18650 battery Kit development and discussion[testing done]

Batteries, Chargers, and Battery Management Systems.
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agniusm   10 MW

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Re: 18650 battery Kit development and discussion

Post by agniusm » Sep 13 2014 7:58am

Preliminary sizes:
14s10p - 218x304x85mm
14s6p - 135x304x85mm
10s10p - 218x223x85mm
10s6p - 135x223x85mm

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agniusm   10 MW

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Re: 18650 battery Kit development and discussion

Post by agniusm » Sep 14 2014 2:02am

Purchased pressure sensitive resistor sensor. I will test the compression and set of the foam to see if it does not loose pressure. Any info on those FSR402 sensors, how reliable they are?

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agniusm   10 MW

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Re: 18650 battery Kit development and discussion

Post by agniusm » Sep 15 2014 8:18am

What would be best thermistor to use for monitoring temps inside to work with majority of existing hardware? Is it NCT 10k?

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Allex   1 GW

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Re: 18650 battery Kit development and discussion

Post by Allex » Sep 20 2014 4:31pm

Would you consider doing a kit so the cells are oganized in a more dense pattern like this:
Image

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agniusm   10 MW

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Re: 18650 battery Kit development and discussion

Post by agniusm » Sep 20 2014 5:11pm

It would be hard to achieve. Existing holders are designed with the gap. I dont see why you would want it dense as it is good to have a gap for cooling reasons.

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Re: 18650 battery Kit development and discussion

Post by \/ampa » Sep 20 2014 5:28pm

agniusm wrote:It would be hard to achieve. Existing holders are designed with the gap. I dont see why you would want it dense as it is good to have a gap for cooling reasons.
If the air can move on top and bottom where the spot-welding is. Than it is for the new high power 18650 cells no problem to stay cool.
So i would also consider it useful to have only a 1mm spacing and cells shifted for maximum dense.
Its always better to overbuild a battery to higher Wh than the actual need. For longer cycle life.

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Allex   1 GW

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Re: 18650 battery Kit development and discussion

Post by Allex » Sep 20 2014 5:29pm

I have my cells orginized like that , 20s14p and I am drawing 130-150Amps from them(peak).
The pack is no more than 45C at most so I never felt the need of cooling.
Hi-drain LG HE2 cells
So with your current design would give me less Whrs and probably put more stress on the cells because I have to use less "p" which gives me more heat and less life cycles.

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agniusm   10 MW

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Re: 18650 battery Kit development and discussion

Post by agniusm » Sep 21 2014 4:41am

The idea of using existing brackets is to have the cost down. Allex, was it easy to get your cell out when you discovered a dud? You need to have support for the cell for the pack to be rigid otherwise glueing them. I think 45C is already shortening cell life and soldering them beforehand does not help either. You and perhaps someone else need high capacity and for me to concentrate on 100 users who need less capacity makes more sense.

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Re: 18650 battery Kit development and discussion

Post by stompatompa » Sep 21 2014 8:11am

Very interesting thread agniusm!
How far have you come in the development?
What price range do you have in mind?
I would probably buy a 14s 6p kit from you (or 7p works fine too).

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agniusm   10 MW

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Re: 18650 battery Kit development and discussion

Post by agniusm » Sep 21 2014 8:19am

Thanks. I have ordered some parts for beta test units. It wont be quick thou. I want a polished product and input from people ads to developement. At the moment I am a bit stuck with polyurethane material, no one wants to sell me small quantity for testing.

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Re: 18650 battery Kit development and discussion

Post by jkbrigman » Sep 21 2014 8:38am

agniusm wrote:The idea of using existing brackets is to have the cost down. Allex, was it easy to get your cell out when you discovered a dud? You need to have support for the cell for the pack to be rigid otherwise glueing them. I think 45C is already shortening cell life and soldering them beforehand does not help either. You and perhaps someone else need high capacity and for me to concentrate on 100 users who need less capacity makes more sense.
Wise approach. +1 for the frames, +1 for being able to remove bad cells.
I am the kind of person who ALWAYS has bad luck, so repair and servicing are CRUCIAL to me.
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Allex   1 GW

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Re: 18650 battery Kit development and discussion

