Either you have a GoPro, Contour or any other camera this one is for you!

Camcorder batteries are often a problem. Either you are shooting long videos and they don't last long enough, or you just forgot to fully charge it before. Maybe it is verry cold and the internal resistance cuts their life in half? Getting a few spare ones? Sure, but they are usually expensive and not to mention many are low quality and their working time gets way shorter when they are a few years old.

Some camcorders like GoPro can accept external power, but usually do not want to record and charge at the same time, so that's not the best option to use.

I was thinking for some time should I buy spare batteries but decided not to. As I have many other batteries in my workshop I decided to make a simple and effective hack that will let me use any 1S (single cell) lithium battery (3.6V or 3.7V nominal) in addition to the original one.

Step 1: How Did I Do It?

My plan was simple.. getting the direct battery contacts out and wiring additional cell or cells in parallel.

Doing so, you must be aware if one battery is totally empty and the other one totally full, you will get verry high currents running threw them and you may even do some damage to the wiring because of overheat.

Avoid this by connecting together only cells that are on similar SOC (state of charge) or voltage. You can also avoid this by connecting a 1S lithium charger to it instead of a spare battery. This way the charger will control the currents.

In practice (my case) the original battery of the camcorder was in such a bad state (high internal resistance) that the above mentioned effect would not happen, as the original cell is too lazy and would not accept high currents, so this really is not an issue in most cases, but definitely important to know about, to avoid any damage to the equipment.

Fixing the external battery can be done by many options. The best ones are Velcro, cable ties, elastic band, or just make a longer cable and put the aux battery in your pocket.

Step 2: Tools and Material

Yow will need:
-copper tape
-kapton insulation tape
-soldering iron
-basic tools like wire strippers
-some connectors (many different options)
-any 1S lithium battery (Can be pouch like most model airplanes use or can be cylindrical like 18650 being the most common of them)

Step 3: Connection

Getting the main battery contacts out is not so easy, as there is no place for wires. I solved this by using copper tape instead. Copper tape is easy to work with and can be soldered. This makes it ideal for tiny flat areas.

I made 2 copper tape lanes on the battery housing and out to the camcorder housing. One for positive, one for negative terminal. Be sure to insulate all conductive metal parts around those 2 lines with kapton or other insulative tape.

Solder the 2 lines to the battery terminals on one side and onto an aux connector on the outer side of the housing.

Insulate also the copper lines when you are done soldering them.

The video I attached describes this steps better than a 1000 words, so feel free to watch it and you will definitely get the concept in no time if this description does not answer all your questions!

For the connector I used a standard 2 way JST connector that is common in the RC model world, but you are free to use any kind you have.

Make sure the positive and negative poles are correct by measuring the polarity during the process, as they are easy to mix while turning things around and making copper tape connections.

Step 4: Charging

The final result is here!
Ither you keep your external battery connected all the time or not, you have 2 options for charging.

If you charge the camcorder threw its original port it will charge both batteries at the same time and you don't need to bother with any external charger. The only problem here is this will be a slow charging process.

Speed things up by removing the aux battery and charge it separately with any suitable 1S lithium charger.

By doing so, you can also charge multiple aux batteries on your external charger while filming and change them during filming! No need to stop filming as the internal camcorder battery will do the job for the short time you need to change the aux battery.

I hope this topic helped at least some of you that struggle with short battery life on your cameras. If you have any additional questions, feel free to ask in the comments!