How to remove a car battery:
1-park the car and turn off all accessories. if it's not completely turned off, drain as much power as possible by disconnecting the cables (for example, pull the strap under the hood) and make sure it can't be restarted–either sit in driver seat or better yet, push it somewhere safe if you think these steps won't do enough.
2-make sure there is nothing that could cause an electric arc–this includes any metal tools which might create sparks and anyone who can touch both ground and battery terminals simultaneously. if necessary, lay out a plastic sheet to catch any leaking acid from this procedure.
3-fix one terminal of your battery charger
which battery terminal do you take off first?
to disassemble the battery, first remove the negative terminal. this will prevent anything from overheating or sparking during removal of any other terminal.
the positive first or negative first rule is not something you need to be concerned about if it's just your toy batter that you're building. it could be seen as an advantage though if for some reason your toy battery were smaller than the regular aaish number of wires that usually connect to it. one way could be to reverse solder joints one by one and turn them off before each next joint (positive reinforcement). this might make the task slightly easier, but only slightly better than doing it in a more conventional manner (negative reinforcement). you flip-flop back and forth between this two
how do you safely remove a car battery?
the car battery on average will last 4-5 years on average.
this is true for the majority of cars, but this time varies depending on how often you drive your car and conditions in your area (porosity). the longer the battery lasts the better condition it is in. if you live in a hot or humid climate, or one that doesn't hold rain well (desert), it's possible that its lifespan can be shorter than 4-5 years. a good way to monitor whether your battery is dying more quickly than usual is to check out yellow or orange “instant fuel” cans at gas stations, these are empty containers that turn yellow when exposed to high levels of sulfuric acid found in batteries which lets you
what happens if you disconnect the positive terminal first?
in most cases, nothing. in some rare cases, you can get a harmless but bright electrical arc.
in the vast majority of cases, disconnecting a car battery from any terminal won't do anything because there is no charge stored on the battery's terminals. disconnecting one wire first does not change this at all since there is no live electric on it to drain back to the other side of the circuit – if it happens on an operational circuit then something has gone wrong and current would be going through both wires anyway. it is unlikely that doing so in the complete absence in load voltage will cause any spark, but you can't rule out that possibility either when connected directly to earth ground or to raw power supply in many types
