MeepMoop

I have the Raystech 5100s. Same battery, different brand. Voltages are below. Cutoff is 49v

I don't know, tbh.

@Tronic No problem. The firmware does change the "bottom" SoC to 95. Not sure what the actual firmware version is, I checked on Smart BESS, no value there. And on the batteries self hosted "admin site", but the values listed there did not change after the update. Perhaps @PieterO knows the version? To confirm the 95 bottom, charge limit stats from yesterday:

Never knew about that stat, thanks! Shows the scenario quite well

Okay, let us know how it goes, or if you need some extra evidence from me etc.

Here it is

Hey @PieterO For the record, Raystech did a firmware update on my batteries 2 days ago and the update makes that they now only cycle between 95 and 100. which is not perfect, but seems to be as good as it will get

Not Pieter, but I do of the Raystech batteries (which I believe run the same internals) SoC hits 90 at about 12, batteries then discharge to assist with covering load down to 90(on a zero cloud day). then charging starts again and only made it back to 97 or 98 before the sun disappeared

This looks nice! Where do you configure that on SolarAssistant?

Not solved

Correct. But if you have panels connected, the battery will always charge to 100, regardless of the percentage configured in the timer

Also check the battery wattage at the time. I have this funny situation where once the batteries hit 100%, the inverter decides to use some battery power mixed with PV power to cover the load, even when PV power is way below what it was right before the batteries hit 100.

That's a big "maybe". With pure lead acids, If it's done often enough, like once every 90 days, while the batteries are still generally healthy it can extend their life and reduce capacity loss. Not sure if it works for Gel batteries though. See thread here:

Addendum: new Raystech batteries installed, continuously cycle between 90 and 100. Once they hit 100, they stop charging (expected) but then refused any charging all the way down to 90. Once they hit 90, they charge to 100. And cycle like that over and over. So, if the sun is out and the battery hits 100, the inverter happily ignores incoming PV and runs the load from the battery down to 90. Maybe in a country where the grid is reliable and it doesn't matter if you enter the evening on 100 or 90 percent, that's probably fine. But overall, my review on the Raystech 5100S battery is that they have a terrible BMS, and are totally not suited to South African users. 1/5 stars Oh NICE, the sun is hitting my panels! OH, but the load is coming only from the batteries because they recently hit 100%. And of course, there's no way to stop charging from PV at 99%.

Also consider that the inverter uses 80w or so as self consumption.

I would've thought so too. The "stop charging" command is definitely the BMS and the discharging might be a "quirk" of the Sunsynk inverter with these batteries. I have confirmation from Raystech support that "yes it's normal".

Agreed. Trash BMS on Raystech batteries

*

This is a "feature" of Raystech batteries. Their BMS is utter crap. Once they hit 100%, they tell the inverter to stop charging, and will discharge to 90%, regardless of the status of PV or grid. Sun is out, but battery discharges. Utter trash, would not recommend Raystech batteries or any other 5100S "clones" on the market. (CFE, Raystech etc)

Considering that the battery runs CAN communication by default, the standard CAN RJ45 pinout should help? Inverter side would probably be T568-A and battery side T568-B. From CFE manual

I agree that it shouldn't be the case. I'll see if they have something planned to fix it

Should be very similar on Deye. Sunsynk is a Deye rebrand

Finally got some panels. And yes, the batteries do cycle between 90 and 100%. Asked Raystech support and they said "yes it's normal". 🙄

Geewiz. With Bluetooth "monitoring". (Super basic monitoring, only shows voltages) https://www.geewiz.co.za/hubble-battery-balancer/185922-lithium-24v-battery-balancer-equaliser-with-bluetooth-suitable-for-all-battery-types-24v.html Without monitoring: https://www.geewiz.co.za/hubble-battery-balancer/185924-lithium-24v-battery-balancer-equaliser-suitable-for-all-battery-types-24v.html

Final update: Batteries replaced under warranty.