Author Topic: PowerJack 5000 inverter starting current.  (Read 302 times)

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Offline Pete

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PowerJack 5000 inverter starting current.
« on: March 03, 2017, 10:50:40 PM »
I recently purchased a Power Jack 12 volt 5000 watt inverter. It states that it is capable of 20kw surge when starting loads. I have tried it with my 1500 watt air compressor and it will not start it. It runs other loads such as 1500 watt power tools and my lathe.
I have 600 amp hours of batteries, and have the inverter connected to them with around 1 metre of 75mm aluminium cables.
I am wondering if anyone else has had this experience with starting large loads.
I also have a 3kw Power Star W7 which won't start the compressor either.
I must say that Power Jack must have been reading this forum, as the 5kw inverter only uses around 25 watts on idle.
Any ideas?
Pete

Offline welshman

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Re: PowerJack 5000 inverter starting current.
« Reply #1 on: March 04, 2017, 06:20:33 AM »
does the pj fault?

Offline Pete

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Re: PowerJack 5000 inverter starting current.
« Reply #2 on: March 04, 2017, 02:53:11 PM »
Hi Welshman, yes it shuts down, I have to manually turn it back on to get it to power up again. Maybe my batteries are not up to supplying the starting current, or maybe the PJ specs are nowhere near what they claim.

Offline oztules

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Re: PowerJack 5000 inverter starting current.
« Reply #3 on: March 04, 2017, 03:47:16 PM »
20kw@12v is in the 2000amp range...... not sure your going to get that through the wires in the PJ for more than nano seconds. When I was testing the 48v units for driving the big welder for example, the over current was just a hesitation and retry... not a shut down that needed restart.

The 24v 5000w units I have worked with would have easily started your compressors..... both of those have met a sticky death ( environmental in nature ie spiders and water) and now have 8010 boards in them... so cant check any more for you...... but I assume the 12v is just too low to drive that sort of power for anything other than capacitor carried peaks.

For any 12v unit, I think 150 amps is enough.. after that go to the next voltage.... so 1.5kw cont is about my limit.


...........oztules
Flinders Island...... Australia

Offline Pete

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Re: PowerJack 5000 inverter starting current.
« Reply #4 on: March 04, 2017, 06:09:48 PM »
Thanks Oz, I should have said that the inverter does pulse the compressor. It tries to start it a few times, then decides that It can't do the job. So I will use it for the other shed loads and keep the generator tuned to run my welder and air compressor.
Like you say, 2000 amps is pretty heavy going. Guess the batteries can't supply the current either.
Even if the compressor is only drawing 6 times the run current to start it will still be in the 900 amp range required from the battery. Oh well, still it is a good inverter for all the other stuff I run.
Thanks again.
Pete

Offline sunnypower46

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Re: PowerJack 5000 inverter starting current.
« Reply #5 on: March 04, 2017, 08:49:05 PM »
Besides the cable, you're fighting the internal resistance of the batteries at that starting load.  While auto batteries aren't recommended for solar backup, their plate structure provides higher cold cranking amps (CCA) and might do the trick in your situation, if you're curious.  Add a couple with jumper cables to your battery bank and see if you get lucky . . . .