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Add Battery to Grid-tied Solar Edge

dmholmes

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I have a neighbor that is interested in adding battery storage to his grid-tied system (Solar Edge HD wave). Is there an opportunity for DIY in this setup or does he have to go with a solar company?
 
From this reference:

StorEdge is compatible with high voltage LG Chem RESU batteries as well as 48V batteries supplied by multiple battery vendors.
From that I'd say yes; but the LG RESU10H is 400 V / 9.8 kWh. So from that I'd say it might be tricky (e.g., need another part). I'd write the company and ask for a list of compatible 48V batteries and hookup instructions. If you find out, let us know!
 
The StorEdge data sheet I see calls for 400V battery


"Nom DC Input Voltage 380"
"Supported Battery TypesLG Chem RESU 10H & RESU16H Prime(6)"

It is possible there is a BMS available that could be used DIY. SMA battery inverters, both 48V and 400V, are compatible with LG batteries. REC makes Sunny Island compatible BMS, and BMS for up to 240 cells.

The LG battery uses small explody type lithium cells. In fact, some of the RESU10H packs were recalled in December due to house fires.
I would be more comfortable with DIY LiFePO4 than UL listed lithium polymer.

If someone did build a DIY 400V battery with 100 Ah or 280 Ah cells, that would be huge capacity (38 kWh or more). The commercial packs range from 3kWh to 30 kWh. Cost of BMS for DIY would be disproportionately high for < 100 Ah cells.

If using the UL listed lithium polymer battery, I would suggest locating it away from the house.

Don't know how StorEdge manages Solar Edge. Probably communications, but if it supports frequency-watts, then maybe any of the battery inverters that do frequency shift could be used.
 
I have a neighbor that is interested in adding battery storage to his grid-tied system (Solar Edge HD wave). Is there an opportunity for DIY in this setup
Yes a number of hyybridinverters could be AC coupled to that Solaredge inverter. Swapping out the Solaredge GT inverter for a Solaredge Storedge could also be done but the cost of the LG Chem battery is a lot more than a hybrid and DIY lithium. In either case a separate sub panel would need to be installed. My system with an Outback Skybox is an example.
 
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I would be more comfortable with DIY LiFePO4 than UL listed lithium polymer.
LG Chem batteries are Lithium NCM not Lithium Polymer. They are more explody than LFP but less than Lithium Polymer. I do not know how the recall has affected their availability to the DiY sector.
 
Thanks guys. It looks like his most straightforward path is to have the same installer swap the current inverter for the StorEdge inverter and add the critical load panel. I don't believe he is interested in doing that, and the real shame is he has 100 kWh of batteries between 2 EVs sitting in the garage but no V2H option.
 
the real shame is he has 100 kWh of batteries between 2 EVs sitting in the garage but no V2H option.
I have 130kWhr sitting in my garage in two Teslas and would never want to use them to power my home. V2H is a nice concept but I spent $10,000 for 42kWh of LFP batteries and a hybrid inverter. Vehicle batteries are a lot more expensive to replace than LFP cells.
 
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I have 130kWhr sitting in my garage in tw Teslas and would never want to use them to power my home. V2H is a nice concept but I spent $10,000 for 42kWh of LFP batteries and a hybrid inverter. Vehicle batteries are a lot more expensive to replace than LFP cells.

Indeed, but he is only looking for emergency grid down use. When the arctic blast came though here in February his panels and car batteries were useless of course.
 
Thanks guys. It looks like his most straightforward path is to have the same installer swap the current inverter for the StorEdge inverter and add the critical load panel. I don't believe he is interested in doing that, and the real shame is he has 100 kWh of batteries between 2 EVs sitting in the garage but no V2H option.

Oh, so StorEdge doesn't interact with Solar Edge, rather is installed as a replacement?
I guess that's why StorEdge lists specs for battery/PV input.

I would like to say in that case replace Solar Edge with a suitable PV/Battery system, whether hybrid or AC coupled. Except, Solar Edge optimizers are the RSD units per PV panel, so that locks him in to a Solar Edge product.

Indeed, but he is only looking for emergency grid down use. When the arctic blast came though here in February his panels and car batteries were useless of course.

A system with LG RESU or similar battery will typically be 3kWh to 10 kWh, possibly 30 kWh.
If an EV charger port supported providing DC of ~ 400V, possibly something acting as a compatible BMS could connect it with StorEdge (or Sunny Boy Storage.)

If the EV or anything that plugs into it could provide AC, that could either supply critical loads for additional hours or possibly feed the home battery backup system. Depending on the home system, power from EV could go to a battery charger, or feed a GT PV inverter to recharge home system.
 
I have a neighbor that is interested in adding battery storage to his grid-tied system (Solar Edge HD wave). Is there an opportunity for DIY in this setup or does he have to go with a solar company?

The supported 400V batteries like LG RESU are far too expensive to be used for backup during occasional power failures. They may approach cost effectiveness is cycled every day, either off-grid or for shifting time of export/import from grid.

He could plug a stand-alone UPS into an AC outlet to power things like communication gear, or refrigerator if large enough battery. A hybrid with its own PV and battery could be the way to go for a small system to ride through a couple days of power outage. Leaving the Solar Edge system as strictly grid-tie.
 
