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View Full Version : Power loss in sabers... how to fight against this...



erv
05-21-2007, 01:34 PM
I hope I'm not polluating too much with my electrical engineering blablabla but...
Making a lot of tests and measurements with my lab power supply and voltmeter, I noticed that you can easily loose some autonomy on the saber due to voltage losses. It's very simple : any conductive material has a resistance, more or less important. When a high current is passing thru (like when you power a luxeon LED), the resistance creates a voltage loss.
For instance, you use a 7.4V battery pack but reaching the driver or the resistor you have only 7V. The resistance of the material (the wires in general) produces heat, makes the saber less efficient, and reduces its autonomy.

Different kinds of voltage loss / drop
- MR battery holder. The spring pins of the holder are... awfull. 200 to 300 mV if the holder is not pressed enough on the matching part to power the MR board.
- MR coupling diodes. Some MR uses 2 sets of 3 AA batteries in //. Coupling those 2 uses two diodes which leads to a 700 mV loss. Added to the spring pins, you lost a total of 1V.

solutions :
* Use some contact cleaner liquid to improve conductivity.
* Suppress the diodes on the input of the board and use only 3 batteries.
* Replace the battery holder by a 4 AA nimh rechargeable battery pack

- Wires. Small gauge wires with high current = big loss.
solution :
* Use appropriate gauge when current is passing thru. Use short wires. Minimise the distance between the battery output and the board/luxeon/resistor.

Erv'

Hasid Lafre
05-21-2007, 02:04 PM
Thanks for that info, Very informative.