Digital LCD Voltmeter hookup

[Bdbodger]

I bought one of these Digital Voltmeters . It has 4 terminals . I determined that hooking up from the outside in terminal 1 to negative and 2 to positive on a battery gave me a backlight . I don't know how to hookup the other two terminals 3 and 4 . Can anyone help ? I can't seem to get any kind of display . I know it says 12 supply power but I only use what I had at hand and that was a aw imr 18650 battery . I though I would get something even if it was a weak display .

 

[NicksVap3]

3 1/2 5V Digital Blue LCD DC 200V Volt Panel Meter NEW | eBay
scroll down, and it has a diagram to wire it
one set will be to power the unit, the other set is what you want to measure.

this meter only requires 5v, but should be close

 

[cappadoc]

It says it needs 8-12V input. 2 fully charged Li ion batteries = 8.4V. A single 18650 won't give it enough power.

 

[Bdbodger]

Well still no joy . I use a 9 volt battery to power the unit and I used the 18650 batter to light up an led light . I hooked it up as in the diagram and no readout although the back light was brighter .

 

[Rocketman]

Two different meters are being linked. One requires 5V DC to power the unit and the back light. The other requires 8 - 12 v to power the unit and the backlight. The unit needs this voltage not only to light up but to run the meter. Just like putting a 9 volt battery in a Harbor Freight multimeter

It should then display volts connected to the remaining two terminals, if it ain't bad.

 

[NicksVap3]

the unit i linked only for the diagram, the one he linked didnt have one. both the same idea, just different voltage to power the unit itself

 

[VpnDrgn]

The way I read it, it says 1 & 2 should go to a 5v power supply and 3 & 4 go to output that you want to gauge.
Would supplying too much power to 1 & 2 make it not work correctly? 9v may have fried it.

I would recommend one of these, no need for operating power and easy to wire.
Or, you can find one on ebay and save a few dollars.

edit : didn't see the 8-12v on the first link, curious how it is listed as "DC/AC8-12V"

 

[NicksVap3]

his meter uses 8-12v to supply main power. 9v is right in there. im guessing maybe the layout for wiring may be different than the diagram i posted

 

[NicksVap3]

THIS is what im thinking about using in a later project, no external power needed

 

[Bdbodger]

THIS is what im thinking about using in a later project, no external power needed

I have about 4 of the madvapes LED voltmeters but I just wanted to see if this LCD was usable . Two of the madvapes one I have are the preassembled ones with the atomerzer and battery connections . Anyway might try again tommorrow with a fresh 9 volt the one I used was almost done maybe . I will have to go out and get one . I might also have to find a better load to use the one led light should have worked but maybe wasn't enough .

 

[TomCatt]

THIS is what im thinking about using in a later project, no external power needed

Good find Nick!