I have one of those. It’s supposed to have a resistor load in it to more accurately display voltage. The voltage it shows should be different than a DMM unless yours is adding a load also. Mine does not.
I’m not sure how accurate ANY of these cheapies are. Mine seems to be a lot better than my DMM for simple NiXX testing. Since the resistor seems to be a constant load the readings on button cell are quite low, even when new, but they are quite a bit higher than used so I can use it as a ‘relative scale’.
I suspect your one reading lower is more accurate for testing purposes than the one agreeing with the DMM.
exactly, it’s supposed for a quick check. My readings are also very dependent on how much I press on the battery contacts. It’s good thing for recognizing empty Zinc cells as they tent do to show relatively high voltage (1.4-1.5V) on classic DMM even when drained.
Wow, didnt expect that much response for this lil cheapie :D!
Im using these cheapo testers/DMM's exactly as Bergtjie /Milan said - for quick check, I think I have pretty reliable batteries(few Eneloops and bunch of Turnigys and then some GP ReCyko, not sure they are legit tho) to be quite sure about their approximate usability for the task once I test them :).
Bergtjie that load-tester seems like a nice thing, for that accurate measuring of battery power state, pitty its so expensive, Id get one :D!
Flydiver - Im not sure Im reading you correctly - do you imply that cheapo battery tester that shows whole 0.1V lower readings than known good multimeter is the one being more accurate?
Chloe, here are pics of dissembled ones, "good" one thats on par with DMM is on the left where both shown:
Accurate one, top of board
Other side of the board
The one that shows >0.1V lower
Other side of the board
So, what you, electronics wizards can say, can this be re-calibrated?
The DMM is likely giving you unloaded voltage > accurate VOLTAGE, but mostly useless for actually measuring anything meaningful on a NiXX battery.
Therefore I……think……the one with the lower reading ‘may’ be the more useful if it is applying a load that is meaningful.
Having said that I completely agree with the folks that say these are simple checkers. They are mostly useful for simply checking yes-no-maybe on batteries and should not be considered accurate.
I haven’t got the electronics chops to comment on the boards. Hope someone does.
I serious doubt you can adjust them, maybe replace components IF you know what you are doing. But, they’ll still have the same limitation.