question

alda avatar image
alda asked

Low batt. voltage alarm

After one and half year running, I get two times this alarm :

1709121340732.png

Really don't know what's a reason or how to trace a reason of this alarm

Do you have any idea what is reason or how to find a reson ?

Thank you for your help


MPPT Controllers
1709121340732.png (8.5 KiB)
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brucesterj avatar image brucesterj commented ·

I got more where that came from.. Wanna see 'em..?annotation-2024-02-28-215314.jpg


It could be a hardware issue but probably in the settings.. or a combination. Who setup yours..?

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alda avatar image alda brucesterj commented ·

But you have only warnings. Warning I have disabled, because I had also a lot of warnings. But I received alarm. Setup was done by the specialists.

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Alexandra avatar image
Alexandra answered ·

@Alda

Without knowing more about your system, it probably means the battery disconnected for a short period. This is possible in the case of a lithium. It is also possible for a breaker type disconnect to partially and cool down and reconnect.

What other components are in the system, how are they connected.


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alda avatar image alda commented ·

Sorry. I will try give you more details. Battery is 3x pylontech US3000c

and looks like alarm was in 11:38 today :

1709128884298.png

1709129034520.png


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alda avatar image alda alda commented ·

1709129483458.png

0.5V difference, not sure if it's ok

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Alexandra avatar image Alexandra ♦ alda commented ·
Pylons start balancing at 90% SOC or around 50v. So you would.need to charge them up to at least 51 or 52v for balancing to happen.

47v is quite close to the cut off voltages for pylontec. Chances are the VRM is missing the lower dip as well.

In short your batteries need a good charge.


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alda avatar image alda Alexandra ♦ commented ·

Strange.

A day before was SOC 100% :

1709223730909.png

So I think must be balanced

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1709223730909.png (52.1 KiB)
alda avatar image alda Alexandra ♦ commented ·

Maybe any Victron setup is wrong ? I see a Voltage peak down, when load increased to 5k. I'm sure that main of this load was on the AC input.

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Alexandra avatar image Alexandra ♦ alda commented ·
The battery voltage does collapse rather alot.

Usually that is a sign of a weak battery or weak/high resistance DC.

So let's look at set up. How many batteries do you have and what model? What Inverter do you have?

What are your loads?

How is it wired to the inverter?


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alda avatar image alda Alexandra ♦ commented ·

Thank you for your answer. My system picture :

1709283108892.png


one difference is that actualy I have 3x pylontech US3000C :

1709283157952.png


Inverter is Multiplus II 48/5000.

MPPT on the picture is SmartSolar RS 450/100-Tr

Later I added second MPPT 250/60 (not on the picture) which is for next panels on the other part of the house.


Big loads like heat pump, oven etc... are on the ACin.

On the Backup ACout I have only small loads (TV, lights etc...)

You can see that load on the AC output is quite low :

1709288924890.png

Thanks for help

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