EG4 Chargeverter While Batteries Under Load

[Dasos]

I have an offgrid system with 6 48V EG4 LifePower4 batteries on busbars connected to 3 Growatt 5000ES which are in turn connected to my solar array and a 24kw generator.
I'm wanting to add an independent set of battery chargers and potentially disconnect the generator from the Growatt units completely so they're always simply inverting and there is no switching between inverting and line pass through.

I was thinking of getting a few Chargeverters and wiring them to my generator subpanel and connecting their output to my busbars to charge the batteries when the battery SOC gets low. However as I understand it, when there is a load from the house the inverters would effectively be pulling from the Chargeverters instead of the batteries without a true guarantee of exceeding their individual 5.1KW output.
I called Signature Solar technical support and asked about this and they said that the Chargeverters can't be run while the batteries are under a load. On one hand that confirms my thinking of the problem. But on the other, I can't really imagine a use case where you would turn off your house load center while you charge your batteries.

Does anyone have any experience using these chargeverters in a similar way? Or have any idea how you're supposed to use these Chargeverters if you can't have any load on the batteries while using them?

 

[42OhmsPA]

Use them like you have planned. It will be fine.
Gen or grid power to chargeverters, chargeverters to battery bank.

As long as loads aren't greater than chargeverter output you'll charge the batteries.

 

[sunshine_eggo]

I have an offgrid system with 6 48V EG4 LifePower4 batteries on busbars connected to 3 Growatt 5000ES which are in turn connected to my solar array and a 24kw generator.
I'm wanting to add an independent set of battery chargers and potentially disconnect the generator from the Growatt units completely so they're always simply inverting and there is no switching between inverting and line pass through.

Good idea.

I was thinking of getting a few Chargeverters and wiring them to my generator subpanel and connecting their output to my busbars to charge the batteries when the battery SOC gets low. However as I understand it, when there is a load from the house the inverters would effectively be pulling from the Chargeverters instead of the batteries without a true guarantee of exceeding their individual 5.1KW output.

Doesn't work like that. The battery is still there. If the draw exceeds 300A, the additional load will be drawn from the battery.

I called Signature Solar technical support and asked about this and they said that the Chargeverters can't be run while the batteries are under a load.

This person didn't understand the question, has insufficent training, or is stupid.

The chargeverter is specifically recommended so folks can run lower power generators on higher power inverters. This almost guarantees a load can exceed the chargeverter input.

 

[Zapper77]

I have an offgrid system with 6 48V EG4 LifePower4 batteries on busbars connected to 3 Growatt 5000ES which are in turn connected to my solar array and a 24kw generator.
I'm wanting to add an independent set of battery chargers and potentially disconnect the generator from the Growatt units completely so they're always simply inverting and there is no switching between inverting and line pass through.

I was thinking of getting a few Chargeverters and wiring them to my generator subpanel and connecting their output to my busbars to charge the batteries when the battery SOC gets low. However as I understand it, when there is a load from the house the inverters would effectively be pulling from the Chargeverters instead of the batteries without a true guarantee of exceeding their individual 5.1KW output.
I called Signature Solar technical support and asked about this and they said that the Chargeverters can't be run while the batteries are under a load. On one hand that confirms my thinking of the problem. But on the other, I can't really imagine a use case where you would turn off your house load center while you charge your batteries.

Does anyone have any experience using these chargeverters in a similar way? Or have any idea how you're supposed to use these Chargeverters if you can't have any load on the batteries while using them?

ChargeVerter is self limiting, you set the voltage and amperage.

 

[Zapper77]

I think @timselectric use the CV in a similar setup. I think he has a relay hooked in to the generator dry contact.

 

[timselectric]

I have an offgrid system with 6 48V EG4 LifePower4 batteries on busbars connected to 3 Growatt 5000ES which are in turn connected to my solar array and a 24kw generator.
I'm wanting to add an independent set of battery chargers and potentially disconnect the generator from the Growatt units completely so they're always simply inverting and there is no switching between inverting and line pass through.

