Does AirCon damage Inverters over time?

[Al D]

Hello,

I'm trying to decide if I should put a $300 soft start on my air conditioner even though it runs fine on my inverter. I just don't want to take off years of life from the inverter if there's a better way.

Ironically, the AC costs much less than the soft start. The inverter was used on AMZ for $250. I'm sure I could dedicate a second inverter for less than the softstart, but I want to know if anyone has the answer, and more notably, to what degree of degradation occurs.

Thanks for your time.

Specs:
3kw PSW inverter that has handled the inrush previously.
5k BTU AC, <500w continuous power

 

[Bluedog225]

I suspect the surge shortens the life some. Depends on a lot of factors.

That’s a small ac and a small inverter. I’d just run it. And get a larger inverter, mini split, or soft start ac next time.

And welcome!

 

[Al D]

Thanks. I suspected the same. Wear and tear is expected from any use, and especially from high current draw. I was hoping someone could point out a general relationship of life expectancy and inductive load usage on an inverter. That would answer when the 'next time' will be ?

Speculations welcomed.
Ex: the electrolytic caps will probably blow first with high inrush.

Experiences preferred.
Ex: I ran my 5000BTU AC for 3 years on my old 3kw PSW inverter. Something to that effect.

Thanks again.

 

[PlaneBatteries]

Assuming this is a window shaker unit?
They do not make an easy start or soft start for window units.
"if " you were to spend that kind of money I would replace the AC with an inverter technology unit such as the Midea U shape window AC. The smallest they make is an 8k but it draws next to nothing and the inverter hit is next to nothing. They are amazing units

 

[rmaddy]

I have a 5k BTU window A/C unit that uses no more than 450W running full out. I use it on a 1600W inverter (Victron MultiPlus 24V 2000VA). I have no issues with startup or running. Though I have only run the A/C about 7 days in the last 11 months.

 

[Danke]

Do those soft start units increase compressor life?

 

[Al D]

@PlaneBatteries
I appreciate the recommendation. The current draw for the 8kBTU unit is about double what I was after. The AC I am referring to is a window unit. It is to cool my van, so even 5kBTU is quite powerful.

@rmaddy
Thanks for the anecdote. That makes me feel better about my setup.

@Danke
The soft start lowers the inrush current on inductive loads such as the compressor of an AC. The inrush lasts for a moment, but can be very high.if it's high enough, some lower power inverters can trip. I was hoping to ascertain how much degradation on my inverter I'll sustain over time by not having a soft start.

 

[Danke]

Understood, just wondering if it is also beneficial for compressors.

 

[Browse]

Watch this video. It is a technical discussion between a seasoned HVAC Tech/Owner/Trainer and the guy who designed the EasyStart. The Micro-Air EasyStart has many benefits and should prolong the life of your compressor.

 

[PlaneBatteries]

Ahh gotcha... yeah 5k should make it dead body storage capable ! lol

 

[efficientPV]

Amazing how a soft starter which should cost $30 coats so much

 

[Al D]

Not saying it shouldn't cost less, but there is a lot of time and development put into technology. You don't see it, but there are 100 failed devices that all had their own costs and will never show a profit. Companies can't make money on failed devices, but they can recoup it in the success. Also, marketing and sales expenses make it into the cost as well as other expenses.

Putting it into perspective: how long will it take you to figure out how to build this device (neglect the time taken for getting an EE degree)? Also, write a manual for how to use and connect it. Multiply that by how much you make per hour at your current job. What's the cost of your time spent?

You can see that the price for this (and most any tech, really) is a lot more than just the cost of parts. Side note: people have built their own. You can search YT. I certainly have. One person cited around $50 for the cost of parts. This didn't include the cost of any testing equipment. In the end, if you have the time and skills, it might be worth it. If you're just "good" at everything, this will probably cost you more time and energy than it's worth. I know I have unfinished projects that I could build, but just never did.

 

[PlaneBatteries]

Amazing how a soft starter which should cost $30 coats so much

Think you are confusing the soft start unit with a hard start kit (capacitor) - There's much more to the soft start unit internals and I don't think too many have the capability to build their own. Think of it as someone putting you in a wheel chair and gently shoving you down the hill vs getting a hard kick in the arse to get you going. That's what a hard start cap does

 

[Smoked~black16v]

There are a handful of YT videos with schematics of peoples soft starts they made. If all items are up rated properly any number of them would do the trick. once that's done you can send the schematic to a place that makes PCBs and they can turn your schematic into a board that is a simple plug and play.
soft starts are nothing new so the idea that there is crazy amounts of time in to them, i would agree only for making them compact thats it. I fully agree that 300+ is a price base on the fact no one is there to say "hey we can provide you the same for half the price" there isn't a big enough market.

hell amatherm has thermistors that can be used that will do the same thing, they just need a place to sit safely since they get really hot while the unit is running. Because A/Cs don't cycle on and off a lot, a thermistor would do the trick just fine because they would have plenty of time to cool off and regain there resistance for the nice startup

That's my .02 on soft starts... If i had to guess those units cost them under $60 to produce (easystart)

 

[73powerstroke]

Have run as many as 3 window ac units on my 3k 24v inverter. No issues yet. But I have a older 10,000 btu 1000w 10amp unit that gives it trouble just alone

 

[JRH]

Hello,

I'm trying to decide if I should put a $300 soft start on my air conditioner even though it runs fine on my inverter. I just don't want to take off years of life from the inverter if there's a better way.

