Issue starting submersible pump with Growatt 3500ES

[miborion]

Hi,
For my off-grid cabin, I just set up a solar array, 6 pieces - 575W PVs, one string paired with a Growatt 3500ES unit (rated 3.5kW as a DC - AC converter)
I used before setting up the PVs a gas generator, rated 3500W with a peak of 4000W, which worked just fine for my submersible water pump.
I have measured before designing the PV array and installing the Growatt inverter the power drained by the water pump, using a small outlet with a measurement display (i don't know the exact name of such device) which showed 1.3 kW as peak wattage consumption and around 1.1kW when the pump was running. The exact pump model is not known since I've installed it two years ago and I think it was a no-name, but rated 1.0 kW ( @220V).
Right now I do not have a 48V battery for my Growatt 3500ES, but without it, it starts, as in boots up and It even starts the converter: was able to charge my laptop, have some lightbulbs on and others small consumers.
But when I've turned on the pump it "crashed" the inverter. By crash I want to say it shuts down the convertor module only (display works, the invertor is not working anymore); even if I switch off the water pump it doesn't starts the invertor. I have to shut down the PV input and restart it after.
My question is, would this issue will be fixed once I will install a 5kW 48V battery (100A x 48V) ? Or, I should consider changing the submersible water pump to a newer model, maybe something around 500 - 700 W?
Or is it the Growatt 3500ES which cannot handle the load?

Regards,
Bogdan.

 

[AshleyL]

..........do you know the pump surge power rating? I got a feeling your Growatt 3500ES can't handle the surge.

 

[miborion]

I tried to measure it using a outlet with display. I plugged in the outlet into my gas generator, then I plugged the pump cord into the outlet.
The outlet measures the active used Watts and the peak (guess is what you called surge power).
I never got a value larger than 1300W, but guess maybe the outlet isn't a precise measurement tool.
The main reason I've addressed my question here, is I don't know what to do... extend the PV array, by adding two more panels, go and buy a 48V battery, try to change the pump, to a different brand, as there is (at least in Europe) a producer which has low Watt rating pumps for the same pumped water volume.
Is there a precise way of measuring the exact power surge issued by the water pump, when it starts, using the gas generator as source?
For the question of either the Growatt 3500ES can or cannot handle the pump, can I test it by using the gas generator as its (Growatt's) AC source and then test if the Growatt can start the pump using Solar and Utility as it sources? Or, it is not a conclusive test?

 

[Mattb4]

Likely your unit can not pull enough power from PV quickly to handle pump start load. Once you have a battery in place it should help ballast things though whether it will be enough to run the pump is a bit difficult to guarantee. Many of the batteryless AIO's have difficulty operating without a battery.

 

[OzSolar]

You'll do yourself a nice favor by getting a clamp meter capable of capturing peak DC amps. DC ones aren't as common as AC ones but there plenty for less than $50USD on amazon.

There's also plenty of how to videos on YouTube on how to use them.

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