question

thanar avatar image
thanar asked

Battery Charge Voltage adjustment on an ESS system

Hi.


I just set up an ESS system, consisting of a Cerbo, a Multiplus-II, a SmartSolar and a 48V LFP battery with no connected BMS.


I find it difficult to locate the battery voltage adjustment parameters. I would also like to limit the discharge current of the battery.


Could anyone chime in as to where these are located in the various interfaces?


Thanx.

Multiplus-IIbattery chargingESS
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4 Answers
cotje avatar image
cotje answered ·

Hello @thanar , the devices using battery params are generally the chargers (MP/MPPT) or the BMS telling those devices how to charge. For your system I would recommend to use a BMS, even if it is not connected to the Cerbo. You can still control the voltage/current by enabling DVCC. Hope this helps!

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thanar avatar image thanar commented ·

DVCC requires a BMS that can talk to the GX platform. The BMS in this specific battery doesn't have this ability. So I guess I should not be enabling DVCC. As far as the Multi or the SmartSolar adjustments go, as soon as I enabled ESS, there are no such adjustments available anymore. This is why I am trying to locate them.

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cotje avatar image cotje thanar commented ·
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thanar avatar image thanar cotje commented ·
Andy is adjusting charging current through DVCC here; there’s no option to adjust DIScharge current. Even more, I still haven’t found where to set the charging VOLTAGE for the battery.
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Stefanie (Victron Energy Staff) avatar image
Stefanie (Victron Energy Staff) answered ·

@thanar

I suggest reading the ESS configuration chapter step by step and then go through all necessary sections.

Charging parameters must be seit in the MP-II. The MPPT will follow these charging parameters in an ESS system, but you need to set the charge current in the MPPT itself.

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thanar avatar image thanar commented ·

OK, this doesn't make any sense...


I ran a new ESS assistant on VEconfigure and adjusted all settings as required. My main concern is that the charging voltage should not exceed 54.50V, because I've got a slightly unbalanced LFP battery. So I set both absorption and float at 54.00V through VEconfigure as per the screenshot:

screenshot-2023-03-14-at-222302.png

However, when connected to the SmartSolar through Remote Console, "Charge Voltage" still shows as 58.00V, as per the below screenshot:

screenshot-2023-03-14-at-222142.png

What am I missing?

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thanar avatar image
thanar answered ·

Upon further reading of the ESS guide (chapter 4.2), I understand that the charge parameters should be set in VEconfigure. I should first add the ESS assistant, and then go back to “Charger Tab” and adjust the needed parameters. I should then upload the configuration file back to MP-II through VE remote. Well, kind of makes sense, but it still looks like a mess afaik…

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thanar avatar image
thanar answered ·

Answering my own question. Bottom line is, the target charge voltage is set in the MultiPlus-II through VEconfigure, after having completed the ESS assistant as per the directions on chapter 4.2 of the ESS manual. Which means that you should also enable the charger on the MP-II, even if you only want to charge from solar. Doesn't make sense really.

Something else that makes even less sense, is the fact that the charge controllers will show a different voltage setting, which is something completely counter-intuitive. In my case, charge limit was set to 54.00V, while the charge controllers would report 58.00V for some reason.

Which leads us to the next question: what if I want to adjust the battery charging voltage by 0.5V? I guess I will have to edit the MP-II settings again using VEconfigure and then upload it to the inverter, which could lead to a system restart and the ESS relay tripping and stuff. This is kind of a mess.

All these options should be configurable through the GX device's ESS options. I don't get it why there's options and settings all over the place, since adding a GX device is supposed to unify the whole system.

Victron's user interface department is in need of an overhaul, imho.

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nickdb avatar image nickdb ♦♦ commented ·
You're criticising a product that you seem to know little about, having expended little effort to train or indeed search on the topics you are raising.

While no product is perfect, no user interface will compensate for a lack of knowledge.

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thanar avatar image thanar nickdb ♦♦ commented ·

This is exactly what I am doing. However, criticism makes for better products and services, and I really appreciate the product, along with its drawbacks.

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ejrossouw avatar image ejrossouw thanar commented ·

There are many systems out there that don't use ESS or have a GX device so you clearly have a lot learn. Also, voltage is problably something you will set up once at the time of installation. I don't have a problem to use remoteconfig to adjust and upload changes to these settings which also affords you a means to create multiple profiles for e.g. testing purposes.

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