So, I've got this '97 f350 aka Mongo. I rarely drive it but it's useful as hell when I need it. I recently put the block heater plug in a sweet flange mount in the bumper with a nice rubber cap. Simple job, cut the plug off and wire it to new one. But it got me thinking about putting a battery tender on the dual batteries off the same plug. So I can just run one extension cord to the truck and power both things. It's still a 12v system so would I just connect the tender to the positive of one battery and the negative of the other? Or would I run it to just one battery and it'll maintain both?
Are you going to put a switch on for the block heater? You don't want that chugging away unnecessarily 99% of the year.
But yeah, you can just connect the battery charger to one battery, they're connected together so you'll charge both.
Noddaz
PowerDork
3/4/23 4:32 p.m.
I can see the Battery Tender. Just plug in the block heater in the day before you use the truck. I live in a more temperate area (Maryland) and have found as long as the batteries are maintained I do not need the block heater running.
The batteries are connected in parallel, so they're already hooked pos/pos and neg/neg. Hooking to one battery will charge both.
You might want to look into something a bit beefier than a battery tender. They're designed to keep a fully charged battery topped up, but not two monster batteries, both of which could discharge faster than the tender can keep up. I know that the Battery Tender I have won't keep up with the series 6v golf cart batteries in the tractor. It's just way too much battery for the tiny tender to handle.
Maybe two battery tenders, or a small smart charger?
