BMS for EG4 Inverter

[Balazar]

I am looking for a new BMS. I am switching from a 12v setup to 48v and just purchased an EG4 3kW off grid inverter. I currently have 24 280ah cells and 6 JBD 4S BMS's. The EG4 will replace my Midnite Classic 150 and Xantrax SW3012. Yes I know I need 8 more cells to make two 48v batteries in parallel. I have had balancing issues with these cells no matter how many times I top balance them. I would like a solution with active balancing. JK BMS seems to be the most obvious solution. I will also need to fab some new boxes as I am using 8D battery boxes right now that house 12 cells each. If I can buy prefab boxes that would make the project a lot easier.

Is there a BMS that will communicate with my EG4 inverter? Do I even need coms from a practical stand point? (I really just need accurate SOC that my wife can read)
Is JK the only solution that incorporates active balancing?

What can you tell me from a place of personal experience?

 

[PreppenWolf]

I am using Overkill 100A 48V 16s BMSs. 8 of them. You can monitor each bank via Bluetooth.

 

[Balazar]

I am using Overkill 100A 48V 16s BMSs. 8 of them. You can monitor each bank via Bluetooth.

I currently have six of those. JBD and Overkill are the same product. It's not ideal because I have to use a device and connect to each one individually to check on them. No easy at a glance read out. Don't get me wrong. They have been a great product. I know there are displays for them too. They just don't have a way to integrate an active balancer and I have no idea what data protocol they use or if they can be setup to communicate with the EG4 inverter.

 

[PreppenWolf]

If you want to monitor your system from a central spot, you should use a shunt with a remote screen. The EG4 isn't going to allow you to have fully visibility.

 

[Balazar]

If you want to monitor your system from a central spot, you should use a shunt with a remote screen. The EG4 isn't going to allow you to have fully visibility.

I'm not sure I understand about visibility? The inverter will not show individual cell voltages, but with BMS communication it should show the SOC. That is why I was wondering about battery communication protocols that different BMS's support. The manual for the EG4 says that there are 5 different BMS communication protocols, but the only specified one is the EG4 protocol. You are left to guess what the other 4 are. If you look at the manual for the MPP Solar LV6548 that it is based on, it specifies compatibility with Pylontech, WECO, Soltaro, LIb-protocol, and "3rd party lithium battery". There is no assurance that these are the other 4 available on the EG4. Seplos seems to support a few of these protocols, but has no active balancing. JK and JBD/Overkill are unknown to me. JK is the only one that I know of with active balancing. If there is another that has an active balancing solution for 16S I would be interested in that.

 

[Adam De Lay]

I have 2 16S packs with JK BMSs. They don't hook into the inverters for SOC, so I use Solar Assistant to view and monitor my entire environment.

 

[Balazar]

I have 2 16S packs with JK BMSs. They don't hook into the inverters for SOC, so I use Solar Assistant to view and monitor my entire environment.

I think that is the direction that I am going to go in. I'm ordering a JK with all of the accessories including the screen. I was hoping to get the inverter <-> BMS comms working so that I can use some of the inverter features that rely on SOC. One of the more notable ones is the use of battery/solar power when available. The inverter can use invert until the battery reaches a specified SOC eg. 20%. Then switch back to shore power until a specified SOC is reached and repeat the process. That would save me some money on electricity in the winter instead of having my expensive solar setup just sit all winter doing nothing.

 

[Adam De Lay]

I think that is the direction that I am going to go in. I'm ordering a JK with all of the accessories including the screen. I was hoping to get the inverter <-> BMS comms working so that I can use some of the inverter features that rely on SOC. One of the more notable ones is the use of battery/solar power when available. The inverter can use invert until the battery reaches a specified SOC eg. 20%. Then switch back to shore power until a specified SOC is reached and repeat the process. That would save me some money on electricity in the winter instead of having my expensive solar setup just sit all winter doing nothing.

I wanted to have the same ability with changing inverter settings based on SOC but since I built my own batteries, there wasn’t a way for the inverters to communicate to the BMS (and visa versa) and then I saw people on the forum talk about Solar Assistant. Solar Assistant gives you the ability to manipulate the inverters settings based on your batteries SOC. You can program in SOC thresholds and timeframes and have the inverter change from SBU to SUB to get power from the grid till your batteries get recharged to a set SOC.

I actually did a video on Solar Assistant if you’re interested. Not only can you remotely control your inverters, but it also gives you access to historical data that you really don’t have access to with just Watchpower.

 

[Balazar]

@w8dev Thank you so much! This is a solution that will work for me. Orange Pie is on the way!

 

[Adam De Lay]

Your welcome!

 

[Cardude]

I’m trying to get a more accurate SOC of my eg4 life power4 batteries. I’ve been using the SOC values generated by the inverter and fed to Solar Assistant, but was attempting to hook up the the battery BMS currently (and kind of struggling with it).

After watching your video maybe I should just go the smart shunt method? I’m worried now my inverter displayed SOC (from the BMS) is not really accurate after seeing how far it was off on your system compared to the smart shunt.

Also, have you experiment with the SA emulated BMS? I tried I briefly but it also seemed way off. But maybe I didn’t give it enough time.