reducing input voltage

[Neilo]

I have a minelab 3500 which has a built in regulator which runs the machine on 6volts. I want to mount a 7.2volt lithium battery but have been told that this voltage is too high for the regulator to handle.The maximium safe level would be 6.8volts. What can I do to reduce the voltage down to this level. I am hoping for a simple in line solution that I can attach to the battery lead.thanks Neilo

 

[ian@vaccent]

TRY CHARGING WITH A 6 VOLT OUTPUT,THEN YOU CANNOT OVERCHARGE

 

[GaryL]

Small resistor to drop the voltage, would have to experiment a little for the proper size with a volt meter. Some one on here can probably tell ya what size resistor you would need.

HH

GaryL ....

 

[jimmyjiver]

Hi, A Simple Way Is To Get A LM7806 3-Terminal 1A Positive Voltage Regulator And Run Your 7.2 Volt Lithium Battery In To It And Get 6 Volts Out...To Be On The Safe Side Don't Forget To Put A Small Heat Sink On The Back Of The Regulator.........Thanks

 

[JB1]

The one with the voltagecontroller won't work very well, the voltage to begin with needs to be at least 4 - 5 volts higher.
But there is a much simpler solution, you just have to put two silicium diodes (ex. 1N4001 ) in series with the + wire, this way you will get a voltage drop of aprox. 1.2 volts over the diodes.
You can't do anything wrong, just solder the diodes one after the other in the same direction and place them between the battery + and the + supply wire.When you place them in the wrong direction between the batt. and the wire nothing will happen.And if so you just have to change the direction of the diodes .So you can't damage anything.

Good luck,
JB1