EG4 Chargeverter, 2 racks of EG4 Lifepower batteries-wiring to charge both?

[Balrog006]

Hey folks-I have a battery charging wiring question for you here in the know.

I have 2, 6x racks of EG4 Lifepower 4 batteries (60kWh total) with my SolArk 15k.

I’ve just used the Black Friday sales to buy an EG4 Chargverter to charge them rather than using my 7.5k gas powered portable generator directly tied into the 15k. This setup was less than desirable for a couple reasons, it’s an older, non inverter (dirty) generator and the 15k really didn’t like feeding from it. The software in the 15k uses the generator as primary power to loads first then sends the overage to charge the batteries. This leads to surging and more distaste from the 15k having to use the generator feed. The 15k drops the gen if it surges and meanders out of range of the 60hz(which I have widened as much as their tech support recommends) 15k likes until it levels back out and then reconnects. Wash rinse repeat, this seems a pretty inefficient way to charge the batteries during grid down without PV input due to bad weather.

Long story short I got the Chargeverter to eliminate this situation, but now I’m wondering how to use it to charge more than one rack of the batteries?

Each of them is in an EG4 cabinet with its own bus bar and each has a set of 4/0 copper leads to the 15k battery bus.

If I mount the Chargeverter on one rack cabinet and connect it to the cabinet bus bars as per the manual, it should charge that rack, but I don’t think it’ll charge the other? Am I correct in thinking this? Or will the charging current feed thru to the 15k battery bus and be shared between the two racks?

Thanks for any thoughts on this.

 

[Balrog006]

Or as an alternative, should I do as is described in this thread and wire the Chargeverter into the Gen input of the 15k (a’la AC coupled PV) and let it clean up the generator power and let the 15k charge the batteries from any excess?

Chargeverter on Gen input?

How would the Chargeverter handle shifting loads on the 15k from the house? As long as there is something left in the batteries would it handle surge loads? As long as I’m not running the batteries up to 100% there would be reserve there to shunt power to if loads dropped….

Thoughts?

 

[DIYrich]

I have a 15k, 3 racks of batteries, and a CV. The batteries connnect to a busbar, and the two battery terminals of the 15k connect to the same busbar. The CV also connects to the busbar.

CV is set to the float voltage of the Sol-ark. Total watts is 85% of the CV rated capacity. That should be in a good operating range of your 8kW generator.

In your setup, if you connect to one battery bank, you will also charge all other batteries too. All your batteries are at the same voltage. You will get a slight unevenness because of wire length, but for infrequent use, I wouldn't worry about it.

If the draw on the batteries from the inverter is more than the CV puts out, the batteries will support load. You can test this by going off grid, and setting the amps on the CV to something low, and watch what happens.

In theory, if the CV is outputting 4kW, and you consume 40kWh per day, you run the generator for 10 hours to produce 40kWh, and you are good for 1 day (with no sunshine). The battery buffers the excess generator power until needed.

 

[Balrog006]

I have a 15k, 3 racks of batteries, and a CV. The batteries connnect to a busbar, and the two battery terminals of the 15k connect to the same busbar. The CV also connects to the busbar.

CV is set to the float voltage of the Sol-ark. Total watts is 85% of the CV rated capacity. That should be in a good operating range of your 8kW generator.

In your setup, if you connect to one battery bank, you will also charge all other batteries too. All your batteries are at the same voltage. You will get a slight unevenness because of wire length, but for infrequent use, I wouldn't worry about it.

If the draw on the batteries from the inverter is more than the CV puts out, the batteries will support load. You can test this by going off grid, and setting the amps on the CV to something low, and watch what happens.

In theory, if the CV is outputting 4kW, and you consume 40kWh per day, you run the generator for 10 hours to produce 40kWh, and you are good for 1 day (with no sunshine). The battery buffers the excess generator power until needed.

@DIYrich , this type of personal experience and input was precisely what I was looking for. Much appreciated.

Couple questions for clarification-
The CV is attached to the inverter bus bar-do you just double up the lugs on the bolt? How does this work-do you have any pictures?

This would be a possibility for me but for my use (grid down, no sun) very infrequent emergency type I think connecting to one banks bus bars would produce perfectly acceptable usage.

 

[DIYrich]

I have an 8 position bus bar, so each connection gets its own post. No doubling up. The 15k has two positions at positions 3 and 6 to distribute the power across the busbar.

 

[Balrog006]

I have an 8 position bus bar, so each connection gets its own post. No doubling up. The 15k has two positions at positions 3 and 6 to distribute the power across the busbar.

I’m not sure I understand your setup or how you’re describing it. You have a common bus bar between the battery racks and the 15k?

My 15k has 4 bolts/studs on the battery bus, 2 + and 2 -, so there can be a max of 4 cables terminated on the inverter DC bus below the integrated DC breakers.

I have 2 racks so each of them has their own set of copper 4/0 +|- leads to the inverter DC bus. The cabinets have the standard front side bus bars to connect all the batteries to and to connect the leads out to the inverter-I’m pretty sure there is also room to connect the CV to the cabinet bus.

Even if the charging is somewhat uneven or the connected rack charges ahead of the second rack I think it’ll still be acceptable in a grid down, temporary SHTF scenario where I have no choice but to run the generator.

 

[DIYrich]

Sounds like you have each rack directly connected to the 15k. Two racks, and two battery connections. I have everything going through a common busbar (one for positive, one for negative).

I belive your plan is to connect the CV to the busbar in one of the racks. The power will have to flow through the 15k battery connection to charge the other rack. It should work.

 

[Balrog006]

Sounds like you have each rack directly connected to the 15k. Two racks, and two battery connections. I have everything going through a common busbar (one for positive, one for negative).

I belive your plan is to connect the CV to the busbar in one of the racks. The power will have to flow through the 15k battery connection to charge the other rack. It should work.

Yes that’s correct and what I understood from your first reply. But then you talked about connecting the CV at the inverter and your setup and I didn’t follow because I know there aren’t enough spaces on the inverter DC bus for that many connections.