Battery trickle charge
 

2006 F-250 Power Stroke
This truck will be barn stored for the next two months.
Does it matter which battery is hooked up to a trickle charger (Battery Tender - type). It is cold here in Michigan and I don't want the batteries to discharge and freeze. This is my first Power Stroke and I don't want to mess things up through "lack of knowledge".

I don't know and have never tried it but could you hook up both to the battery minder? Just a thought.

If you are using Optima batteries. DO NOT trickle charge as It can damage them and void the Warranty. Can someone start it once a month and bring it to operating temp? If ya can put pos to one batt and neg to the other and get a reading on the charger than it is going through both. Although most isolators that I have seen will only work with the Alt charging.

Put a charger on a timer. Weekly - if possible and have it charge for 3 hrs. this should do you well.

For just two months I would put a block heater in it and cover the front clip with heavy blankets to help hold the heat from the block heater. If it has good batteries and no power drain it will start just fine. I have rigs in the back 40 that I can start after setting a year. Doing no more than disconnecting the battery when parked or ran last. Boats the same way.

Thanks to everyone for the feed-back.
Since it is too cold to mess with installing the block heater cord at this time, I will just put the charger on and store it inside the barn. I just wasn't sure where the charger should be hooked up. I connected it to the passenger side (primary battery) and will see if that works OK.