question

maha avatar image

Limit dc charging power

I have a Fronius Symo 8.2-3-M as well as a MPPT 250/100 in use. DVCC is activated and the charging power is limited to 20A. Nevertheless, the batteries are charged with more than 20A from the MPPT. The DC charging power is therefore not limited! Is this a bug or a feature?

battery chargingess mppt
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Do you have a shunt?

Yes. Victron BMV 702 is in use.

And that current >20A is read/indicated by the shunt (BMV) or by the SolarCharger?


SVS and SCS are enabled in DVCC?


The current limit set in DVCC is a limit for the current into the battery, not a limit for the solar charger current (Amps) output.

The dc-load into the batteries is not limited. The MPPT sends all its power into the batteries during bulk-loading and this is not desired because the load is too high for the batteries.

List the entire system you have.

It seems that you do not recognize the problem...

DC-load from MPPT will not(!) limited during bulk-loading!


OK, good luck.

2 Answers
Al avatar image
Al answered ·

Hi,

Seb71 already asked if SCS was turned on? Is it? and is it 'Active' or 'Ext Control'?

There was an issue with VE.Can MPPT's not working with SCS, but you also didn't answer seb71 what your system is for him to help.

If it is VE.Can then there is an update soon that works, in the meantime maybe limit the MPPT output to protect your batteries.

Is your battery bank quite small as 20a charge limit is quite low for how much solar I guess you have?

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1615638854255.png


@Al If it is VE.Can then there is an update soon that works, in the meantime maybe limit the MPPT output to protect your batteries.


Then I will hope that the update really comes soon...:-)

To limit the MPPT is no option for me.

1615638854255.png (29.2 KiB)

So reading between the lines I guess you do have VE.Can 250/100, and we can see SCS is not active.

Then your option is to limit in Victron connect the MPPT output to 20a.

But still we don't know what or how big your batteries are, if they are BMS controlled and we don't know why:

"To limit the MPPT is no option for me. " ?

I've not tested it but the 20a MPPT limit may not limit the MPPT output for AC loads used by the Multi/Quattro, only the DC Charging Limit.

From the DVCC Manual: https://www.victronenergy.com/media/pg/CCGX/en/dvcc---distributed-voltage-and-current-control.html

dvcc-841.jpgSo if you can limit the charge current, and you want to limit the charge current, why don't you just limit the charge current?

dvcc-841.jpg (61.3 KiB)

My MPPT 250/100 is connected to 5,3 kWp panels. I will use all the power but only 20A for loading the batteries. In this case it is uninteresting how big the battery is.

If I limit the charging power of the MPPT, then I lose a lot of the electricity that can be generated.


maha avatar image
maha answered ·

Two screenshots for showing the problem:


screenshot-2021-03-13-114855.png

screenshot-2021-03-13-115620.png


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Hi @MaHa

What are your ESS settings? (feed in allowed? limited?)

as soon as feed-in is enabled, MPPT is not limited anymore.

maha avatar image maha Daniël Boekel (Victron Energy Staff) ♦♦ ·

1615649548483.png

With these settings, the MPPT charges all the power to the batteries instead of only 20A and the rest to the grid. It's a bug!!!!

In a german forum you can read an explanation:

DVCC bug

1615649548483.png (24.7 KiB)