SolarEdge Storedge + LG Chem battery for back-up power

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Does anyone have any experience with these systems yet. We will be installing a few shortly and I wonder how they will perform.

Our first customer wants to be able to run his well and septic pump off it (9.8 KWH version)

He is concerned with the high start up current hurting the battery.

Has anyone installed this setup for someone looking for backup power? If so, how was the install and performance so far?


thanks
 

GoldDigger

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Location
Placerville, CA, USA
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Retired PV System Designer
The effective internal resistance of the battery is known (at least to the manufacturer) or can be measured. For lithium chemistry batteries as long as the thermal effects are not damaging the short term high current drain will not adversely affect the life cycle of the battery.
Excessive charging currents are more likely to be sustained and to affect the active material directly or lead to thermal runaway if not monitored.
The high current demand for starting is more likely to be limited by or else harm the inverter. To the extent that the terminal voltage of the battery drops, the inverter will draw even greater current in an attempt to supply the required power.

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jaggedben

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Location
Northern California
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Solar and Energy Storage Installer
Both the battery and the inverter have a nominal 5KW power limit in backup mode. The backup panel is supposed to be protected by a 25A breaker, so anything that might trip that would be too much.
 

jaggedben

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Location
Northern California
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Solar and Energy Storage Installer
Thanks.

So is that 25 amp breaker required by the manufacturer?

Yes, it's in the installation manual.

If there is a bigger load aloud on the system can it be damaged?

There's something in the install manual or somewhere about the autotransformer needing to be protected by the 25A breaker. I've thought about asking SolarEdge if a higher rated autotransformer can be used in place of theirs, but haven't gotten around to that. In any case, if backup mode is limited to 5kW then all your really doing is increasing the possible pass-through current from the grid in grid-tied mode.

I just looked at the data sheets and I was wrong, there's actually a 6600W 'surge' capability, and the battery can do 7kW for 10 sec. I guess that shouldn't trip a 25A breaker though. You'll have to consider the sump pump specs. I haven't gotten far enough with my installations to give you feedback on performance, and none of my customers so far have an appliance like that.
 
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