How do I use the controller to get a good idea of how everything is working?

DIY
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1

We have a SmartSolar 100/50 MPPT.
We have 4 AGM GPL-4DL 210 aH batteries (unknown age)
We have 3 new Voltify Mono PERC Solar Panel 200W in parallel.
How do I know if all is working as expected? The reason I ask is we have an old Xantrex RV2012GS Inverter charge with a remote display/panel
The panel shows Battery ‘full’, the Xantrex LinkPro monitor shows 81.1% (today) and generally always indicates current going out.
The panel occasionally shows error HighBatt/StopChrg
At that point, the Solar controller showed batteries over 16v

Any tips would be appreciated please

2

I am going to start by saying it is not normal for AGMs to be charged to 16v.

How is the mppt programmed? Did you use an agm profile?

Are you able to post your mppt histroy?

3

History from today attached

(Attachment DOC-20250831-WA0000..xlsx is missing)

4

A screenshot will probably work better

5

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6

The 16.0V can occur if your MPPT is not set up correctly or your system is very cold due to temperature compensation. Send us a screenshot of your MPPT settings including the expert option.

7

Here you go

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8

Your settings are too aggressive for standard AGM, the lifeline manual recommends a charge voltage of 14.3V for absorption and 13.3V for float and a tail current of 0.5A per 100Ah. You have 840Ah so tail current should be 4.2A. Finally, the temperature compensation from the manual should be -24.5mV/C. Edit the profile to suit.

You have tail current setting to end absorption as well as a 6 hour time. 6 hours is a long absorption, the Lifeline manual recommends a shorter time. Is your MPPT connected to a GX device with a SmartShunt or BMV battery monitor. If it is not then the tail current setting on the MPPT measures the MPPT output not battery current so this includes loads. If you have a steady 3A load then the MPPT will be in absorption for the full 6hrs because it can not get down to 2A. In this case, the tail current needs to be 4.2A PLUS your steady load current, so 7.2A. This could also cause overcharging, however your absorption times are much lower than this so the adaptive absorption is limiting the time.

I do not know if the overcharging is contributing to the problem or if the batteries have been damaged, but over charging AGMs can cause problems. I would makes these changes and then monitor the performance. If the batteries are too full when a large load suddenly stops then they will have no buffering capacity, but the MPPT should still not overshoot so much.

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