Growatt 3500 error 52 with SOK 48v 100ah (2024)

Hello,

When I use my 10” compound mitre saw I am occasionally having an issue where the SOK battery seems to go into a protection state causing the Growatt to no longer see the battery and thus throw an error 52 “bus voltage too low”. I am guessing the bus voltage is too low because the battery completely disconnects itself. During these errors, The battery is at 75% or more capacity. Cells are balanced too.

If I turn off the PV array off and on to let the growatt reboot, it clears the error 52 and also the SOK battery kicks itself back in after something like 60 seconds.

The AC output on the inverter connects to a breaker panel with a single 15A breaker which feeds a receptacle. I use a 75’ extension cord to reach the mitre saw.

I run a fridge 24/7 and various other items including an electric kettle which has a high watt surge I believe. These do not use a long extension cord and they do not cause the error 52. In fact, nothing else has caused the error.

Any ideas?

When using the SOKTools software to view the battery does the Memory Info tab show anything.
Just before operating the 10” compound miter saw start up the SOKTools software and on the Multi Monitoring tab check the "Save data to database" checkbox which will start data collection. If you get the error then check the status of the DISCHARGING-Off (or -On) and DISCHARGING MOSFETS. Also look for any Alarm or Protection status(s)

You will need a serial to USB cable to connect to computer to run the software.

Download SOKTools form the Current Connected website, use last link on gthe page.

marionw said:

When using the SOKTools software to view the battery does the Memory Info tab show anything.
Just before operating the 10” compound miter saw start up the SOKTools software and on the Multi Monitoring tab check the "Save data to database" checkbox which will start data collection. If you get the error then check the status of the DISCHARGING-Off (or -On) and DISCHARGING MOSFETS. Also look for any Alarm or Protection status(s)

You will need a serial to USB cable to connect to computer to run the software.

Download SOKTools form the Current Connected website, use last link on gthe page.

SK48V100 Server Rack Battery Owner & Operator's Manual | Current Connected

Full instruction manual for the SOK SK48V100 server rack battery. Everything you need to know is contained within this document!

www.currentconnected.com

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Ok I will try this next time I am up at the cabin.

Thanks!

timselectric said:

The saw has a high start up surge. It's overloading the BMS.

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Wouldn’t the 15A 120v AC breaker limit the startup surge to 15A?

Bhilton said:

Wouldn’t the 15A 120v AC breaker limit the startup surge to 15A?

Click to expand...

No
Surges are brief, and the breaker is designed to let them happen.
Breaker has a trip curve that decreases over time.
A surge is short enough to not trip the breaker.

A BMS is very fast.

timselectric said:

No
Surges are brief, and the breaker is designed to let them happen.
Breaker has a trip curve that decreases over time.
A surge is short enough to not trip the breaker.

A BMS is very fast.

Click to expand...

Ok, can I use any devices to avoid hitting the BMS, such as a small AC UPS to handle the surge, if it even works that way lol

Bhilton said:

Ok, can I use any devices to avoid hitting the BMS, such as a small AC UPS to handle the surge, if it even works that way lol

Click to expand...

Not really.
You should either decrease your loads or increase your battery/BMS capacity.