MPPT high voltage cut off

Gareth George

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Feb 2, 2021, 4:36:51 PM2/2/21

to electrodacus

Hey, transferred my solar onto my new Lithium cells controlled by a SBMS. Connected to my Victron MPPT by a victron none inverting cable thing.

As the batteries are still quite full they reached their maximum voltage on one cell as they were balancing. The solar controller kept on switching on and off. Should I change the settings to turn back on the controller until the battery has discharge a bit as or increase the cut off time? I feel this may put stress on the MPPT. Or am I just worrying about nothing and it's what the controller was designed to do?

Appreciate your thoughts.

Dacian Todea

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Feb 2, 2021, 7:52:54 PM2/2/21

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How fast is turning ON after it turned OFF ? What sort of charge rated do you have ? Also is there a significant load also ?

Normally it will not turn ON to fast after it turned OFF so there may be problems in your circuit but it depends on all those questions above.

The default is set to start charging when all cells drop below 3.4V but you can go in to DMPPT settings menu and set the SOC limit to something lower than the default 99% say maybe 95% then charging will not restart until SOC is below 92% and will stop charging at 95% (except for first charge in a day that is made to 100% SOC for calibration).

Gareth George

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Feb 3, 2021, 2:47:24 PM2/3/21

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So far they're fully charged cells with currently no load. I am attaching the inverter and 12v load tomorrow. Switching from my current system that is still used every day. Have booked some time off work so I can get it all switched over to the new batteries and make sure it's all working.

I'll bare what you've mentioned in mind. I'll get the load connected and will go through the settings once I've got my inverter and battery protect connected up to the SBMS, update the settings on the Victron. I can then keep an eye on it for the next few days. See if everything settles down after a bit of a cycle.

Gareth George

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Feb 3, 2021, 2:52:14 PM2/3/21

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It's like giving birth to a battery.

IMG_20210130_200021.jpg

Gareth George

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Feb 4, 2021, 10:34:02 AM2/4/21

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Had my head down the engine bay today and its was a loose cable. Thought I'd checked everything.

Now have the 12dc connected and am just about to turn on the multiplus to adjust the settings.

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