I looked on-line for what was available that would have some legs to it so I wouldn't have to keep turning the camera on and off all of the time; thus missing all of the great shot. If I had a nickel for every time..........
"Oh son! Can you do that funny thing again so papa can record it on the video camera? Make sure not to hurt yourself this time."
After thinking about it for a while, I came up with the idea of making my own battery!
After reading Tim Anderson's Lost Your Charger? How to Charge any Battery Survival-Style, I decided to make an instructable of how I did it.
WARNING: Just because I have not blown up my camera yet with this external battery pack, doesn't mean you won't blow yours up. If you do create a battery pack such as this, and you do blow up your camera, it isn't my fault! I didn't tell you to do it nor did I twist your arm about it.
Step 1: Specifications
I wanted to use rechargeable batteries and I wanted my pack to be small. AA battery seemed the logical choice. They are easy to find, just about everyone has a charger and if they don't, you just run down to the ESSO station and buy one (if you forgot yours or didn't think you would use up the 5 hours of battery life.)
My camera's external power supply has an output of 8.4 volts and 1.5 amps. Rechargeable batteries put out 1.2 volts. After some high powered calculations, I found that 7 rechargeable batteries would put out exactly 8.4 volts! What luck.
I was not worried about the current output of the batteries. They are 2500mAh and should provide plenty of current for my camera.
By looking at the plug on the external power supply, I was able to find the polarity being delivered to the camera. In my case, the barrel is negative and the inside is positive. This is important to know when you wire up your new plug and hook it up to the battery pack.
I also matched the plug from the external battery pack. It turns out that I have a size "H" coaxial.
Step 2: Parts list
- 8 AA battery holder (series) - less than $2
- 9volt battery connector (I had one from another project)
- Size "H" Coaxial plug (came in a 2 pack so I have an extra now) - about $2.50
- Mobile phone car power adapter (for a phone I no longer used)
- 7 AA rechargeable batteries (I already had these)
- Thin, neoprene mouse pad (if you want to make the case for the battery pack)
Step 3: Make the cable
Then I stripped back the insulation and found 6 wires. These are very small wires and I didn't want to overload them nor did I want to lose any power in my cable. So I took three wires and soldered them together and took the other three wires and soldered them together.
Now I have my positive and negative wires.
I soldered one end of the cable into the new size "H" plug (keeping track of which was positive and negative so I could hook them up on the other end correctly.
Before soldering the 9V battery plug onto the other end, I tested my soldering connection to the size "H" plug using my multi-meter. I wanted to insure that the positive was only feeding one set of wires and that negative was only feeding the other set of wires.
With that checked and correct, I soldered the 9V connector on.
Step 4: I'm missing a battery!
I tried putting the batteries in several different ways but each time I had an open circuit. No luck.
After hours of research, I finally came up with a solution. I created a dummy battery out of a jumper. Now I have a complete circuit! This also gives me the flexibility to use 5 or 6 alkaline batteries if I need to.
The battery pack was ready for testing! My first run with the external battery provided me with 5 hours of operation on one charge. 5 hours!! Count them! One, Two, Three, Four, Five!! I had hoped for 3.
Another bonus to this setup is that your camera battery will charge while you have this external pack hooked up.
Step 5: Neoprene battery cover
I wanted it to be black like all good photographic equipment. I also thought it would be nice to have it a little water resistant. Just in case it rained or someone tried to spill Coke on it.
Neoprene was my thought. Some thin neoprene. I had never worked with neoprene before. I figured there must be a good way to glue it together. After all, they make dry suits out of the stuff and they don't leak.
I found some stuff on-line but it cost too much and I would have to wait for it to arrive. I already had my neoprene. I took an old mouse pad and pealed off the fabric top leaving me with a nice thin piece of neoprene.
I cut my pattern out of the neoprene and used contact cement to glue it together. It worked great! Once it was all glued together, I added some Velcro to keep it closed and I was done (for now. I need to add a clip or belt loop to it.)
8.4 volt, 2500mAh external battery pack for my DV camera.