Battery Maintenance on 2005 F350 diesel

He was wrong. Never mess with the positive terminal until after you have disconnected the ground terminal.

Lon

Could it be that someone replaced the batteries before you got the truck? "Someone" includes folks like the dealer.

It doesn't matter one bit either way. The practice of removing the negative cable is rooted in the desire to prevent dropped tools from causing a short. If the positive cable is removed, the positive battery post is still hot relative to the vehicle. Drop a wrench between the post and the chassis and a short results.

A related hazard is bumping against the chassis with the wrench while it's on the positive terminal's nut or bolt. Again, a direct short.

Remove the negative cable and the only short path is directly across the battery posts.

(presumably) since you're not going to be working under the hood with the vehicle in storage, either cable can be removed. I'd pick the one easiest to get to. If you pick the positive, just be sure not to bump the wrench against anything.

Everything I own uses traditional top posts and almost all cable ends use a 1/2" bolt (or 13mm, the same thing). I have an old combination wrench that I cut the box-end off of and applied heat shrink over the shank. Only the jaws of the open-end are exposed. That's my "battery wrench".

What I love about buying used tools at the flea market. I don't mind mutilating a tool for a special job like I would one that I paid real money for :-)

John

This is why it is the standard in the industry to remove the negative terminal(s) first , unless you're working on a "positive ground" system.

13 mm is (.51181) inches --- not really the same thing

I have an old combination

I suppose anything is possible. I bought the truck new from a dealer.

But, but, but, If I disconnect the positive from battery A it is going to flop around somwhere before I am able to disconnect the positive from battery B. If it makes contact with the engine, frame, or body the circut will be closed. Remember the two batteries are connected in parallel not in series. Plus both batteries are connected directly to the electrical system instead of battery B being connected only to battery A. In other words there is a wire coming from somewhere in the engine to battery A positive terminal, a wire from the engine to battery B positive terminal, and a wire from battery A positive terminal to battery B positive terminal. Battery A negative is connected to the frame/body as is battery B.

*sigh* There's always one pedantic *sshole in the crowd.

Do a little experiment. Take your 1/2" wrench and apply it to a 13 mm bolt. Fits, doesn't it? Now take your 13 mm wrench and apply it to a

1/2" bolt. Fits again, doesn't it? Manufacturing tolerances make them the same as a practical matter.

Since few of us manufacture our own wrenches, to a mechanic, that *is* the same. BTW, if you're going to be pedantic, at least get it correct. There are 0.5118095 inches in 13 mm, expressed with the correct amount of precision.

John

flea market 1/2 inch wrench probably does.

very sloppy , yes , i won't use it though

tolerances make

They are "Maintenance Free" from the manufacturer, but more often than not the dealer with replace them with NON-maintenace free batteries to save money and maximize profits on resale.

This keeps heat from the engine compartment from acting directly on that battery and causing them to boil the water out that much quicker, by allowing an air blanket in between the battery and the plastic cover. It was probably decided by one of the designers that the particular covered battery is in a "hot zone" or a place where engine heat could get to more easily than the other one.

Rvfulltime,

If you disconnect the positive first and dont have the "proper" insulating material then what I always do, regardless of which I take off first, is wrap the positive in a shop rag. This will keep it from contacting ANYTHING. It always works for me. Worst case scenario is that you have to tape the rag to the terminal, but for $0.85 I can get a roll of electrical tape that will do the job just fine.

Ford Tech

Duct tape a shop towel over the end of the cable if you are worried. I just installed a new "direct to battery" headlight harness and had no problems with removing the positive battery cable and having it "flop" around.

mike in montana

Not meaning to pick on just Montana Mike. IMHO, it is foolhardy to remove the positive terminal without first disconnecting all negative terminals. It just makes sense. Wear eye protection, and take precautions when working an an RV or automobile battery. While removing the negative terminal, the only danger is in contacting the positive terminal at the same time. After all negative terminals have been removed, the only danger in removing the positive, is contacting the negative at the same time. If you work on the positive terminal while the negative terminal is still connected, (even on a second battery in the system) then your wrench contacting any metal on the vehicle will complete the circuit, and your wrench will become part of an arc welder. You can be severely burned, and/or your battery can explode, covering you with battery acid.

It just makes sense to do the job the safest way. Plenty of people get away with doing stupid and dangerous stuff. Some don't. Minimize your danger and enjoy your RVing. I don't want to read about you in the newspaper, or see you on the news. They don't usually show the fun stuff.

The BRITE BOX?

Since I have you all battery experts right here in a circle, let me throw in one question:-) I have a trickle charger I don't use. I was thinking about hooking it up permanently to my F350 batteries and periodically put in on trickle charge....I thought it wouldn't hurt. Do I just hook up the charger to positive/negative posts like as if I am jump starting? If so, which battery or does it not matter?

My truck is 2005 and one of the batteries went bad, which warranty replaced. How come that one battery was shot completely and the other was still good? Beside it being just a fluke? y

Put this in perspective a "TOW TRUCK DRIVER" told you to disconnect the positive battery cables. Check any repair manual, even the most lame one and they all say disconnect the negative cable first when disconnecting a battery. Its a no brainer

Whitelightning

Not the brite box - just a harness with relays. I got spoiled with the Euro lights in my Audi - the Ford lights really suck in comparison and any additional output will be appreciated.

mike

I've had a trickle charger on my battery for some time, about ten years. Works great. See

under the motorhome and step fix links. The steps were keyed to the engine battery. When it got weak, the steps would not work properly.

Steve

Did you have two batteries in parallel that left the positive battery cable hot when you disconnected it? If not, you don't have the set up described.

Steve

under the motorhome link

Yes, I have two batteries in parallel - the battery cable remains hot when disconnected as the other battery is still powering it. What description of the setup are you refering to?

mike

I love that site Wolf. That is some great advice on there.

Ford Tech

Thanks. I also put a trickle charger in my Jeep and ran a socket out to the front bumper. When I store it for the winter, I plug it in. It is ready to go if I need it. Works great.

Steve Wolf