I have recently moved into the mech mod world. I have an AV mod with the option of using two 18650's. I'm currently just using one, on a 0.20 build. I have good batteries. Sony's. Done a bunch of research and I'm coming to understand the ins and outs. I'm just curious as to what kind of build would allow the use of both batteries and why it will allow the said build. Until I 'get it' the second battery will not be used, I have a healthy beginners fear. Any info would be greatly appreciated as I seem to find little on that particular subject on the net. Thanks!
What Sony's and where did you get them, first. They're probably legit these days, but that info can't hurt. A .2 build with stacked (essentially series) 18650's will theoretically have 8.4 volts on a full charge. Disregarding voltage drop, that build would put out 42 Amps and 352 watts. Please someone correct me if this is incorrect, but I'm almost certain it's accurate. That equals boom quite possibly. No 18650's can handle that safely unregulated especially. So if your going to stack, which I would not, I'd get a dual battery mech box. You will need to build higher with the stacked batteries. .5 for instance is pushing 16.8 amps and 141.12 watts with stacked batteries. That's presumably safe with your Sony's if they're legit, but I just wouldn't go there. Rotating batteries becomes essential, and likely metering them occasionally while vaping to make sure one isn't drawing faster is also probably prudent. And again, remember you're doubling you're voltage, but the amp drain is not shared, nor is battery capacity. So each battery is taking that stress, just both working together, thus boosting voltage.
I'm possibly wrong, but I just don't see any appeal at all in stacking batteries. Too much to go wrong, and better options. Again, I have no personal experience so take this as you will.
Bottom line, enjoy and be safe. Sounds like you have a healthy dose of respect for what you're doing, important, and .2 is already damn low. I hope others will chime in and either confirm, or tell me I'm full of shit. If so then stack those batteries and rip away.