MPPT not enabling pv input after restart

Q&A and troubleshooting
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1

Hi all

The other day my batteries voltage reached the full charge limit on the mppt and it shutdown with an #81 error, which was the correct behaviour.

But when the battery voltage dropped below the limit the mppt did not clear the error. The mppt is a smartsolar 250/100.

I then disconnected the pv panels and disconnected the battery to reset the mppt. After it rebooted I connected the pv panels again but the mppt states there is no pv Voltage. When I disconnect the pv panels, I can measure 180v on the panels.

Any ideas, why this is happening?

Br

Jens

2

That is not a correct behaviour that is a protection being activated.
The moot should switch from bulk to absorption and then float not send out an error. The error means there is a problem

See the manual.

If the procedure from the manual does not help then your mpot is damaged

3

The error got triggered because the battery reached the float voltage limit of 53.6 volts.

In the mppt log it actually says #80 PV input shutdown. So it is actually a battery protection, so the mppt did not do this to protect itself.

It seems like the MPPT stays in the protection mode even though the error has cleared.

4

So the battery it sending what message to the mppt and how?

I know it is the mppt shorting the input to protect the battery, what i am saying is it should not be doing it in normal operating conditions ever (and especially when the battery is at float since that is not an overcharge condition). It is an error condition indicating a problem.

This is the reset procedure.
If the fault does not clear the mppt is broken.

5

I think what triggered the over float voltage was my multiplus had a higher float limit. I recently connected it to the grid, so when it charged the battery it passed the float limit on the mppt. I also found the procedure you linked and will try it tomorrow.

6

Ah right.
One of the causes of the error in the system is another charger with different settings.
It is usual for all devices to have the same settings for bulk and float set on them.

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