What's problem with parallel connection in vape world?

[Whocares]

Hey. I like parallel connection, in my information it gives bigger capacity and you can combinate different batteries.

When you use serial connection, total copacity and amperage depends on the weakest battery. The only advantage of serial connection (in vape) - it gives more power.

Without good balancier (most of devices like RX 200s even does not have this) you can not charge battery well. Also, it's more hard to convert USB 5v to, for example 2*4.2=8.4 or up to 12.6v.

When you use parallel connection you don't need balancier and can charge your device calmly.

Now the only good device which allow you use parallel connection is iStick tc100w.

It's good and quite tight, but it's tall. I think it can be more compact if manufacturer decrease wattage (I use 10-35w). Also, powerbank mode is funny too).

As I know, there is no parallel devices, I can be wrong and dont know something (I live in Russia), but...

 

[fq06]

You need to balance charge or charge each cell separately regardless of parallel or series orientation. Otherwise you can over charge a cell either parallel or series.

Some people like the higher voltage output or higher mah capacity but the only way a parallel orientation has an advantage is when you are running builds that use a lower voltage. If you are running a build that wants ~4v or more, series will be more efficient, less stress to the cells and most likely more run time.

Your cells should be in about the same health as each other parallel or series. Internal resistance being close to the same otherwise the weak cell will be drawn from more than the stronger cell making the balance further away from each other every cycle.

 

[Whocares]

You need to balance charge or charge each cell separately regardless of parallel or series orientation. Otherwise you can over charge a cell either parallel or series.

In parallel connection cells have absolutely same voltage, as I know. If one battery theoretically have bigger voltage (or you Putin battery with different voltage) it starts give away power to battery with lower voltage.

You can not overcharge, as I know, even if them have different resistance if you use small Amp. As for me, I used absolutely different battery and check them - they have identically voltage

 

[HondaDavidson]

Volts are not what determines a strong vs weak battery. Amp are...... the mod will pull from the weakest battery based on amp draw availabilty...para or series... I know you have a married set of batts... that doesn't mean the are all equally in condition though. Are all 20 year old men capable of same physical feets? Granted the lowest voltage battery will have a lower amp limit

Sent from my SCH-I605 using Tapatalk

 

[fq06]

Cells are dumb, a charge goes into all cells the same. The charge will terminate at your set voltage... say 8.4v. A non balancing charge will charge up to 8.4v whether both cells are 4.2v or one is 4.1v and the other is 4.3v... parallel or series.

A smart charger will balance the cells to peak at 4.2v each by pulling a small amount of juice from the strong cell until all cells peak at 4.2v independently.

Your voltage will eventually drift if you don't balance charge or charge separately, when it does you just did damage to one or more cells by over charging it.
It's your money, keep doing it your way

 

[fq06]

Volts are not what determines a strong vs weak battery. Amp are...... the mod will pull from the weakest battery based on amp draw availabilty...para or series... I know you have a married set of batts... that doesn't mean the are all equally in condition though. Are all 20 year old men capable of same physical feets? Granted the lowest voltage battery will have a lower amp limit

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Exactly, and amps are the charge rate, volts are the termination point in the world of charging.

 

[Rickajho]

s for me, I used absolutely different battery and check them - they have identically voltage

They might - because current drain is fairly linear across the useable discharge capacity of a lithium battery. But when it comes down to the end of their usable capacity voltage dropoff is rather sharp - and that's when the problems begin using mismatched batteries.

 

[Whocares]

Cells are dumb, a charge goes into all cells the same. The charge will terminate at your set voltage... say 8.4v. A non balancing charge will charge up to 8.4v whether both cells are 4.2v or one is 4.1v and the other is 4.3v... parallel or series.

On parallel you need to set 4.2 volts. Hmm. I dont believe that in parallel connection batteries can have different voltage when they charge. It's like communicating vessels, yeah, one vessel could have bigger level of liquid, if you pour liquid very fast and some vessel have small hole... But USB 0.5-1 Amp *5 volt is not very high load.
Usually it should looks like

But i will try to combine powerbank battery with 30Q to test voltage diffferrence on charge/discharge

 

[Whocares]

A smart charger will balance the cells to peak at 4.2v each by pulling a small amount of juice from the strong cell until all cells peak at 4.2v independently.

