Surge Voltage Drop

[JohnSol62]

I have 2 LifePo4 batteries on my EG4 6000. I can start my chop say anything during daylight while getting 230v DC 4000w from my panels available.
However to start the same saw from battery I get undervolt issue and inverter shuts down with battery disconnected. (Solar Power app shows "Battery Under" and "Battery Open") Which is assume is battery undervoltage from sag from chop saw and then battery open is open circuit for the battery since its disconnected.

Since it works on solar, is this just the voltage of the battery drooping too far for the saw and the inverter cutting itself off for undervoltage? Seems the inverter can handle the surge but the supply of DC power on battery can not?

Thanks for having me on the forum.

 

[rilonau]

Look up the surge current your saw draws! Big motors can draw an immense surge current for starting due to induction! Is it a 3phase engine? Does it use a capacitor? You can try to add a surge current control device to reduce the initial surge current. There are several types availabele. Also check the max. surge current of your BMS!

 

[Nobodybusiness]

I have 2 LifePo4 batteries on my EG4 6000. I can start my chop say anything during daylight while getting 230v DC 4000w from my panels available.
However to start the same saw from battery I get undervolt issue and inverter shuts down with battery disconnected. (Solar Power app shows "Battery Under" and "Battery Open") Which is assume is battery undervoltage from sag from chop saw and then battery open is open circuit for the battery since its disconnected.

Since it works on solar, is this just the voltage of the battery drooping too far for the saw and the inverter cutting itself off for undervoltage? Seems the inverter can handle the surge but the supply of DC power on battery can not?

Thanks for having me on the forum.

From your description that appears to be the case.

Check battery BMS max current and cable size / routing going to inverter.

 

[JohnSol62]

Cable to inverter is 2awg and standard length i believe about 4-6ft. Im not sure about the installation of surge control devices. Will research how. Would more batteries help it or would that just be throwing money and guessing?

I probably was looking at it wrong that I need a low frequency inverter for the surge but now my batteries are possibly ineffiecient. Thanks for info.

 

[Nobodybusiness]

Cable to inverter is 2awg and standard length i believe about 4-6ft. Im not sure about the installation of surge control devices. Will research how. Would more batteries help it or would that just be throwing money and guessing?

I probably was looking at it wrong that I need a low frequency inverter for the surge but now my batteries are possibly ineffiecient. Thanks for info.

From what you said it looks like the current draw is drawing battery voltage down below the cutoff.

Could be cable not big enough.
Battery isn’t big enough or combination of the 2.

If it will start while sun is out then inverter can handle the surge.
The battery can’t.