Ann-Marie

If space is a problem, there is no law that says the battery charger has to be built in. Set it up as a portable charger that clips onto, or plugs into the 12 volt side and save the space and weight. You don't need the 110 volt input equipment when you are out on the water.

Yes, you can leave it on the float mode indefinitely. If you are running an outboard as well as the trolling motor you can use the alternator on it to charge the trolling battery as well as its starting battery. This will extend your running time without increasing battery size.

On units like that, there are typically two access screws. So if you get the loob in a toob it may be a little more expensive but it is 10 times easier to fill. I remove both plugs and let it drain, then put the tapered nozzle of the fill tube in the lower one and squeeze until liquid arrives at the top hole. Put the plug in the top one and then you can remove the tube without it running out as you put in the bottom plug.

Consider the weight also. I switched from a 2 to 4 stroke on one of our boats and after that I had to get my mother in law to sit in the bow so I could see where I'm going and get it up on a plane. The other half of the disaster was there was no insect filter in the air intake so the mud daubler wasps decided that the honeycomb air filter and the cooling fins on the cylinders werea perfect condominium and proceeded to fill everything up!