Battery Knowledge Base - WIP - Rough Draft

ESK8 Electronics
#1

Hello everyone, I’ve been meaning to get this thread going for a while. This is a tutorial on everything about batteires. From chemistries and their dangers to how to assemble and get your settings right.

#Disclaimer #Batteries are dangerous. If not treated right, you may burn your board/self/home. So please be careful #This is still in progress and very very rough draft at the moment Here is the general layout for this post:

#Chemistries Li-Po Li-Ions and Lifepo4 These are the main three types of cells to look into. Lipos are mainly used in RC due to their high power density.

When to use Lipos? The only time you should use LiPos is if: You have a very low budget You don’t have the tools/skills/time to build a liion pack.

Another exception is wanting a pack with tons of power and you don’t need great range

When to use Liions? In any other scenario that isn’t described above consider using Li-Ions, whether DIY or bought.

When to use Lifepo4? In my opinion, never. They are safer than both technologies above but they are wedged so tight between the performance of both Li-Ions and LiPos, that there really is no use for them in electric skateboards

#Lipos

Dangers and precautions:

Where to buy: The main source of Lipos is hobbyking

Performance

#Li-Ions

Dangers and precautions:

Where to buy There are several places to source Li-Ions but in my opinion the most reliable with decent prices are the following

Liionwholesale.com for the US Nkon.eu for Europe

Gearbest offers really cheap batteries and members of endless-sphere seem to agree they are authentic but I have personally never bought from them as they ship from HK and it usually takes months

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#2

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#7

Might want to add in risks and dangers and what to do to prevent fires during builds and charging

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#8

Will do! I’m just getting started with the layout. I hit create by accident.

#9

Or how to DEAL with the fires.

#10

Dont throw them off a balcony :wink:

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#11

PS If you want to contribute, PM me and we’ll discuss on what you can write or improve and I’ll add it to the OP. @Okami

#12

Hey! You should mention lifepo4 can be used for a powerful little battery, like boosted one! 70amps continuous is pretty useful if one doesn’t want to use lipos and can’t stack liions up to 3p or more

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#13

Link please. Do they sell the batteries? I don’t think there’s a good argument there.

Not wanting to use Lipos, doesn’t mean that it’s right. Unless you’re constrained in space, in which case I still think that a good Li-ion cell (not 25R) performs better than Lifepo4

#14

Im a little bit on a fence on this… but I will get back to this in about 2days… Ive got my own ‘‘esk8 building’’ seminar in two days and I still got to put a few info piecies here and there… after that (on Sunday / Monday) I could think about some sort of contribution to this…

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I think for now @PXSS just continue as you started… when I will see some progress and areas which might need further ‘‘develeopment’’ I will maybe step in and offer resources / quotes / graphs and other stuff I have found on the net, which might adress these additional issues / fields not covered in the text.

#15

What do you mean? They who? I don’t think there’s any liion battery that can deliver 70 amps in a 1p configuration, correct me if I’m wrong

#16

@SirDiff I think he meant can you easly buy / access 123A cells… to make lifepo packs with 70A discharge…

I know they’ve been used a couple of times and Nkon Eu site actually does have some in stock but they cost crazy expensive for regular builds, I think.

#17

Yeah, they do cost a lot, like double a normal 18650, but if you compare it to a basen for 8 euros, you just pay the extra for the discharge rate instead of capacity. Basens have nearly double the capacity, a123 have nearly double the discharge current. I wouldn’t actually buy them, cause a compact liion 10s3p could work just as well as a 10/12s2p of a123, and take the same space, but if one wanted a better boosted board with like 140A continuous in a split enclosure configuration, that would be key

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#18

I will look into it tonight and add a section for that.

Again, I am not looking forward to writing this all by myself. There are a plethora of members with valuable knowledge and experience whose contributions would be appreciated. If you feel lime writing something up yourself and added into the guide then by all means do so. All the credit will go to the writer.

The main reason for this thread is to help those without much knowledge.

@SirDiff @Namasaki @Jebe @Maxid @Ackmaniac @whitepony

This invitation is open to anyone!

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#19

I compared sony vtc6, sanyo GA and a123 26650 to see more clearly why a123 does not fit well in esk8 applications. If we consider 80amps as the optimal max discharge rate of an esk8 battery pack, these are the following results:

  • a123 “wins” only for 1p packs; adding parallels will just increase dramatically cost and max amps.

  • sony vtc6 wins for 2p,3p…7p packs; after 8p, further gains in max amps are useless, range and price is worse than sanyo.

  • sanyo GA wins in any configuration above 8p; price and range are the best, amps already reached the optimal value at 8p

    battery comparison.PNG890×374 54.1 KB

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#20

@PXSS To be honest, while you are still ‘‘recruing’’ the crew for writing, I think we should adress the problem with mountainboards and some unclarity for typical power consumtion.

This comes into play when designing the power output of the battery for the build.

For example, with longboard builds it is somewhat clear, that the ‘‘expected’’ consumtion is: ~10wh/km or even less.

With mountainboards it gets a bit more tricky, where a somewhat average figure is 20wh per km.

This does not really include dual drive setups, about which im not super clear about too, how much more do they actually consume and how much extra power / watthours per battery pack are needed to run a dual.

So yeh, if you got someone to recommend for these matters, that would be cool!

I know @Ackmaniac should have some extra longboard data, @Duffman also knows a thing or two about power consumtion… but generally, there is info lacking in this field or it is scattered around the forum in short one post type replies under different topics.

So yeh, If I were to make a more detailed list of battery info, I would go extra deep on what the typical power consumtion might be… This, unfortunately, includes speed / terrain data and this is where it might get a bit tricky…

@fedestanco some good info there!

I remember someone made a list of prices of nkon batteries and the best cell for the money in terms of capacity per $.

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