I would really appreciate getting step by step directions for disconnecting a car battery. Thank you.
Just pull the negative cable, and then make sure that the negative can’t contact any metal on the car (e.g. just wrap it in a rag or something). Negative & positive are normally indicated on the battery with a “+” and “-”. The positive terminal should also be marked with red in one way or another (a red terminal, or maybe cover). Negative is normally black.
If you have top terminals, then the cable ends will probably be a clamp type connector, where you just loosen the nut, and then twist the terminal on the post until it loosens up. If you have side terminals, there is probably just a small bolt that you remove.
Wear safety glasses. Some like gloves too.
If you’re looking to pull both, cables, then just pull the positive after the negative.
It’s pretty easy. When you’re removing the battery cables, remove the negative cable first.
A modern 12 volt automotive electrical system is not any more complex than a flashlight. You have a positive side and a negative side, and when they’re connected, electrons flow from the - to the +.
In a car, the metal chassis of the car is connected directly to the - (ground) side of the battery, and the various electrical components of the car also connect directly to the chassis. They also connect back to the + side of the battery via the fuse box.
With that in mind, you usually want to remove the Negative (-) cable from the battery first. Why? Since the negative side is connected directly to the car’s chassis, if you remove the positive side first, you’ll create a short and sparks if you accidentally touch a wrench to the battery terminal and the car’s chassis at the same time (and if you’re as ham-fisted as I am, it’ll happen again and again).
So really, the process is not any more involved than removing the battery cables. You’ll need a wrench (probably a socket wrench) that will fit the battery terminals and they’re usually 7/16". Or if your battery has the threaded “side-post” connection (where the terminals are on the side of the battery, rather than the top), I think those usually require a 7 or 8 millimeter socket.
When you go to reattach the battery cables, attach the positive first, again, to avoid shorting / sparking. Best of luck.
Make sure you have the security code for the car’s radio (if equipped) before you disconnect the battery cables.
if your radio requires a security code it will not work without it after you reconnect the cables.
Also, if you plug one of these into the cigarette ligher with a 9 volt battery connected prior to removing the battery terminals, it will retain the computer/modules/radio memory presets so you can avoid the problems that can arise from disconnecting a battery from one of todays vehicles.
Thank you so much for your help!
As cigroller noted, wear safety glasses.
Chances are a battery will never blow up on you. One did on me, and the acid sprayed all over my face. I was lucky I didn’t lose my eyesight, but now I always wear safety glasses.
It is a good idea to remove any rings and bracelets you might be wearing. If you touch one to a post you may be shocked.
“Also, if you plug one of these into the cigarette ligher with a 9 volt battery connected prior to removing the battery terminals, it will retain the computer/modules/radio memory presets so you can avoid the problems that can arise from disconnecting a battery from one of todays vehicles.”
I believe this only works if the lighter socket has power with the engine off. Please correct me if I’m wrong.
Most circuits for the cigarette lighters/power ports are uninterupted circuits, or hot all the time, and are protected with fusible links. Like how the interior/head/brake light circuits are protected. And these function with the ignition off.