Just finished my first serial box - Battery/Voltage Help

[Psychedelic Biscuit]

Well I was really bored today and decided it was time to build a serial 18650 box.
I took a hammod B and put in a mosfet, some ugly wires, an voltmeter, a ridiculous big switch, a FDV 510 with 30mm cap and a small switch to put that thing to sleep.
So far its working great, big clouds and good taste from the most boring build ever: 1.13 ohms dual macros with 16!? wraps of something either nichrom or kanthal I dont know because the spool was not labeled :S

I understand which batteries I have to use with which resistances and that a serial box is kind of dangerous if you mess it up, but I was wondering till which Voltage I can vape on it?
The voltage under load is 7.5 right now, which means each battery is at around 3.75 V.
Is it safe to say I change batteries at 7.2V because each is at 3.6 then? 3.6 seems to be a reasonable cutoff to me.
And how about pairing the batteries? Do I have to swap the first battery with the second every time I recharged them and put them back in?
My phone is dead, thats why the shitty webcam pictures... thank you!

 

[BoomStick]

3.2v each when unloaded is about as low as you want to run them. Using a matched pair of batteries and swapping their position after each charge is recommended.

 

[Psychedelic Biscuit]

so 6,4V if I fire it with no atty attached?

 

[BoomStick]

Yes. Running them any lower stresses the batteries too much.

 

[Psychedelic Biscuit]

Ok thank you, I will keep checking them without atty and try to get a feeling for it.
It is fun to vape this thing, running a 0,5 ohm dual twisted 0,4mm kanthal build right now but at 100% VG and 0mg.
I dont think this is more than a fun thing to do once in a while, definitely not my allday setup.
My Kayfun4 at 20 Watt is much nicer xD

Im wondering how you can build a parallel/serial box, I saw someone doing it but didnt find any wiring diagrams for it.
Talking about a box with a switch to switch between serial and parallel mode.

 

[Fishman1704]

Read up on employing a DPDT switch. There's plenty of schematics online to walk you through it. Just please, please pay attention to your atty's resistance whenever you hit the switch so you don't end up on the news. Just sayin'. It could be easier than you think to forget to remove that .12 build you have going on when you switch over to series.

Good luck.

 

[Psychedelic Biscuit]

Read up on employing a DPDT switch. There's plenty of schematics online to walk you through it. Just please, please pay attention to your atty's resistance whenever you hit the switch so you don't end up on the news. Just sayin'. It could be easier than you think to forget to remove that .12 build you have going on when you switch over to series.

Good luck.

Thanks and yes its a bit scary, especialy with all these tc builds around, I dont wanna know what happens if I accidently screw on a 0.05 build. But I guess the coils will give up before the batteries vent.

 

[Fishman1704]

One can only hope. I think it'll be fun to build one of those switchables. Post some pics when you're done.

 

[PaulS]

I dont wanna know what happens if I accidently screw on a 0.05 build. But I guess the coils will give up before the batteries vent.

Hope is eternal, lol.