Can someone explain why I need to pair batteries in my vv? Stacked 18350's. I've heard others talk about this but I've never heard why it's necessary.
Pairing Batteries on a VV
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I can only answer you from seat of the pants experience - no single AW IMR batteries I own fit.
I'm not sure if there is also an electronic reason why but an 18650 is about 1/4" short of making contact.
I also think that it would defeat the purpose since you would be limited to 4ish volts ?
Sorry, you misunderstood my question. Actually I didn't word it clearly.
People number their 18350's and use them in pairs. Why is that done?
People number their 18350's and use them in pairs. Why is that done?
Sorry, you misunderstood my question. Actually I didn't word it clearly.
People number their 18350's and use them in pairs. Why is that done?
Double post has happened to me twice now and I don't know why.....sorry
People number their 18350's and use them in pairs. Why is that done?
Double post has happened to me twice now and I don't know why.....sorry
You need sets because as you use batteries, they sort of decay. Like if you buy one new, it holds voltage great. After months of use, it begins to discharge faster.
When running batteries in series, they need to be the same voltage, unless they're protected. But we usually don't use protected. If the voltages are different you can reverse charge them, which would damage the cell. Too much damage to the cell and BOOM WHAM BLAM POP SPLOOEY.
So by pairing your batteries, they should decay at the same rate thus reducing the risk of reverse-charging. It's like they'll try to balance each other out to still get their combined voltage equal if they're at different voltages.
My electric theory never really covered this, but that's about all I could come up with. There are a lot of posts warning of dangers of stacking, but none really explaining why.
Edit: I don't know that reverse charging is even possible in a series circuit anymore. http://www.acopian.com/acopianPowerSupplies/entry.aspx?nsid=17 That describes connecting different voltage power supplies in series to come up with a desired voltage. The reverse bias diode plays no part in batteries as far as I know, because they are always "on", not turned on by an external source. I'm beginning to think that people dis-advise stacking because they weren't familiar with amp draws. You go from 4.2v to 8.4v with the same ohm coil, you're doubling your amp draw. In series your amp capacity of your batteries is still the same, say 7amps. So your 4amp 1 ohm coil was just fine with a single battery, now you've got an 8 amp draw on that same available 7 amps. And without really knowing the specifics of what people were doing when their mods blew up, it's a crapshoot.
I'll try to get a definitive answer tomorrow from some master electricians. But they may have no idea on the subject either because almost all voltage is AC now, DC is mainly electronics and some motor loads. And not many people do electronic repairs anymore.
Another though I had was that since the voltages are dropping at different paces, the amp draws on the batteries could be different. I don't know if that's possible or not because in a series circuit your amps are equal, but that's talking about dividing up loads.
This is above my pay grade. Sorry lol. Really wish I wouldn't have posted before I had the definitive answer. Hopefully I'll deliver tomorrow if anyone's still interested.
When running batteries in series, they need to be the same voltage, unless they're protected. But we usually don't use protected. If the voltages are different you can reverse charge them, which would damage the cell. Too much damage to the cell and BOOM WHAM BLAM POP SPLOOEY.
So by pairing your batteries, they should decay at the same rate thus reducing the risk of reverse-charging. It's like they'll try to balance each other out to still get their combined voltage equal if they're at different voltages.
My electric theory never really covered this, but that's about all I could come up with. There are a lot of posts warning of dangers of stacking, but none really explaining why.
Edit: I don't know that reverse charging is even possible in a series circuit anymore. http://www.acopian.com/acopianPowerSupplies/entry.aspx?nsid=17 That describes connecting different voltage power supplies in series to come up with a desired voltage. The reverse bias diode plays no part in batteries as far as I know, because they are always "on", not turned on by an external source. I'm beginning to think that people dis-advise stacking because they weren't familiar with amp draws. You go from 4.2v to 8.4v with the same ohm coil, you're doubling your amp draw. In series your amp capacity of your batteries is still the same, say 7amps. So your 4amp 1 ohm coil was just fine with a single battery, now you've got an 8 amp draw on that same available 7 amps. And without really knowing the specifics of what people were doing when their mods blew up, it's a crapshoot.
I'll try to get a definitive answer tomorrow from some master electricians. But they may have no idea on the subject either because almost all voltage is AC now, DC is mainly electronics and some motor loads. And not many people do electronic repairs anymore.
Another though I had was that since the voltages are dropping at different paces, the amp draws on the batteries could be different. I don't know if that's possible or not because in a series circuit your amps are equal, but that's talking about dividing up loads.
