I have been a strong proponent of stacked batteries for regulated mods capable of it. Like zmax and vamo. I have a sigelie zmax v3 and it is capable of handling stacked batteries. I only recommend stacking safe chemistry imr batteries! There are some major benefits below; but first safety.
Some of the strict practices and over caution was very true just less than a few years ago. But now with the wide spread use of safe chemistry imr batteries; I think some of this needs to be revisited.
Aren't laptop batteries stacked 18650's, I recall the were just solder tabbed end to end. Stacked Icr I believe.- And the answer used to be well they don't take high drain loads on the laptop... Well now we have high drain safe chemistry imr batteries to play with.
Stacking imrs is safer than using a single icr or protected battery. I also think stacked imr in a mod designed for it is also safer than a unprotected mech mod with a single imr, no short protection or cut off .
You will be fine if you follow some basic simple safety practices.
a. Yes you should be able to test them with a meter.
b. The batteries should be a new matched set of safe chemistry batteries; marked and cover with clear tape if you use a marker.
c. Rotating is good. The top battery will run down .02 v more than the bottom. This should be checked regularly (like once a week) to confirm they are discharging correctly. I don't obsess on rotating it happens enough naturally for me.
d. You should test the batteries off the charger at this time also to ensure they are both charging to the same voltage.
e. Since one is .02 lower than the other realize that one will take a little bit longer to charge than the other. Most dual bay chargers are independent bays.
g. Only use stacked imr batteries in a regulated mod capable of handling it. Not a mech!
There are some amazing benifits to using stacked batteries in a regulated mod in my experience. Especially above 2.3 amps load or ohms below 2.3.
1- more power; and being able to reach the stated 4 or 5 amp limit on the device through out the charge. Late model chips are limited with one battery.
2- longer battery life! I only change batteries once a day now. - *I run one set of efest 18350 IMR - against 3 efest 18650 imr. I get triple the life and double the power on my zmax v3
a.The buck converters are so much more efficient at stepping down voltage as opposed to the boost converter trying to boost the voltage . = longer battery run time
b. You have 2 volts of run time! Yes 2 volts run time not one. 8.4-6.4 instead of 4.2-3.2 ... = double the run time
c. The mod is not stressing itself & the battery to push 6v from 3.7v for instance. You would have 7.2v off the stacked batteries. Easy to push 6 from 7.2. = longer run time and less stress on gear and batteries.
d. The amp load appears to be split between the two batteries. It's the only way I can explain getting 3 times the life from the stacked configuration. There seems to be much less strain on the battery in the zmax v3. voltage drop isn't such that hey have to be changed before cut off.
e. With single batteries running high wattage or low ohms you can notice the voltage drop on a regulated mod as the battery runs down. @15w I would have to change around 3.7 -3.6 because it wasn't putting out near 15w anymore. With stacked batteries voltage drop isn't noticeable till near the end of the charge... = you can leave batteries in longer
g. With a single efest red 18650 2000mah battery in the zmax I get ~2.6 amp limit and cap out on that. I would use at least 3 in a day due to voltage drop pushing it at 15w. With the stacked batteries I can run 4 amps out of the zmax and I do have it maxed out at 1.3 ohms and 6v pushing over 20w. (24w fully charged)
*I wouldn't even attempt this with a single battery it would be terribly weak. But I run the one set of stacked batteries for 24 hours with this And get 60% more power/ watts out of it.
Some of the strict practices and over caution was very true just less than a few years ago. But now with the wide spread use of safe chemistry imr batteries; I think some of this needs to be revisited.
Aren't laptop batteries stacked 18650's, I recall the were just solder tabbed end to end. Stacked Icr I believe.- And the answer used to be well they don't take high drain loads on the laptop... Well now we have high drain safe chemistry imr batteries to play with.
Stacking imrs is safer than using a single icr or protected battery. I also think stacked imr in a mod designed for it is also safer than a unprotected mech mod with a single imr, no short protection or cut off .
You will be fine if you follow some basic simple safety practices.
a. Yes you should be able to test them with a meter.
b. The batteries should be a new matched set of safe chemistry batteries; marked and cover with clear tape if you use a marker.
c. Rotating is good. The top battery will run down .02 v more than the bottom. This should be checked regularly (like once a week) to confirm they are discharging correctly. I don't obsess on rotating it happens enough naturally for me.
d. You should test the batteries off the charger at this time also to ensure they are both charging to the same voltage.
e. Since one is .02 lower than the other realize that one will take a little bit longer to charge than the other. Most dual bay chargers are independent bays.
g. Only use stacked imr batteries in a regulated mod capable of handling it. Not a mech!
There are some amazing benifits to using stacked batteries in a regulated mod in my experience. Especially above 2.3 amps load or ohms below 2.3.
1- more power; and being able to reach the stated 4 or 5 amp limit on the device through out the charge. Late model chips are limited with one battery.
2- longer battery life! I only change batteries once a day now. - *I run one set of efest 18350 IMR - against 3 efest 18650 imr. I get triple the life and double the power on my zmax v3
a.The buck converters are so much more efficient at stepping down voltage as opposed to the boost converter trying to boost the voltage . = longer battery run time
b. You have 2 volts of run time! Yes 2 volts run time not one. 8.4-6.4 instead of 4.2-3.2 ... = double the run time
c. The mod is not stressing itself & the battery to push 6v from 3.7v for instance. You would have 7.2v off the stacked batteries. Easy to push 6 from 7.2. = longer run time and less stress on gear and batteries.
d. The amp load appears to be split between the two batteries. It's the only way I can explain getting 3 times the life from the stacked configuration. There seems to be much less strain on the battery in the zmax v3. voltage drop isn't such that hey have to be changed before cut off.
e. With single batteries running high wattage or low ohms you can notice the voltage drop on a regulated mod as the battery runs down. @15w I would have to change around 3.7 -3.6 because it wasn't putting out near 15w anymore. With stacked batteries voltage drop isn't noticeable till near the end of the charge... = you can leave batteries in longer
g. With a single efest red 18650 2000mah battery in the zmax I get ~2.6 amp limit and cap out on that. I would use at least 3 in a day due to voltage drop pushing it at 15w. With the stacked batteries I can run 4 amps out of the zmax and I do have it maxed out at 1.3 ohms and 6v pushing over 20w. (24w fully charged)
*I wouldn't even attempt this with a single battery it would be terribly weak. But I run the one set of stacked batteries for 24 hours with this And get 60% more power/ watts out of it.
