I'm not driving my F-350 as much any more and would like to put a battery tender on it but I'm not sure how to attach the leads with 2 batteries.
Any suggestions?
Thanks.

 

The batteries are already wired in parallel. So you can attach the leads to the positive and negative terminals of either battery and it will charge both.

 

What he said.

I can't imagine it would matter, but technically the passenger side battery is the 'primary', so I'd opt to hook it up there just because if I could. If you put a volt meter on either battery pre and post hookup, I'm sure you'd see the difference you're after.

 

Hook it to the battery closest to the outlet.

 

Not to highjack the thread but thanks for asking the question and for the right answer!

I do have a question regading giving someone a jump start from the battery....I was at the bank the other day and the guy parked infront of me had a dead battery. I wanted to give him a jump but I didn't know how to hook up the cables nor did I know if it would mess with the electronics of the vehicle. Any thoughts?

 

Connect the positive clamp to either positive terminal and the negative clamp to a frame ground. Make sure you don't hook them up wrong because that's how you mess up electronics.

With my two big batteries, I jump start most other rigs without even starting my engine, which pretty much eliminates whatever chance their is of damaging anything in my truck.

 

Back to Battery Tender hook up. Use the included adapter with a plug on one end and eyelets on the other. Connect the eyelets to the + and - terminals on the passenger side battery. The adapter is just long enough to tuck between the passenger headlight and grill.

Now, you don't have to open the hood to plug in.

Just make sure you remember to unplug before driving off. If you don't, it's OK. I've yanked my Deltran Battery Tender off the shelf onto concrete many times and it still works perfectly. make sure you buy a Deltran Battery Tender Plus. It's the best on the market. Remember, you'll be topping off two big batteries, so it will take longer to bring the batteries to float charge than one car battery. Don't buy the smaller Deltrans as they are lower power and will take much longer to top off your truck batteries.

 

Thanks guys. I knew I could count on FTE to come through!

I have several battery tenders that I use for everything from my race car to my lawn mower.

Thanks again.

 

Can you elaborate on this for me? I've always been under the impression that if you short out the batteries you did so at the expense of the diode trio and perhaps other internals of the alternator not to mention the possibility of hurting anything with an EEPROM. Am I mistaken?

 

(whether the vehicle was running or not)

 

I suppose it's possible to damage the alternator even if it's not running, but I've always been taught that you were far less likely to do damage if the engine was not running when you hooked up.

Especially the PCM, since the PCM power relay would be off when the key is off, so the only power to the PCM would be the keep alive memory power.

 

Is the above a correct statement regarding hooking up a battery tender?

My understanding is that you do NOT want to hook up both of the BT leads directly to both battery terminals.

Rather, it is better to hook up the positive BT lead to the positive battery terminal, and hook up the negative BT lead to a frame ground.

I was searching threads to get a better understanding of the 6.0 PS battery system, and trying to figure out if putting a BT on one of the batteries would charge just one or both of them.

Based on what I found, it seems people believe charging one battery will charge both, as they are wired in parallel and always hooked together, regardless of ignition switch position.

This may be the case, but I have some doubt, becasue after fully charging one of the batteries in my 2005 Excursion 6.0, I immediately hooked the other one to the BT.

It then took several hours of trickle charging to bring the second battery up to a full charge.

Resurrecting this thread to get your opinions and input on this subject.

Thank you.

 

Won't hurt a thing. You can go pos. to neg, pos. to frame gnd. or pos. on one battery and neg. on the other battery. All of the mentioned scenarios will work equally well providing the batterys have a good gnd. connection.