18650 batteries in 48v 20ah config vs. 48v 20 ah lithium

[BrianVoltagegt500]

18650 batteries in 48v 20ah config vs. 48v 20 ah lithium. my question is this i have seen a triangle battery in a 48v 20ah lithium configuration that seems alot smaller than putting together the same config using 18650's. which gives more range and output? which is safer? the config in 18650's seems like alot of batteries taking up alot more space on the bike. does anyone have experience with both? or perhaps those that have done the 18650 config this way can give me there impressions ( mph range etc) and those using the triangle 48v 20ah lithium give me there experiences? I am wondering why the triangle is so much less space taking yet claims the same ratings etc. thanks in advance

 

[amberwolf]

18650 is just a cell shape and size. All the ones I know of *are* lithium.

So there is no difference in total watthours between the pack you'd build out of those, and a pre-built triangle pack (which is probably also made out of them).

But there are dozens, possibly hundreds, of different types of cells in the 18650 format, and each one has a different capacity, discharge rate (c-rate), internal resistance, charge rate, etc.

So if you actually want to compare the two packs, you have to decide *which* 18650 cells you would use on your own pack, and you have to know which ones were used in the other pack.

I highly recommend reading as many of the threads in this list as you can, because it sounds like you need a lot more information than you have.
https://endless-sphere.com/forums/search.php?keywords=18650&terms=all&author=&sc=1&sf=titleonly&sk=t&sd=d&sr=topics&st=0&ch=300&t=0&submit=Search
Many of htem are not relevant, but the titles (or the first post) should let you eliminate them.

 

[dogman dan]

To get the smallest pack,, or the biggest ah size in the smallest area, you need to seek out the best 18650 cells. The ones with a good discharge rate and higher capacity than the cheaper ones.

If your desire is only for the smallest price per watt hour, or the highest c rate, then the square pouch cell lithium cobalt batteries might be your choice. RC or LIPO batteries, like drones use.

They are not as compact or light as the current crop of 18650 lithium. But they are not hugely heavier. A smaller, and thus light pack that can fit in a triangle bag can punch hard because of the discharge rate may let you carry less ah.

Depends on what you need most,, amps, or amp hours, from your pack.

Many choose the cheap 18650's, sometimes recycled laptop batteries. In general, you need to make huge batteries from these, like at least 20 ah, to even pull a modest bike motor, like 20 amps, 1000w. To work without much sag on that size motor, more like 30-40 ah.

 

[BrianVoltagegt500]

Hi again, thx for the replies but the point of my question was this. why is a 48volt 20 ah pack of 18650's so much bigger than the triangle battery i am seeing that states it's also a 48volt 20 ah battery? is the triangle battery of different composition of lithium? and does it pack the same or lesser punch? less or more dangerious to use? do they both take the same motor and weight the same distance? basically i am trying to figure out which to use and why. thanks for your replies.

 

[amberwolf]

We can't answer your questions, because we cannot know what hte packs are made from. You would have to find out what they are made from to be able to compare them realistically.

That is why I posted the info and pointers I did.

Since you are the only one at this time that knows what cells and packs you are wanting to know about, only you can determine this.

 

[dogman dan]

If they were made from the same cells, then they would be the same number of cells, and the same size. If not, then one cell may have much better capacity than another. The cheap pack, likely the bigger one, requiring more cells to reach 20 ah.

If they are different chemistries, then for one example, lifepo4 18650's need more cells to reach 48v. 15 in series vs 13 for limn. And capacity of lifepo4 18650's is typically low compared to limn. Are you comparing lifepo4 with limn?

Or,, one vendor lies about the capacity.