Is it possible to set the maximum battery charge when charging from grid?

[dangermouse]

Hi all,

I'm still planning my install, and still trying to find an installer, but in the meantime a question occurs to me.

I know that most inverters on the market allow you to set a time period when the batteries will be charged from the grid (eg overnight on cheap power). But if you fill the batteries overnight, and the next day is very sunny, a lot of PV power will go to the grid instead of to the batteries, where it would be more useful and economical.

I've been mainly looking at the Solis hybrid inverter but can't see any mention of such a function in the manual. Is there an inverter on the market that will allow you to set a charge limit when charging from grid, but still fill the batteries to 100% if using PV?

Many thanks

[pudding]

My Sunsynk can do that. Set a % charge level for several time windows, and then choose to charge from either grid, or another generator. So you'd set it to say 70/80/90/100% for an overnight window, then if the battery is run down the next day, excess solar will top it up as normal.

[Caesium]

Yeah my Luxpower lets you set a maximum % for AC Charging as well.

I'd be surprised if most inverters didn't.

[Oldgreybeard]

Same with the Sofar. I have ours set so that in time of use mode it will charge to 55% SoC during the off-peak period in summer and increase that to 75% SoC in the winter. This means that the battery rarely ever charges overnight during the summer, so we mostly run using stored PV from the day before, but 55% is enough for the following day if we happen to get a really bad day for solar.

As the daily average PV generation starts to drop, I increase the SoC for any overnight charge to 75%, just to give us a bit more of a buffer, as we use more electricity in winter (lights on earlier, less normal consumption offset by PV generation). This seems to work OK. If we get a forecast for a few sunny days in a row in summer I switch the inverter over from time of use mode to auto, so we run off the batteries and PV 24/7. Doesn't make a big difference, saves maybe 50p to 60p for each day it's on auto. Worth doing for a sustained bit of good weather, but a bit of a faff having to cycle through the settings to change it back and forth.

[Tinbum]

I use SOLCAST to predict the PV for the next couple of days and then set an overnight maximum SOC value.

[dangermouse]

Same with the Sofar. I have ours set so that in time of use mode it will charge to 55% SoC during the off-peak period in summer and increase that to 75% SoC in the winter. This means that the battery rarely ever charges overnight during the summer, so we mostly run using stored PV from the day before, but 55% is enough for the following day if we happen to get a really bad day for solar.

Thanks for the reply (and everyone else)!

To clarify, is that the Sofar HYD3600-ES? Price looks reasonable, about the same as the Solis, and it sounds like it's more capable.

Is it easy to configure? I've seen quite a few people complain about the awkward Solis user interface.

[Oldgreybeard]

Same with the Sofar. I have ours set so that in time of use mode it will charge to 55% SoC during the off-peak period in summer and increase that to 75% SoC in the winter. This means that the battery rarely ever charges overnight during the summer, so we mostly run using stored PV from the day before, but 55% is enough for the following day if we happen to get a really bad day for solar.

Thanks for the reply (and everyone else)!

To clarify, is that the Sofar HYD3600-ES? Price looks reasonable, about the same as the Solis, and it sounds like it's more capable.

Is it easy to configure? I've seen quite a few people complain about the awkward Solis user interface.

I have the AC coupled Sofar ME3000SP, but suspect that the hybrid models have a similar capability. The user interface for the Sofar is OK. Could be better, as it involves an awful lot of key presses to navigate and change the settings, and Sofar have put the most commonly changed settings (like "work mode set", which allows access to the time-of-use sub-menu) towards the end of the settings, on the second page.

It works OK, but it would be a lot easier to use if the settings you need to get to most often were at the top of the menu, and those you only need to change once at installation were at the bottom. Always seems daft that I have to button-press past the settings for things like the battery type, your country, language, time etc on to a second page of settings where item 11 in the list is the setting to change the working mode and time of use settings. They are the only things I ever need to change from time to time, seems daft for Sofar not to have put this setting near the top.

[dangermouse]

Can anyone with a Solis RHI 5G inverter confirm this is possible please? I intend to buy a bundle from Bimble but they only offer the Solis or the "Fronius Primo" which is more expensive, and doesn't seem to support any but their own brand batteries.

[marshman]

__

[Caesium]

One other point to note which I have only just confirmed is that even though the spec says "max charge power 5kW" it will only do that for 15 minutes before throttling back to around 3.6kW - so 100A max for 15 minutes then drops back to 70A. I can still get a full charge into my 6 x US3000C in the E7 period so it is not really a major issue, just wish it was clear in the data sheet. If you restart the inverter it will immediately charge at full wack, 100A for another 15 minutes before dropping back. Seems OK when supplying loads it, though not done a thorough test with a constant 5 or 6kW load.

This is invaluable information, thanks for posting this. You might've saved me buying one at some point in future! Is this mentioned anywhere or did you have to find out after you bought it? :/