Have a 92 Coleman. Currently doesn’t have a water tank and is fitted with a hand pump faucet. My plan is to install a normal faucet (cheap builder grade ones since they are very small) and an electric water pump. I plan to have my 7 gallon water jugs outside the camper and have a hose go from the outside to the pump then to faucet. This allows me to have more space under the sink for storage and have water loaded on my truck and not the pop up. So my only issue is I don’t have power. Apparently the converter doesn’t work and I don’t even have a battery. I’m looking at installing a small battery underneath the sink to run my pump. It’s 12v and 3amps What solutions do I have without spending $150+ on a big ass deep cycle battery ?