Homemade Battery Packs

Batteries, Chargers, and Battery Management Systems.
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DrkAngel   10 GW

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Re: Homemade Battery Packs

Post by DrkAngel » May 09 2018 3:52am

.
...
Electric Wheelbarrel Battery Upgrade - Update

Moved about 4 cubic yards of topsoil, about 30 x 150' round trips, half with ~200lb, half empty.
12.3V full to 11.6V, about 50% of 25.92Ah pack.
25.92Ah is oem new rated, actual probably still greater than 20Ah, even with moderated charge voltage.
Wheel barrel with "new" lipo battery, certainly, a very usable tool!
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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DrkAngel   10 GW

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Re: 7s12p 25.9V 26.4Ah (2017 Build)

Post by DrkAngel » May 13 2018 10:59pm

DrkAngel wrote:
Nov 05 2017 7:55pm
.
...
25.9V 26.4Ah #1 finished

7s12p Samsung cells are capable of 120A continuous 240A surge but controllers are <30A and installed 40A fuse (trying new 58V fuses & holder)
Just finished 1, had to test drive it ... rain stopped for awhile.
No BMS installed! Turned out were only 20A continuous.
Mostly worried about parasitic draw when customers let set for the Winter.

Image

10s2p Bricks disassembled into 8s2p + 2s2p and I was oh so tempted to build as 8s12p ... but needed for 24V bikes and I already have the 7s chargers.
Image

25.9V 26.4Ah #2 nearly complete
Just need to run the parallels and power rails and install fuse.
Samsung eZip pack builds ... both doing very nice.
Mine is holding balance nicely and sold one just passed Spring checkup!
New owner of my rebuilt 2009 eZip LS is very happy.
12ga wheel rebuild doing great with geared down 24V 450w motor (14mph 25.9V @ ~485w for HD load or hills.)
Samsung ICR18650-22p cell doing excellent in all builds, so far. Wish I'd bought another 20 36V 4.4Ah packs!!!

2015 eZip LPo build, for other neighbor tuned up and doing great.
Upgraded him in 2015 with 16T freewheel and 25.9V LiPo battery for a comfortable 20 mph.
Now he wants more speed ... hmmm.
Could gear him for 23 or 27mph, but would stress the Laptop LiPo!
Could bump him up to 37V for a near 30mph, but would waste the 25.9V build.
Think I'll just change his speedometer from MPH to KPH ... charge him $50 ?
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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bobbill   10 mW

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Re: Homemade Battery Packs

Post by bobbill » May 14 2018 7:15am

Am only a newbie and feel "small" with the wee 10s3p still underway...

Almost went bigger, but decided to do two of these instead of big one, no need speed.

BTW I think the cells are Pan... PFs, still have to assemble the mess, clean off bench first, raining anyway and one thing at a time.

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DrkAngel   10 GW

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Re: Homemade Battery Packs

Post by DrkAngel » May 30 2018 8:42am

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...
Laptop LiPo vs Samsung ICR18650-22p

eZip RMB battery rebuilds-upgrades
laptop LiPo = 25.9V 25.92Ah with 4.20V - 3.70V usable voltage limited to 1C continuous - 2C surge (recommended)
Samsung 18650 = 25.9V 26.4Ah with 4.20V - 3.40V usable voltage limited to 4.5C continuous - 9C surge (recommended)

eZip 24V 450w motor @ 25.9V can output ~480w
24A controller means pack is never tasked at greater than 1C

Weather is warm and my old 2014 eZip laptop LiPo build is shining again - loves 80 degree weather!
Main advantage is the narrower voltage range keeps up speed and performance, (in warm-hot weather).
29.4V - 25.9V (560w - 480w motor outputs : 20.5mph - 18.2mph)

25.9V LiPo.jpg
25.9V LiPo.jpg (216.97 KiB) Viewed 2243 times
2018 Samsung build is most impressive in cold weather, the low IR offsets the detriments of a cold battery!
Downside is that its deeper-lower usable voltage noticeably degrades speed and power, as discharge progresses.
29.4V - 23.8V (560w - 430w motor outputs : 20.5mph - 16.9mph)

25.9V Samsung.jpg
25.9V Samsung.jpg (217.82 KiB) Viewed 2243 times
For casual cruising either is just great, but in my typical WOT mode, the Samsung build is a bit annoying.

