LG CHEM/SMA battery retrofit

We are an independent solar company installing a battery retrofit on an existing PV system. The PV system was installed by a different company a few years back. They are a sunpower dealer and we are not. The existing system includes two Sunpower (SMA) inverters: SPR3000M and SPR 6000M. We are installing one new SMA S.B. 5.0 inverter with an SMA ABU and an LG CHEM RESU10H battery meant to be compatible with SMA.

The first issue we have is to get the older sunpower inverters to communicate with the new SMA unit/LG battery.

The second issue we have is that apparently, when the grid goes down and the battery shifts to back-up mode and the SBS loses contact with the PV system, effectively shutting down the PV as a power source for loads and recharging.

We've reached out to Sunpower and SMA and both have given us very little help. Our thought is we can't be the first installer to have come across this issue. Is there anyone else that has experienced one or both of these issues and what did you do to resolve it?

We would appreciate any insight!


  • AmpsterAmpster Registered Users Posts: 173 ✭✭✭
    edited September 2020 #2
    I am not a professsional, and merely a hobbiest but I have had success AC coupling two GT inverters to an Outback Skybox. I can only give you a high level insight into AC coupling, which is that it is easier if the GT system and the hybrid (in your case I assume is the SMA SB 5.0) conform to the same exact UL1741 spec. I also assume the SMA  ABU is the transfer switch and when I refer to the SMA below I mean both the SMA 5.0 and the ABU.
    Are the new SMA SB 5.0 hybrid and the older GT inverters wired to the same essential loads panel? If so, do you get any diagnostics from either inverters, like frequency or power or voltage? Is the SMA 5.0 providing power to the essential loads panel? Sorry if my questions are insulting but I wrestled with these issues in my installation. 
    What is the UL certification of the older GT system? I assume the new SMA is UL1741SA compliant?

  • Dave AngeliniDave Angelini Solar Expert Posts: 6,224 ✭✭✭✭✭
    Too many of my pro friends have had problems with LG chem and integration. I can't remember how many had good luck but they were in the minority. SMA is usually pretty good, not on this one.

    The battery itself being high voltage (400dc) is also an issue in starting motor loads. I was involved in the Schneider XW & LG chem field test. We had battery failures with the LG 48vdc product. LG decided not to market the 48vdc in north america. They have had problems worldwide with large inverters and hi charge rates. It was a great learning experience for me. Especially how many of them I was planning to use. It sounded too good to be true.

    Anybody want to have for free one of the 48vdc LG batteries can contact me if they pick it up at my shop. It blows 200 amp fuses.......
    "we go where power lines don't" Sierra Nevada mountain area
    E-mail [email protected]

  • jakobwjakobw Registered Users Posts: 19 ✭✭
    edited December 2020 #4
    I know this is many months late and although I have not experienced your exact problem, I would suggest that the solution generally for this is the SMA COM Gateway and the SMA DATA MANAGER M. This allows the newer Speedwire and RS485 inverters to communicate. You may need to retrofit the older units with RS485 piggyback modules if they do not have any (I'm sure you know that). Contact me if you need some.
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,224 ✭✭✭✭✭
    Recapping this as there are still people getting burned on this one. Heard of 2 last week!

    Too many of my grid solar installers buds have given up on SMA for the LG10H. The Solar Edge Inverter/ LG works pretty well for them in the 400vdc app. Terrible support from SMA on this. The solution from my buds it only use SMA with BYD bats for North America.

    For others here, the LG would not recharge after it's first discharge in a grid outage. Some said it was the dc to dc converter in the LG. Many got their money back. Some did not!

    Thanks for the offer !

      SMA is culpable for not supporting this LG problem. I learned the 48v lesson with LG, a flawed design.
    I give LG some credit for trying in 2016. Those were early years for lithium offgrid. The LG resu48 / Schneider project was good for me and Schneider really did all they could to make it work. LG never cared to find the root cause They still do not care.

     Oh well, water under the bridge.
    "we go where power lines don't" Sierra Nevada mountain area
    E-mail [email protected]

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