Something on the vehicle is on pulling power.
I assume you're asking how can you tell which is positive and which is negative? The red cable is positive in the black cable is negative. But if they are not color-coded the positive battery post is slightly larger than the negative battery post. If you try to connect the negative cable to the positive post it would be a tight fit and if you connect the positive cable to the negative post it would be loose.
Any wire or other metal object which touches the positive (+) connection of the battery AND the negative (-) battery connection OR the metal bodywork will spark
It would be essentially the same as connecting a battery in the car, except with longer cables. You would have to use jumper cables to extend the car battery cables. Be sure to follow ALL safety procedures. Do NOT let anyone or anything metal touch anything else except where you make the connections. Do not touch the metal connectors themselves. I assume there is no battery in the car. I will call the battery that is not in the car the "external battery". First connect the positive ("+", usually red) jumper cable to the positive car battery cable, & then the other end of that jumper cable to the positive external battery terminal. Then do the same with the negative ("-", usually black) car battery cable & jumper cable. The last thing you connect should be the far end of the negative jumper cable to the negative terminal of the external battery. When you are ready to disconnect the external battery from these cables, do so in reverse order, starting with disconnecting the negative ("-", usually black) jumper cable from the negative external battery terminal.
It could be lights on in the trunk or a short someplace, your best bet would be to touch positive cable to the battery and if you get a spark something is drawing power from the battery, pull one fuse at a time and recheck the spark at the battery and when you have a fuse pulled and it finally doesn't spark when you touch the positive cable to the battery terminal you have found the circuit that your problem is in.
There is no way that the positive battery terminal was ever connected to the chassis. This would be a dead short and would fry the battery. Negative to chassis is correct, but positive to chassis, no way. That positive cable goes somewhere else.
Poor connection. remove and clean the connector and post and retighten
It is a bad negative battery cable or weak ground conection. I would just replace the negative battery cable. This should fix the problem.
Take it to an experinced mechanic and do not pass go!
Replace it with a longer cable. That is the safest and best way. You could splice another cable on to the original but I would not advise it.
If the battery continues to go down even though the system is charging it normally indicates there is an amperage draw. to test it without any meters; disconnect the negative battery cable and observe when you touch the connector to the battery. If there is even the slightest spark, you have an amperage draw and that will run your battery down.
The negative cable can be removed from the post under the hood that is attached to the left wheel housing. The negative cable is only about a foot long and is connected directly from the upper post to the negative post on the battery. It would be best to remove the battery completely if it is going to be stored for a lengthy period. If you place a trickle charger on it, eventually the battery will require water to be added to it.
most likely the battery or battery cable where the positive and negative termials connect to the battery. cold would have no effect on the coil pack.