question

semiraue avatar image
semiraue asked

Charge pylontech us3000c from smart solar mppt without bms communication

Hi All,

I'm upgrading my smaller 12v solar setup that I had for few years to 48v system

I changed the battery voltage of my scc100/20-48 from 12 to 48 v and bulk 52v and float 51v. Then I change my JA 460w solar panels to series. After that I connect the pylontec battery to scc100/20-48

For few hours all went good without any issue. I was able to see the scc charging the pylontech with 850+ watts. and pylontech charged to 4 bars(leds). but today when I was checking the scc, it was charging only 15w of power even with full sunlight. Inverter connected to pylontech is turned ON always and running without any issues (meanwell ts-3000) but the battery is not charging.

Then after some time it again start charging with full 850w power. but this idle stage went like 10-15 mins and I'm loosing the solar energy from this period.

My setup not configured with any communication between pylontech and scc 100/20-48. I'm waiting for my cerbo-gx to do this part. Also my inverter not support any communication with battery or scc

What is the reason for this ? is pylontech BMS doing this ? if yes why and how to fix it. And is there any way I can keep using this setup for few weeks without damaging pylontech ? what are the risks ?

Regards
Semira


MPPT ControllersBMSPylontech
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3 Answers
rikhf avatar image
rikhf answered ·

What is the state of charge when it has this behavior?

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semiraue avatar image semiraue commented ·
it's around 3 LEDs. means 50%
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Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

If it is the very first charge of the batteries it could be a cell imbalance and the battery shut off.

You should not charge the batteries that way, wait until you have the GX device.

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semiraue avatar image semiraue commented ·
Battery never shut off. the inverter is working all the time. Just the battery refuse to charge for few minutes and start again. I'm really trying to get the cerbo-gx as fast as possible. but not sure I can get it soon or not.
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semiraue avatar image semiraue commented ·
Hi, what is the proper absorption and float voltage for pylontech US3000C battery that I should set from the SCC100/20-24 ?. without any communication
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rikhf avatar image
rikhf answered ·

The battery can shut off charge and discharge separate so that can be happening as well. Again what is the SoC and can you monitor cell voltages? Are they not too much apart from each other?

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semiraue avatar image semiraue commented ·
Hi SoC is around 50% when this happend. But I'm not sure it happens on certain SoC level. I noticed this happened few times
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rikhf avatar image rikhf semiraue commented ·
Cell voltage cut-off? Temp cut-off?
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semiraue avatar image semiraue rikhf commented ·
sorry what you mean? I'm not sure what causing this issue. I don't have much visibility to pylontech at the moment as I'm waiting for my cerbo-gx



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kevgermany avatar image kevgermany ♦♦ semiraue commented ·
Battery can turn off charge input if a cell inside it goes over voltage. Not unusual on new batteries. It will balance out with slow charging. But listen to the warning from @Matthias Lange - DE
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