By the way, how it possible, to have balancer on true parallel connection?

 

[HondaDavidson]

By the way, how it possible, to have balancer on true parallel connection?

It's not.... has to be an independent connection to the board... which draws from batts in para.

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[Whocares]

Cells are dumb, a charge goes into all cells the same. The charge will terminate at your set voltage... say 8.4v. A non balancing charge will charge up to 8.4v whether both cells are 4.2v or one is 4.1v and the other is 4.3v... parallel or series.

A smart charger will balance the cells to peak at 4.2v each by pulling a small amount of juice from the strong cell until all cells peak at 4.2v independently.

Your voltage will eventually drift if you don't balance charge or charge separately, when it does you just did damage to one or more cells by over charging it.
It's your money, keep doing it your way

From http://fpvlab.com/forums/showthread.php?29653-Different-Capacity-Batteries-in-Parallel

Well I suspect there will always be debate on this topic that often times gets very heated. I also have run different sized batteries with no ill effects. Even VERY different sizes. Companies that make parallel lipo chargers (iCharger for example) say that it is perfectly fine to charge batteries of different sizes in parallel. The capacity and C ratings may be very different so long as you don't violate the lowest C rating of your mismatched pack and are sure the voltages are similar when you connect them.

When you connect batteries of different capacities in parallel they will discharge (or charge) just fine together since the batteries terminals are connected and the voltage each battery sees will be the same*. That means, contrary to what Hans said, that one battery, the smaller, will not discharge first. They both will walk right down the lipo voltage curve together in lock step*.

Now for the asterisks. There are some cases to worry about. If you are charging or discharging at low C rates all of the above is very true, but what happens at high C rates? You have to make sure you don't run the parallel pack any harder than the lowest C rating (e.g. you have a 20C and a 50c battery the parallel pack should not be run harder than 20C). If you are a full throttle, run your packs to 3.3V per cell guy you are possibly headed for trouble.

Another asterisk is what happens (in any parallel pack) if you have a cell failure? Say you have a parallel 3s pack and one cell goes bad. Now you are breaking a rule to NEVER mix voltages. Basically you have connected terminals of an 8.4V battery to those of a 12.6V battery. What happens is those two batteries will drive the voltage to the same level (since they are connected) and the 8.4V's will go up and the 12.6V will go down and meet in the middle. The battery with the bad cell will now effectively be charging to a voltage greater than the allowed cell voltage of 4.2V...and fireworks ensue. The fireworks had nothing to do with a mismatch of capacity though one could argue if the smaller battery is the one that had a cell failure the fireworks will be bigger than the case where the larger battery had the cell failure.

My final asterisk is that the flying I do is at a very low C rating. Usually 1.2C or less so I am never close to the possible high C issues that can come up. I have mixed batteries as different as 3s5100 with 3s1400 in such conditions (with 10 seconds of high C launch and 1.2C flight for over an hour afterwards). Battery chargers are also run at low C ratings and likely (I will email iCharger on this) will detect a bad cell and shut down the charger. You have no such safety net in the air beyond watching your OSD and going to high throttle when you see a strange voltage drop...

 

[Whocares]

Also. http://www.icharger.co.nz/buying/resources-faq/what-is-parallel-charging-and-why-is-it-for-me/
What is Parallel Charging and why is it for me?

What is parallel charging?

Parallel LiPo charging allows you to charge more than one battery at the same time (with a computerised RC battery charger). The big advantage of parallel LiPo charging is it saves time. You can charge your entire collection of (same cell) LiPo batteries on one charge cycle.

Parallel charging will only work on same cell count batteries, but they can have different capacities, within reason. They can also be at different states of discharge, again within reason. We wouldn't recommend trying to parallel charge a pack that was 5% discharged with one that was 50% discharged for example.

No more taking one pack off when it is finished and then hooking the next one up and starting the charge cycle all over again. The important thing to remember is the battery packs all have to be the same cell count. You CANNOT parallel charge a 6S pack with a 4S pack for example. All packs in the parallel charge circuit must be of the same voltage rating.

