Homemade Battery Packs

Batteries, Chargers, and Battery Management Systems.
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ridethelightning   1 MW

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Re: Homemade Battery Packs

Post by ridethelightning » Feb 14 2015 6:52am

sorry, should have made myself clearer...

im keen to find a modular, readymade, solderless/spotweldless battery pack building solution for 18650, not so much a diy one with magnets and bits of copper and/or springs and sometimes foam.... :|
which i believe i have seen all es threads about already :roll:

since there was mention of ordering such a system from china(?), i was interested.
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tomjasz   1.21 GW

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Re: Homemade Battery Packs

Post by tomjasz » Feb 14 2015 4:44pm

ridethelightning wrote:sorry, should have made myself clearer...

im keen to find a modular, readymade, solderless/spotweldless battery pack building solution for 18650, not so much a diy one with magnets and bits of copper and/or springs and sometimes foam.... :|
which i believe i have seen all es threads about already :roll:

since there was mention of ordering such a system from china(?), i was interested.
Apparently there are finished solderless packs also available. If I understand what you're saying?
I'm waiting to hear from them. I know 36V are available but don't know the lead time, volume needed to access etc.
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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tomjasz   1.21 GW

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Re: Homemade Battery Packs

Post by tomjasz » Feb 14 2015 4:47pm

ridethelightning wrote:
was it something like this?-
http://akbattery.en.alibaba.com/product ... _Pack.html

Exactly. Ankoa builds them and has a USA distributor. Waiting for more answers.
You can get to their direct site. Emails to them get referred to the US distributor in Utah, Electric Car Parts. Exciting stuff IMO
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Motobikewheels   100 W

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Re: Homemade Battery Packs

Post by Motobikewheels » Mar 10 2015 8:25pm

Figured i would get in on all the fun and build some cheap packs :wink:
IMG_20150310_142159[1].jpg
14p
IMG_20150310_142932[1].jpg
Kapton tape between each series group/ ptfe wire with coating striped soldered on to the tabs. Each cell top was cool to the touch right after soldering.
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Heavy duty pvc shrink wrap
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IMG_20150310_204209[1].jpg
2 x 3s packs for a total of 6s 30ah Tested from 4.1v to 3.6v. Not bad for used laptop packs
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\/ampa   100 W

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Re: Homemade Battery Packs

Post by \/ampa » Mar 10 2015 8:49pm

ANKAO sucks!
bshit.jpg

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DrkAngel   10 GW

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Re: Homemade Battery Packs

Post by DrkAngel » Mar 10 2015 9:29pm

roadrash wrote:Figured i would get in on all the fun and build some cheap packs :wink:
IMG_20150310_142159[1].jpg
IMG_20150310_142932[1].jpg
IMG_20150310_185748[1].jpg
IMG_20150310_191347[1].jpg
IMG_20150310_204209[1].jpg
IMG_20150306_115530[1].jpg
IMG_20150306_115506[1].jpg
6s pack 22.2V seemed inadequate for my 24V controller - bike.
LVC is near 21V and my controller seems to restrict current as LVC is neared, rather than an abrupt shutoff, so it acts near empty prematurely.
OK for meandering, but lacking for performance.

I went 7s and installed a cell level meter - alarm.

I have a 22.2V 30Ah pack built but am waiting till I can isolate LVC circuit and mod lower or defeat.
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.

I enjoy enlightening ... and enlivening the spirit of the innovators.

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tomjasz   1.21 GW

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Re: Homemade Battery Packs

Post by tomjasz » Mar 10 2015 9:46pm

\/ampa wrote:ANKAO sucks!
bshit.jpg
What sucks? Why? When? More information!
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Motobikewheels   100 W

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Re: Homemade Battery Packs

Post by Motobikewheels » Mar 10 2015 10:04pm

DrkAngel wrote:
roadrash wrote:Figured i would get in on all the fun and build some cheap packs :wink:
IMG_20150310_142159[1].jpg
IMG_20150310_142932[1].jpg
IMG_20150310_185748[1].jpg
IMG_20150310_191347[1].jpg
IMG_20150310_204209[1].jpg
IMG_20150306_115530[1].jpg
IMG_20150306_115506[1].jpg
6s pack 22.2V seemed inadequate for my 24V controller - bike.
LVC is near 21V and my controller seems to restrict current as LVC is neared, rather than an abrupt shutoff, so it acts near empty prematurely.
OK for meandering, but lacking for performance.

