Good day, does anyone have experience in connecting different series Pylontech batteries? I was selling my existing 3 x US3000 batteries then found out that it is okay to mix different series batteries as per other posts and advice from a supplier. So I am going to buy two UP5000 or possibly two US3000C (which may be better idea, not sure).

However I am still not convinced as the advice given was that I should put the one UP5000 as master (fine, happy with that) then the 3 x US3000, and last in the string the second UP5000 (which I am skeptical about).  (And update firmware on all three US3000). I would have thought UP5000, UP5000, US3000, US3000, US3000 would have been correct. Does anyone know for sure?

Secondly, I have a Goodwe GW5048D-ES inverter. When I originally set it up, it recognised the 3 x US3000 batteries quite fine and has worked perfectly for two years. Will it recognise a mix of batteries?

Thanks in advance for advice.

14 minutes ago, Barry8355 said:

However I am still not convinced as the advice given was that I should put the one UP5000 as master (fine, happy with that) then the 3 x US3000, and last in the string the second UP5000 (which I am skeptical about).

This is not bad advice at all seeing as though the top and bottom battery of the stack will usually be taking the most of the current. this will sandwich your older batteries and possibly provide a better distribution of current between them. This will also "baby" your older batteries better i suspect.  

 

19 minutes ago, Barry8355 said:

Will it recognise a mix of batteries?

Yes if the batteries are all connected correctly to each other.

2 minutes ago, Nexuss said:

This is not bad advice at all seeing as though the top and bottom battery of the stack will usually be taking the most of the current. this will sandwich your older batteries and possibly provide a better distribution of current between them. This will also "baby" your older batteries better i suspect.  

 

Yes if the batteries are all connected correctly to each other.

Why would the last (bottom) of the 5 supply more current than those in between? 

The 1st one I agree. 

The Pylons are great for this backward and forwards compatibility. The newer battery - UP5000 for example in this case - would be the master battery and have comms cables between all other batteries in the bank. The inverter will comm with this master and betold that the size of the bank is X. This works 100% ad i know there is a user on MyBBwho has a system like this

I have a mix of US3000C and US3000 batteries. Always make the newest battery the master. It usually has the latest firmware. The new firmware is backward compatible (to a degree, there are always exceptions). The older pylons link up and continue going as normal. No need to upgrade the firmware on the older units. Its a risky operation in my opinion and there aren't a lot of installers that even know how to upgrade pylon firmware.

4 minutes ago, Scorp007 said:

Why would the last (bottom) of the 5 supply more current than those in between? 

The 1st one I agree. 

Well thats where your main wires from the inverter go to ... I observed my stack in batteryview and noticed that .

1 hour ago, Nexuss said:

Well thats where your main wires from the inverter go to ... I observed my stack in batteryview and noticed that .

I have also noticed this on my system.

Yes, it is the recommendation to 'sandwich' the old batteries with the new.

It probably stems from the fact that old batteries can only occupy positions 2 to 8 so don't use these positions for new batteries. (Unless you have less than 9 batteries as then you can't not use them!)

Edited April 13, 20231 yr by Tinbum

4 hours ago, Nexuss said:

Well thats where your main wires from the inverter go to ... I observed my stack in batteryview and noticed that .

If you have connected them as per the manual then the batteries should be equally used as the connection length to each battery is the same.

Many thanks for the comments and advice. Question - better for me to buy US3000C's or UP5000's? Cant seem to find US5000's.  

7 hours ago, Barry8355 said:

Many thanks for the comments and advice. Question - better for me to buy US3000C's or UP5000's? Cant seem to find US5000's.  

One difference I can see is that US3000C has 6000 cycle life (like US3000) whereas UP5000 has 4500 cycle life. US3000C has 37A discharge current whereas UP5000 has 50A. I have US3000C and would rather go for something with a longer cycle life if I was you.

Update on this topic:

I bought 2 x US3000C's

Charged the bank of 3 old  US3000's to 100%

Whilst the US3000's were charging I connected the two US3000C's together to balance them.

Disconnected the 3 x US3000's, connected the 2 x US3000C's. Turned system on and programmed the Goodwe to accept 2 x US3000C's

Whilst the 2 x US3000C's were charging (they arrived at 52% SOC) I contacted Goodwe support and they updated the firmware on the inverter online.

Once the 2 x US3000C's were at 100% SOC I joined all five batteries - US3000C master, US3000C, US3000, US3000, US3000

Turned the system on and programmed the Goodwe to accept US3000Cx4+

All well and system running 100%. I did not update the firmware on the old 3 x US3000's

Hope this is helpful.