Requirements and Recommendations for Parallel Charging

A parallel wiring adapter for the main leads and a parallel adapter for the balance leads. This can be for as few as 2 packs or as many as 6, your choice. You can find these online or most good hobby suppliers. We will also show you a few basic examples to make your own below.

All the packs you charge in parallel must be the same type and cell count. There is no need to match the capacity, C-rating, age or brand for parallel charging. For example, you can charge a 3s 2200mAh 15C lipo, a 3s 3200mAh 25C lipo and a 3s 850mAh 35C lipo together, but you CANNOT charge any 3s lipo in parallel with a 4s lipo.

Balance the charger with adequate power! Just because your charger states that it can output 10amps, it is not necessarily

 

[fq06]

From what you quoted...
"A parallel wiring adapter for the main leads and a parallel adapter for the balance leads"

The only way to do that and have all cells end up at the same voltage is to balance charge them with a smart charger.
What you are linking to is how to daisy chain multiple packs while balance charging. It actually reinforces what we are saying.
I have a powerlab 6 chager that can balance charge up to 6 multi cell lipo packs of the same nominal voltage at 40a.
You need some expensive equipment to do that but fortunately we don't need it for vape gear.

In the end, you can do what you want. I just don't want others to see this thread and make the mistake you are making with your batteries so I am pointing out that you are wrong.
And fluid dynamics have absolutely nothing to do with electricity. Water and electricity don't mix well in many different ways.
And amp output has nothing to do with end voltage, just speed to that end voltage. 0.5a or 5a, end voltage is end voltage.

 

[Whocares]

The only way to do that and have all cells end up at the same voltage is to balance charge them with a smart charger.

It needs balancer for multicells, not one-cell battery

 

[USMCotaku]

while in theory you are correct that a balance charge isn't required for a parallel system (gasp, yes people, he is correct on that account, in many ways, electricity and water flow in similar ways, so the charge will flow from the first cell into the second until they level out), one thing you posted in the OP is NOT correct....using differing batteries. Unmatched batteries would charge fine, but the problems arise in use. Say cell 1 of 2 is older, and discharges quicker, you will end up with cell 2 pulling the slack. Depending upon your build, that slack could easily go into an unsafe amp draw. Another thing to consider, as a battery ages, its internal resistance increases, causing voltage drop...another thing that will cause higher amp draw on the fresher cell.

 

[fq06]

You can do that with one 18650. Add another and you can't.

See the balance leads from those packs? Those are not single cell packs.

Yes, you can daisy chain charge multiple packs but they will not be balanced.
Close enough if you want to get the job done quickly at the rc park for the day like that video is showing but you go home and take them down to storage voltage. Then you balance peak charge the next time you go to the rc park. Most people with a charger that costs more than $20 like the one in that video will balance charge though because they can push more power to reduce wait time.

Anyway, I'm done with this. No point in having a conversation with someone about a subject they don't have knowledge on when they already know everything about it.

 

[USMCotaku]

You can do that with one 18650. Add another and you can't.

See the balance leads from those packs? Those are not single cell packs.

Yes, you can daisy chain charge multiple packs but they will not be balanced.
Close enough if you want to get the job done quickly at the rc park for the day like that video is showing but you go home and take them down to storage voltage. Then you balance peak charge the next time you go to the rc park. Most people with a charger that costs more than $20 like the one in that video will balance charge though because they can push more power to reduce wait time.

Anyway, I'm done with this. No point in having a conversation with someone about a subject they don't have knowledge on when they already know everything about it

You are thinking about this from the stance of multi cell packs.......you CAN parallel charge single cell batteries without balance charging. The batteries will balance themselves to the other batteries when in series. This is the reason you can parallel charge 3s packs together, but not a 3s and a 2s. When parallel charging multiple cell packs, each individual pack will need to be individually balanced, but this is not necessary for 1s batteries.

 

[Whocares]

Unmatched batteries would charge fine, but the problems arise in use. Say cell 1 of 2 is older, and discharges quicker, you will end up with cell 2 pulling the slack.

Bigger battery should gives more power, in the end, they discharge evenly.