I went 7s and installed a cell level meter - alarm.

I have a 22.2V 30Ah pack built but am waiting till I can isolate LVC circuit and mod lower or defeat.
6s is just for the rear rack.

14s is going into the frame bag for a total of 20s. I also have the same case that slides on the top of the rack for 20s rc lipo for a hybrid setup.

Then there is the trailer i'm building that will have at least 30ah of rc lipo.

This will be the first time using anything but rc lipo on my bike. Doubling the capacity while sacrificing power output :cry:

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Re: Homemade Battery Packs

Post by opz.EST » Mar 12 2015 6:52am

Dear members,
I apologize if this is written somewhere, but can not find.
How many cuttof amps on CV stage of charging for 8p 18650 pack?
It takes forever. Do I need to change settings in B6 to higher cutoff current?

Thanks

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tomjasz   1.21 GW

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Re: Homemade Battery Packs

Post by tomjasz » Mar 12 2015 7:51am

roadrash wrote:.

Then there is the trailer i'm building that will have at least 30ah of rc lipo.
Woo hoo! Looking forward to pictures? I here you have a good wheel builder <wink>
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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tomjasz   1.21 GW

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Re: Homemade Battery Packs

Post by tomjasz » Mar 12 2015 4:00pm

\/ampa wrote:ANKAO sucks!
bshit.jpg

Well their answer sure does. Nothing. No a peep. They don't answer their USA contact about the system either. Go figure. Guessing they want to sell batteries not parts.
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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kje   100 W

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Re: Homemade Battery Packs

Post by kje » Mar 19 2015 6:13pm

Like you find used 18650 cells in laptop batteries. Where do you find used A123 26650 cells?

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tomjasz   1.21 GW

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Re: Homemade Battery Packs

Post by tomjasz » Mar 24 2015 9:28pm

https://m.youtube.com/watch?v=pxP0Cu00sZs

Refrigerate batteries before soldering. Go to last 15 minutes...
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

titooon2014   10 mW

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Re: Homemade Battery Packs

Post by titooon2014 » Apr 09 2015 5:12pm

I have to thank everybody in this thread, and a big one to DrkAngel, I have been experimenting a lot with reusing laptop cells and I am thrilled by the results, already three bikes equiped.

It has been a big inspiration, and i hope soon to share some of my work on cell soldering, when i finally reach a decent method to solder and assemble cells that is worth sharing. I am trying individual cell fusing atm.

And big thanks to endless sphere for being there !

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kje   100 W

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Re: Homemade Battery Packs

Post by kje » Apr 13 2015 9:33pm

titooon2014 wrote:I have to thank everybody in this thread, and a big one to DrkAngel, I have been experimenting a lot with reusing laptop cells and I am thrilled by the results, already three bikes equiped.

It has been a big inspiration, and i hope soon to share some of my work on cell soldering, when i finally reach a decent method to solder and assemble cells that is worth sharing. I am trying individual cell fusing atm.

And big thanks to endless sphere for being there !
We are looking forward to your sharing! :D

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DrkAngel   10 GW

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Re: Homemade Battery Packs

Post by DrkAngel » Apr 14 2015 4:01am

Gettin' ready for Spring
(Spring delayed due to snow and prolonged butter cold!- Upstate NY USA)
Still have mountains of snow in parking lots from clearing main streets! - mid April ...

25.9V 26Ah Lipo pack had a failure of the upper side 6 cells. Not enough proper support and poor choice of contact direction.
Image
I previously flipped the upper main brick of cells so they were not resting on the contacts - contact damage.

Since I figured better-safer cell distribution of the 84 cell lipo eZip rebuild, I decided to finally reconvert my 22.2V 30.24Ah (6s14p) to the 7s12p (25.9V 25.92Ah) format.

Image
I "wired" the 12 side cells together with tinned copper braid as a durable flexible alternative to wire.

