit in the bedroom an 15k btu in the lounge. The EMS shows both units using 28 amps, 13 + 15.

The Magnum manual says it can supply extra amps via the inverter, but it seems the EMS doesn’t ask for it to do so. It knows the inverter is there and shows it on the panel display- shows it on or off. But that’s about all except for that first time when I started this thread. I have a vague memory of seeing it add inverted amps one other time, but I don’t know how to repeat that performance.

Is it possible that the Coleman soft start is self learning like the Micro Air? If so, maybe it "learned" the current needs of your unit and adjusted itself accordingly in order to lessen the load on the power source. Mico Air says their units take 5 starts to learn.

 

[creativepart]

Maybe, but I was told that since I purchased the model made specifically for my Mach 8 A/C units that there was no learning needed.

 

[Scotty B]

Sounds like it was a successful mod for you Paul - congrats! One AC in 100 degree heat would have been real uncomfortable. I would imagine it doesn't cool down much overnight where you're at either which would make it more unbearable.
You're all ready for another Canadian adventure!

 

[bigb56]

I didn't like the $150 Spartan Soft Starter. It did quiet the startup thump but my Honda 2000 still struggled to start my unit on ECO mode even if I started the fan first. So I returned it and ordered the Micro Air Easy Start and what a difference! I can now run my AC on a Honda 2000 on ECO mode at 2,200 feet and the Honda doesn't even skip a beat (It came close to stalling with the Spartan unit). It's also a very quiet startup, it starts the fan first which is actually the loudest part, then 5 seconds later you can barely hear the compressor start. The BT App shows starting current between 11 & 12 amps after the 5 learning starts.

It also has a 3 minute compressor short cycle delay which I always wanted because when you lose AC power momentarily the wall thermostat stays energized on the 12 volt system so you get no delay when the power comes back and the compressor struggles to start against high head pressure which is not good for it. I had remedied this by setting my EMS to delay for almost 3 min on every power up but I didn't like waiting for power in the rest of the coach. Today I reset that back to 15 seconds.

So like you, I am very happy I did this, and my testing also proves you get what you pay for. The Spartan is not a bad unit but doesn't do the superior job of the units we used and not worth the savings.

 

[bigb56]

Update

In case anyone comes along in the future and thinks they can run a 13.5 on a Honda 2000, it doesn't work. At first I thought it would because it started and ran fine but I didn't let it run long enough. After about 10 min the Honda cut power due to overload.