Does anyone know is it possible to have a new key made for my 1970 HiLo travel trailer? Is there anything that I should know in advance? What kind of battery is required as well? Much appreciated

Welcome to the forum, GreekChic. I'm sure any locksmith can make a key for your lock. If you take it off the door and take it in that will simplify things. But, you could probably just replace the lock with a new one and you'd get two keys for it, probably cheaper. They are available online. Suggest you look in etrailer.com to start.

Your battery should be a 12V "Deep Cycle/Marine" battery. They are available many places. I buy mine at Costco. You just need one that fits the space.

- Jack

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Hi-Lo 1707T - Tire Minder TPMS on Tow Vehicle and Trailer, 300W Solar Battery Charger, Equal-i-zer WDH, Progressive Dynamics Converter, Fan-Tastic Fan, LiFePO4 battery 12V DC Electrical System, SoftStartRV mounted on A/C
2024 F150 Platinum FX4 3.5L PowerBoost SCrew

The door lock on my 1984 was different from the newer trailers. I took the trailer to my locksmith and he made me a key. As long as you can open the door, I would remove the door lock and take it to a locksmith.