FoxESS Community - Owners & Installers Forum

Good evening people, I am not sure if the settings on my 6kw solis hybrid are correct for my LV5200s. From what i can make out, the settings shown are default and should be higher because i have 2 batteries? I got lost fairly quickly when reading about this. Does the charge setting only refer to charging from grid? As you can probably tell, i have no idea about this! I have 12 x 405w panels. I have never got anywhere near 4kw, never mind 5kw, coming in from my panels. Even in the middle of summer on a really hot, bright day. Are these 2 things connected? If the charge amperage was set higher, would my batteries be charged quicker? Or isnt that how it works? I really wish i knew more about solar! lol!

I'm not that familiar with Solis inverters but from what I know those settings are correct for your batteries.

One of the problems with Solis 'LV' inverters is that they take low voltage batteries ('LV') which requires a very high current to meet the power demands of larger inverters for example - a 50V battery at 50A (a very high discharge current) = 2.5kW.

In you case with 2 LV5200's they are mounted in parallel which means you get a higher discharge current but at the same voltage - I don't know whether this is still true but the Solis hyrbid inverters using LV batteries were only able to discharge at a maximum power of 5Kw (100A * 50V) from the batteries. Obviously solar generation is different and they can provide the full power of the inverter if the panels are producing enough power.

It is one of the reasons that FoxESS use high voltage 'HV' batteries, and depending on which battery you choose the battery voltage is usually between 200V & 450V DC - (The EP5 for example is 200V DC) and this would mean that for a 6kW inverter full power can be provided by a battery discharging at 30A.

Also the reason why I wanted to make sure I mentioned this, is so you can double check the Solis battery discharge limitation is still 5kW as it wouldn't matter how many more LV batteries you fit if it can only discharge at 5kW - it would seem that the higher rated Solis inverters use HV batteries instead (but this would again involve you changing your batteries ).

I think i must have misunderstood what was being said in relation to the charge and discharge of the batteries. It was actually lv5200s and a sunsynk inverter. I should not have got involved with it, i knew i would end up confusing myself! Haha! The more i look into low and high voltage batteries, the more it is obvious that i should have gone for HV in the first place. But, i knew next to nothing about solar and a seller put a package together for me. Just sent you a message on one of my other posts. The cube and 10.5 KH is going to have to be the way to go, i think. My solis will only output just over 5kw, then it shuts down! Its a great inverter but its just not big enough for our needs. You may be able to see from the photo that the EPS output goes to the house CB, so it powers everything. This was deliberate as we wanted power to everything in case of an outage and eventually to go off grid, hopefully. I could not get any installers to wire it how i wanted. Most said they could put an extra socket in somewhere and that would be live if the grid goes down. What good is that!? I started to suspect that they didnt actually know how to do what i wanted. Plus they wanted to put in a smart meter. That is never going to happen! So, a friend and i did it ourselves. I do not get a notification of any replies unless i refresh the page on my PC and that could be anytime throughout the day. So, apologies for any late replies to your comments, Dave. I appreciate them and i am learning a lot. Thanks.

No problem, i’ll answer the question from the other thread here, as you have discovered it’s quite the minefield and you don’t know what questions to ask until you’ve had experience of it.

For an on-grid inverter you would normally wire your loads (consumer unit) via either a manual or an automatic changeover switch to power from the EPS should the grid fail - there are plenty of options but you also need to carefully consider the earthing for when the grid connection is disconnected as the normal house earth may also be disconnected. There is a thread on the forum all about EPS that covers the various options and things you need to consider.

On the cube battery cabling it’s a straight through cable set between the inverter and BMS (Master), nothing is required between - the BMS has a DC isolator and also a contactor that only enables if the comms is good up to the inverter, on top of that each individual battery pack has it’s own internal fuse.

The battery sizes can’t be mixed so you have to stay with all 2900’s, 4100’s or 4800’s and it is typically better to have a larger number of batteries of a smaller size, than a small number of a larger size. That’s because they are connected in serial, so the more batteries the higher the voltage and the lower the battery current which is better for battery life.
The HV batteries typically have a maximum surge discharge current limit of 65A (50A sustained) so to get to your 10.5kW you would want a battery stack of more than 220V.

This is where it gets a little bit complicated as the different cube battery sizes have different ‘pack’ voltages, and to meet your max limits you would need these minimum pack sizes where the number after the ‘Hx’ is the number of batteries - either an ECS2900-H4 (230.4V) or ECS4100-H4 (230.4V) but if you go for the ECS4800 you would need an H5 (224V).

Good morning Dave, "it’s quite the minefield and you don’t know what questions to ask until you’ve had experience of it." That is exactly it, in all walks of life. You dont know until you know! If i had known my solis would shut down on a regular basis, i could have done things differently. You live and learn, i guess. I read your comment late last night and it sent me researching the operating voltages. I saw the voltages of the cubes before but didnt connect it to what the inverter needed. Once you pointed it out, it becomes obvious. Amps x voltage gives you the wattage! Just that one comment could have stopped me buying the wrong batteries! It seems with solar, you are just one comment away from making very expensive mistakes! lol! So, i have just edited another post of mine concerning individual control of cube batteries, after reading your comment. The earth on my system goes to a rod outside. I think thats the only thing that doesnt need to be changed! Thank you for your time again, Dave. I am sorry i am taking up so much of it But, i think i am getting close to making an informed decision about the system i want. So it wont be long before you see the back of me! Well, until i switch it on and find nothing works! Haha! Cheers.

Unfortunately with the way you are using your inverter (‘almost’ off grid) as it’s using the EPS output it is more prone to capacitive and over loads.

If you were running with an EPS changeover switch (contactor), the inverter would operate in traditional grid tied mode, where the grid would fill in for the over loads so the inverter wouldn’t trip, the downside of that is that if you have a power cut, it takes a second for a changeover switch to switch over.

Glad to hear you’ve got the earth rod - one thing people don’t discuss much is the Neutral - Earth bond (honestly in the pub i’m ‘such’ an interesting guy to talk to ) - I suspect Solis is much the same as FoxESS which doesn’t create an N-E bond when it is running on EPS. That’s all fine whilst the grid is connected and intact but if it is isolated you can lose the N-E bond which results in floating Neutral.

On my Fox system I have a single pole relay that creates a N-E bond when it’s running on EPS - if the Solis doesn’t have an E-N bond or create one when running on EPS, that’s something to check just in case the grid bonding is isolated.

I am sure my best friend, who did most of the working out for my system, mentioned the neutral earth bond. Sorry to say, i zoned out after a couple of sentences as i had no idea what he was talking about! You 2 would probably get on well over a drink! Haha! I cant remember what the outcome was. Whether he implemented something to deal with it or decided i didnt need it! I will ring him tonight and try and follow what he is saying! My mistake was going into radar and sonar when we were young, as he went into domestic/factory electrics. Not much call for sonar knowledge on the island i live on! lol!