I precisely equalized all banks on both packs (one at 4.145V)
I will compare deeply discharged voltages.
Any single or few banks slightly higher is fine, any single or few banks "low" will require careful inspection and testing for bad solder connection or blown fuse.
There is always the option, and room, of tacking an 18650 cell, or 2 to any bank of indeterminable low voltage-lesser capacity.

Ordered up 7s extension cables for balance plugs,, (longer than standard balance plugs).
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7s12p Blk.jpg
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.

I enjoy enlightening ... and enlivening the spirit of the innovators.

New & Improved - Acronym Definitions

Index - Homemade Battery Packs - Updated - November 2018

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Allex   1 GW

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Re: Homemade Battery Packs

Post by Allex » Apr 17 2015 10:05am

Here is my latest pack:
I have a simple battery layout, so a zig zag pattern will be best here. Similar to this one:
viewtopic.php?f=6&t=27911&start=150#p890139
The current distribution across cells will be very even this way.
The wire is a 1,5mm solid copper and should be plenty for this amount of current(25A Bafang BBS02).
Image

I used a can with compressed "air" to make the cells cold again after soldering. What I did is to spray while the can is up side down, then instead of gas we have super cold liquid coming out, making the cell colder than 0C° instantly
And of course a powerfull Iron(150W in my case) is important so I only touch the can for one second.

That damn hot glue did not want to stick to the heatshrink on the cells.
Image

999zip999   100 GW

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Re: Homemade Battery Packs

Post by 999zip999 » Apr 17 2015 12:21pm

Allex I love that you use a gasket on the positive end. It may help in keeping the heat away from the pos. end and it's blow out vent. That may blow from a solder iron method. It's time and amount of heat on the positive end where is easier to cause damage. I count 8s 1p ? Right. I want to put a small wire across the 4p neg. and pos. ends for 4p. for cell capacity sharing. Still Looking forward to progress either way.
Roadrash like to hear how this pack will keep up with RC lipo in line

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Allex   1 GW

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Re: Homemade Battery Packs

Post by Allex » Apr 17 2015 12:43pm

This pack is actually 14s4p :)

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madin88   100 MW

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Re: Homemade Battery Packs

Post by madin88 » Apr 17 2015 12:49pm

good job Allex. i very like the idea of using compressed air "spray" upside down for cooling. thanks for the tip.
as for the hot glue: i also noticed it does not stick very well once the cell has been touched. because of this i always clean them (with alcohol) before i apply the glue. after this i only was able to remove the glue WITH the shrinktube :)
further member izeman did a test and he said there can be big differences between different types and brands of hotglue. good brand glue probably will stick better than no name cheap stuff.

:lol: about 8s1p
- 10kW belt drive with Neumotor 8057: viewtopic.php?f=30&t=91144&start=50#p1377787
- Fully road legal (L1E approval) e-bike based on Votec V-FR frame
/ MXUS 3T / 17" Mitas MC11 / Adaptto Max-E / 20s12p 25R
- KTM Hardtail Pedelec / eZee V2 6T / 27,5" / Kelly KBSX @ 1,5kW / Torque PAS / CA-V3 / 13s4p Sanyo GA in Shark case

999zip999   100 GW

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Re: Homemade Battery Packs

Post by 999zip999 » Apr 17 2015 2:07pm

Many types of hot glue I like a low med grade as if needed to take apart the lower grade stuff can be crack off. Some rubbery and some more plastic ect. Maybe some time in the freezer would help taking it apart.

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Allex   1 GW

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Re: Homemade Battery Packs

Post by Allex » Apr 17 2015 4:44pm

This is where my can of compressed air comes in again.
I spray with it upsidedown on the hot glue, it becomes like -20C and is easy to chip off

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DrkAngel   10 GW

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2015 - Cell Testing Methodology

Post by DrkAngel » Apr 29 2015 8:33am

Updated!

2015 - My, presently, favorite developed best-fastest cell testing method.

Stage 1 - Charge cells
Charge all cells equally to a voltage above preferred use voltage. ... (4.20V?)
I charge 40p ... or 56p using modded 5V MeanWell (combine cells when of nearly equal voltage)
I am testing combining using steel wire and 8mm round Neodymium magnets during testing, rather than soldering.
Keep eye, or finger, on cells, remove any that start getting warm, 40p 2600mAh = 104Ah so 30A Meanwell will not create heat while charging unless cells are bad.

