How do I solder wire leads to a 12v 2amp battery?

I am trying to repair my son's electric quad.  I thought it might be the batteries but the batteries are both reading 12v.  I had to cut wire leads that were soldered to the battery so that I can test the batteries.  Now, that I know it is not the batteries, I have to solder back the wire leads to the batteries.  I was soldering the wire to the negative post and I was doing fine, however, I must have touched the positive post and I got a small explosion.  It scared me so I stopped.

The quad uses two 12v 2amp batteries that are wired together.  The wires then have a lead that plugs into the quad. 

I need to wire the batteries back together.

rickharris4 years ago
I guess these may be lead acid and you should be able to get a suitable bolt on or clip on connector.

Most batteries at birth are spot welded to avoid excessive heat.

Off load the batteries may well show full voltage - I would expect a fully charged battery to show slightly above its rated voltage initially.

BUT they may not have the current capacity to drive the bike. Often Lead Acid batteries get a cell that has high resistance limiting the current.
iceng and steveastrouk are right very carefully the two metals melting point difference between led and solder is 200 degrees and it is very easy to mess up.

There may be another way like a clamp or marett core if you can up load a pic it would help.
iceng4 years ago
With automotive lead batteries you have to be superior at Puddling !

With welded tab batteries a resistance welder is useful or a micro-torch. 

A picture of the connector would help us to help you.

Oh you  just joined,
Generally soldering batteries is a bad idea - they aren't designed to take it. What kind of battery is it ? Shape ?