question

Evgeniy Labunskiy avatar image
Evgeniy Labunskiy asked

Questionable behavior of 3 phase MultiRS charging Pytes batteries

Hey folks!

I have 3 MultiRS in 3 phase config + Cerbo 3.50.5 + 4xPytes 48100R. DVCC enabled in the recommended configuration:

Battery BMS response following parameters:

So CCL is 200A, but the battery never charges even close to it, usually 110-120A

On firmware 3.40 there was the ability to turn on SVS (I know the user manual does not recommend it, but I turned it on to see what will be), and when it's ON, the battery is charging with the maximum available current.

I'm wondering if it's normal behavior, a kind of protection, or just a bug.

battery chargingMulti RS
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3 Answers
nickdb avatar image
nickdb answered ·

A couple of comments.

200A DCL is about half what those 3 inverters actually need, that is likely to be an issue down the line, and isn't great for battery life.


You need to manually check the voltages at the battery, inverter terminals and any connections in between.

If SVS has helped it is most likely you have voltage drop which is preventing the battery properly charging.

With Pytes now supported in 3.50, DVCC forced on, and the recommended SVS setting being off, you will experience this issue when the chargers and battery don't agree on voltage.


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Evgeniy Labunskiy avatar image Evgeniy Labunskiy commented ·


img-2762.jpeg

Multi says 54.8

BMS says 54.4

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img-2763.jpeg (8.5 MiB)
Evgeniy Labunskiy avatar image Evgeniy Labunskiy commented ·

I use Power In for battery in and distributor for inverters connection (with Victron 120A fuses)

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nickdb avatar image nickdb ♦♦ Evgeniy Labunskiy commented ·

If those were taken at the same time, the inverters report 54.8V and the battery 54.3, so that is 0.5V out, not dramatic but not ideal.

You need to run that comparison under increasing loads to see if the delta increases.

At top of charge, the greater the variance, the less likely your battery is to charge near its CCL.

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Evgeniy Labunskiy avatar image Evgeniy Labunskiy nickdb ♦♦ commented ·

as I see at the end of the charge (now 98%) different is very low: battery shows 56.098 and inverter 56.15

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nickdb avatar image nickdb ♦♦ Evgeniy Labunskiy commented ·

Variances appear under load/charge, the greater the load, the greater the variance.

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Alex Pescaru avatar image
Alex Pescaru answered ·

Hi @Evgeniy Labunskiy

VictronConnect App:

Is there any current limit set for each inverter in Settings - Battery - Max charge current?

How is set for each inverter the Settings - ESS - ESS mode?

dbus-spy:

What says on

com.victronenergy.battery....:

/Info/MaxChargeCurrent?

/Dc/0/Current?

com.victronenergy.multi....:

/Link/ChargeCurrent?

/Dc/0/Current?

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Evgeniy Labunskiy avatar image Evgeniy Labunskiy commented ·

Hi @Alex Pescaru!

Is there any current limit set for each inverter in Settings - Battery - Max charge current?

It's 90A in each inverter

How is set for each inverter the Settings - ESS - ESS mode?

It's "Keep batteries charged

What says on
com.victronenergy.battery....:
/Info/MaxChargeCurrent?
/Dc/0/Current?

I made screens, but now the battery is fully charged (99% says) so not a big number there

com.victronenergy.multi...
/Link/ChargeCurren
/Dc/0/Current?


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Alex Pescaru avatar image Alex Pescaru Evgeniy Labunskiy commented ·

So max 270A total and the keep batteries charged will ensure the battery has priority.

Indeed, not so informative now with the battery charged.

Still monitor that /Link/ChargeCurrent for each MultiRS. That value is sent by Cerbo and the MultiRS will not exceed that value. Also its own limit of 90A will prevail if /Link/ChargeCurrent is bigger.

The sum of all those /Link/ChargerCurrent for all MultiRSes will be the maximum charging current. But beware, this sum will not be bigger than what's battery requesting in /Info/MaxChargeCurrent.

This of course if the battery's voltage is not too close to the final float voltage and in that case, the charging current will be much lower.

For example now that battery is requesting no more than 37.5A and the MultiRS that you've shown is instructed to supply maximum 11.4A, somehow a third of those 37A. The rest is supplied by the other MultiRSes.

But because it's close to 100% SOC and specified CVL, the battery is absorbing only 1.5A and the shown MultiRS is supplying only 0.4A from those 1.5A. The rest, the others.

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andrii-podanenko avatar image
andrii-podanenko answered ·

I'd check what limits are at a moment of expected maximum current.

On my Pylontech setup I see that maximum current could be achieved in the lower voltage range, not close to 'charged'.

You may see that in "Advanced" in respective graph

1000005307.jpg


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