Battery's and multimeter

[jjrbus]

 After much frustration and some help from the board, I have found my multimeter intermitenly will read 1 volt lower than actual voltage and only on the 200 volt DC scale. I am learning far more about electronics than I ever wanted to know. 
                                        Many Thanks  Jim

[Ncbob]

Jim, a 1 volts difference on the 200 volt scale might just be an instrument error. If you could scale it down, for example read that same or a lesser/greater value on the 100 volt scale and finally down to the 20 volt scale (assuming that you're trying to read 12VDC, and that the meter is on the DC scale) and the voltage doesn't change then you're reading the actual voltage.

Now, I really hate to pick on your tester but if it's analog (a needle) they went out with high button shoes!

Accuracy, if that's what you're looking for (as against comparative readings) is with an upper echelon digital meter. I complained years ago at the price of my Fluke 87 but have never regretted the cost of it since.I used to send it in for calibration every 6 months when I was doing standby generators, paralleling systems and multiple transfer switches in Hospitals because my readings HAD to be accurate in order for the Hospital to get their Certification.

You might be able to find a quality digital meter on the Eplace...I'd be sure the seller has 100% feedback though.

Best of luck,

NCbob

[JohnEd]

HF has the digital meter for cheap.  It appears to be a copy of a Fluke.  Regardless, it is accurate.  1 volt on the 200 volt scale is .5% accuracy.  Wouldn't that be an accuracy of .06 volts at 12 volts?  Any way, the error should repeat so you can "correct" your readings on a given scale.  My concern with a cheap meter is how temp affects the reading.  Chill it in the freezer for 20 min and see if you get exactly the same reading.

2 cents,

John

[Len Silva]

Meters (and most all electrical gauges) are designed to be most accurate in the middle of the scale.  In addition, if you have an analog meter and it doesn't have a mirror behind the needle, it's pretty hard to even read 1 volt on the 200 volt scale (parallax error).

[kyle4501]

. . . . it's analog (a needle) they went out with high button shoes!


NCbob

What are 'high button shoes'?



What is analog?





          

[junkman42]

Normally accuracy is percentage of full scale, IE .5% equals 1 volt,generally plus or minus!  John

[HB of CJ]

I thought my old trusty crusty Fluke had fluked until I remembered the battery had been removed.  Put a new 'un in and...ta da!

Duh..would .48465  be 0.0000 or 1.0000?  Sig figs.  So long ago and far away.  I do try NOT to learn all of this electronic stuff. 

[jjrbus]

Guess I should have explained a bit better.   This was a top of the line Craftsman digital mutimeter when purchased several years ago.  I am testing a 24V system with a choice of 20V or 200V DC scale. The meter will read 25.X volts + - a couple tenths everyday for 10 days with a slight change in  X. then for no apparent reason it will read 24.X volts and the next day will read 25.X volts. It will read 25.X volts for several days and then 24.X volts then the next day will read 25.X volts. This is with several atempts to  make sure the reading does not change. All other readings with the old meter are accurate!!
The new Sears Digital Multimeter which I have used as a comparision, gives the same reading everyday within a few 10ths on the 200V scale.
If I am reading this right and a 1 volt error is acceptable on a 200 volt scale then the digital multimeter I have is  unacceptable for testing a 24V system or do multimeters come with different scales?
In my next life I may take a couple electronics courses.   Jim

[Sojourner]

. . . . it's analog (a needle) they went out with high button shoes!


NCbob

What are 'high button shoes'?



What is analog?

What are 'high button shoes'? Just like it said...high button shoes  http://www.reproduction-vintage-shoes.com/highbuttonshoes.html
In otherwords, What NCBob saying is that analog meter is the old state of art or the high button shoes days. Am I right NCBob?


What is analog? A meter using needle indicator that scan over scale is a analog meter. http://en.wikipedia.org/wiki/Analog_signal

FWIW

Sojourn for Christ, Gerald

[Sojourner]

Guess I should have explained a bit better.   This was a top of the line Craftsman digital mutimeter when purchased several years ago.  I am testing a 24V system with a choice of 20V or 200V DC scale. The meter will read 25.X volts + - a couple tenths everyday for 10 days with a slight change in  X. then for no apparent reason it will read 24.X volts and the next day will read 25.X volts. It will read 25.X volts for several days and then 24.X volts then the next day will read 25.X volts. This is with several atempts to  make sure the reading does not change. All other readings with the old meter are accurate!!
The new Sears Digital Multimeter which I have used as a comparision, gives the same reading everyday within a few 10ths on the 200V scale.
If I am reading this right and a 1 volt error is acceptable on a 200 volt scale then the digital multimeter I have is  unacceptable for testing a 24V system or do multimeters come with different scales?
In my next life I may take a couple electronics courses.   Jim

A good bus nut digital meter that is 200v dc range with point at tenth scale (200.0). In otherwords, without the tenth scale (digital) is either less than half or over half of 1 volt. Which is not a good meter for the bus nut electrical tool box.

Example of a Sears digital meter on page 7   http://download.sears.com/own/03482141e.pdf
At 200v range +/- .1v

FWIW

Sojourn for Christ, Gerald

[Busted Knuckle]

What are 'high button shoes'? Just like it said...high button shoes  http://www.reproduction-vintage-shoes.com/highbuttonshoes.html
In otherwords, What NCBob saying is that analog meter is the old state of art or the high button shoes days. Am I right NCBob?


What is analog? A meter using needle indicator that scan over scale is a analog meter. http://en.wikipedia.org/wiki/Analog_signal

FWIW

Sojourn for Christ, Gerald

Hey those look like the new pair of shoes Kyle just got! LOL!   BK 

[Sojourner]

LOL....LOL

[jjrbus]

Hey Jerry, that is the meter I just bought!!!!

I still dont get it, is an intermitent reading off by 1 volt acceptable on the 200V DC scale? If it is acceptable by meter standards, it is not acceptable to me.

I think NC Bob may give Kyle an example of a high button shoe to look at. After removal by DR's of course!!

                                             Jim

[uncle ned]

bob 

I don't know why you talk about my meter.   has done the job for over 50 years.
still doing good   my shoes are also good

ned

[JohnEd]

OWWWW!

Try this, put that digital meter on "AC" 10v and measure the "AC" that is "riding" your 12 or 24 volts "DC".  There will be an AC component unless "everything" else is disconnected or shut down.  No line AC connected to shore power either.  The reading you take on a battery should not vary any amt from one reading to another unless some time has passed or there has been some charging and it should always diminish.  My experience!

I once resolved a "phenomenon" concerning an add on electronic ignition.  Seems it worked if the B+ was connected to the bat terminal but it was erratic when connected to a B+ source at the other end of a 4 foot wire that was part of the original wire circuit.  Different ends of the same wire determined wether it worked?  Hmmmm.  I switched to the AC scale and found that one end of the wire had zero AC volts but the other had 6 or so AC volts of "noise" riding the DC.  Adding a capacitor would have resolved the issue but the ignition module was defective and replacing it made the install power source more tolerant.  The internal cap on the module was probably defective or not connected.  All I got for that was an "you SOB" with a grin from the owner of the shop.  And that was enuf.

John