Post by Allex » Sep 21 2014 11:06am

agniusm wrote:The idea of using existing brackets is to have the cost down. Allex, was it easy to get your cell out when you discovered a dud? You need to have support for the cell for the pack to be rigid otherwise glueing them. I think 45C is already shortening cell life and soldering them beforehand does not help either. You and perhaps someone else need high capacity and for me to concentrate on 100 users who need less capacity makes more sense.
Not my pack in the picture, but yeah, it is very time consuming to find a dud cell when you have everything spotwelded. This is why I asked about defferent layout for us with limited space in our bike frames(think raptors, phazors, fighters bombers and many more) Regarding the support, spot welding and heatshrink/tape work good as long it sits cramped inside the frame. Ok you and I may see it like unprofessional. But this is how most packs look like! Stealth is using pouchpacks, tape them together and apply heatshrink on top of everything, so nothing unuasual or expensive.

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agniusm   10 MW

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Re: 18650 battery Kit development and discussion

Post by agniusm » Sep 21 2014 12:05pm

Allex wrote: Not my pack in the picture, but yeah, it is very time consuming to find a dud cell when you have everything spotwelded. This is why I asked about defferent layout for us with limited space in our bike frames(think raptors, phazors, fighters bombers and many more).
Yeah, i know it was not yours. You were welding urs with ur wife or something. OK. I still stay on my concept and if it works and works good which i believe in (otherwise i would not work on it) i will let you gather at least 100 ppl with deposits and i will make a line special for you :)
Allex wrote:Regarding the support, spot welding and heatshrink/tape work good as long it sits cramped inside the frame. Ok you and I may see it like unprofessional. But this is how most packs look like! Stealth is using pouchpacks, tape them together and apply heatshrink on top of everything, so nothing unuasual or expensive.
I am not a fan of duck tape and heatshrink. Battery is a major component in any electric vehicle. I am surprised that Stealth is putting such battery, very unprofessional, still cant believe it.
This is the battery pack (although 4S) that i was somewhat happy with:
Image
This time i want something more finished.
It is impossible to satisfy everyone for someone like me without funding using my own cash and hoping to break even.
I am taking all the info and suggestions in and it stays on my "hard drive" to make some sense of it later.

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Re: 18650 battery Kit development and discussion

Post by Wrecker Magoo » Sep 21 2014 7:38pm

I think you should make a battery case to fit into a frame. maybe like the one madmechanic is building:
http://endless-sphere.com/forums/viewto ... =3&t=62345

I've just been bugging him to build a compression case into his frame.
Maybe someone already down the road of cases could build one that already fits a frame. :wink:

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Re: 18650 battery Kit development and discussion

Post by Synon » Sep 23 2014 1:28pm

Great project! I'm definitely watching your progress on this.

Curious why you decided on 10s (41v when cells are charged to 4.1v each) and 14s (57.4v total). Why not 12s which would be 49.2v? I'm still pretty new at all this, but I see a lot of kits that are 48v.

How will the end user determine how much pressure there needs to be on the cover to keep good even contact with the cells?

Looking forward to seeing more! I'm waiting for 200 of those 18650 brackets to arrive so I can do something similar to your kit. I'd probably buy one, but it would be very expensive to ship to the western USA and I'm hoping for something that will fit in my triangle box but I understand you can't make a product that will fit all needs.

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agniusm   10 MW

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Re: 18650 battery Kit development and discussion

Post by agniusm » Sep 23 2014 2:43pm

3 lead acid batteries = 3×14.4V=43.2V
12 lifepo4 cells = 12×3.65V=43.8V
10 lipo cells = 10×4.2V=42V and so on. 2 × 10S kits gives you 20S. Its all in this thread.
The end user will be able to determine pressure from bolt depth from the back side and by the feel.
In my experience to do one battery costs a lot. Think time doing your cad, studying and sourcing materials, fabricating. It all ads up in the end. Shipping to States, Aussies cost about 30 to 40usd insured.
It might fit depending on the battery size you will use.

