jholler

For anyone else in the future reading this thread, what is now working for me is a cut-off voltage in Program 29 of 46.5V. In last night's extended load-shedding the inverter ran the house for 3 hours while the under-load voltage gradually dropped. The inverter shut itself off at around 46.5V as expected (I was manually watching it and last saw it at 46.9V before it dies a few minutes later). Power-cycling the inverter with its rocker switch had it turn on again and show the no-load battery voltage as 47.7V, before turning off again. (The inverter not turning on again is now what I expect, since the battery is flat at this point - unlike when I posted this topic wondering why the inverter wouldn't stay on with a reasonable charge level in the battery.) Most importantly for me, when mains power came back, the inverter was able to turn itself on again. This is the behaviour I was missing before when I had the cut-off voltage at 45V and the batteries themselves cut power to the inverter - forcing me to go manually start things up again at the end of each extended load-shedding event. So there might be a better magic number than 46.5V, but its working for me, and hopefully will: * prevent premature shutdown of the inverter during load-shedding * allow auto-recovery of the inverter after load-shedding * and go some way (but not all the way) towards not fully depleting the battery each time and shortening its life. Thanks to all for the replies and help!

Thanks for the detailed info Coulomb. That makes sense that its using 'lead-acid thinking' 'cause lithium-based batteries were pretty new on the scene when I bought this guy. My inverter goes up to 58.4V for Prog 26, so I'll go checkout the recommended firmware with interest. (And brace myself for robust conversations with the wife if I turn what's an annoying situation into a permanent outage 😅) If you have the insight/time/inclination to explain, what I still don't understand is this: * I hear what you're saying about the 2.0V spread, and how my setup might droop below the cutoff level with this spread under load. * On startup, however: The no-load voltage of my battery this morning was 49.8V, which is 2.9V above the cutoff voltage of 46.9V. I would still expect the inverter to 'try' energize the AC load (and lights to at least momentarily flicker right? maybe even a relay inside the inverter to click or something), before the voltage drooped again under this load and with the 2.0V spread to then dip below my cut-off point and turn off again? Maybe this does happen but in milliseconds and so I don't see it, or maybe deep in the firmware the code works on a 2.0V allowance under running conditions and, like, 3.0V during cold-start to handle inrush current? I find it surprising (and interesting) that the inverter doesn't seem to do anything but turn off and sulk. I think I will risk the family's patience and fiddle with Prog 29 again (set it back to the 45V cutoff point I had before) and see at what point it turns on again, for science; then do the firmware updates, for quality of life. Thx again!

Hi, Thx for the replies. Yes, the inverter was under load when it shut off. Having thought about it some more a bit, I could also imagine that some of the randomness could be when a family member turns on a heater without realizing we're on battery backup, the Axpert tries to bypass to mains, and turns off. I think the title for the topic was poorly framed by myself. Its less the inverter turning off that bothers me ('cause it might just be some transient overload) - what I really don't understand is that it won't turn on again when the battery looks decently charged and there is no hectic load as far as I can make tell (this morning there was nothing much happening in the house with everyone still asleep). If I power-cycle the rocker switch it will turn on for about 30 seconds or so - make no attempt to energize the AC load (that I can see - maybe this happens too fast for me to see with the eye) and turns off again. When this problem happens again I'll try lower the cutoff voltage a bit more per Namreh's suggestion, and I'll also try disconnect all AC load and see if it wants to turn on then (and if so, I guess I'll then enable breaker-by-breaker and see if I can track down some long-forgotten industrial-grade load 😄). Thx again.

Oops. I wrote RCS when I meant RCT! Its the RCT Axpert 5kVA. Model number RCT-AXPERT 5K. Jammer.

Hi, I have an RCT Axpert 5kVA inverter connected to a Pylontech US3000 battery. The inverter has a tamper sticker on the side marked May 2015, the battery is 12-18 months old. The problem I'm having is that the inverter turns off when the battery is at 49.8V which is long before the low battery cutoff voltage in program 29 of 47.5V? Its happened a couple of times in the last few days, but specifically, this morning when I woke up (about an hour into load-shedding) the inverter was off, with the Pylontech showing 5 out of 6 green lights (ie: mostly full?). Turning the inverter off then on again with its little rocker switch got it to start up and run for a few seconds, during which time I paged through the status screens and saw battery voltage as 49.8V and the little battery icon on the inverter showing 2 bars (out of what looks like 4 total). I fiddled with Program 29 a little to reduce the cutoff voltage progressively down to 46.9V, but each time I turned the inverter on, it turned itself off after a few seconds - without apparently even attempting to energize the AC load (I see 0V AC out on the inverter display panel). I don't understand this behaviour? As further context, this is a recent problem. A few days back I changed the cutoff voltage to the recommended 47.5V after having inadvertently been running it at 45V since installation. What made me change it is that the Pylontech battery was (I believe) shutting off the inverter due to low SOC. When loadshedding ended I always had to pad out to the garage to push the button on the Pylontech to turn the house back on, which was getting old with the extended Stage 6 schedules. I was surprised I had 45V configured on the Inverter, so changed it to 47.5V so that it would be the inverter deciding when to turn off, but hopefully still be able to turn itself back on when mains came back. Now however, the inverter usually turns itself off too soon. But last night we had an extended power outage during which the backup power ran for nearly 3 hours (which is what I expect for my average load and the battery capacity). So it doesn't *always* turn itself off. The inverter doesn't drive the fridge or the heatpump or the pool pump or washing machines - those are all mains-connected and go off during load-shedding. So I can't imagine its some inrush current/voltage droop issue from big inductive loads. The slightly random nature does maybe hint there's something like a fridge turning on and off at different times that triggers an overload and prevents recovery, but I can't think of anything like that - its pretty much PCs, TVs and other light electronics plugged in. What I'm gonna try when this happens again is to shut off the AC load output breaker on the inverter to see if it turns on with no load whatsoever and therefore if its something about the load that it gets unhappy about? The other settings on the inverter are per the recommendation in the Downloads section of this forum: Program 2 - 30A (although recommended is 25) Program 4 - SdS Program 5 - USE Program 12 - 48V Program 13 - 51V Program 26 - 53.2V Program 27 - 50.5V Program 29 - 46.9V (current value. I'd like to change this back to 47.5V) Thanks in advance for any assistance!