jumper

You can find the battery specs here: https://www.solarwaysuppliers.co.za/wp-content/uploads/2021/07/Shoto-Residential-Battery-V131.pdf Strangely everyone seems to be calling the 48-100 a 5.12kwh battery, but the specs have it as a 4.8kwh. The 51.2-100 is 5.12kwh in the spec. Be very careful to use the right settings as they are very different.

Sorry, I realise I may not have been clear, the inverter side does not run on panels alone, but the machine (inverter in general terms) itself runs, screen, settings etc., so if you need to restart/reboot the machine (because the inverting part doesn't work from the switch anymore) then you need to disconnect the panels (my guess is to reset the relay that switched off the ac inverting in the first place).

I started out exactly the same, I think a lot of us do, but I would seriously suggest a combiner box, they are not cheap, but they are worth it for safety because if there is a short circuit or earth leakage in the panels, it can become very dangerous for your wonmenfolk to operate 😉 My inverters operate the same way, if the battery is flat and there is no ac in, it can run from the panels, so you need to disconnect them to switch off.

Are you using a PV combiner box? If so, you can pull the fuses to turn off PV, if not, I would suggest you get one as it will have earth protection which I would recommend and then pulling the fuses is easier than pulling PV connections. You can also get combiner boxes with a switch.

That's the pwm cable for speed control, different fans use different cable colours (I know it's crazy) and some don't have pwm, I don't remember all the details it was a long time ago that I dealt with fans, you may need to switch some of the wires by pulling out the connectors and switching them around. You might find some better info here: https://forums.aeva.asn.au/viewtopic.php?p=54866#p54866

You are correct as far as my experience is concerned. Something I learned from bitcoin mining in 2015 is that these types of PC fans are designed to pull air and not push it, they are actually quite useless at pushing air. The best configuration we found was a push-pull relationship where if you had one fan pushing air in then you needed another fan pulling air out the other side (this reduces pressure against the pushing fan) or chip temps just increased higher than they were with 1 fan pulling. I would suggest against changing the fan configuration without adding another to pull out the top.

Now this has piqued my interest... I have had similar behavior from my inverter, but before it deteriorated to the stage of switching itself off with relays clicking I would get the normal fault beep with fault 03 [Battery voltage too high], at night about 2 hrs after dark which went against all my logic. Sometimes the screen would report the battery voltage at 120V which couldn't be right because they were all just under 13V when I measured them. I was told that it could be the gel batteries because when they get old the plates can warp and touch each other and cause a short... is this possible if I could restart the AC inverter using the switch at the bottom right of the box and everything would run fine through the night, just like Johan? I ask this here because even though the battery voltage on the inverter was also around 51.3V, I have since done a load test on the batteries and I think they are indeed on their last legs, so it might be relevant... here are the readings, maybe someone can shed more light on things: 12.99V - at rest 12.03V - under load (washing machine at +-350W for 1hr) 12.61V - load removed 12.68V - rested for 2hrs 13.12V - after charge I am concerned that under load, the battery voltage might be too low or collapsing as you say, even though the error I was getting was battery voltage too high [03], but I'm not sure if both together mean the batteries are toast. I know the rest voltage seems high, but from the manufacturers spec (Leoch) they are correct and very much the same as the Trojan T-105 specs too. P.S. I have seen other errors since and my machine is now at the same stage as Johan's, but I'm wondering if it could have originated with the batteries or if it is simply the hot weather where I am that has slowly sucked the life out of it and the batteries are fine.

Thanks for the reply Yeah, I figured this when I saw they are joined to each other and to the casing internally, but then I saw the N/E relays and circuits (which led me down another rabbit hole) and just wanted to be sure I wasn't going to cause anything to go haywire. Yep, exactly, as I don't have grid power I figure I'd use that instead of shoving 2 wires in the AC-out earth. Thanks again, much appreciated. Here's a pic for reference in case anyone is interested: AC-in and AC-out earths are joined at the casing bolt just outside the rhs of the pic

Batteries lose their capacity as the temperature goes down. It's 100% at 16-25C and goes down to 50% at -20C, so as it gets colder your battery won't charge to full capacity.

Hi Coulomb, (hope I'm not hijacking this thread) I am totally off-grid with no AC-in and my AC-out Earth runs to a spike about 30m away just before it enters the house and mainDB. Everything has been running fine for years, but I'm going to be doing some work on the inverter side and was thinking of running another earth from the AC-in Earth connection to a spike closer to the inverter (PV combiner box uses this spike), for extra safety. Is this justified or will my paranoia just make things a lot less safe in the end or cause my inverter any damage due to having 2 spikes on the same earth line? I have an axpert (clone) 5kva with 0.8pf and 145V mppt with the same N/E relay as above. Thanks in advance

I'm sure it won't be a major problem with modern bms, but I don't think you'll find a supplier who will say "yeah sure it'll be fine" and take on the liability when things don't turn out as expected.

This is because Power = Voltage X Current... you will have some voltage when there is some ambient light, but the current will be 0, so P=0. As the sun increases, your current will increase and therefore your power too.

Age of a battery will change the internal resistance over time and it is important to have balanced batteries in a bank or you will have different batteries charging at different speeds causing them to become unbalanced. When you add a load to the bank you will probably find the new battery doing most of the work, shortening its lifespan. I don't think the issue is that it can't be done, I think the issue is that it's not a good idea, especially with what they cost.

Just FYI a 42V Voc panel at 25C, with a temp coefficient of 0.3%/C [0.126V/C per panel] will have a 45.15V Voc at 0C and 3 in series will take you to 135.45V Voc

Just a word of warning with the 145V Axpert and panels in strings of 3. I have read that going over 120V Voc is not recommended and can lead to damage of the inverter. Remember that the panels are tested at 25C, so if you live somewhere with cold, frosty mornings, you can end up with a very high Voc spike. Just be sure you have a good safety margin to that 145V.

Hi, you can find the specs for the shoto batteries here (make sure of the model number): https://www.solarwaysuppliers.co.za/wp-content/uploads/2021/07/Shoto-Residential-Battery-V131.pdf My suspicion is that with a nominal voltage of 48V and a setting to start charging at 52V is what is causing the issue, as well as the discharge voltage of 42V is TOO LOW, the specs say 45V for the 48-100. I would suggest changing the settings to start charging at 47-48V, your cut-off voltage to 45-46V and the end voltage of 54V (at 100% SOC) is correct and go from there. You may have been over discharging the battery with such a low cut-off voltage (3V below the spec).