For the past 3 years I have been running with a Deye12KW and 10x Pylontech US3000C.
Back in 2023 I sent a notice to Pylontech about one battery misbehaving and they told me to charge it full and let the stack sit for 24-48h ... since then I forgot about it and now it started to throw OV and of course Pylontech denied my warranty until now... we are still arguing and debating about the BMS role and #(^T#*$^T@#$T #HFIG#F ....

Anyway as I still have 10 good batteries and can not run Pylontech BMS with any other BMS on the market I needed to replace this run away battery and still be able to work with a PACK and control the batteries by BMS rather
than voltage.. So I decided to play around a bit ... bought a defective US2000C , bought 16x 105AH Prismatic cells and built a little Frankenstein. Frankenstain was not pretty but was alive :)

Now , all good but we know the US2000C only has 50Ah .. same BMS though as the US3000C .. so I changed the capacity of the BMS to 100Ah (seems only possible to change to 50Ah , 74Ah and 100Ah ) as 105Ah not possible.
Then battery model changed into UP5000 ....

I've set the Frankenstein UP5000 as a master and put it in the pack...

All good until now , until I realized the UP5000 is rated (in the manual) at 0.5C / 50Ah.
Will this be an issue ?
Also when charging I can see this little Frankenstein will charge at almost 3 times the rate of the other 10 ?

Is there any firmware for US5000C floating around ? Willing to take the risk and try and flash it.

Ideas

2 hours ago, Jaxone said:

For the past 3 years I have been running with a Deye12KW and 10x Pylontech US3000C.

2 hours ago, Jaxone said:

I've set the Frankenstein UP5000 as a master and put it in the pack...

All good until now , until I realized the UP5000 is rated (in the manual) at 0.5C / 50Ah.
Will this be an issue ?

That won't be an issue. With 10x US3000C + 1x UP5000 Frankenstein you have almost 900Ah of capacity, while 12kW inverter will charge/discharge roughly 300A in the worst case scenario. Therefore, you should not hit 0,5C charge/discharge limit of UP5000.

2 hours ago, Jaxone said:

Also when charging I can see this little Frankenstein will charge at almost 3 times the rate of the other 10 ?

When connected in parallel, the charging speed is determined by the internal resistance of the cells.

• Higher capacity = lower resistance.

• Quality cells = lower resistance.

• Youger cells = lower resistance.

When the chemistry and age of the batteries is the same, then you would normally see that the charging speed of each brick will be inverse proportion of it's relative capacity. In short, 100Ah battery would charge twice the speed of 50Ah battery. And same when discharging.

Edited September 19, 2025Sep 19 by Youda

Thanks for taking the time :)
I never charge with more than 150A ... and never discharge with more than that either , so hitting the limit is not the main concern.. It was just me wanting to set up everything as close to "reality" as possible.

I have been monitoring the system for the past 2 days and everything seems to work as it should be... one thing I saw was the Farnkie never hit 100SOC , was always at 99 ... but did not had to much
sun last few days here in Northern europe , so we will see in the future.

The DYI case I bought came with a JK BMS ... to bad it can't talk with the Pylontechs in some way , else I would have tested the JK also.... Pyllontech board is to wide to fit into the custom 105ah DYI case
so I had to wrap something just to test.
Will see if I can somehow 3D print a custom case for the Pylontech BMS to smack it on the top of the case instead :) Time till tell.

Also gave it a proper name now 🤣

Edited September 21, 2025Sep 21 by Jaxone

6 hours ago, Jaxone said:

one thing I saw was the Farnkie never hit 100SOC , was always at 99 ... but did not had to much

In order to hit 100% all the cells have to be at 3,480V.

Wow a custom pylontech with pristatic cells 🤩

@Jaxone you have made the thing i want to make on my batteries for years 😅

Congratulations for your Frankenstein 🤣🤣

Cheers

@fhocorp I've run with it for a while now just to see how it works as one of the Pylontech cells is fcked ... but I realized the passive BMS not good enough for balancing so I started going the other way around. Installed JK BMS on the Pylontech pouches ... that goes a bit better :)
Although JK is not the best when measuring SOC it still better to balance.
Now I am in the process of replacing ALL the Pylontech BMS boards with JK.
In order to be able to control both JK and Pylontech at the same time , I have installed one iBMS for JK batteries and one iBMS for the Pylontech, this way I sum up the data and send one stream to the inverter so everything works together.
Link to iBMS : https://shop.jamestronics.com/

Will make a review in a short time :) and explain the functions and how all works together.

11 hours ago, Jaxone said:

Although JK is not the best when measuring SOC it still better to balance.

It is not really measured, I reckon, but calculated and it is based on coulomb counting.... once it determines the battery (the cells connected) are full/100% it has a baseline and uses current out(-) and current in(+) to calculate a SoC value...

You wrote you used 16 X 105Ah cells, I thought PyledOnTech uses 15 Cell banks?

14 hours ago, Jaxone said:

@fhocorp I've run with it for a while now just to see how it works as one of the Pylontech cells is fcked ... but I realized the passive BMS not good enough for balancing so I started going the other way around. Installed JK BMS on the Pylontech pouches ... that goes a bit better :)
Although JK is not the best when measuring SOC it still better to balance.
Now I am in the process of replacing ALL the Pylontech BMS boards with JK.
In order to be able to control both JK and Pylontech at the same time , I have installed one iBMS for JK batteries and one iBMS for the Pylontech, this way I sum up the data and send one stream to the inverter so everything works together.
Link to iBMS : https://shop.jamestronics.com/

Will make a review in a short time :) and explain the functions and how all works together.

@Jaxone OK i am interested for the results ;) And also by your pylontech boards when you swap them 😁

Also, what type of thermal sensor (NTC) did you use for the temperature measurement (could you share the exact référence) ?

Best Regards

Edited October 31, 2025Oct 31 by fhocorp
corrected typo