Upgrading the solar panels on my widebeam boat. 

I wouldn't be too concerned about a reading of 12.4 volts. The batteries are between 70-80 % full at that voltage. You have been keeping your batteries very happy by the sounds of it. Definitely add them to the existing bank.

Can never have too much solar 😀. It just means you can use more power during the day without affecting the batteries reaching 100% by evening. When you are painting the frames of the old ones. If you have some of the roof paint left then possibly paint the mounting blocks the same colour as the roof. Would make them stand out less and might give the impression they are steel the same as the roof. It may also deter theft if it looks like the mounts are steel welded to the roof rather than plastic. It would also reduce any UV damage or ageing of the plastic. So then you wouldn't have to mess about treating the old ones and trying to get them to look like the new ones. They would all be the same colour as the roof. Also if you have one charge controller for the new panels and another controller for the old panels then shading on one set won't affect the others. It would also give you some redundancy in case of a controller or panel failure. If you keep the old set of batteries and add them to the new set, then combined with the large amount of solar, you may be able to look at more power hungry devices. Not sure what sort of heating you have but nearly 5kW of solar should allow things like heat pump heating and cooling. An efficient model can give 2kW of heat output for about 350W of consumption. We use one on our house to heat and cool a large open plan living, dining and kitchen area, it works very well. But you would have to check how they work in your local weather conditions. We have a Mitsubishi Heavy Industries and it has been faultless for about ten years and whisper quiet. The outdoor unit is mounted on the wall just above the outdoor entertaining area and is so quiet I can't tell if it is on or not. Even being able to run smaller loads 24/7 without having to worry about them depleting the batteries overnight. Things like a security system with cameras. LED lighting that can be left on when you are not around to make the place look occupied.

can i ask if you could run through your set up. It would be helpful to understand the size of panels in watts, but also volts and therefore amps. Are you running in series or parallel or a bit of both. What size MPPT, or how many. One complete array or multiple arrays. How many amps of batteries, 12v or ?, and what type, Lithium AGM, etc. and im sure many people would like to understand the maths of it all. Many thanks

Hay ya. Watts ya total watts lol ?