How much solar?

Pentland

I've got a 2013 Bailey Ancona and a couple of times this year we stayed on sites with no hook up, last time everything worked apart from the blow air Whale heating system, took it back got it repaired!

this time same problems, heater says check flue for blockage, took it all apart all clear.......

So off it goes back to be repaired again!

Now the battery was loosing power so when its back in being repaired i can have a Solar panel fitted on the roof, my Bailey dealer says they fit a 40w Vison Plus Solar panel and more can be added if needed, how much power will i require to keep it all topped
up?

No TV is being used off 12v and much of the rest is on gas, all lights LED etc?

Mamy thanks for any info.

Keith