Original Battery Bank Configuration

Unfortunately the Radar Trailer didn't come with the original (3) 31DCM maintenance free batteries for a total of 345ah at 12v.

This is the spot in the front of the trailer where 3 12v batteries belong.

Each battery has a plastic cover and a metal bar that goes over the threaded  rods to hold the batteries securely in the trailer. the metal panel (that the battery cover  on the far right is resting on) hinges up.

The only concern I have about using lead

The only concern I have with using lead-acid batteries is that when being charged they generate oxygen and hydrogen gas by electrolysis of water.  To control the cost I may have to stick with this option.

For now I am going to use an extra AGM battery I have just sitting around.

This used Genesis XE 70X battery was another golden find on craigslist a few years ago.  I think it is 68ah sealed AGM battery.  I paid $65 for it new they are much more .

They still sell this battery new for $569 ( I wish I would of got more than one)

For now I am going to mount it in the first battery position after I double check (and tape up) the positive leads for the other (2) battery bays.

Ready to be added to the battery bay.

I will use this battery for now and watch craigslist for other options.  This will allow me to connect in a small inverter so I can play a radio when I am working on it.  I checked the battery specs and it is ok to charge this battery to 14.4v, so it will work with the charge controller already installed in the trailer.

More details of the battery compartment can be found below:

According to the original trailer operator's manual the vent door needs to be opened up when you charge the battery using the 120v charger (not included with my used trailer)

I was wondering what this bar was for.  I think it is to prop up the vent door?

I just stuck the bar in the expanded metal and it holds the door up.