DragonQ

Well it randomly woke up and started working again 17 hours later. I've asked my installer to open a support ticket with LG to investigate (if I do it myself I'll have to wait 2 months for a response if my previous experience is anything to go by).

Since 05:30 today, our RESU 16H Prime has been stuck in "power saving" mode, as indicated by the battery status via modbus and the slowly flashing "on" light on the battery itself. There's nothing in the manual indicating what this actually means or how to fix it. The battery has ~22% charge. The battery's WiFi isn't available either. I've tried changing the battery's mode via modbus to try to wake it up, to no avail. Has anyone seen this behaviour before? Is it worth trying to reset it? As far as I can tell this involves turning off the inverter, turning off the battery, then flipping the AC isolator, then doing all of those in reverse. I don't want to break things further though (e.g. stop solar working).

Looking in more detail at the data, it does seem as if most of our unnecessary export is because the battery is unable to charge at more than 3.2kW most of the time, and only at 1.6kW when it's 90+% charged. I've reduced how much we charge it overnight based on solar forecasts and since then our self-usage is now 96-97% which is more like it. Hopefully that was the primary issue. I've asked LG why their supposed "7kW" charge rate is nowhere near that most of the time, but I cannot find a working technical support email so I might get a marketing blurb response, who knows.

I have this setup as of this week. SE5000H, StorEdge, LG RESU 16H Prime. Works well generally and I have full control using modbus via TCP (no SolarEdge apps have been set up yet). I'm having 2 main issues. One is that the battery is almost always limited to charging/discharging at 3.2kW, even though the inverter's limit is set to 5.4kW and the battery's spec sheet says it can charge/discharge at 7kW. I have seen it briefly charge at 4.9kW from the grid (as expected) but only for a 10 minute period or so. SolarEdge say everything looks fine their end and it's a battery config issue, but LG have no technical contact number/email that I can find, and no config options are listed in the manual. Any ideas? The second issue is we are always exporting or importing a small amount and the response to solar generation or house load changing seems really slow, which means we sometimes import or export say 1kW for 10s or so. All of this adds up so yesterday we exported 1kWh and imported 0.5kWh during the day! I don't expect self a consumption to be 100% but surely it should be 98-99% rather than the 90% it was yesterday? Thanks for any help.

Any other ideas for a 48V ("low voltage") battery inverter that has local data access (via modbus TCP for example)? GivEnergy's only non-hybrid inverter is 3 kW only, would prefer something slightly beefier, say 4-5 kW.

Thanks for that, sounds similar to what we'd be doing. Is that the Gen2 3.6kW hybrid inverter? The issue with GivEnergy is that they only sell 1 standalone inverter (non-hybrid), which is only 3 kW. Given SolarEdge optimisers require their inverters, this limits the possibilities somewhat. What's your average daily consumption? Over the last 3 months our average daily usage is 23.5 kWh, with around 50% of that being at peak times. Background usage is ~350 W. So the breakdown is: - Peak usage: ~11.75 kWh - Car off-peak usage: ~7 kWh (hard to tell exactly as we don't have a smart charge point yet) - Background off-peak usage: ~2.1 kWh - General off-peak usage: ~2.65 kWh (dishwasher, washing machine, timed charging of hoover/mower/toys/etc.) Obviously these are averages. Any day we use the oven sees higher peak rate usage, weekends see lower off-peak usage for car charging. Heh, I saw our usage jump from ~500 W to a steady 3 kW with the ketlle on, so I'm guessing it's around 230V/10A. By itself not a problem but if we have anything else on (oven, washing machine, tumble dryer, air con) that means drawing from the grid if we have a GivEnergy battery. What brand inverter+battery do you have?

Bit of an update, turns out it's more complicated to get parts that both do what we want and work together without costing a ridiculous amount. I didn't realise SolarEdge single phase inverters only work with high voltage batteries, which are more expensive and also there's fewer of them to choose from. I was offered a Solis inverter for the battery instead, allowing a wider range of low voltage batteries, but Solis don't allow for data/config locally (at least not easily), whereas SolarEdge and GivEnergy do. GivEnergy has the disadvantage of only allowing 3.6 kW to be drawn from the battery, meaning every time we turn the kettle on we'll have to draw from the grid. Probably not much cost-wise but just feels silly. Also, we may have to choose between a 10 or 16 kWh battery, which is mildly annoying as we use ~12 kWh during peak times (range over the last month is 9.5 to 13.5 kWh). So if we get the 10 kWh we'll have to draw from the grid at peak times maybe every other day during winter. If we get the 16 kWh we'd never need to import at peak rates and we can store a bit more during the summer if the car is fully charged, but it'll never pay for itself unless we can exploit Octopus Agile import/export rates. I have no idea whether this is worth it compared to just sticking with a low flat rate at night (for the car and battery during winter). It's difficult to choose the "right" system but given it's so expensive I want to get it right! 🤔

Currently FTTC but FTTP is being installed in our road as we speak. I have no idea if FTTP will continue to work during a power-cut, I doubt we will know until one happens. Given the lack of mobile signal we may have to fork out for a standard copper landline as well just in case.

I think given the relative costs of the system, losing a few percentage points of efficiency by having 2 inverters won't make a difference in the lifespan of the system. We're going to go with quote 1, assuming they pass all our other criteria (availability, fast track G99 understanding, etc.). Thanks for the advice everyone.

I think both systems would offer that based on this link: https://www.solaredge.com/solutions/grid-backup#/ I can double check though because we'd definitely want that. There is no phone signal here so having internet + WiFi during powercuts will be very helpful.

Yes the hybrid inverter proposed in quote 2 is a StorEdge: https://www.solaredge.com/sites/default/files/se-storedge-single-phase-with-hd-wave-datasheet.pdf

EV charge point is 7.4kW. Quote 1 is Eurener panels with GivEnergy battery & inverter. Quote 2 is Tiger panels with LG battery (apparently compatible with SolarEdge hybrid inverter). In summer the plan would be to charge the battery with solar on sunny days and the car too if there's any excess. Given EV charging requires a minimum of 1.4kW and we're never likely to have that spare during winter, I suspect we'd charge the car at night (cheap rate). The battery would also charge at night on less sunny days, maybe topped up during the day on sunny days.

We've narrowed down to two quotes for a solar/battery system to go alongside our existing Zappi EV charger. Both quotes feature SolarEdge optimisers (because there are several trees shading our roof) and a ~10kWh battery. However, quote 1 features 5.4kW panel output and an AC coupled system (SolarEdge inverter for solar, another inverter matching the battery brand). Quote 2 has 10% lower peak panel output (4.9kW) but uses a hybrid SolarEdge inverter. Which would you go for out of the two and why? I figure the higher capacity solar is better overall, whereas having a hybrid system will be more efficient in summer due to having 2 less AC/DC conversions for solar -> battery -> house. Having 2 separate inverters will mean we can draw more from solar and the battery at the same time but this would be rare (e.g. charging car if we forgot to plan ahead). Quote 1 is a bit cheaper but quote 2 can start sooner. We will likely be adding more panels in a couple of years. Is there anything else I should consider? Thanks for any input.