Im looking for a battery for a dual emtb for riding around the town, roads are rough here so thats why im building a emtb
My worries are if they will puff and sad with dual motors, I have red lots of negative posts about multistar but all those were in 1p configuration and because of that there was a lot more stress on the batteries.
If it wouldnt puff and sag it would be a huge 12s 16ah 710wh battery for 200$
Are you planning on using vesc as esc?
You will be able to pull max of 160 amps from the battery(probably less because the c rating is not
accurate).
How Many amps you are going to pull?
You will probably have some sag but not something series.
Yeah 12S2P 16Ah will be fine with 10C batteries, that will be a very nice pack.
Imagine that they can do like 100A with no problems, for a 12S setup that just perfect and very powerfull.
I run a 10S1P 5Ah 10C multistar pack and they donāt get hot or puff.
How will there be sag with 100amp continious it just doesnt make sense to me, ify i never used lipo before and prefeer liion heavily over it but im just too lazy to make a flexible li ion pack
In one setup running lipo buttery I see a sag with 240A continues when pulling maximum 40A.
The sag is minor though compared to my second setup running lion with 30A continues when pulling 20A.
I have a second board, never ridden with a 80a continuous (10s4p) 30Q cells, I suppose that it wont sag at all or something that is really small, waiting on other peoples opinion on this, I would like to have batteries as small as possible without any sag, but also for them to be within my budget
Unfortunately there will always be voltage sag, regardless of load size. With smaller currents this will of course be smaller, but donāt lull yourself into thinking that you can eliminate the sag completely with bigger batteries.
Itās all about that internal resistance that the cells have and unfortunately the most reliable way to see and test the sag is to test and monitor the battery in use. Simple Li-Po chargers that support IR-testing may give an idea what the IR is, but still the practical use and test case is very different. In actual use with prolonged discharge times and cell temperatures you might get quite different results.
Acido,
Exactly what @SimosMCmuffin said. Aaaand,
All Iāve read suggests that although not directly related, nor associated with, or measurably linked to each other, āC-ratingā of a battery indicates (but does not reflect) what you might be able to expect in terms of internal resistance. I.E: A small pack with a REALLY high C-rating, like a 5000mAh 90C pack, probably tests low on IR values, whereas a 8Ah 10C pack will drift in per-cell-voltage and sag, more than the smaller, more ācapableā battery.
My pack, which is a 22Ah 25c 12S lipo can supposedly do (22*25)= 550A continuous (wtf, right??). Doesnāt mean I can actually pull 550A without causing an inferno of some-magnitude. It does however, imply that this pack is going to perform predictably well under normal to extreme (lol) demand
But again, low C-rating per mAh of capacity doesnāt equate to anything, it just proposes a class. Real world performance will likely be better in the longrun with higher levels of quality, however suggestive and biased their metrics may be!
Your setup will probably be able to draw plenty of current when the pack is fresh and new, but I found that after around 100 cycles the multistar batteries really show how low quality they are. I used multistar 10c batteries on my first build, and within 75 cycles, some of the cells were already starting to lose a lot capacity, to the point where I was getting less than 50% range than when the board was new. It kept getting worse and worse until I finally decided to go with a 10S4P 18650 setup that has shown little signs of degradation after around 200 cycles.
The setup on my build was 8S2P with the multistar 5200mAh batteries, so it was an 8S 10.4Ah pack running a single 6364 SK3 motor, with the battery current set no higher than 50A, which the pack should have been able to handle 104A, based on its 10C rating.
According to some posts on endless sphere, multistar batteries are more like 2-3C real world than the 10C advertised by Hobbyking. Iām using 12Ah 15C Graphene Packs and they work well, but thatās no comparison price wise to multistar batteries.
I, too, am trying to build a electric longboard. Do you know where I can get a 18650 customly built for me? I need ~900wh because Iām not using a BMT to restrict the current to the motors (Although I am using one to charge).
are there any reliable websites to make a custom pack? It would be much more convenient to get one online (or even just a bunch of small ones).
It should be able to easily charge fully in a whole day (24 hrs). Because its so large, it should ideally last a long time. I would need the BMS to still regulate it, and now Iām thinking twice about regulating it going to the battery. Lastly, the BMS makes sure it doesnāt go below min voltage.