Proposed battery bank for large inductive load's surge

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The soft starter finished it's relearning process and the inrush current of the HVAC came down from 61A to 52A. I changed the settings on the Growatt from Li to USE, disabling comms between the Inverter and the batteries and the Growatt was able to start the HVAC unit. Running current from the batteries was about 105A, with total AC power draw about 20A @ 240V. There must be something about the Li mode that causes the low voltage error 04 prematurely.

Tomorrow I will set up the generator and have it running the Chargeverter while the Growatt powers the house and the HVAC. I want to see how quickly the batteries go down while still being charged at around 4kW. This whole experiment is to see how the system performs in the event power is lost during a heat wave. The generator alone could never start the HVAC unit.

 

[Ampster]

There must be something about the Li mode that causes the low voltage error 04 prematurely.

I do not know if this is related but when I turn on Li Batt settings, some of my BMS settings take over the previously set SolArk settings. I do not know if the low voltage setting is affected. Just a hunch it might be related.

 

[Browse]

Well, I tried the whole setup today with my Honda EU7000is generator (running on natural gas with ECO mode on) powering the Chargeverter to keep the battery rack topped off while the Growatt 12k powered the house, including the 4-ton HVAC. The highest startup surge I measured was about 15kW, or about 62.5A @ 240VAC. The Growatt groaned a little whenever the HVAC compressor started up, but no errors. Running the house averaged about 20A to 25A per leg (5-6kW total for both legs) into the load center, or about 120A from the batteries. I was initially a bit concerned about the current draw on battery fuse during the compressor startup which would have approached 290A...much larger than the 200A rating, but I looked at the fuse curve and it allows for 200% of rated current for up to 50 seconds, so no issues there.

The cool thing to see was when the HVAC was running the SOC of the battery rack came down a few percent, but when the HVAC cycled off the Chargeverter brought it almost fully charged until it turned on again. This should allow us to extend our run time of the HVAC to almost infinity. If we have an outage and the AC isn't needed, there will be little reason to run the generator except for recharging the batteries once a day. Hopefully we won't have any super long outages, but I think the system will perform well...even for days or weeks at a time.

 

[50ShadesOfDirt]

"I wish they made a rack mount inverter that you could just slot in above the batteries."

If you have a rack system holding rack batteries with room left over for the inverter, it seems possible/reasonable that you could mount the inverter on a rack mount "tray" (stationary or pull-out)? Assumes inverter width is under that of standard rack opening width ...

Do any of the AIO's and other inverters have restrictions on mounting orientation, or air flow, such that horizontal mounting is out?

 

[BentleyJ]

"I wish they made a rack mount inverter that you could just slot in above the batteries."

APC uses this type of architecture for their modular UPS systems. Data Center rack with slide in battery modules on the bottom and slide in power modules on top. Makes one wonder if inverter engineers ever get out of their offices and observe what others are doing.

 

[wheisenburg]

3hp pump, correct.

Yeah I'd have to figure out where and how to mount this all. I guess that was the once nice part about the smaller 6kw bricks .. much easier to mount. But I'd also need to account for non-flammable backing material, wires, breakers/fuses and all the rest, too. I wish they made a rack mount inverter that you could just slot in above the batteries.

I went the other way. I got everything wall mounted. I guess it depends on what your garage space is like. For me having everything up off the floor is a big benefit. Getting those Schneider inverters up on the wall is a challenge even with two people. If I did that on a regular basis, I would build some kind of a lift. Maybe something like an engine hoist. The batteries weren't too bad.

 

[BentleyJ]

I cheated and used a cable puller to hoist the Schneider, had no help and didn't want to drop it on my foot.

Completely agree with the wall mounted set up to save space. I have this strange idea that a garage is for cars and limited storage that doesn't impede parking. Our 1995 Mercedes Wagon (doggie car) has original paint still in good shape. This is what a garage is for.

 

[wheisenburg]

I cheated and used a cable puller to hoist the Schneider, had no help and didn't want to drop it on my foot.

Completely agree with the wall mounted set up to save space. I have this strange idea that a garage is for cars and limited storage that doesn't impede parking. Our 1995 Mercedes Wagon (doggie car) has original paint still in good shape. This is what a garage is for.

My dad had a 1969 280SL when I was growing up. He got rid of it 10 years ago or so. It was restored nicely on the outside. It was bright red. Beautiful car, but it DID drive like a 50 year old car. Not that fast, and when you hit the brakes hard, it would fish tail violently. The seat belts were a joke. Kind of a death trap.

I was thinking something like a come-along anchored to the roof might work. Unlike the batteries, there isn't really a convenient place to grab hold of these inverters.

 

[BentleyJ]

If memory serves, I ran a small twisted wire cable through the hold down screw holes on the top flange of the french cleat and made a loop. Then hooked the loop with the cable puller.