Normally only two, a positive and a negative terminal.
Positive & Negitive
connect its two terminals with a wire.
Positive & Negitive
The function of battery terminals is to connect a load or charger to a cell battery. Battery terminals are necessary and common in a lot of batteries.
It depends how they are connected. If the terminals of two 12 volt batteries batteries are connected to the same circuit (in parallel) then there is no change in the flow of current- it will just last for twice as long a time. But if two opposing terminals of the batteries are connected to each other first and the free terminals then connected to the circuit (in series) then there would be a total voltage of 24 volts and twice as much current would flow. The two batteries would last for the same length of time as one battery on its own.
Yes, it's not because of the material inside the battery, but to prevent the terminals from touching other batteries. If battery terminals touch they can create heat which, in turn, can cause a fire. So to prevent a fire, you should tape all battery terminals when shipping for recycling.
With enough batteries to get sufficient voltage - sure. Put your tounge to the terminals of a 9 V battery and you'll see.
If the charger is a 12 volt DC machine, connect the leads to the two battery terminals that the load is taken from. Take care to note the polarity of the leads to the polarity of the battery terminals. There will be a short jumper cable between the two six volt batteries. The charger leads go on the opposite terminals of the two batteries that the jumper is connected to.
Negative and positive terminals are reversed.
You can easily touch both the positive and negative terminals of a 9V battery to your tongue. This is much harder to do with other batteries.
Soldering BatteriesSoldering on the terminals of "drycell" batteries probablywill not cause an explosion, BUT... soldering on any drycell battery WILL DAMAGE the "seal" where the terminals penetrate the battery housing/case. That seal failure will allow leakage of electrolyte which in turn can, and usually does, cause a lot of corrosion and related damage to the batteries themselves, AND adjacent electrical/electronic components!Also, depending on the amount of heat allowed to "sink" into the batteries, the practice of soldering on battery terminals can result in immediate failure of the batteries.Most, if not all, of the terminals of commercially manufactured battery packs are connected using "Spot Welding" which does not create as much damaging heat.
Wire the batteries in "series". Place jumper from neg (-) terminal to the pos (+) terminal on the other battery. You will have 24V across the remaining terminals.