Discharging Batteries

shenry

Member
Hi

I'm in the midst of designing a circuit and I have a relay setup to switch from a 9Volt battery to a 9volt wall wart when the wall wart is plugged in to save drain on the battery. Not just wire them in parallel and put load on both.

My question is if I have the positive terminal of the wall wart leading to the negative terminal of the battery will this discharge the battery whilst it's connected to the negative of the wall wart as well? Or will I have to setup so that the negative of the battery is disconnected as well when the wall wart is plugged in?

Sorry if this is in the wrong section.


Thanks in advanced.


EDIT: After conducting an experiment with a power supply, battery and meter I've found the no current flows between two different sources(Or at most very little). EG the power supply will only flow to the power supply and the battery will only flow to the battery.
 
Last edited:

tremmor

Well-Known Member
I don't think your doing it right. At least not with good design. Myself i would use a 3 switch. up would turn on one duplex, center would be off and down would turn on the bottom switch if that makes sense. Example i have a electric heater on the ceiling in the garage. up i can operate the heat during winter, center is off and down i could operate just the fan during the summer.
 
Last edited:

shenry

Member
I decided not to use a switch like that so if for some reason the wall wart fails it would switch back to the battery automatically without me physically having to operate a switch. The part of the circuit that requires the electricity only shows what the circuit is doing by powering some LEDs so if it is interrupted for a moment the functionality of the circuit isn't affected.

The circuit itself is an A/B/Y box for my Bass Guitar so if I was in the midst of playing I wouldn't have to stop and reach down for a switch to turn the lights back on. Although I could use another foot switch there's a chance I could hit that whilst playing and leaving it automatic just makes it easier in the end. Although not whilst designing it.

Thanks for your input. Seems this thread didn't go to waste.
 

Okedokey

Well-Known Member
look up wheatstone bridges and zener-tranistor sensor circuits to start with. I would suggest you putting them in parallel though with a rechargable battery, due to the ease. Add a diode to prevent discharge.
 
Last edited:
Top