Solar PV battery options

Was it every cell or just a few ? It sounds like you were just very unlucky / unfortunate.

Reflects my own experience, they wear you down replying with rubbish and wait for you to go away. It is important for anyone going down this route to understand that purchasing cells from Aliexpress is risky and PWOD and or OYE in my case is no guarantee of quality or any level of service if you have an issue.

Personally I purchased a cell elsewhere to swap into my pack and gave up on trying to get anywhere with OYE.

Maybe pay using paypal and try to get set up/tested within the protection period but even at that I doubt it will be straightforward.

Not a great price is right. €2200 shipped for 5kWh? I paid €2300 shipped for 20kWh of quality CALBs a few months ago.

So €1739 for 100A but we can build 200A with a separate BMS for less 🤔

David Poz just tested that Jakiper battery. It's ok but not great. The cells look like decent prismatic cells (not the crappy pouch cells that are inside Pylontechs). He did discharge it at nearly 100A for nearly an hour though. It's what it is specced at but still, that's impressive. Two Pylontechs totalling the same capacity can only do 50A.

I'd say if he ever tested the Pylontechs, he would slate them 😂

Aye! He gave me a right scare a few months ago when he changed his appearance. He used to look normal but now he looks like a red neck off grid mad US prepper. Which I suppose he is 😂

If I was you, I'd get the batteries first. Who knows how long we'll get away with the tax, and you see the potential generation in even 4kWp

Why not just go for more panels without bumping the inverter? Or to phrase the question another way, how many times have you hit the 4Kw threshold with your existing panels. I've (had) 5.3Kwp of panels with a 5.4Kw inverter, and i never experienced "clipping". Sure there will be times that your inverter may limit your generation, but I would say that for the vast (vast) majority of time you'll still not see the 4Kw anyway, even with the increase in panels.

Here's a very good day that I had back in May

Well short of my max potential. Sure, middle of June, sun overhead at the perfect angles your might get "clipping", but I'd crack on and increase the panels. Wait a few months and then see what you telemetry tells you and then if you feel that your missing "a lot" of generation by plateauing at 4Kw (I doubt it), then upgrade the inverter.

This way has the added advantage of you having data to decide about the inverter/battery size you can fill.

One caveat is that your existing inverter has dual strings and you have capacity spare (within voltages usually) to get yourself to 6Kw. E.g. if you have only 1 string and you have 10x panels on it, your unlikely to be able to get to more than 12 panels.

Also it looks like I am getting some clipping already with 4.5kWp of panels installed. This was pretty much the best day of the past few weeks so definitely not much clipping most days. But with a bump of nearly 2kWp I'd expect the clipping to be a bigger factor?

Thanks for the input all. If just going the panel route I might consider DIY installing them as it's on a lowish garage roof so would be safe enough. Is there a limit to the amount of panels to a dual string inverter in terms of kWp or number of panels?

The limit depends on the spec sheet of the inverter, there is usually a limit for total voltage on one string and total voltage overall for the inverter. I.e. on my Solis 6kW I can not have more than 12 panels on one string - well 13 really unless we have a blue sky day while it is minus 20 degrees Celcius or something like that 😂

What make / model inverter do you have?

And it's a pitched roof, but low height and I'd be comfortable enough on a roof so don't think it would bother me. Would definitely consider it. Might see if I can source the same panels.

Thanks! That's fairly straightforward. 11.97 panels. So could go to 24 panels max 2x12. Don't have space for that many anyway. I think 2 strings of 8 each would be most I could fit unless I do the north face of the roof too. They're 410wp panels so max I could do on the inverter is 15 I think based on the spec anyway. So one string of 8 and one of 7. Thanks all!

Ah sorry. Misunderstood. My panels have VOC of 50.1. so that means my max is 12 panels total? Not 12 per string?