box mech mod amp rate
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Not to sure but be aware of this: Cherry Bomber box mod - may have auto-on issue | E-Cigarette Forum
Hey buddy, not sure if you know but when batteries are in series their output is added, be careful, but when they are in parallel you essentially just have doubled the battery capacity with the same output. That's my understanding, please ream me if I have this backwards. Crosses fingers.
With a matched pair of batteries in parallel, in theory you can draw twice the continuous discharge rate of a single battery. In practice, it is very unlikely that each battery would supply exactly half the power draw, so you should derate it. I can't give you a "safe" derating percentage -- all depends on how well the batteries match and how well you take care of them.
Those Samsung 25R's are 20A batteries. The "25" refers to the 2500mAh capacity rating.
Using two of them in parallel will give you a higher discharge rate than using one. I would start with 30A total for now until you better understand battery limits and safety. The same goes for using a mechanical mod!
Yup, the current is split between the two. It is 50/50 if the battery voltages are the same. If there is any difference in battery voltage the higher voltage batt will take more of the load until the voltages match.
However be very careful not to inset one battery upside down, that will I believe instantly short both batteries, even without hitting the switch. That could get nasty fast.
ETA: After reading Mad Scientist's post #11 below I think this may be a safety issue and added the strike-through above. Please see this post for more info.
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This issue only affects the copper and aluminum mods being that they are fully capable of completing the circuit by making contact with the housing to atty. I have the black one, which is simply painted black, however the paint being of krylon material inhibits an electrical current. I thank you for your concern, however my question was not is it safe to use, it was a question about how the batteries operate in parrallel.
To those who have answered my question, thank you.
It sorta is a safety issue. One battery provides more power than the other. Also, when connected together through the low impedance path of an atomizer, the higher one will try to "charge" the lower one, drawing even more power from the higher one. If the build is bumping up to the CDR for both combined, it can exceed the CDR of one of the two. That one may vent or, if it gets hot enough, explode.
Good catch Mad Scientist, I think it may well be a safety concern
Actually the higher voltage battery will start charging the lower one immediately after the batteries are inserted and continue to do so until their voltages are the same. They are connected pos-pos and neg-neg at all times. I'm not sure exactly how that circuit functions when you hit the switch and introduce the atty. I'm a bit too brain-dead right now to go looking for an answer, but I think it may well raise the amp draw on the higher voltage battery past what it would see with both batteries fully charged.
I edited my first post with a strike-through and a note to this one.
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I've had a few questions in my mind for a while now regarding paralleled cells and exactly how they behave during a discharge. Think I'll going to run some simulations and see exactly what is going on.
One cell will always deliver more current than the other but since both external cell voltages are always the same it seems like one cell can't charge the other. But, the internal resistances are different and that causes different internal voltage drops (that's why they discharge at different current levels). This could cause current to flow between the cells while firing the coil.
I think getting the results is going to really hurt my head but hopefully it can explain some things.
One cell will always deliver more current than the other but since both external cell voltages are always the same it seems like one cell can't charge the other. But, the internal resistances are different and that causes different internal voltage drops (that's why they discharge at different current levels). This could cause current to flow between the cells while firing the coil.
I think getting the results is going to really hurt my head but hopefully it can explain some things.
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I've had a few questions in my mind for a while now regarding paralleled cells and exactly how they behave during a discharge. Think I'll going to run some simulations and see exactly what is going on.
One cell will always deliver more current than the other but since both external cell voltages are always the same it seems like one cell can't charge the other. But, the internal resistances are different and that causes different internal voltage drops (that's why they discharge at different current levels). This could cause current to flow between the cells while firing the coil.
I think the results are going to really hurt my head but hopefully it can explain some things.
I think you have accurately stated what is happening. The cells are in parallel so they will necessarily have the same voltage when at rest. When you fire, the ballgame changes. A cell with higher internal resistance will have higher voltage drop. Current has to flow from the higher to the lower cell. It will, essentially, charge it. Also, the discharge curves are flat enough that in theory at least, it would be possible to have cells with identical no load voltages but different states of charge. The state of charge of each cell is revealed under load. The cell with less charge will also have more droop and yup, current will flow from the higher to the lower.
Hmm. I have a Dimitry Clone that is Dual Parallel Box Mod. I did now know this, I only used it a couple of times, maybe 2 battery charges from it. Would I notice something when I put the batteries on the charger? Such as the cells having the exact same voltage? I dont believe they were those couple times. Deff. would like to see some testing done @Mooch
Coming right out of your mod they would have the same voltage. But, they would most likely settle to different voltages over time due to their, slightly, different states-of-charge. When you put them in the charger you could see them the same voltage or different. If the charger measures each bay's voltage independently there will probably be a difference betwen the bays in how they read the same voltage. So, the batteries could be the same voltage but the charger would say they were different. Or, they could be at different voltages but the charger would say they were the same.
If you have a multimeter you could measure the cell voltages immediately after you take them out of the mod and then again after two hours. They will have pretty well settled to their final resting voltage by then. Then see what the charger says.
If you have a multimeter you could measure the cell voltages immediately after you take them out of the mod and then again after two hours. They will have pretty well settled to their final resting voltage by then. Then see what the charger says.
Good thinking, if I decide to use it anytime soon(or long time) I will deff. check them with a good multimeter!
Also food for thought check out cherry bomber version 2, it has a mosfet and voltage meter as well. I think they did listens to the reviewers and fixed their problems.
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