Somebody could think that it's insafe, but true is:

1. Batteries have little difference - there is not equal batteries
2. When you use serial connection weak batteri will discharge/charge first. And device without balancer must stop charge/discharge. For example, if device cuttoff is 3.0 volt, when weak battery has 3.0 volts, bigger battery could has 3.3 volts, for example. You can not use device in this situation.
If start voltage is same, for example 3.4, weaker battery will charge to 4.2 volts faster, bigger battery will not charge full.
So, weak battery has deeper charge/discharge cycles, it shorts it's life and weaker battery will fail faster.
Capacity in serial connection= weakest battery*numbers of battery

3. In parallel connection in short perspective cells have same voltage and same deep of cycles. So, they wear out evenly and it's comfortable. May be it could be microoverload and volts difference, but it will be selfbalanced and it's better than serial connection.


Disadvantage is higher Amps for same wattage. 40A*4v=160W and 20A*8v=160W too, but in first situation bigger amp load. So, make parallel mod with high wattage is more expensive, but as for me I will glad to have 30-50W mod if it will be more compact and comfortable than TC 100W

 

[fq06]

You are thinking about this from the stance of multi cell packs.......you CAN parallel charge single cell batteries without balance charging. The batteries will balance themselves to the other batteries when in series. This is the reason you can parallel charge 3s packs together, but not a 3s and a 2s. When parallel charging multiple cell packs, each individual pack will need to be individually balanced, but this is not necessary for 1s batteries.

You can't charge 2s and 3s balance or no balance. That just doesn't work at all, correct.
But 2s and 2s still should be balance charged every few cycles to make sure your cells are not drifting too far apart.

Single cells in parallel will get very close to each others peak voltage but not exact so that still alows one to surpass 4.2v. Maybe for a while they will both be ~4.2v at the end. But all cells are different and at some point there will be a runt in the group that lags behind the rest. The other will charge over 4.2 leaving the runt at 4.1x. The harm is done to the one over 4.2.

 

[USMCotaku]

Bigger battery should gives more power, in the end, they discharge evenly.

Somebody could think that it's insafe, but true is:

1. Batteries have little difference - there is not equal batteries
2. When you use serial connection weak batteri will discharge/charge first. And device without balancer must stop charge/discharge. For example, if device cuttoff is 3.0 volt, when weak battery has 3.0 volts, bigger battery could has 3.3 volts, for example. You can not use device in this situation.
If start voltage is same, for example 3.4, weaker battery will charge to 4.2 volts faster, bigger battery will not charge full.
So, weak battery has deeper charge/discharge cycles, it shorts it's life and weaker battery will fail faster.
Capacity in serial connection= weakest battery*numbers of battery

3. In parallel connection in short perspective cells have same voltage and same deep of cycles. So, they wear out evenly and it's comfortable. May be it could be microoverload and volts difference, but it will be selfbalanced and it's better than serial connection.


Disadvantage is higher Amps for same wattage. 40A*4v=160W and 20A*8v=160W too, but in first situation bigger amp load. So, make parallel mod with high wattage is more expensive, but as for me I will glad to have 30-50W mod if it will be more compact and comfortable than TC 100W

You may use whatever you wish, but I'm telling you that using unmatched batteries as you alluded to in the opening post, is dangerous whether parallel or series.

Sent from my SM-N920T using Tapatalk

 

[Whocares]

You can't charge 2s and 3s balance or no balance. That just doesn't work at all, correct.
But 2s and 2s still should be balance charged every few cycles to make sure your cells are not drifting too far apart.

Single cells in parallel will get very close to each others peak voltage but not exact so that still alows one to surpass 4.2v. Maybe for a while they will both be ~4.2v at the end. But all cells are different and at some point there will be a runt in the group that lags behind the rest. The other will charge over 4.2 leaving the runt at 4.1x. The harm is done to the one over 4.2.

How does this possible? If one cell have bigger voltage then it always sends energy to another cell until they stabilize.

It's only one demand to parallel cells - they should have same voltage on start, if they not, some cells give big current to another battery.

It's how " parallel balancer" look with resistors, it's just protect from big current if cells have absolutely different voltage. If they not and have same voltage on start it does not need.

 

[Rabbit Slayer]

and you can combinate different batteries.

