SoftStart unit?

[roadbiker1]

Hiya.. anyone used this thing on their CoolCat Dometic A/C? The poor Onan 2.8 sounds like it is going to hernia when this thing kicks on. "Currently" "on sale" for the "low price" of about $270.

The testimonials routinely say they can run their A/C on a 2K Honda with this soft start thingie. Anyone done this?

And beyond all that, anyone put a scope on this unit? The manufacturer claims it "ramps up" the juice to the A/C compressor, so let's chat about how. Only guess I have is something like triac or quadrac devices being fed a control voltage that does the ramping, and would control where in the AC cycle the quadrac device conducts to send on to the A/C compressor. Note the words
"only guess" and "something like" above, not claiming much here ;- )

Cheers

[Bud]

Originally Posted by roadbiker1

Hiya.. anyone used this thing on their CoolCat Dometic A/C? The poor Onan 2.8 sounds like it is going to hernia when this thing kicks on. "Currently" "on sale" for the "low price" of about $270.

The testimonials routinely say they can run their A/C on a 2K Honda with this soft start thingie. Anyone done this?

And beyond all that, anyone put a scope on this unit? The manufacturer claims it "ramps up" the juice to the A/C compressor, so let's chat about how. Only guess I have is something like triac or quadrac devices being fed a control voltage that does the ramping, and would control where in the AC cycle the quadrac device conducts to send on to the A/C compressor. Note the words
"only guess" and "something like" above, not claiming much here ;- )

Cheers

Either 2K Honda or 28/2500 Loud onan will run a Cool Cat.

That is IF all is running ok. If there is a problem with the LOUD or quiet generator, the whatever can assist in the Cool Cat continuing to run.

So, yes this 'kind' of solution is doable, If Needed.

ymmv

[hbn7hj]

Yep, I installed an EasyStart. It looks the same as the Soft Start. I haven’t asked if they are from the same source or Soft Start stole it. Easy Start was first.

Don’t need to put it on a scope. It makes a world of difference. Keeps you from having heart failure when the compressor kicks in. EasyStart will send you a schematic on how to install it on a Cool Cat. The bad news is the Cool Cat has to come off the roof to do it.

[jakegw2]

I went a different route and installed an extra starting capacitor on my AC unit. It doesn't provide as much starting relief as something like the Easy Start, but it made enough of a difference that my 2k inverter can start my Mach 10 without issue (as long as I am not trying to run the fridge on 120V at the same time). It is easier to install and only cost about $20 on Amazon.

Suppco SPPE6E

The extra capacitance stores enough energy to reduce the locked rotor amp requirement from 63A (according to the AC spec sheet) to somewhere south of 30A (the max instantaneous supply my inverter can manage per its spec sheet). I don't have an ammeter that can measure instantaneous peak values, so I can't report exactly what is going on, only that everything works with the extra capacitor installed.

[peteco]

Originally Posted by jakegw2

I went a different route and installed an extra starting capacitor on my AC unit. It doesn't provide as much starting relief as something like the Easy Start, but it made enough of a difference that my 2k inverter can start my Mach 10 without issue (as long as I am not trying to run the fridge on 120V at the same time). It is easier to install and only cost about $20 on Amazon.

Suppco SPPE6E

The extra capacitance stores enough energy to reduce the locked rotor amp requirement from 63A (according to the AC spec sheet) to somewhere south of 30A (the max instantaneous supply my inverter can manage per its spec sheet). I don't have an ammeter that can measure instantaneous peak values, so I can't report exactly what is going on, only that everything works with the extra capacitor installed.

Great. Could you please describe the installation process?

[mloganusda]

Here is an article about the Soft Start that he has installed. Also great reading at RVtravel.com that covers a lot of RVing. If you like the newsletter, contribute as the newsletter is all on line.
https://www.rvtravel.com/rv-electric...-hrdl-testing/

MLogan
2017 Trend 23D
Smyrna, Tn

[InterBlog]

EasyStart, installed so that we could run our 11,000 BTU roof a/c off our lithium battery, but it works very well for generator use also (inrush current was too high to start on battery without it).

That thing has a mind of its own - a GOOD mind. I turn on the roof unit and wait until it makes the decision to proceed with powering it up.

I have read that the latest gen roof a/c units, the better ones, come with an EasyStart-type mechanism built in.

