So im building a dc charger for electronics and there is one problem. I hooked up my circuit to 4 3v batteries (they are the flat ones) and at this point you would think the circuit would work but turns out voltage drops and it is unkown what is going on. When I cut the positive wire and measured the volts it clearly read 11-12 v so why when i connect it does it drop? Also when i connected it to a dc power supply and set it to 9v it was perfectly fine the circuit worked (the initial plan was to have 9v but since i had 4 batteries i decided to go for 12v).

 

Obviously something is wrong with your charger or setup.
But I'm greatly puzzled as to you how think we can tell what's wrong when you give us no information about the charger or how it's connected.
This is not the psychic hotline.

 

Your batteries are weak, dying or dead.
If you are attempting to use button cells they may not be big enough for the job.

 

Your batteries are weak, dying or dead.
If you are attempting to use button cells they may not be big enough for the job.

It can't be that because I measured them all individually and all read 3v perfectly fine

 

It can't be that because I measured them all individually and all read 3v perfectly fine

Batteries can only deliver a maximum amount of current. The voltage drops beyond that.
When you measure battery voltage with no load connected you will see a higher voltage. It tells you nothing about how much current the battery can deliver under load.

Are these batteries button cells?

 

Obviously something is wrong with your charger or setup.
But I'm greatly puzzled as to you how think we can tell what's wrong when you give us no information about the charger or how it's connected.
This is not the psychic hotline.

sorry about that but I couldn't find the schematics for my circuit online at the time hears something similar to it though.thanks for any help or information

 

Batteries can only deliver a maximum amount of current. The voltage drops beyond that.
When you measure battery voltage with no load connected you will see a higher voltage. It tells you nothing about how much current the battery can deliver under load.

Are these batteries button cells?

yes

 

yes

Well that's your problem.
Button cells are not big enough for the job.
Get one of these:

 

I appreciate the idea but the battery has to be small which explains why I used the bottom cells in the first place but I'll try it.

 

sorry about that but I couldn't find the schematics for my circuit online at the time hears something similar to it though.View attachment 126811thanks for any help or information

That's the circuit for a cell phone charger. Likely doesn't apply. I suggest that you hand draw the schematic directly from your circuit, take a picture and upload it here.

 

I appreciate the idea but the battery has to be small which explains why I used the bottom cells in the first place but I'll try it.

I am just trying to make a point.
If you want to make a portable 5V charger, use two 18650 lithium-ion batteries and a low drop-out regulator or a switching regulator, not a 7805 regulator.

 

That's the circuit for a cell phone charger. Likely doesn't apply. I suggest that you hand draw the schematic directly from your circuit, take a picture and upload it here.

that's the circuit I am building

 

hey so Thanks to everyone who helped me out but I think I found my problem the batteries I am using doesn't have enough current to work (each are maybe about 5 milliamps but I need about .5 to 1 amps) My professor told me I can try to use the current batteries in parallel but voltage will be an issue. Anyone have an idea or another button battery I can use that works for my circuit?

 

hey so Thanks to everyone who helped me out but I think I found my problem the batteries I am using doesn't have enough current to work (each are maybe about 5 milliamps but I need about .5 to 1 amps) My professor told me I can try to use the current batteries in parallel but voltage will be an issue. Anyone have an idea or another button battery I can use that works for my circuit?

Hey Killer, what makes you think that there exists a button battery that is fit for the job?

 

Hey Killer, what makes you think that there exists a button battery that is fit for the job?

to be honest I don't but in order for my project to be convenient I need to find a small enough battery. Also I was looking online and the br3032 seems like it would a good candidate for the job.

 

to be honest I don't but in order for my project to be convenient I need to find a small enough battery. Also I was looking online and the br3032 seems like it would a good candidate for the job.

What makes you think that BR3032 would be a good candidate for the job?

 

What makes you think that BR3032 would be a good candidate for the job?

According to many sources it has enough amps to work with my circuit and not only that but it's also a botton battery cell and comes in 3 volts

 

Looking at the Panasonic datasheet, this part is capable of 500 mAh @ 20 degrees C and a continuous load current of 0.03 mA. That is a pretty low current. Higher currents, above a couple of mA, quickly degrade voltage.

Datasheet was found on Digikey.com.

 

Looking at the Panasonic datasheet, this part is capable of 500 mAh @ 20 degrees C and a continuous load current of 0.03 mA. That is a pretty low current. Higher currents, above a couple of mA, quickly degrade voltage.

Datasheet was found on Digikey.com.

Thanks but do you think three would be sufficient for this circuit?

 

Three in parallel will give specified characteristics with continuous load 0.09 mA, still 0.03 mA in series, and you are looking for up to 1000 mA. Your tests back up this data.