I took a leap of faith and upgraded from Pylontech to three of these Must batteries. At first i was very disappointed- could be my inverter who knows but getting support from Must or the Distributer of these must batteries is a dead end. my experience is all i can work on. So eventually i got them to work. They did work on the pylontech protocol on my Axpert 8kw inverter but showed wrong values as in the capacity and state of charge. Was all over the show. Good thing was the Values required by the inverter like voltage and so on was working. So the communication was working as in the voltages for charging and Amperage request from the batteries was all going through and charging at correct voltages and bms was talking correctly. Just the state of charge was all screwed up.

Contacted Solar assistant as there was no clear indication that the Must batteries are supported on their website and they suggested using a rs485 adapter and reading the values through solar assistant. I bought the Shoto RS485 cable as recommended by them and then she worked after a view failed tries. So if you bought these batteries and struggle with a axpert inverter then just get Solar assistant. I did have it before as the Pylontec batteries was connected to it so i just had to get the correct cable. I tried various RS485 to usb adapters but none of them worked. Have no idea why. Spend way to much money on other adapters that just was a failure. I was worried the cable from Solar assistant wont work but to my surprise it did. :)

I had to Put my Axpert inverter on "User" settings. Fine with me as the coms was all over the place. and its also connected to Solar Assistant.

I used Battery Float and Charge Voltages at (NOW 56.8V) 57.6 V that is what the BMS requests so i left it at that for now might adjust it down to 56 V we will see. I will keep an eye on the SOC and see. I use to run my pylontec batteries at 3.5volt per cell. so at 52.5 Volts

Max Charge current at 90 i have 3 Batteries so thats 30amp each. More than fast enough.

I only charge of solar as im 99% offgrid. Except those long and cold winter days with almost zero solar. then i have to start the genny or switch eksdom on for a couple of hours to charge battery. I prefer the genny. Lets hope not anymore as i have more batteries now. I could not get more Pylontec UP5000 batteries at a decent price. i see they moving to the UF5000 now that is 16cells. So sold mine and tried the Must. In the end the way i see it 100amps is hopefully 100amps. As long as the cells are Lifepo4 who cares. I was almost going to rip out the Must BMS and replace it with a JK or something just to get them to work. I guess thats why we pay that extra for well known branded battery for better compatibility. But then again it could just be my axpert inverter. For all you axpert haters out there these are in my opinion good inverters. They hell of a noisy but that's ok they work. Compared to the other ones still worth the money. I run this inverter with compressor , well pumps, Sprinkler systems and all and they have never really given me problems. It just works. Updating the Firmware is a hit and a miss sometimes but I have stopped on that worry in anycase.

Sorry im ranting long story short.

Axpert settings on User mode.

Plug RS485 cable from SA in to the RS485 coms port. Not the Parallel in port as per their SA website see images attached. Make sure Battery is set to Pylontech protocal on the battery bms. Cycle bms by switching of the battery.

Connect Solar assistant via the cable and now all readings good.

So it was a bit of a struggle but all working now. Some useless info if someone is struggling with these batteries. Capacity test was good so im happy with these, but dont expect help from Must at all. They cant even tell you what app to use on them as i tried almost every app from the app store and none of them work. They could have just left the So called areal off. waist of time. Looks nice and smart but useless.

*****Updated Changes 15/12/2025******

Findings - The Must BMS really push the batteries to their max voltage of 3.65 per cell. I dont like that at all so i adjusted the voltage to 3.55 per cell. setting to 56.8 Charge voltage. I also noticed that the bms waits right to the end of voltage charge range before it adjusts the requested amperage down- So i added a Rule Under power management in Solar assistant to Charge batteries at 70amps from 0-90 SOC and from 90-100% 20Amps max. So that settle the last bit of charge at 7amps per battery. I have 3.

Find the batteries respond better to this. They dont get a over voltages allarm as often. I will see how this works for me.

I am in the process and communicating with must for a firmware updates but this is very slow and all i get out of them is functioning as normal. They really seem to not care. One word answers and thats it. Apperantly CAN coms work but so far i could not get CAN coms to work on my Inverter with Weco or Soltara Option under battery Coms. Made a custom RJ45 cable from inverter pins 6,7 to battery pin 4,5 but that was a fail.

If anyone has better results on these batteries please share. Like newer firmware or even an app that actually does work on the BMS coms that will be fun to see. I wish i knew more so i can get in to the BMS and adjust the setting and charge voltages on the BMS. But my brain to much of a rockspider to get that right.

Fun times.

Thanks to @MrBeauvedere the App from playstore that works is the Paceex BMS app. Atleast that picks the batteries up. So progress there is. Thank you Sir.

Edited December 15, 2025Dec 15 by Henry2501
Adjusted settings to work for me

Thanks.

Helpful to have this sort of feedback for different battery brands.

One often seem to fly solo when straying off the mainstream oft repeated recommendations for "good" brands. Pylontech comes to mind, and there have been many discussions around whether they are really as good as everyone touted them back in the day.

As a personal general rule, I always just assume I would be on my own for any project and any supplier support would be a bonus, and if I have enough information to do task A or B without supplier support ( ala alternative resources and information ), then I go with it :)

This is where this type of post becomes helpful.

@Henry2501 do you perhaps know what BMS the must has? It looks a lot like a PaceBMS.

On 2025/12/14 at 11:45 AM, MrBeauvedere said:

Thanks.

Helpful to have this sort of feedback for different battery brands.

One often seem to fly solo when straying off the mainstream oft repeated recommendations for "good" brands. Pylontech comes to mind, and there have been many discussions around whether they are really as good as everyone touted them back in the day.

As a personal general rule, I always just assume I would be on my own for any project and any supplier support would be a bonus, and if I have enough information to do task A or B without supplier support ( ala alternative resources and information ), then I go with it :)

This is where this type of post becomes helpful.

@Henry2501 do you perhaps know what BMS the must has? It looks a lot like a PaceBMS.

Good Day sir. I have no idea. I have been trying to find out what bms it has but not getting there at all. All i can see is the following on the System Screen.

Tried the JK BMS monitor Software but it does not read the BMS. Will see if i can get the PaceBMS software will google around. Maybe that will work.

Thanks @MrBeauvedere you a bloody legend. Downloaded the PaceEx app from playstore and it works. Bloody hell The Must techs could not even help me here. Ok now i will Do some research on how to adjust charge voltages and stuff. Thank again.

I tried almost 30 different apps from play store this one never came up.

Now i have to learn what i can change and what not.

On 2025/12/14 at 11:45 AM, MrBeauvedere said:

One often seem to fly solo when straying off the mainstream oft repeated recommendations for "good" brands. Pylontech comes to mind, and there have been many discussions around whether they are really as good as everyone touted them back in the day.

I had Pylontech and i was very happy with them. They really are good batteries. I just had FOMO and wanted to get 16cell batteries and all 100Ah batteries. I had a mix of UP5000 and US3000 batteries. They lasted many years and only did 300cycles 2 of them so they still in fresh baby stages. The one US3000A battery did 745cycles and was still healthy This was my first one. I Updated all the Battery BMS firmware's about 3 years ago. I was going to upgrade to the UF5000 but then the must batteries at half the price stole my short concentration span. But so far its been a bit of a struggle.

But i had the same issues with the pylotecs in the beginning not communicating with the Inverter. But after the Battery firmware update they all worked via Coms. So same same. Just different brand.