question

13.2V is nowhere near fully charged. AGM batteries are typically charged to 14.2-14.8V, held there for 2+ hours until current drop to 0.01-0.03C (0.02C = 5.2A in your case) and then floated at 13.4-13.8V. The actual numbers depend on the manufacturer.

Beware of trusting resting voltage to SoC charts. It is not consistent across manufacturers. It's also not accurate if the battery has been charged or discharged within the last several hours. 12.6V is pretty meaningless as a measure of state of charge based on your description. In other words, resting voltage to SoC is only accurate after the battery has sat passing no current for at least two hours. Depending on manufacturer and type, the most accurate relationship is after resting a full 24 hours.

Concerning 50% discharge, yes. All lead-acid batteries should be discharged no more than 50% in most cases. Discharges down to 20% are typically safe, but they will reduce cycle life. Again, this depends on manufacturer and battery type. No, you should not enter 50% as your total capacity. There may come times where you may need to go a little below 50% rather than lose a critical function, e.g., shutting down your RV propane furnace when it's really cold outside. Maybe you'll be okay with the occasional dip down to 20-30% SoC rather than freeze your butt off. If you enter an artificially low capacity, your SoC will be wrong below 50%... when it matters most.

What you do instead is set your discharge floor to 50%. The "time remaining" value uses total capacity and this % to compute your time remaining.

Thank you for your replies. Over the last 6 or so days it’s been quite cloudy so the solar hasn’t had a chance to charge the batteries, below are some screenshots of the battery status. The RV is in the driveway so there’s no use (TVs, lights, etc) over the last 7 days.

Draw is about 0.8amp at rest (modem, raspberry pi Venus OS, some small draw electronics).

It reads 90.6% at 12.28v, which seems a high % for that voltage. All websites I look at say at around 12.3v it should be at 70% charge.

Any thoughts on the stats below?

https://imgur.com/a/rOn57kD

Even the small 0.8A draw is going to pull your battery voltage lower than resting voltage. You are likely > 70% SoC. Voltage vs. SoC is only truly accurate after the battery has been completely disconnected (no charge or discharge of any kind) for several hours.

If you really want to estimate SoC, completely disconnect the battery from any loads or charging for about 8 hours.

Accuracy of the shunt is improved with periodic charges to full with a 100% sync. It's probably a little high, but it's more about potential degradation of the battery vs. rated capacity.

This video shows how to properly configure a BMV-700 series unit, which is essentially identical to the smartshunt:

https://www.youtube.com/watch?v=4ReljfO3k6M

How much solar do you have?

Please include snapshots of your smartshunt and solar charge controller settings.

IMHO, if you can't get your batteries charged daily, you need a new solution. Recommend floating them at 13.8V via an AC powered charger or whatever your manufacturer recommends. This will get them fully charged.

Here’s screenshots of the battery setup and consumption screen https://imgur.com/a/NllRkOk

There’s 240w of solar but it’s partially obstructed by the Maxxair fan. Planning to address solar when I do a off grid upgrade eventually. I’ll review that video on setting up the shunt correctly.

I do have a shore charger for the leisure batteries, I’ll hook it up. Thanks for your help

Per the instructions in that video, you need to set your charged voltage to 0.2V below your SOLAR bulk/boost/absorption voltage.

Shade, even partial, DESTROYS solar output. Depending on panel construction, shading even ONE cell in panel will cut its output by as much as 33%.