question

karli avatar image
karli asked

Venus GX, MPPT150/35 Pylontech US2000: How to change max charge voltage?

Hello,

i have connected my Venux GX, Multiplus 2 48/3000, MPPT150/35 and 2x Pylontech US2000 today. Everything works fine but how can i change the max charge voltage vom 53,2V to 52V?

When i go to the Pylontech settings which i can see in Venux GX, i can read the settings but i don't know how to change them.

Thanks for your help

Karli


MPPT ControllersVenus GX - VGXPylontech
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6 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·
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karli avatar image
karli answered ·

Thank you for the links.

Can anybody give me a simple answer?

Can i change (reduce) the max charge voltage of a pylontech US2000 via the Venus-GX or do i need special cables and software?


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Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Karli

You cannot change the charge voltage, as with CANbus ('managed') batteries, the battery itself tells the system what voltage it wants to be charged with.

There is also a good reason for this, when lowering the voltage, balancing of the cells might not happen (because that is usually done above a certain cell voltage)

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mattin-d avatar image
mattin-d answered ·

Hi,
my System runns since a few years. In this time I added many times different components...
Now it consides of Venus GX, 6x MultiPlus 48/3000/35-50 (in three phases), 2x BlueSolar MPPT 150/70 (VE.direct per USB), 2x BlueSolar MPPT 150/85 (VE.Can).

Now I replaced my old Pb Battery by Pylontech US2000.

First I changed the settings for max. Voltage to 51,5 V.
This works with old Battery very well.
Then I changeed the Battery - all fine...

But when I connected Pylontech and Venus by CAN-Bus, my Settings are ignored and Voltage is setting to 52.0 V. Also my Settings for Curent are ignored...


An other Problem is, the ESS uses only one Phase - no matter The Setting of Phase Compensation in ESS menue.

2 comments
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Hi @Mattin_D

As written: the Pylontech doesn't allow the charging voltage to be changed, and has good reasons for that.

What exactly do you mean by 'ESS uses only one Phase'?

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mattin-d avatar image mattin-d Daniël Boekel (Victron Energy Staff) ♦♦ ·

I am sure, in the beginning this was not so.
But I can not lokate at what Update this came of...

Last week I tried some different combinations of Firmware, but it is always the same.
Maybe my Setting is wrong - but I did not find.


For the Battery-Setting I think, reduce the Voltage makes a very smal reduce of capacity, but a very longer lifetime...

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feedin.png (36.0 KiB)
nebulight avatar image
nebulight answered ·

What version of Venus OS are you on? Version 2.20 overrode the BMS to set the charge voltage to 52v as long as DVCC is turned on:

https://www.victronenergy.com/blog/2018/10/17/venus-os-v2-20-scheduled-charging-equalize-and-more/

You can read more about that here:

https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom#my_system_only_charges_the_battery_to_52v

2 comments
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Thank you for the answer nebulight.

The Venus tells the MPPT150/35 to overwrite the 53,2V max voltage in order to protect the Pylotech Batteries. A good idea but i have read anywhere in the internet, that the cell-ballancing of the Pylontechs would only work at higher voltages. So, if Venus makes a cut at lower voltages, the Pylontechs can never ballance it's cells.

Would it be a good idea to increase the voltage to 53,2V for some hours ? If yes, how can i do it? Which Software and which cables do i need for that?

Many thanks

Karli

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Balancing takes place as the cell level, not pack voltage level. I'm not an expert on these packs, but I believe the BMS will start the balance at 3.45v per cell. Since the Pylontech is 15 cells in series that comes out to 51.75 total pack voltage should all cells be 100% in balance. The absorption phase should maintain the 52v and give the cells time to balance. If you charge to a higher voltage to give your pack the chance to balance, you run the risk of an over voltage condition since the balance current is pretty small on these. I think they are in the 50-80ma range. The BMS will take care of any high cell condition. I'd rather charge to a lower voltage and NOT hit the over voltage condition vs trying to stay in the balance voltage range longer. That's just my opinion. I'm not an expert, just an end user.

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mattin-d avatar image
mattin-d answered ·

I am using the newest Firmware - Multi (v. 473); ESS-Assi (0177); Venus (V. 2.53)

Yes, I read this before.
But look what said in the second Link at No. 4.2 Charge Settings...

For using Charge Curent Linit, I must use DVVC turn on...
for Voltage Limit, I must DVVC turn off...

What is now the feature???

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Sorry, I found the entry in the ESS-menue to linit the charge Power, what shows only when DVVC is turned off...

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