Multimeter (volts) losing accuracy

[Coniferman]

I'm a hobbyist/diyer and have a cheap multimeter, currently one of these:

http://www.maplin.co.uk/Module.aspx?ModuleNo=44679

When new, I beleive it was accurate but now a new alkaline 1.5v battery shows 1.585 volts. I assume it should be 1.500 ?! Not great when you have a spent battery and it still shows just under 1.5.

Is this just what happens with cheap meters?

Secondly, there is a one potentiometer inside the unit. Is it likely that adjusting this will allow me to calibrate and is a good way to adjust it to get 1.5v from a new battery?

 

[tim west]

No dont adjust it! the voltage reading you are taking is off load you need to put a load across the battey then take a reading, try the same with the spent battery to see what voltage you get.

 

[Albert]

I assume that you are using your meter quiet often, if so, I am not saying that you should buy one for hundreds of pounds, but you can find a very good one for a reasonable price.

 

[Coniferman]

No dont adjust it! the voltage reading you are taking is off load you need to put a load across the battey then take a reading, try the same with the spent battery to see what voltage you get.

All the years I have been testing batteries with meters and not noticed this

 

[plugwash]

Try putting a new battery in the meter, some multimeters seem to give whacky results when thier batteries are low.

BTW it is quite normal for a new alkaline battery to have an off load voltage a bit over 1.5V. It's not normal for a dead one to be nearly 1.5V though even off load.

 

[Coniferman]

Thanks for the replies.

I think what threw me was that I was having a problem with a keyfob and the 3 volt battery showed exactly 3.0v on the meter so I could not understand why it was not working properly. Eventually I replaced the battery and the problem was solved and I realised the new battery was more than 3.0v.