If you don't care about safety, sure use different cells in the same mod

 

[Whocares]

sure use different cells in the same mod

%)
Cells are different anyway, but how much. That's why in serial connection of li-ion people uses balancer. I don't use 3-4.2v li-ion + 1.2v NiCd, that's enought for me. For best electrical safety you should not use any electical device.

 

[Rabbit Slayer]

For best electrical safety you should not use any electical device.

But only if/when you have no clue what you are talking about

 

[Whocares]

But only if/when you have no clue what you are talking about

I read about reserch of different cells http://www.sciencedirect.com/science/article/pii/S0378775316300015. I did not found any danger. Technically, OK, if combination of 2 different cells is dangerous, then any 1-cell mod is more dangerous, on same wattage, coz battery give more current. In any combination of different batteries in parallel it's less load on every cell.

 

[USMCotaku]

I read about reserch of different cells http://www.sciencedirect.com/science/article/pii/S0378775316300015. I did not found any danger. Technically, OK, if combination of 2 different cells is dangerous, then any 1-cell mod is more dangerous, on same wattage, coz battery give more current. In any combination of different batteries in parallel it's less load on every cell.

except that single battery mods don't go up to 200 watts. Mods now push the envelope of what a battery can handle.....80 watts on a single cell, 200 watts on a dual cell etc......so what happens when you are using a dual cell mod at 100 watts, and your batteries are not evenly matched making one battery do the brunt of the work? Thermal runaway, that is what happens.

 

[Whocares]

except that single battery mods don't go up to 200 watts. Mods now push the envelope of what a battery can handle.....80 watts on a single cell, 200 watts on a dual cell etc......so what happens when you are using a dual cell mod at 100 watts, and your batteries are not evenly matched making one battery do the brunt of the work? Thermal runaway, that is what happens.

Man, I use 10-30 watts on TC -_- and don't advice use overcurrent on each battery. For using this you should to understand basically things how it works.

If you use different 2 cells at least you should not use double current of weaker battery. For example, 10A battery + 30A battery - shortly, don't use more than 20A. From other side you can get resistance of every battery, to calculate relation on load, to keep in mind impulce load and other things.

But if you use >1 P cells not for power, but for capacity, and don't use bigger wattage than 1-cell mod, nothing dangerous, at least not more dangerous than 1-cell or very popular mech with ~0.0x coils

 

[Rossum]

Hey. I like parallel connection, in my information it gives bigger capacity and you can combinate different batteries.

When you use serial connection, total copacity and amperage depends on the weakest battery. The only advantage of serial connection (in vape) - it gives more power.

Without good balancier (most of devices like RX 200s even does not have this) you can not charge battery well. Also, it's more hard to convert USB 5v to, for example 2*4.2=8.4 or up to 12.6v.

When you use parallel connection you don't need balancier and can charge your device calmly.

Now the only good device which allow you use parallel connection is iStick tc100w.

It's good and quite tight, but it's tall. I think it can be more compact if manufacturer decrease wattage (I use 10-35w). Also, powerbank mode is funny too).

As I know, there is no parallel devices, I can be wrong and dont know something (I live in Russia), but...

The reason parallel devices fell out of favor is that they require boost (or boost/buck) regulators, which are more expensive to build and less electrically efficient, otherwise the mod can never output more than the current battery voltage. With cells in series, one can use a simple, efficient, inexpensive buck regulator.

 

[conanthewarrior]

With regulated mods, series makes sense for higher power mods, due to the input voltage being higher, the amp load being demanded is lower, allowing very high power levels to be achieved quite safely.

For example in a 3S configuration at 200W, assuming a cutoff of 3.2V per cell and 90% efficiency, you would be drawing at a MAXIMUM 23.14A. Most of the time the batteries will be above this, so the amp load will be lower.

If you had a mod in a triple parallel set up, these same 200W would be drawing 71.68A at cut off, this time assuming 3.1V If you was using 20A batteries, and use the 50% per battery as a safety barrier most people use in parallel, you can see you are massively over the batteries rating, while the series example not so much, and with 25A batteries you would be perfectly safe with the series example, but still over in the parallel set up.

Also, as has been mentioned there is bucking vs boosting- bucking is more efficient than boosting.