Next Project
500w Front Geared Hub (eBikeling)

Just ordered one of the cheap ebikeling 500w geared front hub motors for one of my 8spd disc brake mountain bikes. Will upgrade tires and seat and dedicate as my pedal assist transporter. Bike has trigger shifter built onto brake handles, so twist throttle will work nicely, thumb throttle seems imprecise-annoying - imo.

Anyone have better specs on ebikeling 500w geared front hub motor?
Cruising speed?
No load motor speed?

Will graph up speed and assist capability after received and built.
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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DrkAngel   10 GW

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Re: Homemade Battery Packs

Post by DrkAngel » Jun 02 2018 1:18am

The newer 18650 high capacity cells have an even lower usable voltage range, 4.20V - 3.20V usable voltage.
29.4V - 22.4V (560w - 400w motor outputs : 20.5mph - 15.9mph)
25.9V deep discharge.jpg
25.9V deep discharge.jpg (217.49 KiB) Viewed 2168 times
Performance drop is so pronounced as to be ... inadequate-pitiful?
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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jcool3   10 mW

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Re: Homemade Battery Packs

Post by jcool3 » Jun 06 2018 12:27pm

jcool3 wrote:
Mar 02 2018 1:21pm
4 SPIM08HP 3.7V 8AH LITHIUM POLYMER BATTERIES 25C 200A SUPER CELLS 24V 36V 48V on ebay https://www.ebay.com/itm/4-SPIM08HP-3-7 ... 6016.l4276
10 of these in series would run my ebike. 37v Question: best way to charge them and do they need to be balance charged?
Anyone using these packs on ebikes?
Screen Shot 2018-06-07 at 6.01.39 AM.png
Screen Shot 2018-06-07 at 6.01.39 AM.png (45.99 KiB) Viewed 2038 times

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DrkAngel   10 GW

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Re: Homemade Battery Packs

Post by DrkAngel » Jun 10 2018 4:30am

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...
Update on recent battery builds

Floureon 7S 5000mah 25.9V 40C Lipo Battery
Lipo output as rated and after a year of occasional use have maintained within 3/100V equalization. Used mainly with 36V 600w WE brush front hub motor as cruise mode, nice range at ~16-18mph.
DrkAngel wrote:
Jun 28 2017 6:06am
Now that the ...
Floureon 7S 5000mah 25.9V 40C Lipo Battery <$60 delivered from USA are all sold ...

"Recommended for rebuild of eZip 24V RMB battery packs.
Will fit up to 4 x 5Ah = 25.9V 20Ah vs oem 24V 10Ah (5-6Ah usable) SLA.
Every 24V controller I've ever tested works properly with 7s 25.9V battery, but a bit faster with some more torque ...

Image

eZip RMB pack internal dimensions:
150mm x 65mm x 230mm"

... I am forced to ration my 5 brick inventory.
2x = 25.9V 10Ah testbed looking good, but will likely add BMS and sell with a refurbished eZip. 20-30A $10 BMS - is perfect for 1 eBike with 20A controller..
Samsung ICR18650-22p have maintained excellently. Near perfect balance after 7 months on fairly continuous use!
DrkAngel wrote:
Nov 05 2017 7:55pm
.
...
25.9V 26.4Ah #1 finished

7s12p Samsung cells are capable of 120A continuous 240A surge but controllers are <30A and installed 40A fuse (trying new 58V fuses & holder)
Just finished 1, had to test drive it ... rain stopped for awhile.
No BMS installed! Turned out were only 20A continuous.
Mostly worried about parasitic draw when customers let set for the Winter.

Image
36V 4.4Ah Hoverboard batteries (Samsung cells)
Used 1st in my Snow Beast and more recently with my WE 36V 600w front hub build, these hoverboard batteries seem perfect. I do charge to a full 42V to insure protection-balance functions. Confirmed via the external points on the BMS. Usually used in pairs, I quick swap pairs and charge at 42V with a modified 48V 150w MeanWell.
DrkAngel wrote:
Dec 15 2017 10:23pm
While might not ethically be a homemade battery pack ...
... so simple, easy and useful, I had to post it up.

Got a large batch of 36V 4.4Ah (genuine Samsung cells!) hoverboard batteries.
Previously paralleled together 4 for a 36V 17.6Ah battery for testing old brush hub motor.
Image

Anyhow, 3 hoverboard batteries fit nicely in the eZip RMB battery case.

