diy Hasselblad 500 EL rechargeable battery

One of the biggest problems of my Hasselblad 500 EL/M is the lack of economic rechargeable batteries. On ebay you can easily find some but for too much money. There are also a lot of adapters for 9v or lithium cells, but not a real replacement for the original Hasselblad rechargeable battery.

In this page you can find how to build a good replacement for just a few bucks.

Materials needed:
-an empty 35mm Ilford film can
-five Ni-Cd 500mA AAA cells with solder tabs (please notice that i've used 650mA Ni-Mh cells because they were cheaper and easier to find)
-a good knife
-30cm of insulated solid core wire
-a lot of patience ;-)

The idea is to put AAA cells inside the film can and to provide the right connections needed by the camera.

First you should take the film can and shorten it a bit: you can easily cut it with a sharp knife. As you can see from the picture, the unmodified can is too tall and won't let the battery cover to close correctly. Cut just a few millimeters, as shown.

Then you can weld the five cells together to obtain the 6v (1.2v per cell) needed by the camera. It's very important to complete this task without overheating the cells, that otherwise can be damaged.

Next step is to provide the connections. Cut the solid core wire in two halves and connect each part to the positive and negative pole, respectively, as shown in photo. Drill two small holes, one on the top and one on the bottom of the film can, so the wire can pass through.

Insulate the cells with some electrician tape to make sure there's not any short and insert the battery pack in the film can, then close it. You can also secure the film can by gluing the two parts together, to make the battery more solid, or you can simply leave it unglued, as i did.
Now you must remove the insulation from the wire and shape it like a flat spiral, as shown below: this should provide a good connection inside the camera.

Well done! Now you can insert the battery inside the camera and connect the charger. After about 16 hours you should disconnect it to avoid damage to the cells.