Ironically, the AC costs much less than the soft start. The inverter was used on AMZ for $250. I'm sure I could dedicate a second inverter for less than the softstart, but I want to know if anyone has the answer, and more notably, to what degree of degradation occurs.

Thanks for your time.

Specs:
3kw PSW inverter that has handled the inrush previously.
5k BTU AC, <500w continuous power

Fwiw,,,, those little ac units are really long lived… I have used about 5 of them, different brands , in many situations.. they can make “life great again”… I wish everything worked that good.. just keep the filter and coils clean…
I have never had one quit on me , I just move and get a different used one. For 50 bucks ..so you will probably own it a lot longer than you think… good luck ….
jim..

 

[Al D]

Have run as many as 3 window ac units on my 3k 24v inverter. No issues yet. But I have a older 10,000 btu 1000w 10amp unit that gives it trouble just alone

Perfect. I am glad to hear stories like this. I just don't want to ruin my inverter. I know the inrush of inductive loads takes a toll on the inverter. I was trying to see the degree of degradation. Anecdotal stories like yours at least suggests the damage won't be seen for a while. I appreciate you sharing that information.

 

[Al D]

hell amatherm has thermistors that can be used that will do the same thing,

Resistors don't produce the phase change that the LC circuits do (like what can be found in a real soft starter). There's probably a reason why manufacturers don't use a cheap thermistor by default to ease the inrush.

 

[JRH]

Perfect. I am glad to hear stories like this. I just don't want to ruin my inverter. I know the inrush of inductive loads takes a toll on the inverter. I was trying to see the degree of degradation. Anecdotal stories like yours at least suggests the damage won't be seen for a while. I appreciate you sharing that information.

Your welcome.. but remember ,if you don’t have some of your toys giving you issues , not working right or is just plum broken, then you don’t have enough stuff in life…
good luck….
Jim.

 

[Smoked~black16v]

Resistors don't produce the phase change that the LC circuits do (like what can be found in a real soft starter). There's probably a reason why manufacturers don't use a cheap thermistor by default to ease the inrush.

My guess would be the 400 degree chunk of metal the entire time it's running...

Either way, who ever mentioned softstarts cost a lot I agree. I feel they cost to much for what they are. But people will buy them ?

 

[Danke]

Wrote Sol-Ark if the inverter would benefit from soft start devices, their response:

The soft start devices can lessen the in rush current or start up current, often seen as LRA, for the larger inductive loads. These are usually installed
to help prevent the inverters from overloading. If the system is able to start the air conditioner without the soft start, adding one will typically not be
as beneficial. It can still reduce the impact of start up current and allow for other loads to be turned on at the same time.

 

[Al D]

Wrote Sol-Ark if the inverter would benefit from soft start devices, their response:

Wow! That's awesome news! Thank you for that.

 

[RCinFLA]

The term 'softstarter' is not precisely correct for the newer Easystart, SureStart, and other similar microcontroller-based units.

A hardstart kit increases the capacitor in series with start winding (parallel to run capacitor) during startup period to increase rotation torque during startup by making the current phase shift between run and start winding close to 90 degrees for the start period. It actually increases the motor startup surge current a bit but shortens its length of time by about 50-75%. The extra cap is disengaged after motor gets near run speed. The extra start capacitor is typically disengaged by start winding back EMF voltage across start winding that rises when motor comes up to speed. This is used to pull in a relay to disengage the extra start capacitor. Sometimes a PTC thermistor is used for lower power motors. The PTC thermistor is typically used on a refrigerator compressor.




A pure softstarter is a triac 'light dimmer' that effectively ramps the input voltage to the motor during startup. It reduces the startup surge current but makes it last significantly longer in time. It does not provide the optimum 90 deg current phase difference between run and start windings that yields the best rotational torque during startup period. (Proper run capacitor value optimizes the 90 deg phase shift during running period, but not during startup). This is what you find for three phase induction motor softstarters, in typical industrial applications.

Both these approaches, individually, rarely solve the startup issue with excessive startup surge current on battery powered inverters or generators.

What the newer units have are both methods combined. The extra start capacitor, along with run winding are voltage ramped during startup. The microcontroller initially searches out the optimum voltage ramp for a given motor setup by several initial startup cycles, progressively reducing the startup ramping voltage until compressor gets close to a startup stall. This achieves a significant reduction in startup surge, 60-70%, without significantly extending startup time period (typically 0.4 seconds)



Be careful of surge current specs on inverters, particularly HF inverters. A few millisecond surge capability is pretty much useless. You need at least half a second of surge capability to start a typical induction motor.

 

[chess-equality]

When turning on, I put the aircon on fan mode first for several seconds before switching it to cool mode.

When turning off, I put it on fan mode again before finally turning it off.

An aircon salesman told me this many years ago as a sort of "soft start". When we bought our inverter aircon 6 years ago, the salesman told me newer aircons are much more advanced that they don't need a soft start.

Well, I still do this practice. Our first unit lasted 14 years; the newer one is 6 years old and still doing very good, and is connected to my inverter.

Kolin Quad Series Window Type Full DC Inverter with Smart Controller

 

[SparkyJJO]

Doing that basically is preventing a double surge at the same time (blower and compressor). Not really a soft start per se, just not a double punch in the gut.