Stage 2 - eliminate leaky cells
Separate and allow cells to set and self discharge - the longer the better. (Minimum of several days )
Eliminate all with substantial voltage loss - keep only cells that maintain above your preferred use voltage.
I used to charge to 4.20V but have begun charging to 4.05V for certain cells and 4.15V for others.
(Different variations in formulation produce different optimal charged voltages)

Stage 3 Comparative IR
Test cell pairs for a comparative internal resistance.
While monitoring cell voltage, apply modest drain (2A?) and note voltage sag.
Remove any with notably greater voltage sag. These are likely very poor capacity cells or one of pair is bad. Separate and test for alternate use, flashlight etc.

Stage 4 - Capacity rate cells
With all cells at equal voltage, discharge at a measured rate.

2014 - I began using 28s2p, discharging with 2 - 60w light bulbs (~120V DC discharging 120w = 1A=1000mA per hour)
2x2600mAh cells = 5200mAh, 1000mA discharge = ~.2C. Capacity metered by time discharging till "empty" 3.60V*.

2015 - $12 90V V-A-W-mAh meter, (w/external power to maintain mAh reading), and various AC devices to provide ~1A discharge rate for 20s2p cells.

Monitor each cell voltage, remove any that fall below 3.60V* (voltage will drop suddenly at this voltage, so monitor carefully) and mark mAh from meter.
Discharging for 2.5 hours(50%+ oem rated capacity), 3 hours(60%+ oem rated capacity), or, if very good cells, 4 hours(80%+ oem rated capacity). Then rating cells by residual voltage, works nicely.
If cells don't last 2.5 hours, less than 50% capacity, probably not worth building into pack? (unless large bulk pack?)
Mark rated capacity on cells-pairs. (eg "3H 3.82V" or "3000mAh + 3.82V")
Method provides a fairly accurate comparative capacity ... 40 cells capacity tested in 3 hours.

Stage 5 - Build equal banks
Recharge all cells to equal voltage.
Build banks of equal capacity.
1. Using mAh rating of cells, build banks of equal total mAh.
or
2. Line up all cells, best to worst. Shuffle into banks.
7s = 1234567765432112345677654321 etc **
Should provide reasonably well balanced capacity banks.

Stage 6 - In Service test
Test full pack discharge, if not perfectly balanced at deep discharge, reshuffle cells to equalize, or add cell-cells to any weak bank.

Quick and easy and reasonably accurate method to test cells.

* See - Capacity Mapping (Optimal Charge-Discharge Voltages)

** See = Cell interconnections for cans - ES Wiki

Updated INDEX
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.

I enjoy enlightening ... and enlivening the spirit of the innovators.

New & Improved - Acronym Definitions

Index - Homemade Battery Packs - Updated - November 2018

EBike Toolbox - Bargains! $

Endless Sphere Wiki - Lost?

ASK1   10 mW

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Re: Homemade Battery Packs

Post by ASK1 » May 09 2015 12:03pm

Question for you guys - I'm making a 13s8p pack of 18650s. What are the rules for connecting the 8p groups in series?

It would be ideal if I could set it up like this:
Image

And have all of the parallel group connections on one side. However, this means the electrical path length (don't know if there is a better term for this) will be much shorter to battery 8 than it is to battery 1. And it seems that there would also be an increasing current gradient going across the conductor from battery 1 to battery 8.

Does this matter? Is this configuration ok?

If it matters, I am using 32A-rated tinned copper strap as my conductor, similar to the Zero motorcycle battery design.

Thanks.

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DrkAngel   10 GW

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Re: Homemade Battery Packs

Post by DrkAngel » May 09 2015 5:22pm

Current equalization is helped by providing extra heavy wire on the end "rails".
See = Cell interconnections for cans - ES Wiki

Alternate method for true equalization...
P1.jpg
P1.jpg (26.86 KiB) Viewed 3711 times
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.

I enjoy enlightening ... and enlivening the spirit of the innovators.

New & Improved - Acronym Definitions

Index - Homemade Battery Packs - Updated - November 2018

EBike Toolbox - Bargains! $

Endless Sphere Wiki - Lost?

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