Does a car battery need both terminals occupied to work?

I've been troubleshooting some power issues with my car's amplifier. I got a second battery and hooked it up, but I could only get power when I used both the positive and ground from the new battery. I couldn't use the positive from one battery and the ground from another, or vice versa. Is this normal?|||you absolutely have to have both terminals of one battery...you cant use the pos from one and the neg from another...you have to be able to make a complete circuit....my advice is use just one battery....and if you are still having power issues you should check for loose wires ie a bad ground or a bad pos feed....if you can get your amplifier to power up ..once it is powered up you should then go through and shake the wires leading to it and from it...and when you lose power you will be a lot closer to your bad connection than just guessing you will at least then be in the right harness or real close toit....once you find the harness with the bad connection...wiggle them again to regain power to your amp carefully cut open the harness and go through the wires in it one by one by wiggling them it should help ypu find your problem|||yes. that's what makes the circuit.|||The circut is completed through the same battery. This is normal.|||pos from one...neg from another..LOL..wheres the connection...u need plus and minus|||ye positive out neg. in makes a circuit , the only was it will work|||yes very normal...the battery or power source must have a complete circuit so you must ground whichever battery's power feed you are using.|||when you want 12 volts and use two battery you connect pos to pos neg to neg if you connect pos to neg at the two left over term tou will have 24 volts not 12 most cars use 12 volts only limted cars some hybreds and other cars use 42 or 48 vdc make shure both batts good get and learn how to use volt meter amps can be tricky to trouble shoot as some have capacitors in side which will spark when you connect to batts even when off|||yes