Share your AC easy start results...

[BAP911]

I'll repeat what I just posted in another thread. A squirrel cage induction motor, like the one that powers the compressor on those A/C units will normally pull up to 4 TIMES the current on start up vs. running amps, WITHOUT a soft start unit installed. That initial inrush of current only lasts milli-seconds, but it is there, none the less. That is called Locked Rotor Amperage (LRA) or Locked Rotor Current. And using a Hughes watchdog, is simply not fast enough to catch the actual inrush current, that's why it is showing you that 15/16 amps on start up. When you get into 3 Phase Induction motors (a bit off topic here), they can sometimes pull up to 7 times the FLA (Full Load Amperage). If you ever get a chance to look at the data plate on one of these A/C units (it's probably a sticker under the cover of the unit up on the roof), look for the current draw at LRA. I've seen 53/54 amps for the LRA on a 15K BTU unit before, so seeing a 50A inrush on start up, without a soft start, is totally normal. If the outside temperatures are very hot, that number can be even higher, depending on how quickly the unit cycles off/on and whether or not the refrigerant in the cooling loop has had time to equalize between the high side and the low side of the refrigeration loop.

Thanks for providing a great detailed explanation. Before I installed my easy start, inrush draw was 58.7a. The only thing you didn't mention was that you need a decent clamp on amp meter with Inrush capability. Even with easy start my 2000 watt generator is generally over loaded at the 5,000' elevation where I live, and always beyond capability at 8,000' where I camp. I have to use 2 gen in parallel.

[xrated]

Thanks for providing a great detailed explanation. Before I installed my easy start, inrush draw was 58.7a. The only thing you didn't mention was that you need a decent clamp on amp meter with Inrush capability. Even with easy start my 2000 watt generator is generally over loaded at the 5,000' elevation where I live, and always beyond capability at 8,000' where I camp. I have to use 2 gen in parallel.

You're welcome, glad I could offer up some detail as to the why and how of the motors and soft start. Yes, you absolutely will need a meter that is capable of capturing peak/inrush and holding that reading for your viewing pleasure. I'm not surprised at all seeing that kind of inrush current, but then again, I've been in the Electrical field since 1977 when I started my apprenticeship and then topped out at the end of 1980. Thankis for the kudos.

[toolman.dustin]

Okay smart people, maybe you can help me understand this... I read an amperage of 14 while the AC is running connected to my 50/30/20 amp pedestal at home (connected to the 30 amp plug as my trailer has one AC and 30 amp cord). Then I go to my niece's house and plug into a 20 amp circuit with an adapter and read 11 or 12 amps on the AC while it is running. Is the lower amperage due to the wiring in the shed, or because the adapter, cord, or amperage draw outside the shed is dragging amperage down?

I guess I am trying to understand if low voltage/amperage situations exist because the power "source" (shed in this case) is underpowered, or if the various items drawing power can create a low voltage situation. Does this make sense? So if you took a reading at the AC could it show a lower voltage than taking a reading say at the wiring inside the shed before the electrical outlet? Or are the two not separated that way? Yikes, I don't know how to explain the question...

Chad,

Interesting thread, I just spent several days studying this topic so since you're trying to understand how the softstart works, these links will help.

https://www.youtube.com/watch?v=7Gim96oyczw&t=686s

https://www.softstartrv.com/differen...nd-soft-start/


https://hvacrschool.com/videos/hard-...eo-giovanetti/


This is a lot of work to read and understand, but after a few hours of reading it over and over and doing some research this makes a LOT of sense.

https://www.forestriverforums.com/fo...ow-236115.html

If you want more info, let me know, I have more links that were offshoots of these "learning" links.

Dustin

[dpisano]

You could always pose that question to @jkwilson He is a retired electrical engineer.

The breakers we all have inside our homes or RVs are thermal-magnetic circuit breakers, which have bimetal switches and electromagnets used to trip a breaker. The excess current causes the bimetal to heat and "open". As others have said, an in-rush of 50A for a few milliseconds is not going to be present long enough to generate the heat. Electronic breakers have a time and instantaneous setting, which is inverse of current and might trip, but not thermal breakers.

[dfleming103]

As already stated you will Never see the actual in rush current drawn by your AC units unless you use an oscilloscope.. the various BT applications and multimeters are not fast enough to measure that in rush current

Most RV A/C units don’t with their versions of soft start. Some units .. such as the older Brisk Air II and Penguin II don’t even have a start capacitor in the circuit so a good SoftStart unit or MicroAir unit would actually help these units

Many of the Coleman and Dometic NXT series come with a start capacitor and timer relay …it’s their version of a soft start..