I was thinking of getting a few Chargeverters and wiring them to my generator subpanel and connecting their output to my busbars to charge the batteries when the battery SOC gets low. However as I understand it, when there is a load from the house the inverters would effectively be pulling from the Chargeverters instead of the batteries without a true guarantee of exceeding their individual 5.1KW output.
I called Signature Solar technical support and asked about this and they said that the Chargeverters can't be run while the batteries are under a load. On one hand that confirms my thinking of the problem. But on the other, I can't really imagine a use case where you would turn off your house load center while you charge your batteries.

Does anyone have any experience using these chargeverters in a similar way? Or have any idea how you're supposed to use these Chargeverters if you can't have any load on the batteries while using them?

I use two of them, in this exact way.
There's no issues. They are power supplies, that's what they are designed to do. They just also are very good at charging batteries.
Like any power supply. You should avoid trying to draw more than their capacity. But if you do, they will shut down. Or the breaker will trip, because voltage sag will increase amperage.
It's very unlikely that you could overload them, while connected to a battery bank, anyway.

 

[Dasos]

Thank you all for your replies and for confirming what I thought about how these units work. It didn't make sense to me that these couldn't be used at the same time as the inverters. I'm glad to hear others are using the CVs for this same purpose. I also have a voltage sensing relay to trick the utility sense on our generac generator to turn on and off. (unfortunate workaround due to a fault in the Growatt 5000ES's dry contact signally logic)

In case others find this thread and are wondering why myself and others might want to bypass the battery charger and line pass through of an all in one unit with a separate charger(s) I'm doing it for the following reasons:

• Maximize battery charging power from a generator while minimizing generator size and run time extending its lifespan.
  • The typical way you size a generator is by adding your house loads to the highest in rush current appliance (well pump in our case) and then adding that figure to your desired battery charging rate.
    • This results in an oversized generator to accommodate unpredictable house loads.
    • House Load + Highest In-Rush + Battery Charge = Generator Size.
    • For example: 5KW (HL) + 5KW (IR) + 10KW (BC) = 20KW Generator. (ignoring derating for now)
  • In reality the house loads are usually only 1-2KW with occasional spikes. So the generator is running only at 12KW of it's 20KW capacity.
  • So by bypassing the all in one units and simply charging the batteries, we can peg the generator at a constant, near maximum, production as long as it's larger than our predicted loads with a safety margin.
    • Using the same example above of 5KW house load, 5KW In Rush Current and providing a 20% safety margin we could use that same 20KW generator and 4 ChargeVerters pegged at 18KW Battery charging knowing that the power provided exceeds our 12KW potential load. The generator runs less time at a constant output which extends it's lifespan and the batteries charge faster.
• Provide Redundancy to the Generator System.
  • Our generator is currently hardwired to a subpanel and from the subpanel to our growatt units. So if it goes out, we do not have a backup to use another generator.
  • With the ChargeVerters plugged into 240 outlets on their own breakers in the subpanel we can easily unplug one and plug it into any portable generator as a backup.
• Eliminate the Line Mode and Battery Mode switching
  • Even though the switch is incredibly fast between line mode and battery mode, sensitive electronics like our Starlink dish and routers notice and have to reboot. This results in a 5min interruption in internet, which for us working at home on video conference calls can be a really big deal.

 

[Onehand]

Very interesting thread.

 

[LydMekk]

I let the 2 Chargeverters trickle charge the batteries while my 3 inverters use the battery bank parallel at the same time.
No issues.

 

[wpns]

we can peg the generator at a constant, near maximum, production as long as it's larger than our predicted loads

Your generator doesn’t even have to be larger than your predicted loads, all your generator is doing, is charging the batteries. If the load exceeds the Generator->CV output capacity, the inverter will never notice, as it continues to draw power from the batteries. The battery charge will be negative for a while, but when the house load drops two less than the generator capacity, the batteries will go back to charging. as long as your generator makes more kilowatt hours during the day then your house load, your batteries will charge.