SteveP

How big is the inverter? One thing you want to be mindful of is having batteries that are too small to provide the desired current as that will damage them.

If you want peace of mind - take a look at installing a "battery balancer" to manage the batteries in absence of a global BMS connected to the inverter. Also, just make sure you wire things up something like THIS to be sure of equal charge/discharge (even if using a battery balancer).

Yes, but as I mentioned, when there is LS, you run the risk of the system shutting down abruptly which is not great. See THIS video.

Just as with lead, to have the batteries in series or parallel, you want them to be the same age/charge/brand/size etc so typically you buy two at once and use them. Otherwise you get one discharging at a different rate to the other, leading to extra stress on one of the batteries. For parallel connections, make sure that you wire them together and then put the positive of the first battery to the inverter and the negative of the second battery to the inverter. This will ensure that both batteries get used the same amount as the cable lengths and current path is the same for both. See picture HERE if I am not making sense. The lithium batteries all have some form of BMS, even if it is a simple comparator circuit so they will manage their charging just fine, regardless of series or parallel provided you remain within their charge/discharge spec. Edit: Just took a look at the datasheet. They even give you the correct wiring as described above. From what I have seen, almost every battery like that has the same warning - mostly BS to cover themselves IMO

Yes, this is how many of the guys in the UK use the inverter. It will blend solar and grid nicely. The inverter will use as much solar as it can and then add grid power only when necessary. During loadshedding, the inverter will pull from solar only - but be careful because if there is no buffer (battery or grid) then you might find the inverter tripping if the load exceeds the available solar.

@Gavin286 possible. Although we are not talking very high loads given that the mppts are rated for 10.4kW.. I guess more testing is needed. With that said, I have not had my system run through a winter cycle so it could very well have something to do with temperatures given how hot it is and the fact that it has only happened to me when running my 30k BTU non-inverter aircon - because it is so hot XD Edit: I initially suspected the issue was due to the very high inrush current caused by the old aircon toggling on and off during its cooling cycle but again, more testing required. Speaking to my installer, he said that he has seen a similar thing in a factory that has a large non-inverter aircon on a 12kW sunsynk so theres that..

This is correct. How much passthrough depends on the inverter and not all of them can do it. Assuming you are talking about the sunsynk and deye derivatives, then yes. This is quite a nice reason to go for the 2x5kw but do remember that the 8kw sunsynk does have higher current ratings on the MPPTs so you can use larger panels without clipping. In the end I went for the 8kw as it works out cheaper upfront and is a single install rather than having to pay for two installs at different times. 8kw is more than enough for most households and the batteries tend to be more of an issue at the end of the day anyway. For me, the only benefit of the 2x5kw setup is redundancy and that might be a major driving factor for some - even if more expensive overall. One thing to note is that the 8kw sunsynk/deye has quite loud fans which come on every so often. This is not an issue if you install inside a garage but if installed in earshot, it is irritating. AFAIK the 5kw (and therefore 2x5kw) synsunk/deye inverters do not have this "issue". Edit: I must add, if you have a few aircons and a pool pump - we have an old school aircon that draws 3kw when running - then the 5kw one is likely not enough. With that said, I have a friend who put his whole house on a 5kw system and has had no issues.

For what its worth, I have an 8kw sunsynk and have the same thing happens to me. I thought that it was due to me having a high inductive load kicking in such as an aircon but after seeing yours do the same thing with less load.. now I am not sure.