Upgrading a $60 Video-Camera batteries from 700mAh to 2600mAh or more

Haven’t been around for a while, but here is my latest project. A battery upgrade project. I’m trying to get back into technical blogging, so ignore my bad grammar. I might be editing this too, adding in some more photos to make the post flow properly.

Recently I bought a Hitachi camcorder off ebay for doing hobby videos because it was cheap. It didn’t come with a charger and that was a problem.

When I opened the box I found that there were three batteries and they were very small in size. That really led me to believe that the standard batteries provided for the unit weren’t really satisfactory. 700mAh? please, and that was when they were new. These batteries were all dead too. I wasn’t prepared to spend $20 on new factory batteries if they were going to have such a small capacity anyway. I decided to use the dead batteries and reclaim their connectors and internal circuit boards.

The camcorder was rated on the panel as being for 7.2 - 7.9V so I couldn’t see any reason why some partly charged 18650’s operating at 3.6V wouldn’t work.

I set about to cut open one of the existing batteries with my dremel. Carefully cutting only through the plastic and not into the battery cell underneath. The thickness of the plastic is about 1mm. Once that was complete it revealed the battery material and a small circuit board with a couple of IC’s and other components.

First I tried soldering the battery leads to the existing battery leads but I found that it wouldn’t turn on. Actually after a couple of tries after everything had been completed I found out that the minimum voltage marked was the correct minimum voltage for the unit. But it wasn’t really enough to get the unit started.

The unit definitely worked best with a full 8.0v coming from the two fully charged 18650 cells, but this was something only discovered at the end of the process after all the physical connections were made.

The 18650 battery case was designed in solidworks at work and printed on a 3D printer. I don’t have his design file just yet but will share it when I get it.

It was joined to half of the existing battery and the wires were all soldered back. Internally, inside the battery, all the + and - terminals were all marked clearly so it wasn’t so difficult.

The new battery just plugs in where the old one does and it really does seem to last a long time.

For recharging, I just pull the 18650 cells out and put them into a seperate charger. That’s fine.

Finally, just to show that it actually works:

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