Charge 8 or 10 batteries NiMh :

When I wished to use a 10 NiMH type R3 batteries I realized that there was no available charger device available for such 12V pack. This is how I managed it:

I got a charger with two 9V output for batteries 6F22. With a 4 pins plug, I made the hereunder cable and connections.


  Batteries and rechargeable ones
Verify the needs:
The receiver of radio remote control needs 6V. I use a CR-P2 lithium battery which weights only 35g.
The tension of cameras and modules range 5V, 6V, 9V, or 12V. It is advisable to be the most homogeneous as possible. It is possible to feed a camera or an emitter in 9V with a 6F22 battery, light, but the lifetime is short. The rechargeable batteries 6F22 are usually delivering only 7.5V and are not convenient.
The solution that I recommend for the camera and the emitter are rechargeable Cd-Ni batteries, type R3, also called AAA size, and soldered one to the oher as a pack: for example, 9 batteries x 1.2V will deliver between 11V and 9V during more than one hour for 110g weight, whilst 9 batteries type R6 (AA size) would weight 240g. The NiMH rechargeable batteries are more expensive than the Cd-Ni ones, their capacity is more important, but their auto-discharge is high. In both cases a special charging device is necessary.More and more devices apply to both.
On the contrary, for the video receiver and the viewer on the floor, do not hesitate to have a fair battery capacity: batteries R14 or R20, or batteries for computers, usually more expensive, but more performing..

 Verify the Ni-Cd batteries:

When the batteries are empty, wait 24 hours, then with a multimeter controler, check the tension of each element. It is frequent to find some out of order. Remove and replace them. They generally have internal short-circuit. All elements of the same pack should have the same internal resistance.



Battery Li-Ion
These new batteries are really performing, and also more light. There is for portable telephones 3.8V batteries with 900mAH capacity, which dimensions are 67x33x6mm. Set together as a pack of 3 to get 11,4V, it only weights 90g. It must be compared to a 10 pack of 10 NiMH batteries delivering 12V with 800mAH capacity, and weighting 160g.
A specific charger is necessary for LI-Ion batteries. They have almost no auto-discharge.