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freewayrandy49's avatar
freewayrandy49
Explorer II
Jan 31, 2024

A/C amperage draw?

How many amps should a 15K a/c pull at startup? I have a new Cougar 5er and am going nuts getting a generator that will run my a/c on boondock trips. I had soft start installed when I bought it. So far I've tried a Generac 3300, a Champion 4650, now a Predator 5000 and all have overloaded at a/c startup! A friend came over and did a amp draw test and the rig pulled 42 amps at startup! Could I have a bad soft start? Was it wired wrong?  Totally frustrated!!!

  • Assuming it's running on 110v, then a 5000 watt generator is 45 amps (watts/voltage=amps), if it's 120v then it's 41.6amps.  Either way that should be surge current and will decrease once running.  However, if you have other things running at the same time that are already pulling current, then the total load during that surge can be very high.  

  • a 15K will run on a 30amp breaker no issues, the start up should be way less than 30amps considering the running amprage is around 14 to 16 depending on the brand.  I would find out about the soft start on it and if it is hooked in right or if it is even in good shape.  is it a digital soft start of a capacitor setup and does it still use the factory capacitors.  if so there might be a bad capacitor as that will cause an unusualy high starting current and is easy to check and replace.

  • Does it pop a breaker if you run it off a 15-20A household circuit?

    From what you said, it will, but idk, something don’t sound right. The odds you got 3 junk 2nd rate generators is quite low, but the odds of a 2nd rate generator performing like it should are a bit higher. 

    • nickthehunter's avatar
      nickthehunter
      Nomad II

      Grit_dog wrote:

      Does it pop a breaker if you run it off a 15-20A household circuit?

      From what you said, it will, but idk, something don’t sound right. The odds you got 3 junk 2nd rate generators is quite low, but the odds of a 2nd rate generator performing like it should are a bit higher. 


      The generator isn’t the problem (1st rate or 2nd rate) if the A/C was pulling 42 amps at startup as the OP stated.

      • Grit_dog's avatar
        Grit_dog
        Navigator

        Oh ok. Sure the soft start might not be working and if not, a 15k will pull a min 30-35a briefly and easily could be more (on startup). 
        if it only pulled 16-18amps then soft starts wouldn’t have been invented. lol. 
        Just being helpful, buddy. 

  • Yeah doesn't sound right.  Those size generators seem like they should run the AC even without soft start.  With soft start installed when you got it, I assume you can't confirm if the AC worked before soft start?  soft start is supposed to go through several cycles of compressor startup when on true shore power so that it can be "trained" on the AC's startup profile, do you know if that happened?  Although I'm not sure how that could describe this, I remember it is a thing.

  • Why does the User/OP show "not applicable"? Their name/user name is gone. 

    • StirCrazy's avatar
      StirCrazy
      Moderator

      because he was never a member, he browsed the site as a visitor and posted a question.  

  • It should only draw about 16-18A on startup and about 13 when running. I can run one AC on a 20A circuit without issue and without a soft start. Sounds like your soft start is bad or wired incorrectly. 

     

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