Indeed, but he is only looking for emergency grid down use
In that case the easiest solution is a 12volt inverter connected to the 12volt battery in his EVs. That is what I did with one of my Teslas. I think Will Prowse has a video on that. The Tesla has a robust DC to DC converter that can charge the 12v battery from the high voltage pack. I was able to keep a refrigerator and some LED lights going before I had my hybrid inverter running. My refrig is a newer model with no starting surge and I was able to run it with a 800 Watt inverter.
Every EV is different in how the 12volt battery is charged by the motive pack so one would need to do some research before imlementing such an idea. I have had four different types of EVs and at least two of them needed the 12 volt battery jumped to start the electronic when the 12v was depleted.
 
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Oh, so StorEdge doesn't interact with Solar Edge, rather is installed as a replacement?
I guess that's why StorEdge lists specs for battery/PV input.
The Storedge is DC coupled to the battery, so it would need some solar panels to charge the battery off the high voltage DC bus.
As to your other question about AC coupling, I do not know if the Storedge can also AC couple to another Solaredge GT inverter. Good question.
 
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In that case the easiest solution is a 12volt inverter connected to the 12volt battery in his EVs. That is what I did with one of my Teslas. I think Will Prowse has a video on that. The Tesla has a robust DC to DC converter that can charge the 12v battery from the high voltage pack. I was able to keep a refrigerator and some LED lights going before I had my hybrid inverter running. My refrig is a newer model with no starting surge and I was able to run it with a 800 Watt inverter.
I've suggested that for the Tesla 3 and his other EV, it's a Kia. And we could use my 12v inverter to try it out, but is there a concern of voiding warranty?

I recall Will's video, he tried it via a 12v connection at the very front of the car but it didn't work well? Ended up connecting further up? I'll have to watch that again.
 
And we could use my 12v inverter to try it out, but is there a concern of voiding warranty?
That was my concern as well. That is why I did not use a permanent solution.
Initially I used the 12v lighter socket which was good for 100 Watts but the Tesla would shut that down if there was no activity. Now there is camper mode but 100 Watts is not enough to power even the most energy efficient refrig.
For the 800 Watt inverter I used jumper cables and did monitor the 12 volt battery to make sure it was being charged by the DC to DC converter. My advice would be start with a fully charged motive pack and not take it past 50 miles of range. Also have a source of 12 volts to start the electronics if for some reason the DC to DC converter stopped working. Tesla does gather metrics from all cars via the cell connection. The trick to not void the warrant would be to not place a service call for a bad 12v battery.
 
In addition, even though the power was out for three days, there was a Supercharger 15 miles away that had power. I also had another fully charged Tesla in the garage.
 
In addition, even though the power was out for three days, there was a Supercharger 15 miles away that had power. I also had another fully charged Tesla in the garage.

Nice! I saw it recommend to hook up to the PCS? Not sure what this is.

I'm thinking a PHEV would be nice for emergency power outages. More battery than a regular hybrid, and still have the ICE to autostart and recharge the 12v for inverter use.
 
Nice! I saw it recommend to hook up to the PCS? Not sure what this is.
I had to look that up. Apparently that is the Power Conversion System. The link I saw suggests that may be a combination of DC to DC converter and battery charger. The guys in that link are trying to pull a lot more Amps than I needed and are diving much deeper into hacking the Model 3/Y than I needed. That is another Tesla Forum that might suck up more of my spare time. ;)

I decided to go the hybrid inverter route because I wanted to do load shifting and power my loads from solar stored in batteries during peak TOU rates. I also wanted to have that system work all the time and be able to drive my Teslas whenever I wanted. It all depends on where you are standing.
 
Thanks guys. It looks like his most straightforward path is to have the same installer swap the current inverter for the StorEdge inverter and add the critical load panel. I don't believe he is interested in doing that, and the real shame is he has 100 kWh of batteries between 2 EVs sitting in the garage but no V2H option.

Your neighbor may want to upgrade to a new EV (
) for V2H. It'll be cheaper than putting in home battery system of the same battery capacity.
 
Was looking into this myself recently, because StorEdge is meant to take that LG RESU10H battery. I've done some DIY EV work with batteries and initially thought to use reclaimed modules to make a DIY backup, but I stopped short because after I did some research, I don't know that it'd be worth it.

Looking through the install manual, the Storedge looks like it already has the transfer switch included in it, so adding the RESU10H-R at $5000-6000 depending on supplier becomes a matter of 3 big wires and 5 little ones, plus an auto-transformer. For that you're getting 9.8kWh guaranteed to 6000 cycles. If you're going to DIY the battery bank on a grid-tied system you've got to figure out the BMS (and hopefully you get that right!) and the auto-transfer, which is already part of the LG RESU10H-R and the Storedge. If you DIY using something like Tesla modules, it's going to be about $2800 for 14kWh, plus the cost of a really good BMS, and the transfer switch, and you're nearly to the cost of the RESU10H again.

From looking at this video:
and using that math, call it $6000 (although you can get it cheaper) for 9.8kWh and 6000 cycles means the LG RESU10H-R comes out about $102/kWh/1000 cycles, which is cheaper than everything else on the list aside from the Tesla Module and DIY cells, but don't forget it already includes the grid-switching equipment and the BMS, which you'd need to add to the others. So honestly, between that and having a manufacturer to back it up, that looks like a pretty darned good deal to me.

The problem I'm having is getting someone that's willing to install it onto my system. My original installer says they've moved on to a different company, which means what should be a $6k-7k add on is now a $20k project, for the same kWh as the LG, which seems to be easy enough to DIY on the StorEdge. The hardest part looks like just moving the critical loads to a subpanel, and that's just standard house electrical stuff. I'm fairly sure I can do ALL of it, but then the warranty is void.
 
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