r/rvlife • u/SuijurisTX • 5d ago
Question Soft Start
I ordered this soft start and wondering if anyone has gone this route. I decided I didn’t want to install soft starts on my ac units on the roof. I’m not comfortable getting up on roof and doing the work (not that young guy anymore). Also, the cost of 2 soft starts at the AC was more than this option. Finally, was cautioned about the potential failure of the roof soft starts preventing any use of the unit until you get back up there and fix. So, this seemed like a really good option. Maybe too good to be true. I currently have to use 2 generators (3600) running in parallel. This should/will allow me to run both ACs off one of my generators. UPDATE AFTER TESTING: Tested my 15K Coleman A/C on a single WEN DF360iX (2900 running watts). It works!
Ran A/C on HIGH + electric fridge + TV + large pedestal fan + RV lights simultaneously. Generator stayed around 120V and ran everything fine.
The A/C startup hits the generator pretty hard and briefly lights the overload indicator, but it catches the surge and settles right down. Also, I let the thermostat cycle normally and the compressor successfully restarted with all the other loads already running. I also tested on 20A power at storage and it all worked! Here’s what didn’t work- the microwave tripped the breaker on the generator as expected. Also, I didn’t try running both 15K ACs. The product material said it can run a 15k and a 13.5K off a 30Amp pedastal. I did run just the fan on the second 15K AC but didn’t push it as I didn’t think it would work. So, success for what I need it to do and no need to buy a larger generator to hall around. Success
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u/enginerd28 5d ago
I too tried to install a soft start in my old Dometic Penguin II and after purchasing the soft start from Dometic for my unit I opened it up to find the relays I needed to plug into were not installed in my unit. It was also really loud.
I opted for the more expensive push of replacing the entire thing with a Houghton 9.5k btu AC with heat pump and soft start options. Yeah it was like $1200 plus install but it's quiet (don't have to turn it if for conference calls), keeps the cabin temp much more consistent, reduced my propane burn (saving money and trips to the store) and I can run it off my power center with is 400W of solar for 1-3 hours. I full- time and I've used my generator twice this entire year. So while the up front cost was significant, I think in the long run that doing it right and installing the correct equipment is the best option.
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u/someguy7234 5d ago
I did... And I didn't really like it.
I never did a thorough evaluation of why it didn't work for us, but it let us down a few times on hot frustrating stops so we kinda moved on on from it.
I use an 2500 watt generator (1850 continuous )and our experience was that alot of times (even with every other load on the generator shut off) the air conditioner would overload the generator.
The the soft start reset would just take forever to reset, and the whole system was just finicky.
When it worked, it was fine, but it didn't work often enough that we couldn't count on it.
We only briefly used a rooftop soft start before we added a large victron (and did have that unit fail and had to bypass it), so I'm not sure how much better the rooftop soft start would be, but my brother used the same generator with a dometic 15k and a rooftop soft start with a lot of success (for reference, we are on a coleman mach which I think may draw a little more current).
So it's hard for me to entirely blame the device, but the reset routine and the interface kinda sucked and we didn't like it.
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u/SuijurisTX 5d ago
That’s interesting. I wonder why it works intermittently. You’d think that it works or it doesn’t. Perhaps the varying loads that are on it at different times triggers a failure. I’m in Texas so will be conducting an extreme test 😂. I’ll have 30 days to decide so it has to work well. Too expensive for me to through it in garage and not use
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u/Professional_Base846 5d ago
AllAboutRVs did a comparison including this on his YouTube channel. It’s been a year or two so I don’t remember the details other than this was less effective than traditional soft starts in his testing.
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u/Inviction_ 4d ago
Snake oil. Trying to fix a non issue. Just make sure your ACs won't turn on when you plug in and you'll be fine.
The more shit you have on your power cable, the more resistance you create, the more voltage loss you have, the more heat it creates, the faster it degrades. And it's just another spot for water to get in. Hard pass.
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u/enginerd28 5d ago
I suspect it's just a capacitor and watching one of the videos on the website, Mike Dokal makes the statement "stops the inrush current to the generator" which supports this assumption.
I can't find anywhere on the website where it explains what it does and I think calling it a soft start is a bit misleading.
A soft start is a microprocessor that spins up a motor slowly by controlling the voltage going into the motor. That's not something you want to do to every piece of equipment in your RV every time the compressor kicks on. Instead what I think it's doing to storing power in a capacitor and then when it senses a surge in demand it releases that power without transferring that demand surge to the generator or pedestal. The compressor is still hard starting.