How do I add a Voltmeter to Unregulated Series Box Mod?

[TheVapesta]

Hello all, my first post here!!

I'm building an unregulated series box mod. I'm currently sourcing all of the parts and decided "what the heck, lets get a voltmeter to really top this build off!".

The only problem is, I have no idea how to install it. There's no diagrams online that show how to do this for a "series box mod" and most of the parallel diagrams show the voltmeter connected to a on/off switch of some sort.

NOTE: I don't want to connect a "on/off switch" to the voltmeter.

I only want the voltmeter to light up/display when I fire the vape button. This is possible because most box mods I've seen do exactly this. But how??

Can anyone help with a diagram, or give thorough instructions that a newbie can understand?

A diagram would help more than anything though, I understand things better visually.

 

[Zamazam]

Negative wire to the negative pole on the battery sled, positive wire to the positive solder contact on the switch. Easy Peasy.

 

[TheVapesta]

Negative wire to the negative pole on the battery sled, positive wire to the positive solder contact on the switch. Easy Peasy.

Do you mean the positive end of the 510 connector when you say "switch", or the actual switch/fire button?

 

[Zamazam]

The fire button. Or the positive 510 connector, either/or is fine. The meter will only light up when you complete the circuit by depressing the switch button.

 

[TheVapesta]

The fire button. Or the positive 510 connector, either/or is fine. The meter will only light up when you complete the circuit by depressing the switch button.

Okay thank you! I don't have to technically solder to the 510 right, I can solder to the positive battery contact that the 510 is connected to?

 

[Zamazam]

Oops, never mind the 510 connection. your description describes the negative poles of the battery being connected to the switch. connect one lead to the POSITIVE battery contact in the sled (last battery in series) and then connect the other lead on the meter to the switch output solder point (the one that runs from the switch to the negative connector on the 510.)

 

[TheVapesta]

Oops, never mind the 510 connection. your description describes the negative poles of the battery being connected to the switch. connect one lead to the POSITIVE battery contact in the sled (last battery in series) and then connect the other lead on the meter to the switch output solder point (the one that runs from the switch to the negative connector on the 510.)

Now I'm confused, haha.

Let's see if I got this right:

 

[TheVapesta]

If this isn't right, my guess would be the negative wire of the voltmeter connects to the top left battery pin (which would be negative right?).

 

[Zamazam]

Didn't realize you were using a Mosfet. Connect the negative on the volt meter to the D Pin on the mosfet.

 

[TheVapesta]

Thank you! And that's a 100% verified diagram? Don't mean to be doubtful, just want to take one shot at building this sucker My o.c.d. gets in the way and hates desoldering!

 

[Zamazam]

Yes, since the mosfet is acting as a high current switch, the D Pin is not active unless the switch is depressed. When it's pressed the volt meter will light up and display the volts going to your 510 connector. Make sure to solder the resistor between the G and S pins on the mosfet, otherwise once the switch is pressed, it won't turn off.

 

[TheVapesta]

Yes, since the mosfet is acting as a high current switch, the D Pin is not active unless the switch is depressed. When it's pressed the volt meter will light up and display the volts going to your 510 connector. Make sure to solder the resistor between the G and S pins on the mosfet, otherwise once the switch is pressed, it won't turn off.

So wire the resistor just as shown in the diagram?

Thank you so much for your time and help! I've searched the deep web to figure this out to no avail, but now i'm finally getting somewhere!

 

[Zamazam]

Yes, solder it to the G and S Pins on the mosfet.

 

[TheVapesta]

Yes, solder it to the G and S Pins on the mosfet.

Lastly, this is another question that riddles me and can't find a straight answer to.

When it comes to series (8.4v) and parallel (3.7), what's the lowest, or safest limit that the voltage can drop to before needing to recharge?

 

[Zamazam]

3.1 Volts or 6.2 in series.

 

[TheVapesta]

3.1 Volts or 6.2 in series.

You're the man!

Would you be able to explain the reasoning behind how or why 3.1 and 6.2 is the limit?

 

[Zamazam]

IMR Lithium batteries have a shut-off at 2.8 volts to stop the cell from being drained completely, which would render it useless. 3.1 Volts is a compromise between using the available current in the battery and not taking it too low on discharge, which drastically reduces the overall life span of the battery.

 

[TheVapesta]

IMR Lithium batteries have a shut-off at 2.8 volts to stop the cell from being drained completely, which would render it useless. 3.1 Volts is a compromise between using the available current in the battery and not taking it too low on discharge, which drastically reduces the overall life span of the battery.

That makes perfect sense!

Thank you so much for your help, i greatly appreciate it!

 

[Zamazam]

You are very welcome.

 

[Minamus]

This just answered my questions too! +1 to @Zamazam. I was confused in another thread because they were add a master switch to it and i didn't need one lol.

 

[circa.03]

speaking of master switches where in the diagram would it go? if anyone knows?

 

[circa.03]

Does this look right?

 

[circa.03]

View attachment 30153



would this work?

 

[Anchorbox]

Found this thread on google images, The Vapsta needs to delete that pic he posted, its coming up as the 3rd image for a voltmeter on a series mod, with Mike's (Relayer) pic, so it looks legit. Lol