Calling the battery experts

Can only assume that the Hydraulic ram is going to take a fair amount of current. If this is the case a cranking battery would be my recommendation. If you are using a cranking battery just keep it charged (don't run it down all the time) and it will be excellent for the job.

Have you thought about changing the trailer connections and running some 4g or 8g wire from the vehicle to the trailer. That way you could be charging the trailer whenever it's hooked up. May some of these trailer plugs people are using for their campers/caravans. I'm sure someone here would be able to help you out with those.

Why can you not charge the battery from the car alternator?

I would think very heavy duty if your going to drain it regularly.. it wont have a long life span which ever you go with

You can also run a Deep Cycle battery "deeper" without killing it.

If you continually "drain" a normal starting battery you'd stuff it up in a short period of time.
A starting battery (rated on CCA) is designed to be drained "slightly" and then topped up" by a vehicle alternator.

I would use a cranking battery and just charge it after use and occasionally when not in use to maintain it at full charge. Don't wait for it to get near flat. Batteries do not like this and reward you by diieing early.
I can see no reason to do anything complicated for something which is just used occasionally. If you were using it daily it would make sense to arrange some form of charging system from the car system to avoid having to connect up a separete charger.

Phil I

The logical question to ask is what type does it have in it at the moment?

Google the manufacturer and model number to bring up some specs.

A gell cell deep cycle battery would probably be the best but are expensive. Good vibration protection, about the right capacity (55amp hour) & most importantly low self discharge which is probably the biggest killer of batteries left sitting around like most tippers would be. Certainly importantant to fit a charge circut from the car but ideally for long battery life we now use small solar panels on our intermittant plant. Batt life has jumped from 6 months to 3+ years. Additional benifit of running a circut from the car is that if you keep the motor running you'd get 20 to 30 tips+
Cheers Craig.........

Philip,
If you are running a wire from the vehicle to constantly charge your trailer battery, why do you need a trailer battery at all ? I would just leave the car running and plug the trailer into the back of the car and not have a battery on the trailer at all. I and friends of mine do this all the time with electric boat winches without a problem. I plug into the fridge socket inside the back door. If you are using another car you could always make up an extension lead that clips straight onto the cars battery for those times. May save alot of money on a battery.

Tony.