This is above my pay grade. Sorry lol. Really wish I wouldn't have posted before I had the definitive answer. Hopefully I'll deliver tomorrow if anyone's still interested.
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Oh, yeah man, my bad. I dunno. I heard it too and run then in pairs also. But since one pair is always in the mod and another on or by the charger, I don't even worry about the numbers any more. Good thing cause the sharpie job faded a long time ago
It may stem back to the days when chargers didn't charge consistently? Mine always come off the i4 charger at 4.20. Sometimes there's a slight variance in voltage when I pull em out of the mod but I don't sweat it. They go in at the same voltage.
I don't worry about what one goes on top either.
About a year on my mod and batteries and it fires every time.
It may stem back to the days when chargers didn't charge consistently? Mine always come off the i4 charger at 4.20. Sometimes there's a slight variance in voltage when I pull em out of the mod but I don't sweat it. They go in at the same voltage.
I don't worry about what one goes on top either.
About a year on my mod and batteries and it fires every time.
I see, so you don't want to use old with new. Up until yesterday I had just one vv Reo, and only had 4 18350 batteries (2 charging and 2 in the mod) so it hasn't been an issue. I'm about to buy more so now I need to number old and new. That makes sense. Thank you.
I don't know what mod you're using, but in most you don't need to stack batteries.
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My top batteries are usually at a lower voltage when I change out the batteries. I believe the reason people rotate is to keep from having 1 battery always taking the lions share of the load so they last longer.
I have six sets of batteries and I forget what I did yesterday so now I just stick them in and go. I vape a REO because it is amazingly good and simple. Why over complicate things trying to figure out what battery was on top the last time that set was used.
I have six sets of batteries and I forget what I did yesterday so now I just stick them in and go. I vape a REO because it is amazingly good and simple. Why over complicate things trying to figure out what battery was on top the last time that set was used.
The VV REOs take a pair of 18350s.
For the OP: Keeping pairs ensures identicle numbers of charge and discharge cycles, as noted by others in the thread.... - Some people go so far as to make sure they swap bottom and top battery every time they go back in the mod. The reason for that is that there is more than anecdotal evidence to show one battery position might sometimes drain faster than the other. I have never experienced that with my VVW. However, I have experienced it with batts stacked in mechanical mods and I have seen it in other applications requiring batts in series circuit. I don't swap bottom and top battery, but I won't say it's a bad idea.
A Reo vv. Sorry we are in the Reo mod thread and only one Reo uses stacked batteries.
When I first got my VV Woodvil I started using stacked sets.
I didn't number them or watch top and bottom use. They were in pairs though.
I lost two batteries in a couple of months. They would not charge or even read volts.
That is when I bought new and lettered my sets. Now I could keep record of top and bottom on each cycle.
I have checked and the top battery will be lower than the bottom coming off the VV REO.
Rotating them has allowed me to use my batteries without problems for over a year.
Yes, it is a pain. I wish it was different. But it is not. And I do not wish to sell my VV REO's!
I have been contacted from people that were losing batteries just like me. They started watching pairs and position and have had good results also.
I didn't number them or watch top and bottom use. They were in pairs though.
I lost two batteries in a couple of months. They would not charge or even read volts.
That is when I bought new and lettered my sets. Now I could keep record of top and bottom on each cycle.
I have checked and the top battery will be lower than the bottom coming off the VV REO.
Rotating them has allowed me to use my batteries without problems for over a year.
Yes, it is a pain. I wish it was different. But it is not. And I do not wish to sell my VV REO's!
I have been contacted from people that were losing batteries just like me. They started watching pairs and position and have had good results also.
Batteries are similar to tires. You want them to wear out evenly. Keeping them matched and rotating them (top vs. bottom) after each subsequent recharge has proven to help them last considerably longer.
Thanks everybody I just got my VVG and I thought it was place the higher voltage coming off the charger on top. Now I know to change them each time. My VVG came with 6 batteries one was DOA the others are good but I don't know how they were used. I have 2 ultrafires and 2 A Dubs when they die off, they will be replaced with 4 A Dubs marked 1ab and 2 ab.
I have never worried about keeping my batteries in pairs. I just throw them on the charger and let randomization take care of it.
The main thing is the battery on top will drain faster/more and is under more of a load then the bottom. So you don't want to use two bottoms and two tops on a regular basis. You want to swap whatever battery is on top with the one on the botttom each charge cycle.
