battery for volt meter

Les Jones said:

I agree with ag. If you are not going to fit a new battery then connecting a 3.9 volt zener diode in place of the battery whould prevent the voltage going too high. It looks like there is quite a lot of space inside the case so you may be able to use a different battery. I have had plug in digital timers go faulty due to a faulty NiMh cell. I have found the cheapest source of thes single cells to buy solar garden lights from one of the pound shop chains and remove the cell from them. As your battery consists of three cells you would have to get three of these.

Les.

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what are the most important things in doing that?
must be NiMh?
must be 3 in a row with sum of 3.6 Vdc or can be 1 of 3Vdc for example?
must be a rechargeble battery? (i guess this is not a relevant question cause its must be a rechareble one)

thanks

Why do you want a battery chemistry different from Ni-MH?
A lead acid battery is too big and heavy.
Old Ni-Cad batteries are not made anymore because Cadmium is very toxic.
Lithium needs a special charger circuit.

My Fluke multimeter uses a disposable 9V alkaline battery that lasts for years. The meter is smart enough to turn off when it is not being used.

AAA Ni-MH cells in my cheap Chinese solar garden lights are much better than the old Ni-Cad cells they used to have. But the cheap Ni-MH cells are mostly filled with rice or something because their capacity is about 1/3rd a modern Western battery cell.

Hi alec,
I agree that any items bought from pound shops are poor quality. I did link to one on Ebay that would probably fit in post #13. This one from RS would also probably fit.
Les.

itaishi said:

my new 220v AC meter display stopped working.
my guess is that it is a battery that got empty.

1. how can i now if it rechargeable (i guess not)
2. why a device that is connected to 220VAC cant function without been depended on the battery.
3. how can i solder this battery like it is now? (stright to the battery)


this is the device:
https://www.terapeak.com/worth/eu-p...er-lcd-monitor-advanced-ammeter/231055360826/

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Hi Itaishi,

Get a power source over about 9V (a 9V battery would do)

Connect a 4.7 Ohm resistor to the positive terminal of the power source and connect the free end of the 4.7K resistor to the battery positive terminal.

Connect the negative terminal of the power source to the negative terminal of the battery.

Monitor the voltage across the battery with your multimeter set to around the 10V DC range.

If the battery voltage rises to its specified voltage, the battery is probably OK.

If the battery voltage does not rise or it is above its specified voltage the battery is faulty and you need a new one.

spec