Electrical people: What's a normal battery voltage?

Toggle sidebar Toggle sidebar
R

raptor13

Golden Member
Oct 9, 1999
1,719
0
76
I just bought me a new multimeter (on an impulse) and was just testing it out with some things around the house. I grabbed a couple batteries off the shelf of varying sizes, such as AA and AAA, and was expecting to easily get a reading of 1.5v since they were all new.

Much to my surprise, I am getting readings of around 2.2v for all the batteries! So, my question is: is that normal? Does the 1.5v advertised for all alkaline batteries represent its average voltage or something? Or am I just doing something wrong with the multimeter? Further, I get readings of a little over 2v for all the charged NiMH batteries I've got.


I'm confused. Please help.
 
L

LAUST

Diamond Member
Sep 13, 2000
8,957
1
81
when you have a battery in an electronic item and it is turned on the batteries powering that item are now "Under Load" and at that time you will monitor a 1.5V~ output from those batteries
 
thebestMAX

thebestMAX

Diamond Member
Sep 14, 2000
7,505
134
106

How are you going to learn if you dont ask questions?? :D

Punch line from an old joke.
 
Scarpozzi

Scarpozzi

Lifer
Jun 13, 2000
26,391
1,780
126
Saying that there's no load would be the only answer to your question that makes sense, but every battery I've ever tested that's new out of the box was at or around the advertised voltage of 1.5v or 1.25v for some NiCd Rechargables. Of course, I haven't tested one for some time and they're really getting battery technologies down these days on the dry cells.
 
O

Ornery

Lifer
Oct 9, 1999
20,022
17
81
Try this raptor. Switch it to AC and plug it into your "120V" outlet. What does it read with "no load"? Now check it with a load on, like the toaster. What does it read? Hmmmm...

Try your 12V car battery. What does it read with "no load"? Now turn the headlights on. What does it read? There are many types with different characteristics.
 
D

dman

Diamond Member
Nov 2, 1999
9,110
0
76
Originally posted by: Scarpozzi
Saying that there's no load would be the only answer to your question that makes sense, but every battery I've ever tested that's new out of the box was at or around the advertised voltage of 1.5v or 1.25v for some NiCd Rechargables. Of course, I haven't tested one for some time and they're really getting battery technologies down these days on the dry cells.
Click to expand...

For AA 1.5v rated batteries:
Most alkalines read 1.6-1.7v when new when I'd test them. 2.2v seems too high.
NiCd and NiMH are 1.2v usually.

For A/C Voltages, meter needs to be 'true RMS' to display an accurate voltage. Not sure the details but has to do with phase of the voltage IIRC and time. You can figure it out yourself if you know the calcs. Also, the displayed value of a non true RMS is still usable for certain things, but, not easy to use for others. To see that you have A/C power, for example, it's good.



 
K

Kk4JC

Senior member
Mar 5, 2000
435
0
0
Originally posted by: dman6666
Originally posted by: Scarpozzi
Saying that there's no load would be the only answer to your question that makes sense, but every battery I've ever tested that's new out of the box was at or around the advertised voltage of 1.5v or 1.25v for some NiCd Rechargables. Of course, I haven't tested one for some time and they're really getting battery technologies down these days on the dry cells.
Click to expand...

For AA 1.5v rated batteries:
Most alkalines read 1.6-1.7v when new when I'd test them. 2.2v seems too high.
NiCd and NiMH are 1.2v usually.
Click to expand...

I get the same, but like it was stated above that is under no load.
(Isn't it nice to know all of us computer techs sit around testing batteries?)
rolleye.gif


Kk
 
A

Alphazero

Golden Member
May 9, 2002
1,057
0
0
Your voltmeter might be a little off. I've never seen a regular battery with a voltage over 1.8V.
 
R

raptor13

Golden Member
Oct 9, 1999
1,719
0
76
Most of you seem to agree though there are some conflicting responses.


Would any of you mind measuring the voltage of a new battery with no load? I set the meter to 20DCV, touched the black lead to the negative terminal, the red to the positive, and I keep getting 2.18v, very consistently. That is with a normal AA, mind you.

I'll try the other suggestions with AC current and such later. I'll let you know how it turns out.

Thanks!
 
M

Mark R

Diamond Member
Oct 9, 1999
8,513
16
81
Much to my surprise, I am getting readings of around 2.2v for all the batteries!
Click to expand...

I'd be surprised enough to take the multimeter back. For a cheap multimeter, I wouldn't expect better than +/- 20%, but this is taking the mick a bit. Having said this though, you shouldn't trust any meter unless it has been officially calibrated and certified.

Try measuring something else - connect it to the 5V supply in your PC. Find a spare Hard drive connector. Set the meter to 20 VDC, and connect the black probe to one of the black wires, and the red probe to the red wire. Easiest way is just to shove the probes down the holes in the connectors. This supply is extremely close to 5V (I've tested numerous PCs, even ones where 'health monitoring' programs, and BIOS monitoring report serious voltage anomalies - the true voltage is always very close to 5V - usally 4.85 - 5.15).

You can repeat this for the 12 V supply (use yellow, instead of red) - but this supply is nowhere near as well regulated.
 
R

raptor13

Golden Member
Oct 9, 1999
1,719
0
76
Try measuring something else - connect it to the 5V supply in your PC. Find a spare Hard drive connector. Set the meter to 20 VDC, and connect the black probe to one of the black wires, and the red probe to the red wire. Easiest way is just to shove the probes down the holes in the connectors. This supply is extremely close to 5V (I've tested numerous PCs, even ones where 'health monitoring' programs, and BIOS monitoring report serious voltage anomalies - the true voltage is always very close to 5V - usally 4.85 - 5.15).
Click to expand...



Good idea! I'll try that after lunch. Right now, it's eatin' time!
 
F

fyleow

Platinum Member
Jan 18, 2002
2,915
0
0
When I measure batteries with my Fluke DMM it seems to give the correct voltages even without load....then again it is a Fluke. I'd buy a better multimeter
 
N

nd

Golden Member
Oct 9, 1999
1,690
0
0
I don't think any of you are correctly answering his question.

Under typical loads you're probably not going to see a drop from 2.2V to 1.5V. What I've heard is that companies are boosting the voltage (to 1.7V+) of their higher end batteries in the interest of extending the lifetime.
 
XZeroII

XZeroII

Lifer
Jun 30, 2001
12,572
0
0
Make sure you Zero out your multimeter first. If it's digital, hold the two electrodes together until you get a reading of 0. I've never seen a battery that was that overcharged.
 
M

Mark R

Diamond Member
Oct 9, 1999
8,513
16
81
A typical alkaline battery, when fresh, has a voltage of very close to 1.5 V (off load). As the battery discharges, the voltage gradually declines.

A fully-charged NiMH battery straight out of a charger can have a voltage as high as 1.5 V, but this will quickly decline to about 1.2 - 1.3 V. It will stay at this level, until virtually completely discharged.
 
You must log in or register to reply here.

TRENDING THREADS

COMPANY
RESOURCES
FOLLOW
Top Bottom