I finally had to go and get new batteries for the monty they lasted 5.5 years and they still have a little poop in them but when I use the front satbelisers it realy puts a drane on them and start to slow down, so I went and got 2 of the biggest 6 volt batteries I could find and afford.
The biggest peoblem I had was there height, and weigh, they weigh a ton, 74.5 lbs. each. the other problem was finding a battery box that I could modify to vent the gases out of the front basement compartment and attaching it to the existing venting ststem. a little bondo on the box vents drill a 1-3/4" hole in the lid to accept the vent hoses some hose clamps and the vent tubes are complete.
Next was the man handeling them heavy guys into the boxes which I had to secured to a piece of 3/4" plywood, the reason was to get them as close to the opening to drop them in to there box, then slide the plywood back to fit them both underneeth the wire shelf in the front basement compartment, the lids can come off prity easy to service them with acid if needed.
I then secured the plywood to the floor of the basement compartment to prevent movement of the batteries, which you can see in the picture below, it also allows me to remove the screws just in case the batteries have to be removed from there boxes, again getting them close to the opening.