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agniusm   10 MW

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Re: 18650 battery Kit development and discussion

Post by agniusm » Sep 24 2014 2:00pm

I have thought that it will be nice to have a connectors that you dont need to solder so i have changed copper dimple terminals and added 2.8mm spade connectors, sort of plug&play:

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Re: 18650 battery Kit development and discussion

Post by agniusm » Sep 25 2014 12:00pm

Is there none 10 or 20 or 40 strand ribbon cables in 22 AWG flavor? Went through everything with no acceptable results.

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Re: 18650 battery Kit development and discussion

Post by agniusm » Sep 28 2014 10:27am

While waiting on parts build my shaker machine to test battery kit in vibration enviroment. I dont know how to put it right but if motors rpm is 3000, than the vibration is 100Hz is my thinking. What would be best frequency to test out if batteries performance does not change? Time pf the test and frequency of the vibrations?

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docnjoj   100 GW

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Re: 18650 battery Kit development and discussion

Post by docnjoj » Sep 29 2014 7:17am

Can you elaborate on your math. 100hz is 100 cycles/sec. x 60 sec/min=6000cycles/min. Are you thinking that each rev=1/2 a cycle or 2 cycles?
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agniusm   10 MW

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Re: 18650 battery Kit development and discussion

Post by agniusm » Sep 29 2014 8:09am

Yes, one revolution, 2 cycles, my thinking is that force is both directions, same stregth so there fore 2 cycles. The number poses no real value and I would not want to go hectic with this, but I am sure if I complete 8 hour test on this shaker (if it will not fall apart:) ), sure it will be more than suitable in ebike enviroment no matter how you drive it. I cant imagine any human sustaining such vibrations for 1 hour let alone 8 and most batteries available would fall apart I'm sure.

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Re: 18650 battery Kit development and discussion

Post by dnmun » Sep 29 2014 9:10am

Allex wrote:I have my cells orginized like that , 20s14p and I am drawing 130-150Amps from them(peak).
The pack is no more than 45C at most so I never felt the need of cooling.
Hi-drain LG HE2 cells
So with your current design would give me less Whrs and probably put more stress on the cells because I have to use less "p" which gives me more heat and less life cycles.
you already gave up a lot of life cycles by soldering such huge wires to the cans. there is absolutely no reason to use such a huge conductor to tie the cans in parallel but it appears that everyone who decides they can build a battery does it.

your battery delivers the current in series through the pack so the parallel connection does not carry any current.

all the heat that went into the cans when you soldered it has shortened the cycle life already.

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Allex   1 GW

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Re: 18650 battery Kit development and discussion

Post by Allex » Sep 29 2014 4:56pm

Thx dnum but it is not my picture, I just gave an example on stacking.

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Re: 18650 battery Kit development and discussion

Post by DrInnovation » Sep 29 2014 11:28pm

Nice design, just they type of thing I'd want for an 18650 build. Understand that you can only make so many design. Not sure if it will matter.. but those of use stuck back at 24v.. would be interested in something 8s.. But here is my business arugment -- the others all variations seem to aimed at the same pack voltage. 8S would be a size for another pack voltage which could give a broader market to help recover your design costs ;-D
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Re: 18650 battery Kit development and discussion

Post by docnjoj » Sep 30 2014 7:46am

agniusm wrote:Yes, one revolution, 2 cycles, my thinking is that force is both directions, same stregth so there fore 2 cycles. The number poses no real value and I would not want to go hectic with this, but I am sure if I complete 8 hour test on this shaker (if it will not fall apart:) ), sure it will be more than suitable in ebike enviroment no matter how you drive it. I cant imagine any human sustaining such vibrations for 1 hour let alone 8 and most batteries available would fall apart I'm sure.
Certainly makes sense, agniusm. If a battery survives that test, it will definitely work on our smooth bikepaths. Looking forward to your products.
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E-bike stable at our house

Steintrike Mad Max full suspension trike rear Cute 100H going on: Whoops, Cute wheel broke but I fixed it.
Sun USX delta trike EbikeKit small geared front wheel sort of front suspension for wife

Agniusm/A123 AMP 20 36 volts on the Steini has been taken off.
2x16000 Multisport from HK now gone as they died after 2 years
New Luna 10S bottle battery 13.6AH now on mine
Relatively New 10S4Px2 for wife's bike giving 20ah @ 40 volts home made Panasonic from Tumich. BMS's rule.

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