question

ewalderasmus avatar image
ewalderasmus asked

Pylontech UP5000 not charging to 100%

Good afternoon all,

This is the first time I am using the pylontech UP5000 batteries and I cant get them to charge above 86%, or more specifically 51.53V. The system is a Cerbo, a Quattro, and the pylontech batteries.

1646841039510.png1646841074235.png

This is not my first time setting up a Victron with the Pylontech batteries, and I thought it was pretty straightforward up until now.


I have been through https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom

and all of my settings are exactly as they state here, with the exception of the DVCC.

It looks like the items on the Live page are outdated as the DVCC is now forced on. SVS is forced off, STS is forced off. (I have checked past installations and I see this is now true on all my installations)

In addition to the above the following settings are set:

Limit charge current: Off

Limit managed battery charge voltage: off

SCS : off.

dvcc.png

I also have confirmed the battery and the Cerbo are communicating with the parameters coming through as expected. The BMS CAN is set up correctly and I have no errors.

parameters.png

Additionally, I see that the cell data is now available. I don't know if this is just a Cerbo thing or a UP5000 thing. But I think it's cool.

battery-details.png

History:

When I first charged the battery it charged to 100%, which was at 51.53V. Over time that 100% has dropped to 86%.

What I suspect is that overtime the cells have balanced, which causes the 51.53V to equal a lower SOC. This is just my opinion and could be incorrect.

I dont know if anyone has any ideas on what I can do differently, or if I am missing anything. as at this point, I don't know how to get it to charge to 100%.

battery chargingPylontechDVCC
dvcc.png (33.0 KiB)
battery-details.png (25.3 KiB)
parameters.png (15.9 KiB)
1646841039510.png (22.1 KiB)
1646841074235.png (30.1 KiB)
1 comment
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Did you figure out the solution?
0 Likes 0 ·
6 Answers
uldisi avatar image
uldisi answered ·

I have the same problem with pylontech batteries. SOC maximum is constantly dropping in the summer. Now maximum level is 88%.

Did you find out what causing it?

1 comment
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Same here. Stuck at 88% on my bank of 4 Pylontech US3000 batteries. I just noticed this a couple days ago. Tried re-entering the values published in the Victron-Pylontech compatibility pdf to no avail. On the phone now with the electrical engineer of the authorized distributor who sold me this system. Wow. I was surprised a quick internet search yielded results of people dealing with this same exact issue at the same exact time as me. Even stuck on the same percentage: 88%. double wow.
0 Likes 0 ·
arghhh40k avatar image
arghhh40k answered ·

What are you using to charge the batteries?

Is it connected to the Cerbo to receive battery charge limits?


Is your charge source putting out the battery requested 53.2V? It may be set to a lower voltage limit and limiting the charge.

1 comment
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Hi there.


I realized I didn't put that information into the post.

It is being charged by a 8kVA Quattro


0 Likes 0 ·
ewalderasmus avatar image
ewalderasmus answered ·

@Ned Yu (Pylontech) Can you maybe share some light on this?

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Ned Yu (Pylontech) avatar image
Ned Yu (Pylontech) answered ·

@EwaldErasmus as you can see that the highest one is 3.49V and the lowest one is 3.39V. Please keep floating charge the battery bank for 4~8hrs to equalise the unbalanced cells. The BMS has algorithm to automatically distribute current to different cells,

1 comment
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

@Ned Yu (Pylontech)

Thank you very much. The batteries have been in this state for the last 7 days atleasts.


below is a screenshot from 2022-03-02

2022-03-02.png

It has hardly changed from 7 days ago to now.

Screenshot from now:

1646984108992.png


0 Likes 0 ·
2022-03-02.png (24.1 KiB)
1646984108992.png (31.0 KiB)
Ned Yu (Pylontech) avatar image
Ned Yu (Pylontech) answered ·

@EwaldErasmus The BMS only start the equalisation algorithm when the SOC higher than 89%. So let's try to keep the charging status for 4~8hrs.

4 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

@Ned Yu (Pylontech)

Hi Ned,

I think we are missing each other. The battery has been setup and been "Charging" for close to a month now.

When initially connecting the system up the batteries charged to 100%, where I believe balancing started. As time progressed the voltage stayed the same but the SOC dropped slowly. So within a month the battery went from 100% to 85% by itself.

It looks like the Victron, cerbo and Batteries are communicating correctly, but what isnt clear is why its not charging the battery up more.

0 Likes 0 ·
It's like Ned said, you have a high cell, so you can't charge any more until the other cells all balance otherwise the high cell would go higher and be damaged or worse.

The SOC reduced on its own because of self discharge. All batteries have a degree of self discharge and the Pylontech BMS can account for and report this.
The battery cells may have balanced a while ago, but since then they need balancing again, so you have to wait for this to happen. Balancing needs to be done fairly regularly, it's not just a one-off event. Especially balancing would be needed when the discharge has been due to self discharge, each cell discharging by its own ammount rather than a more equal ammount when the battery is in cyclic use.

0 Likes 0 ·

@WKirby

Thank you.

I understand what you are saying, but I don't understand how it can be solved then. If the internal balancer only kicks in over 89%, but I have an imbalance causing it to not go above 85% then I will never get to a stage where it balances out. So how does one solve this balance issue?

0 Likes 0 ·
Have you considered some deep discharge cycles, followed by putting the system onto "keep charged"?
0 Likes 0 ·
agroventuresperu avatar image
agroventuresperu answered ·

Should you use a smart shunt with Pylontech batteries, or would that be completely redundant?

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.