Low voltage protection / cutoff

[Loco]

Hi, among the hundreds of ideas and problems running through my head, this is one I just cant seem to find an easy answer to.

Is there a simple and effective way to add low voltage protection / cut off to an unregulated mod to prevent battery damage etc.

I'm aware most people have the common sense to stop vaping when the power is clearly diminished however it would be preferable if I could add a fail safe to my build.

The build in question will most probably be a simple lipo build using a fet for switching. However, I seem to enjoy complicating matters

 

[RagingMammoth]

Hi, among the hundreds of ideas and problems running through my head, this is one I just cant seem to find an easy answer to.

Is there a simple and effective way to add low voltage protection / cut off to an unregulated mod to prevent battery damage etc.

I'm aware most people have the common sense to stop vaping when the power is clearly diminished however it would be preferable if I could add a fail safe to my build.

The build in question will most probably be a simple lipo build using a fet for switching. However, I seem to enjoy complicating matters

To be honest, I'd be stunned if you killed a battery by overvaping. The clouds will be so crap you will know that you have to recharge.

 

[Loco]

To be honest, I'd be stunned if you killed a battery by overvaping. The clouds will be so crap you will know that you have to recharge.

Thanks for confirming my suspicions ....i'm sure my brain just wants to make every simple job harder.

Problem is, I do make a big effort to look after my batterys, so hopefully they will return the favour .

I've never discharged past even 3.5 / 3.6v so could only imagine how bad the vape quality really would be.

 

[fasteddie600]

Thanks for confirming my suspicions ....i'm sure my brain just wants to make every simple job harder.

Problem is, I do make a big effort to look after my batterys, so hopefully they will return the favour .

I've never discharged past even 3.5 / 3.6v so could only imagine how bad the vape quality really would be.

Yep I would agree with that too, I can't really use anything below 3.2v as the performance is so far away from normal.

If you want a more positive decline then you can select a MOSFET with a Gate (Threshold Voltage Max) a bit lower than you want your lowest battery voltage to be under load, as performance drops off quickly when you start getting around the Gate (TH Max) voltage or lower-i hope that makes sense.

If you are using high discharge Lipo's I would suggest a FET with Gate TH Max 3.0v I am currently using 2 FET's in my little box with 4 25A Lipo's these- Buy MOSFET Transistors IRF3711PBF, N-channel MOSFET Transistor, 110 A 20 V, 3-Pin TO-220AB International Rectifier IRF3711PBF online from RS for next day delivery.

 

[Loco]

Yep I would agree with that too, I can't really use anything below 3.2v as the performance is so far away from normal.

If you want a more positive decline then you can select a MOSFET with a Gate (Threshold Voltage Max) a bit lower than you want your lowest battery voltage to be under load, as performance drops off quickly when you start getting around the Gate (TH Max) voltage or lower-i hope that makes sense.

If you are using high discharge Lipo's I would suggest a FET with Gate TH Max 3.0v I am currently using 2 FET's in my little box with 4 25A Lipo's these- Buy MOSFET Transistors IRF3711PBF, N-channel MOSFET Transistor, 110 A 20 V, 3-Pin TO-220AB International Rectifier IRF3711PBF online from RS for next day delivery.

Thanks a lot for this, it was the consequences of over discharging lipo's that made me give this consideration. This does make some sense to me, more so as you have pointed out its the N channel Mosfet required as this is the one where the gate has to be higher than the source, right?!

That's the build you added the parallel FET's in I was looking at!...was wondering if the mosfet's ratings were effected by the parallel format though.

Will have to bribe you to put up a circuit diagram for us 'learners', as its pretty similar to what i'm hoping to achieve!

I'm working my way through a lot of literature to become more knowledgeable on this stuff.

Knowledge = power, especially with buiding mods

 

[BaDaBooM]

Awhile back there was battery holders with cut off and you could buy panasonic cut off they used in there 18650 batts.

 

[Chegs]

Thanks a lot for this, it was the consequences of over discharging lipo's that made me give this consideration. This does make some sense to me, more so as you have pointed out its the N channel Mosfet required as this is the one where the gate has to be higher than the source, right?!

That's the build you added the parallel FET's in I was looking at!...was wondering if the mosfet's ratings were effected by the parallel format though.

Will have to bribe you to put up a circuit diagram for us 'learners', as its pretty similar to what i'm hoping to achieve!

I'm working my way through a lot of literature to become more knowledgeable on this stuff.

Knowledge = power, especially with buiding mods

The FET I'm using on 4 x 1000 MaH pack in parallel seems to kill the mod at about 3.3V,I could tell the cells were nearing recharge as the clouds were feeble & I seemed to need to keep the wicks swimming in juice to get any taste.

 

[RagingMammoth]

Hi, among the hundreds of ideas and problems running through my head, this is one I just cant seem to find an easy answer to.

Is there a simple and effective way to add low voltage protection / cut off to an unregulated mod to prevent battery damage etc.

I'm aware most people have the common sense to stop vaping when the power is clearly diminished however it would be preferable if I could add a fail safe to my build.

The build in question will most probably be a simple lipo build using a fet for switching. However, I seem to enjoy complicating matters

I recently got a fancy charger that displays the voltage of the battery when charging. I take the battery out at 3.7 volts.

 

[RicModMaker]

I'm absolutely no expert. Some might say I'm a complete baffoon but how about a zener diode?

 

[Norrin]

I'm absolutely no expert. Some might say I'm a complete baffoon but how about a zener diode?

OK your a baffoon....but seriously the mosfet has a much lower loss than a zener diode so is the best option.