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moeterxl asked

DVCC limiting charging current - Multigrid, Venus, MPPT, Fronius and Pylontech

I`ve got an problem with DVCC on while charging the batteries. My system: Multigrid 48/3000/35-50 with Venus GX and two connected Pylontech US2000 Plus. A BlueSolar 150/35 is DC- connected to the Multigrid. My Fronius Primo 3.0-1 is AC- connected to the output 1 of the Multigrid. The gridmeter is an ET340. The system work fine. But if i activate DVCC the charging current will slow down to about 20A and the excess of energy is load to the grid. If i deactivate DVCC the full energy (about 30A) is load to the batteries. I want to load all the energy to the batteries. All firmware is up to date. Whats the problem?

MPPT ControllersPylontechVenus GX - VGXDVCCmultigrid
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boekel avatar image boekel ♦ commented ·

can you show what the BMS parameters are in the Remote Console?

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ commented ·

Please confirm the current firmware versions on all devices, most specifically VGX and Multigrid.

There have been improvements made in this regard.

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4 Answers
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moeterxl answered ·

Now i`ve isolated the batteries and above 16°C the charging limitation is gone up. Later i want to apply a battery heating / cooling system based on 230V an d switched by an external sensor. Problem solved. Thanks a lot.

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moeterxl answered ·

Multigrid: Product: 2690 Firmware: 433

VGX: Product: 20181201144037 Firmware: 2.22

MPPT150/35 rev.2: Product: 0xA04B Firmware: v1.39

ET340: Product: b00d Firmware: 3

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ commented ·

Please try updating the VGX to 2.23 and report back after a couple of days if there is any change.

https://www.victronenergy.com/blog/2019/02/19/venus-os-v2-23-ve-bus-11-details-small-fixes/

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moeterxl avatar image moeterxl Guy Stewart (Victron Community Manager) ♦♦ commented ·

Hi Guy,

i`ve updated the VGX to the new version 2.23 from today. But now it`s a little bit cloudy so i couldn`t test it . I`ll write back if it works. Thanks for your fast answer. Sincerly - Kay

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ moeterxl commented ·

The information that Boekel asked for in the parameters menu of the battery on the Venus-device is also important.

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moeterxl avatar image
moeterxl answered ·

Hi Guy,

today i`ve tested the new firmware 2.23. It`s the same problem like before. See the uploaded PDF ESS.pdf the requested parameters. The battery set the DCL to 50A and the CCL to 20A by BMS? My MPPT shows already an CCL = 35A (=maximum). What`s wrong?


ess.pdf (215.3 KiB)
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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ commented ·

It is most likely a restriction of the current by the battery BMS due to low temperature.

A similar issue was discussed here - https://community.victronenergy.com/questions/6220/pylontech-charge-current-limit.html

I have been unable to get a copy of temperature derating table for the Pylontech batteries. I do have the similar one for BYD.

It is not documented in Pylontech manuals. Please contact your battery supplier and ask them to provide it (and then post it here so that we can also know for others in the future).

It would appear that everything on the Victron side is behaving as it should. The DVCC feature is receiving the instructions from the Pylontech BMS to reduce current, and it is.

Disabling DVCC to bypass this restriction will be logged inside the Pylontech BMS and can void your battery warranty,

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boekel avatar image boekel ♦ commented ·

Ah so it is the BMS parameters, I'd start by checking the battery manual / asking battery distributor, could it be that the batteries are at a low temperature?

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moeterxl avatar image moeterxl boekel ♦ commented ·

Hi...

See Pylontech Manual: Working temperature range is from -10 to 50, (Charging 0~50; discharging -10~50) with excellent discharge performance and cycle life.

The battery temperature is about 9 - 15 degree all the time. All alerts at BMS are OK. By the way the system works perfect with disabled DVCC. The battery uses the maximum available current for charging. The DVCC- function is important for me? Whats different in detail to disabled DVCC?

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boekel avatar image boekel ♦ moeterxl commented ·

If you want us to read the Pylontech manual, you'll at least have to link to it..

But DVCC is important for preventing to much current in / out of the batteries, You'll void the battery warranty otherwise.

The battery not giving the expected charge current is something you'll have to pick up with Pylontech support (after checking you've correctly wired your batteries)

Are you sure both batteries are 'online' or maybe only one is seen?

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moeterxl avatar image
moeterxl answered ·

Hey Guy,

there`s the answer from Pylontech Support. Sorry, i dont`t get any diagrams about the temperature and the allowed charging current.

------------------------------------------

Hi Kay,

Thank you choose our product!

Just like telephone battery cell, all normal lithium battery will get hurt in low temperature working condition specially in charging mode. For longer cycle of life and calender life we limit the current in low or high temperature. You can google the knowlage of "Lithium dendrites" if you have interesting.

So our BMS of battery work together with inverter to limit the current to protect our battery cells. It is intelligent design.

My proposal is:

  • Install a heating system for our battery (heat in the cabinet). Rise the temperature above 10℃. And the battery's comfortable temperature is 18~28℃.

Thanks and best regards!

------------------------------------------

I´ve checked the VGX and Multigrid to control the internal relay in relation to the batteries temperature. So it should be possible to built a battery heating module. Unfortunately i haven`t found any free configurable function at the assists to use the BMS temperature. There`s only temp high / temp low alarm and pre alarm (LED) available from Multi. Should i use an external temperature sensor wired on Multigrid even though the temperature is available from BMS? I think the best option is to use the BMS temperature for switching the relay of VGX or Multi according to a set temperature. This is an important feature for heating or cooling a battery system to his comfortabel temperature.

Thanks for your opinion

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alaskannoob avatar image alaskannoob commented ·
Did you ever find a heating solution for these batteries that require 64F to not limit charge? I just bought 8 x US5000 under the impression that the max charge/discharge and the charge/discharge temps advertised were accurate.


I live in Alaska. Our hottest summer temp is literally in the 60s. I had planned on keeping the batteries above freezing and massively sized our PV and SCCs to provide as much current as possible to charge these batteries on December 21st to make the best use of our four hours of sun we get on that day. All the math worked out and my bank account is empty, but it would appear I may have just made an enormous financial mistake.

But if there is a heating pad solution... Any luck?


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alexander-uhde avatar image alexander-uhde alaskannoob commented ·

Hi,


I have recently seen a solution on youtube (sorry, did not finf it now), where a guy used some sort of electric heating spiral you have usually in a greenhouse for not freezing the plants.


But his batteries were stored in some sort of an insulated container in his garden in Germany (where temperature does usually not drop below -5° Celsius).


Of course, I guess in Alska you would need more than the 200W of power his heating spiral used.


How are you heating your water? Gas, oil, wood? Maybe you can "engineer" a solution to pump some warm water around the batteries in such super cold conditions.


I also read your other thread/ question.

I think in general it is not so much about the Pylontech but about LiFePo, which needs "warmer" conditions.

I use 6 US2000, coldest temperature in my cellar was 16° Celsius last year.

At that temperature they worked fine, but in my small installation I use no more than 100A discharge/ 150A charge (on the whole bank).

This works at 16° C, I have no personal experience with lower temps on them.


Best regards

Alex

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