I use this one off the video all the time, "Are you enjoying your homework? Good because you will be doing it for the next 15 years!"
So not long after I installed the Espar heater it was nice enough to let me know it didn't have enough voltage to run, what it was really saying is the frame rail mounted accessory battery was toast.
I have learned a few things about the OEM accessory battery option since owning this van. There is a relay under the engine mounted battery that sends amp/voltage via the alternator to the accessory battery. What I also found was that the accessory battery has no purpose on this van. Its being "over charged" and never drained. Looking back at the receipts showed that the "accessory" battery had been changed less than 3 years prior to my ownership, and 3 years prior to that, all under warranty. You would think that someone would have figured it out...I guess when the accessory battery is so low on charge (DOA) that it is putting such a burden on the starter battery when running that it makes the starter battery look like the culprit. The starter battery was a Walmart battery and it was less than 3 years old at this time as well.
So I took the Motorcraft acc. batt. to Ford to be evaluated for replacement and later received a brand new battery from them. Since it is a wet cell I decided to use it as the starter battery and purchase a couple of these "Super Start" Platinum AGM batteries from O'rielly's, and a second frame rail box from "Lincolnpimp" off ebay.
I like that O'reillys is kinda everywhere, and that these don't need to be dropped for servicing.
I also picked up some 2ga. copper wire off Amazon, and some new battery connections to make up the cabling.
...and no I didn't use the battery as an anvil when hammer crimping the connections. lol
For now the alternator is doing the charging duties through the OEM relay. We rarely stay in one place for any length of time so I think this will be good for now. I would like to get a better volt meter/charging conditions indicator as these batteries need to be well cared for in order for them to live a long life.