Installing Trailer Batteries

[buzzcop63]

For those who have taken the battery out of your trailer and now wish to put it back, this information off the net might just help!

Remove The Negative Cable First,
Re-connect The Negative Cable Last:

Why? Because the wrench or socket is touching the live part of the electrical connector. There is a good chance that the wrench or socket handle will accidentally touch something. The entire trailer/car is connected to the negative terminal.

If your wrench is on the positive terminal and it accidentally touches anything metal, you will short circuit the battery. The voltage isn't harmful, but the sudden unexpected sparks will startle the **** out of you, and could even burn you. There is so much current (amperage) available that your wrench literally becomes an arc welder.

If you disconnect the negative cable first, and reconnect it last, then the trailer/car is not electrically connected to the negative battery terminal. After that you can disconnect the positive battery terminal with minimal risk, because if your wrench touches any metal parts of the trailer/car there is no complete circuit, and nothing happens. The only risk comes from touching the other (i.e. negative) battery terminal.

While connecting or disconnecting the negative cable, you don't need to worry about the wrench touching metal parts of the car, because everything is at the same electrical potential. You only need to keep the wrench from touching the positive battery terminal. That's easy.

[66joej]

Hey Buzz good info. Have been doing it this way for over 50 years. Some trade school stuff stays with me.

[Cbrez]

Thanks for the tip. I inadvertently reversed the terminals when hooking up my betteries last spring. Small fire, fried the circuit board for the level up system and crowned moron of the month at the campground. Tips like this are old hat for folks like Joe, gold nuggets for me. Don't know what prompted your post, but much appreciated.

[dcg9381]

And never reach in with a sweaty arm across the terminals. Ask me how I know.. :-)

[chuckster57]

Originally Posted by dcg9381

And never reach in with a sweaty arm across the terminals. Ask me how I know.. :-)

Is it like licking the 9V battery to see if it's good?

[SAABDOCTOR]

VERY GOOD ADVICE. I am going to mix things up. For those that have computer controls in your camper. Before you connect the battery.Take the two cables and touch them together for about 30 seconds. this takes any stray stored electrons and dumps them to ground. then hook up the battery. This will reduce the chance of surge damage. Now before you all go off on me. if you own a code reader that plugs into the obd2 socket on your tv. look at the plug you will see two pins are longer than the rest. they are the grounds. that way they get connected first to dump the stray energy that can damage an ecu. I work on expensive european cars and have never damaged an ecu by doing this. since I do a bunch of Saab work we call this the "Swedish reset" just food for thought

[66joej]

Actually when ECUs first came out way back when as mechanics we were instructed to do just that when changing or reconnecting the battery.