Right after the increase from 52V to 52.4V… there were a handful of issues with an imbalance. Thankfully I could count them on one hand… and all but one recovered on their own.
Must say, if I was supporting clients, I would have “sold” the clients on the 99% SOC, for it is not accurate most of the time and I challenge anyone on that, when using a BMV and BMS together in the same system. 
Just saying.
BMV vs BMS on ONE (1) cell being questionable - deal with the fringes, the average sorts itself better.
And clients who demands 100%, send them to me … no jokes … once I have said my piece, based on what I’ve read here and seen, clients will be happy with 90% SOC displayed. 
Oh that is not uncommon. LG Resu batteries charge to 95% (if I have my facts correct of course). If you ask about it, they simply tell you that that is better for the battery.
For the Pylontech, we actually didn’t care too much about the 99% thing. You can sell that easily, by now lots of people know that running a Lithium battery a bit lower is often a good thing (cause they have laptops and Apple phones that do it already). But the fact that the balancer apparently didn’t have enough to work with was more of a concern. The fact that an additional 0.4V also gave us 100% SOC indications… that was just a bonus.
1 Like
Chapter 2… we had our load shedding last night, 18:00-20:30. Power came back at 20:05 and then the local transformer decided it was not happy about this. We then went through about 3-4 cycles of “power back… 2 seconds… power gone”. At 23:45 for some reason my system shut down. Stats shows the battery was at 49.2V, 68%. No Alarms in the log… just no power. Power came back at 00:30 and inverter started right up and started charging the battery back up (chop-chop toot-sweet). Looking at the numbers in VEConfigure the low voltage cut-off is actually fine.
Long story short, would love to know why it shut down.
Edit:
I can see two alarms on the battery page, one for low voltage and one for low temperature. Was it that cold in Johannesburg last night?!?
Once we had same, power came back, even before the MPII synced, was gone, also 3-4 cycles.
The weeks following, first a QNAP started having more and more issues, was not on the APC UPS circuit, fixed, a LED screen started showing lines, smoke left it eventually, was also not on the Online APC circuit.
When I played with a MP500va, feeding power back, I had EXACTLY the same, SOC was high, inverter was off. Upon further investigation I found a cell too low, BMS having switched off, and because it switched off, it gave silly warnings like i.e. low temperature, and a few others.
Interesting… I’m not seeing Lowest and Highest cell stats at all. Would a few charge/discharge cycles help?
You have Pylontechs, apparently soon they will support providing that info over the CAN bus, but not currently (as far as I know).
As of the first of May 2021, they have firmware that has the stats. It is not perfect yet. And upgrading the firmware isn’t always straight forward (and you need to make a console cable for it). But the firmware exists…
Installable via the regular mechanism? or do I need to Macgyver it?
Other things to check, make sure the low voltage cut-off is not too high. And make sure your ESS discharge curve is not too high.
You can set the low point at 42V, or if that feels too low for you, then 44V or so. The battery’s BMS will kick out if there is a low cell before that point, and technically a well-balanced battery is not yet completely empty before 42V (2.8V per cell).
To be clear, this is firmware for your BATTERY. Not for the GX device or the inverter or any of the other things. There is a little RJ11 socket on the battery, looks like an old POTS telephone plug. That is an RS232 connection. You need a cable for that, plus the BatteryView software from Pylontech, plus the firmware.
Boo.
I can see from veconfigure…
DC input low shutdown: 37.20
DC input low restart: 43.60
DC input low pre-alarm: 43.60
Sigh, I’m not going to attempt doing this myself. Comfortable with the Venus firmware stuff, but not going to give the Pylons a ago. Maybe I’ll try and get Jaco to install another battery for me and then update my firmware… 
ja… this falls in the circus lion category… it’s still a bloody lion.
2 Likes
The saga continues:-P
So last night we had our turn for the free darkness supplied by government… and we were truely lucky… we got more than our fair share! (power came back on after and then went away…)
So similar to last time… though not quite… this time round mom decides that the tiny dictators room is a bit chilly… and not even thinking about it switches on the heater… no probs, the setup can handle that.
At this point we run the battery down to 70%. Now last time we “tripped” at 68%… this time we went past 68% and I though hey, cells balanced, all good. We get to 62% and things get all trippy again. I reset the battery (red button)… everything comes back up for 2 minutes, we shut down again. This time I switched the battery off and on again and this time it stayed on.
Now looking at my alarm logs after I see two low battery alarms - at 62% or 49.12V.
I have now run the VEConifgure settings as per the guide - hope it helps.
As a matter of curiousity - upgrading the inverter firmware. It warns you that if the GX device is powered by the inverter it will fail… so with the GX inverter how does this work?
As a side note… the smug look on my wife’s face when loadshedding starts and we just get a beep on the NAS UPS… priceless.
The GX is always powered from the battery, unless the customer wired it from AC-out on the inverter (which some of them sometimes do). Basically… you will KNOW if you are affected. If you are unsure, you are probably not affected.
That sounds like good news… I did not fiddle under that cover. Now… where’s the “have decent wifi” setting?
I know what you’re talking about! In our case, no beep, just the blue pilot light going out on the DB and the buisligte dipping quickly tells the story. Else we wont even know Eskom is down.
I need to replace that darn fluorescent lights asap!
Just when everyone thought this thread was completely dead…
My trippyness has been resolved… by a transformer exploding (not mine, an eskom transformer) and basically forcing me to go into super power saving mode to try and get 16hrs from a 3.5kwh battery…
Sadly not all of our friendly staff in the house got the memo and upon seeing that some plugs still have power, they promptly moved the kettle. (this is the very definition of mixed feelings… I was well chuffed that my system could indeed boil the kettle - I had not tried before, I was however well pissed about the drop in SoC).
This meant we did not quite make the 16hrs… but we did make it to 13hrs… we ran the battery down to 16% in the process (just very very slowly… after instructing the friendly staff that the kettle, microwave and iron are off limits). We had a couple of trips along the way there (before going into ultra energy saving mode). Since recharging from what I can tell you is the lowest I’ve ever run that battery, we’ve had a couple more rounds of free darkness and all the random tripping is gone. Guess we just needed to balance some cells (also guess I’ll be applying the same process by force when adding another pack).
Now the two other reasons for this rather longwinded post…
- While I do update the venus OS firmware once in a while, I have not updated the actual inverter firmware since getting it… we are on version 470 and I see the latest is 494. The changes seem to mostly relate to grid settings for other countries, multi-phase setups and a few other things. At which point do I pull that trigger?
- I have not yet updated the firmware on the pylontech… anyone in the fourways/randburg area have a working cable they’d be willing to share for a weekend? (that lowest/highest cell info seems important)
You can safely update the VenusOS on your GX, but I would stay on the current interver and pylontech firmware unless you need to upgrade cause something is not working. Those are much more involved and risky updates