Batteries In A Series

[nuttaphong191]

Im Tryin Put Probly Like 20 Small 3 Volt Batterys In Series To Power Somthing That Takes 3.7 Volts.. Do I Just Do The Math And See What Size Resistor I Need.. I Take Every 3 Volts For Each Battery And Times It By The 20 Ill Have In A Series . 60 Volts Right.. Am I Way Off? Can Any One Steer Me In The Right Direction. And How To Resisist It And All That..  ;D

[Omni]

I am not sure as to the overall current demand of the project but you can design a small regulator
circuit using a few components to perform a precise voltage.
The 1N4730 is a 3.9V Zener, i provided a link below to calculate the required current limiter resistor.

Sadly, when powering a project using batteries it is usually always advisable to design the circuit using
a source voltage that does not require any type of loading since battery drain is produced via the regulator circuit.
The latter is somewhat counter-productive.

Perhaps, you can provide more detail concerning your circuit?

http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/zenereg.html

[ante]

Why burn away lots of energy from the poor batterys with a zener and a resistor, a terrible waste! Why not use a regulator and perhaps parallel some of the batterys for better efficiency?  ???

[LostViking]

Parallel the batteries to increase capacity (life), then use a boost regulator to get the 3V up to 3.7V. Since most boost regulator circuits have a very wide input range this will keep working as the batteries drain.

Look up BOOST regulators (these are DC to DC regulators) and you'll see plenty of designs on the web.

[ante]

That

[LostViking]

Take a look at the Maxim MAX878. It can do what you need. The circuit in the datasheet may be all you need. This part will regulate the voltage down, but if the input drops below the needed voltage it will switch over to BOOST mode automatically. Works down to 1V input too so you can really get all the batteries have.