It’s nit a very good circuit addition and has a tendency to fail a lot due to excessive heat at the terminal connections…

Hey Viper,
Sorry if I am interpreting this wrong, but are you saying that the new coleman/dometic units would not benefit from the addition of a soft start? Are you saying that soft starts are not a very good circuit addition, or the start capacitor and timer relay they are adding are not a good circuit addition... Trying to read between the lines, I may have landed in the ditch.

[Viper02]

Hey Viper,
Sorry if I am interpreting this wrong, but are you saying that the new coleman/dometic units would not benefit from the addition of a soft start? Are you saying that soft starts are not a very good circuit addition, or the start capacitor and timer relay they are adding are not a good circuit addition... Trying to read between the lines, I may have landed in the ditch.

What I said and mean is the newer Coleman and NXT series AC units use a cheap start capacitor and resistor and call it their “Quick Start”.. it is better than no form of in rush amp control but is .. IMO a cheap circuit and cheap part sold at an over priced amount when it fails…

And this OEM circuit is prone to failure

Want a true easy or soft start? Then spend the bucks and buy either EasyStart or MicroAir and then you have a much better circuit that should last a long time

This is the typical OEM quick start module … pure junk..l

https://parts.unitedrv.com/products/...pacitor-w-ptcr

[dfleming103]

What I said and mean is the newer Coleman and NXT series AC units use a cheap start capacitor and resistor and call it their “Quick Start”.. it is better than no form of in rush amp control but is .. IMO a cheap circuit and cheap part sold at an over priced amount when it fails…

And this OEM circuit is prone to failure

Want a true easy or soft start? Then spend the bucks and buy either EasyStart or MicroAir and then you have a much better circuit that should last a long time

This is the typical OEM quick start module … pure junk..l

https://parts.unitedrv.com/products/...pacitor-w-ptcr

Got it, Thanks Viper. I was a little worried that I wasted my money! I acquired two of the micro-aire and was just waiting for a good time to install them. I'm guessing that the capacitor and resitor on the coleman units gets disconnected when you install the micro-air devices.
Again Viper, thanks for the insight.

[Ynot4me2]

Just got my Softstart BT today. Hopefully it will go in this weekend.

[lfytsmith]

Posting this thread because I am confused about what I read online about RV AC amperage draw. Curious to know if anyone has had the same results as me. I have a MicroAir Easy Start with Bluetooth. I installed it so we would be able to run air when on a 15 or 20 amp circuit and because I have a Honda 2000i generator which I would use occasionally. Many articles and threads say that the startup load for their AC is much lower than what I experienced prior to and after installing my EasyStart and wondered what others have seen.

During the "learning" phase of installing the EasyStart, the Bluetooth app indicated that the initial compressor startup was drawing 50 amps. After the learning process was complete and to this day, it shows the initial draw is about 23 amps. The running draw post-startup average is 12-13 amps. Of course that initial burst only lasts milliseconds, but the purpose of the EasyStart is to "soften" that initial draw. It does not affect the running amperage at all; this is according to MicroAir.

What confuses me is many say that their initial draw is 16 amps or less and the running amperage is often listed in the range of 8 to 10 amps. I've never seen my start up less than 22 amps, and running amps less than 12. Anyone care to share their experience thoughts? Did anyone else see an initial draw as high as 50 amps prior to installing an easy start? I also wonder if someone seeing an 8 amp running draw is on a 15 amp circuit and perhaps receiving low voltage thus dropping the amperage reading? Or wouldn't that even make sense? Thanks.

I have great success with my MicroAir easystart. I installed an AC meter and can watch the amperage slowly climb until the air conditioner starts. My 16k usually runs between 14-16 amps. I also found that it will draw over 1700 watts which is more than my Champion 2500 will tolerate on propane and I must switch to gas with a max of 1850 watts.

[USA in a Chevrolet]

Inrush or LRA is a real thing and pain in the... When ever we have a Data Center that crashes and comes back up, some of our safety breakers will trip. Especially in the high density computing racks. Grrr. Just to much current at once from multiple devices.
My question which is kind of spinning off is, is the Bluetooth feature worth it? I was hoping to get my Microair with BT before my next trip but they are still back ordered unless I pay a hefty fee. I can however get a softstart for a little less. But the geek in me wants to see the numbers. Lol

I did not buy the Microair with Bluetooth. My Victron Cerbo 50 display shows the wattage used by my ac system. It is a second or two delay & the display shows total wattage used by your ac system but I can compare wattage being used before the ac kicks on to the usage as the ac starts. There is an initial increase as the fan comes on which increases as the compressor comes on. That info is good enough for me to believe the Microair is worth the money from a technical perspective. The fact I can run both AC units on 30 amps satisfies my practical needs.