Batteries - codeniko/vehicles GitHub Wiki

Safety

When dealing with batteries, explosion is possible because battery can leak acid/fumes. As you connect leads or do it improperly, a spark may happen which can ignite. Eye protection recommended if battery is in awful condition. Absolutely avoid short-circuiting the battery by dropping a metal wrench/ratchet on top of positive and negative terminals. Hold onto that thing for dear life.

Also, it is perfectly safe to touch battery terminal with your hands (assuming no cuts/wounds on hands), even both terminals together. 12 volts is not enough to penetrate the resistance of skin. If you happen to have an open cut though, you're on your own. Possible shock, but not enough for anything serious.

Remove metal rings from your fingers. 12V won't hurt much if you get shocked, but a start battery can dump enough current (amps) through your ring to melt it. Remove negative first. Everything in your car is already connected to negative, so as soon as you remove this everything is dead. Battery acid fluid can eat holes in your clothes and skin, and blind you. Baking soda, nitrile gloves, and face masks are useful.

Jump start connection order

  1. Positive to bad battery
  2. Positive to good battery
  3. Negative to good battery
  4. Negative to unfinished metal part of bad car

To disconnect, do in reverse order.

https://www.artofmanliness.com/articles/how-to-jump-start-a-car-the-complete-guide/

To disconnect battery

  1. Unbolt and disconnect negative terminal
  2. Unbolt and disconnect positive terminal

To connect battery

  1. connect positive and bolt
  2. connect negative and bolt

Apply dieletric grease AFTER connecting battery, not between the terminals! It is not conductive, and will inhibit a good connection kill battery faster. Eventually that grease will turn solid, and you will cause a voltage drop across the terminals.