I have 2 leisure batteries being charged via solar panels. I understand the control panel will only give a rough reading due to the fact its not calibrated, however what kind of voltage reading should I see from the panel for healthy batteries??
If it was installed correctly the solar controller should be very accurate, if you are not sure if it was done right, pull the fuse for the panel, and also the one for the batteries, put the one for the batteries back in first, then after a few minutes replace the panel fuse, this allows the controller to read the batteries state of charge, you should then have an accurate reading.
This diagram is worth printing off and keeping handy for future reference.
I would say no, I suspect that is the charge being produced from the panel via the controller, to know the actual voltage you will need to pull the panel fuse, I may be wrong as it's a while since I played with solar, but I think it's correct.
13.8 to me suggested it's fully charged or at least thinks it is and you either havent switched anything on or if you have there is more going in than out. I've seen my solar Controller often peak at 14.x when the sun is belting down and I'm also running a shed load of stuff so under load. If I switch off any load items. Lights, tv, laptop etc once it's fully charged it will rest about 13.5 until I use power. If the sun's gone and there is no more charge under load it will be about 12.7 and gradually go down to maybe 12.5 or 12.4 this time of year on an evening. I think the 13.5 or 13.8 is a bit of a false reading as mine at least rests at 12.7 when there is no charge and under load.
I don't have TV but the last week or so have had the maxxair running till maybe half 8, 9. It showed 12.7 at that stage but when I ran the maxxair again pulling cooler air in, for a bit before bed, it had gone back up to 13.