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The main thing is the battery on top will drain faster/more and is under more of a load then the bottom. So you don't want to use two bottoms and two tops on a regular basis. You want to swap whatever battery is on top with the one on the botttom each charge cycle.
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Ok I think I've got it. There isn't any reverse charging, just a difference in potentials. One battery will be at 4.2 v hot and 0 ground, other will be at 4.2v hot and the negative is also at 4.2 volts. The current carrying capacity is limited to the lower of the two, which I hope you're using the same batteries but if you stack two different batteries you base your capacity off of the lower.
It would make sense that the top has the most wear because it is not at a potential to ground it is at a potential of the positive of the other battery's positive.
Also if the stacked batteries are shorted you can have much more fault current.
I think it comes down to if the battery isn't holding a charge too well it needs to be tossed due to the cell damage. But theoretically you could pair a 3.2v and 4.0v to get 7.2v and it should function fine. If I didn't have new batteries and nice mods I would be glad to test my hypothesis here.
So in my opinion the pairing is to get the most life-cycles out of both batteries. That way you don't have to watch them as closely either if you are rotating them. I'm not going to label a and b, but when I get a noticeable difference in drain speeds I'll probably just toss that one and enter the better one into the rotation.
I'll probably be rather conservative and when one discharges to lower than .3 v difference I'll toss them. The batteries should be able to safely be discharged down to 2.5 not 3.5, but 2.5 is pushing it.
If you're going to check voltages every time you swap I don't think it matters if they're paired because of what I've said above.
But good luck and always be safe with them because of the increased fault current available with stacked batteries. Paired or not id check voltages at least once a week off the charger and after you swap them out.
It would make sense that the top has the most wear because it is not at a potential to ground it is at a potential of the positive of the other battery's positive.
Also if the stacked batteries are shorted you can have much more fault current.
I think it comes down to if the battery isn't holding a charge too well it needs to be tossed due to the cell damage. But theoretically you could pair a 3.2v and 4.0v to get 7.2v and it should function fine. If I didn't have new batteries and nice mods I would be glad to test my hypothesis here.
So in my opinion the pairing is to get the most life-cycles out of both batteries. That way you don't have to watch them as closely either if you are rotating them. I'm not going to label a and b, but when I get a noticeable difference in drain speeds I'll probably just toss that one and enter the better one into the rotation.
I'll probably be rather conservative and when one discharges to lower than .3 v difference I'll toss them. The batteries should be able to safely be discharged down to 2.5 not 3.5, but 2.5 is pushing it.
If you're going to check voltages every time you swap I don't think it matters if they're paired because of what I've said above.
But good luck and always be safe with them because of the increased fault current available with stacked batteries. Paired or not id check voltages at least once a week off the charger and after you swap them out.
The problem with your example above is that one battery is being asked to provide more current than the other and it will drain faster.
The idea of charging them together is so that they are identical in charge when you use them and both are doing equal work. You can see this very easily if you consider a 1Ω coil on your device. I=V/R, so battery at 3.2v is seeing a demand of 3.2A and battery at 4v.......
That's a big difference in what you are asking from them and why it is not recommended generally to stack them. That gets a little blurry when you factor in the regulation from a chip, but the general safe idea is to pair them so they are used equally.
T
The idea of charging them together is so that they are identical in charge when you use them and both are doing equal work. You can see this very easily if you consider a 1Ω coil on your device. I=V/R, so battery at 3.2v is seeing a demand of 3.2A and battery at 4v.......
That's a big difference in what you are asking from them and why it is not recommended generally to stack them. That gets a little blurry when you factor in the regulation from a chip, but the general safe idea is to pair them so they are used equally.
T
From using the Duke for a while now I know that for best results with stacking batteries you are supposed to use married pairs, rotate them half way through discharge, and then the next time you use them, if you started with battery 1 in the first position and 2 in the second, this time you reverse so battery 2 in the first postion initially.
I had that exact thought as well yesterday. Wouldn't current still be proportional to voltage. Except they're still in series. I even thought of trying to rig up something with wires between them and clamp on ammeters between the two batteries and after the second battery. I couldn't knock that idea.
Running power supplies in series is just goofy to begin with. And it really is tough when there's a vv chip involved as well. Your load is going to be constant in the regulated circuit. What I've read is when stacking both batteries have exploded, I read a couple instances of that. I guess I'll have to figure out if series power supplies share amp loads or are different. I guess today I was leaning more towards sharing the amp load for some reason. I know that in parallel they do not necessarily share amp load equally.
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