[jakegw2]

I didn't do it myself, I had it done by the RV shop when they installed my inverter. However, my understanding from looking at the instructions (and having worked on my own central AC unit) is that it is very simple. The Suppco comes with two wire leads that have slot connectors already attached. These are attached to the two sides of the existing starting capacitor so that the two are in parallel. Strap the Suppco to something secure inside the AC housing with a zip tie and call it a day. Something like the Easystart has a bit more invasive installation requirement where you have to connect not only to the start capacitor but also track down the leads to the compressor and connect it to them as well.

The Suppco is not the same as an Easystart, but it is also not just a regular starting capacitor. It has a built-in relay at the top that engages it only when the motor is starting. From what I have read this combination of relay + extra capacitor cuts the startup draw by close to 50%, whereas a soft-start unit like the Easystart can cut it by closer to 66%. The difference in price is significant however, $25 vs. $300. If the Suppco is sufficient for your needs it is a very economical and simple option.

For my installation the Suppco works, but I would consider a soft-start unit in the future since I cannot start my AC on the inverter unless it is the only AC load when it starts up. With a soft-start I would have enough remaining headroom to be able to run minor loads alongside the AC, which would be much more convenient (I have made this mistake more than once and it is annoying to have to reset the inverter because I forgot to turn everything else off before starting the AC).

[mloganusda]

I installed the easy start capacitor on my Winnebago Trend last year and there were 2 capacitors already there, but installed anyway.

MLogan
2017 Trend
Smyrna, TN

[rvsprinterguy]

Based on the comments I've read here, the Supco capacitor seems worth trying. I have a Honda EU2200i that I'd like to have reliably be able to run my AC when boon docking.

I appreciate the tip!

[rvsprinterguy]

I ordered a Supco Hard Start Kit and installed it on my Coleman Mach Roof Air unit. I am able to start the AC using only my Honda EU2200i. Before, when I tried it the generator was overloaded and power was cut to the RV. Now, the generator speeds up for a couple of seconds as the AC starts, then settles back down. I'm happy with this purchase.

[JebTN]

I have been looking for something that will take the sharp thump out of my AC everytime it cycles on. Sounds like any of these start kits would help. Which would be best the EasyStart or would the SoftStart do the job. Not really looking at this with the generator in mind but that would be a plus.

[rowiebowie]

Either unit should work for you. If I recall correctly, previous comments were that the Easy Start came out first and the Soft Start copied them.

[bwatters60]

Before going thru the effort to install an EasyStart or SoftStart unit, I would recommend ensuring that your Onan generator is producing the proper voltage at the proper frequency. My Cool Cat used to start with a bang, and running on the Onan it would bog the genny down upon startup. Per my Kil-A-Watt meter, the Onan was putting out only 108VAC at 55 Hz no load, which is out of spec per the Onan KV maintenance manual - excerpt attached). Since both were low I was able to bring output up to spec by adjusting speed adjustment screw (increase Onan rpm) so that it now reads 118.4VAC at 61.7 Hz, no load. While running the Cool Cat (w/AC or about 2/3 load on the Onan), the genny now puts out 117.4VAC at 60.5Hz. The Cool Cat now starts smoothly and runs great with the Onan. The same can be said about the Cool Cat on the shoreline after I replaced the original Roadtrek shoreline connection with a SmartPlug.

[rowiebowie]

Originally Posted by bwatters60

Before going thru the effort to install an EasyStart or SoftStart unit, I would recommend ensuring that your Onan generator is producing the proper voltage at the proper frequency. My Cool Cat used to start with a bang, and running on the Onan it would bog the genny down upon startup. Per my Kil-A-Watt meter, the Onan was putting out only 108VAC at 55 Hz no load, which is out of spec per the Onan KV maintenance manual - excerpt attached). Since both were low I was able to bring output up to spec by adjusting speed adjustment screw (increase Onan rpm) so that it now reads 118.4VAC at 61.7 Hz, no load. While running the Cool Cat (w/AC or about 2/3 load on the Onan), the genny now puts out 117.4VAC at 60.5Hz. The Cool Cat now starts smoothly and runs great with the Onan. The same can be said about the Cool Cat on the shoreline after I replaced the original Roadtrek shoreline connection with a SmartPlug.

You make a good point. When I first go my van, the generator also had low output (almost exactly what you describe), yet it still ran the roof ac. Though not good for the ac.

Using the troubleshooting advice in the Onan manual, I increased engine speed until I was getting 60Hz and 128 volts. When powering the roof ac, voltage drops to about 119.