Which battery for small travel trailer

Scottishman wrote:
My wife and I have a FR Palonini 132FD. 16' LOA.

We use it for two three-week trips every fall and spring - and occasional camping in between.

We tow it with a Toyota Tacoma, and have a 100W solar panel on the roof, plus a spare 80W 'briefcase' solar panel

I always have problems keeping batteries charged and kill them. So this time I purchased a AmpereTime solid-state 200Ah Nickel/cadmium battery.
It's an awesome battery that is good for 2000cycles and will last many years - but the issue is that it needs 14.6V for charging and neither the tow vehicle, the camper converter on shore power (13.63V) or my solar panels will deliver that kind of oomph.

So I'm faced with spending a bundle on any of the solutions and that just seems like overkill. So I think I should return it and start over again - regrettably.

My question is - what's the best deep-cycle battery for this small camper, considering the type of use. We are VERY careful with power usage - just the fridge control panel; heater fan when in use; and occasional LED lights. Thank you

d) Here's a question about the Victron DC to DC charger installation. All I can find on You Tube for installation is concerning motorhomes. I have Tacoma towing a TT - so the wiring has to be very different because of the Vehicle-to-trailer coupling. Who has suggestions about how to wire up this gizmo - like running the wires through the truck.
e) Continuance of above...there is ZERO room in this camper - even for that charger and I don't want to drill holes in the camper shell or floor to bring it inside anyway. Can I mount it to the tow frame / chassis of the TT? Is it waterproof? It would be ideal for ease of access.