What is the "P" in a Lipo mean

[frickenjoey]

Ok I am getting confused on what the difference on some lipo batteries. Say I have a 5000 mAh 2S 1p rated at 30C....what is the difference between that and a 5000 mAh 2S 2p rated at 30C. I think a 2s p1 is two in series and one in parallel and that the 2s 2p has an extra cell (4) or two in series and two in parallel. But is the 2p going to be a stronger pack than the 1p if it is the same rating? I am not getting it... or am I thinking too deep in to this? What are the advantages of each.....other than the weight advantage of the slimmer 2s 1P?

 

[flm_savage]

S is the number of cells in a pack that are wired in series. P is the number of cells in a pack that are wired parallel. Series raises voltage and paralleling raises capacity

 

[frickenjoey]

I have that part.....no problems. Just say we have two packs side by side...one is 5000 mAh 2S 1p rated at 30C and another 5000 mAh 2S 2p rated at 30C. Which pack would be the stronger pack say they were made by the same company. Since the 1p pack would actually have 3 cells in it and the 2P would have four...so the 2P pack could use smaller capacity inferior cells than the 1P pack and get away with it but with the sacrifice of a bulkier pack and more weight. ...To me the if they are the same "C" rating and he mAh capacity is the same they should output the same....Am I off base here?

 

[flm_savage]

If their rating is the same and its a legit rating, they should perform the same imo. I prefer fewer larger capacity cells.

 

[frickenjoey]

That was my thinking as well....few cells mean less chance of one getting out of balance ect I guess. I think technically I could take four 15 C 2500 mAh cells and put them together in a 2S 2P configuration and end up with a 5000 30C pack. However it would be heavier and bigger than a 2S 1P pack. My thinking the 2S1P is going to be a better quality pack.

 

[abadk9420]

If I am not mistaken the 2P is the charge rate, basically means it can be charged faster, but i could be wrong.

 

[sweetdiesel]

If I am not mistaken the 2P is the charge rate, basically means it can be charged faster, but i could be wrong.

No, it does not mean it can be charged faster. If it can be charged at a higher amperage it will state "Can be charged at 2C" etc.

2S1P is only made up of 2 cells, not 3. In your example the first 5000mah pack is made up of 2 5000mah lipo cells wired in series. The 1P is assumed when the cell is wired as one bank of cells in series only.

The 2S2P pack is indeed made up of 4 cells. In your example the 5000mah pack is made up of 4 2500mah cells. There will be 2 banks of cells wired in series, with each bank comprised of 2 2500mah cells wired in parallel.

If the cells that comprise both packs have the same discharge capability (for example 20C cont, 25C burst), the pack which uses a higher number of cells to attain the same overall capacity will not perform as well as the pack which uses less cells due to the added resistance from the increased length of wiring and/or solder points.

That was my thinking as well....few cells mean less chance of one getting out of balance ect I guess. I think technically I could take four 15 C 2500 mAh cells and put them together in a 2S 2P configuration and end up with a 5000 30C pack. However it would be heavier and bigger than a 2S 1P pack. My thinking the 2S1P is going to be a better quality pack.

Just to clarify, wiring cells in parallel will not also increase their discharge rating. In the case you cited above your final 2S2P pack will still be 15C.

 

[abadk9420]

No, it does not mean it can be charged faster. If it can be charged at a higher amperage it will state "Can be charged at 2C" etc.

2S1P is only made up of 2 cells, not 3. In your example the first 5000mah pack is made up of 2 5000mah lipo cells wired in series. The 1P is assumed when the cell is wired as one bank of cells in series only.

The 2S2P pack is indeed made up of 4 cells. In your example the 5000mah pack is made up of 4 2500mah cells. There will be 2 banks of cells wired in series, with each bank comprised of 2 2500mah cells wired in parallel.

If the cells that comprise both packs have the same discharge capability (for example 20C cont, 25C burst), the pack which uses a higher number of cells to attain the same overall capacity will not perform as well as the pack which uses less cells due to the added resistance from the increased length of wiring and/or solder points.

Thanks for clearing that up for me, Still learning all of this Lipo stuff, switching to lipo is one of the best moves i have made in RC's for sure..

 

[frickenjoey]

Thanks Sweet....I had a couple of folks that thought they knew everything trying to confuse the poop out of me and since I did not know for total sure. That is why I ask. Thanks Sweet the Badge just earned again!

 

[robmob]

SD is the go-to-guy for straight answers on LiPo's, chargers, balancers, motors, etc. I trust nobody else.

Even if I am pretty sure I am right, I will ask SD to confirm before I blow something up. LOL

 

[Hyster]

SD is the go-to-guy for straight answers on LiPo's, chargers, balancers, motors, etc. I trust nobody else.

Even if I am pretty sure I am right, I will ask SD to confirm before I blow something up. LOL

agreed

 

[frickenjoey]

Yup I agree with you Rob. I was getting fed some mis-information....knew it smelled funny so I posted this up for "Sweet D" 'cause I know he would have a good answer.

 

[sweetdiesel]

Glad I could help.