Low Voltage Disconnect Suggestion

[Robbert]

I have EG4-Lifepower4 51.2V (48V) 100Ah batteries with a generic all-in-one inverter from a Chinese kit I purchased on Amazon. It was a mistake and I have learned a lot from it. The low voltage disconnect that is built-in to the inverter is set to 40V with no expressed way from the company or the manual to adjust it. The batteries have a factory recommended 44-47V low voltage disconnect. I have done research on options that I can place in between the batteries and the inverter and am struggling to find any distinct and clear answers as to whether the LVDs will actually protect my 51.2V batteries from over-drawing better than the built-in inverter's 40V disconnect setting.

FYI this is a completely off-grid setup.

If you can connect the inverter to Solar Assistant, you could build can build in node red a simple command to switch the inverter to Utility First if you reach a certain voltage.

 

[ejfluhr]

>protect my 51.2V batteries from over-
>drawing better than the built-in inverter's
>40V disconnect setting.

Maybe I missed this info? The Lifepower4 will protect itself on a cell-by-cell basis...nothing is better than that. Are you looking for a second layer of protection?

It is nicer/valuable to have a higher LVD, but not a necessity. I vote you work towards more batteries than a complex LVD scheme.

 

[time2roll]

FYI I totally agree that I need more batteries VS allowing them to drain on a regular basis. I also totally agree I will need a better inverter. I just don't have the thousands of dollars that will require at the moment, but it is definitely next on our priority list.

Assuming the place is occupied maybe continued manual intervention would get the system through until upgrades are possible.
Simply reduce loads to save power during times when the system will be unattended such as while sleeping.

One way or another power will be cut. Even if an automated system is in place, power will be cut. The idea would be to navigate how to limit consumption and live within the abilities of the existing system. I would add battery as the first upgrade.

 

[Ampster]

The Lifepower4 will protect itself on a cell-by-cell basis... Nothing is better than that.

A lot of people prefer to have the primary protection be the inverter, so that the BMS becomes the backup. Since his inverter does not have a setting that would work, either a new inverter or some other workaround for low voltage disconnect answer the OPs question about LVD.

 

[Daddy Tanuki]

OP what are the specs, model number and hopefully a link to the inverter you have. I would think that at this point in time, even the crappiest inverter would have a LVCO thats adjustable. possible that the inverters paperwork was so badly translated that it is not apparent?

 

[MisterSandals]

I would add battery as the first upgrade.

Post #3 ;*)