Image

For my Snow Beast, eZip (24V 450w) volted up and geared down for 20mph@36V (675w). The Samsung cells seem very cold tolerant! 13.2Ah might not seem like much but great for my short Winter trips, nice for short spurts near 30mph if used on my cruiser eZips (Dual battery rack and switch allowing 25.9V on one side and 36V on the other). Just flip the switch for TURBO
Mower upgrade 1 year report
Excellent! Nice balance and durability, after setting since last season, balance was within 2/100V. Review is more about the mower. Being a mulching mower it bogs on heavy or wet grass. On nice dry moderate height grass it does great ... important to keep blade sharp for nest performance.
DrkAngel wrote:
Jun 05 2017 10:04pm
Mower upgrade
Upgraded my 24V 20Ah SLA mower last year.
Been running with upgraded 22.2V 34.56Ah (6s16p) Old used Laptop Lipo at probably 25Ah++.
Image

Works OK but, since I run as a mulching mower, the extra rpm and torque seems advisable.
So, pushed over the main brick and was able to squeeze in another 1s16p.
Previous 6s were matched in capacity and IR, added bank was just insured to be of better!
Lesser would drag down whole pack - better allows full use, with power to spare.

Image

Yeah, oops ...
6s battery had no fuse installed.
Had to rewire, so dropped in a 40A fuse + holder.
Too wet to try and weather won't dry up for a few days but I expect performance to be noticeably improved!

Home Depot finally has the 20" mulching blade available again so will get a spare, only $9.95 for the Homelite cordless mower.
Straightened and filed the worst nicks out of the old blade but new blade will probably improve even more.

Cells are surrounded and set upon closed cell foam.
Prevents movement and protects from vibration and rough handling.
At probably less than 1C discharge, I am not worried about battery heat.
33.3V 31.2Ah eZip battery
Not used nearly as much as planned, 36V hoverboard batteries cover all its planned applications. Over 1 kWh, I still plan on trip use or extended cruises. Has good, near rated, capacity and showed excellent balance at last inspection.
DrkAngel wrote:
Jan 24 2018 5:33pm
... :lol: ...

Finally finished 33.3V 31.2Ah eZip battery!
Naming MaxCell due to the 9s12p being the maximum number of cells that will physically fit in eZip RMB battery shell.
(And to differentiate from my 33.3V 43.2Ah insulated "Cool Cell")

Simple but very snug fit. To secure cells tightly and to protect solder points, top and bottom are covered with 1/8" closed cell foam sheets. Had to put a little weight on case to close properly ... center bows out a bit, center screw removed to allow 9s12p fit.

Side A was nice and straight forward, nice straight runs with heavy tinned copper braid.
Any connection over positive ends of cells were protected with additional HD duct tape!


Image

Side B required a few curves, which was easy if braid curved before flattening.


Image

Installed the new 58V rated fuse holder with 40A fuse. Upgraded charging wire to 18ga, unlikely to charge over 5A, will upgrade to 14ga if I ever want to charge at max recommended 15A.
Entire battery wrapped in clear boxing tape to stabilize and protect. Meter leads poke through easily, for testing.
Sides wedged firmly with sturdy cardboard.

I did add 1/2 cell height wood blocks to support rows 2-4-6-8
Image

MaxCell Specs:
33.3V 31.2Ah = 1038.96mAh - 1kWh+
9s12p = 108 cells
NOS from HP laptop batteries.
72 Sony 2600mAh + 36 Sanyo 2600mAh
Arraigned as 9s8p(Sony)+4p(Sanyo)
Both types effectively "empty" at a static 3.70V
20-21mph (will go 25mph in my upgeared eZips)
Including shell, battery build weighs 12lb 0oz

Compare to eZip OEM SLA battery:
24V 10Ah = 240mAh < 120mAh usable
15-16mph
15lb 9oz
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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Index - Homemade Battery Packs - Updated - November 2018

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DrkAngel   10 GW

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Re: Homemade Battery Packs

Post by DrkAngel » Jun 22 2018 9:10am

37V 4400mAh Hover board Batteries (Samsung ICR18650-22p cells) are proving excellent beyond all expectation!
Discharge graph shows cells effectively empty at a static 3.40V.
BMS reportedly protects cells at 2.60V.
2 packs in parallel - Recently discharged deeply, but did not hit BMS LVC, discharged voltage was all cells at 3.33V-3.34V, within 1/100V!!!

With 2 packs, Typical discharge range is 1C (8.8A) -3C (26.4A)
Battery (combined) rated 40A continuous 80A surge.
BMSs (combined) rated 40-60A?

Just putting together 3x 37V 4.4Ah(37V 13.2Ah) "pack" for local eBiker, as auxiliary pack for with his 6 year old 20Ah LiFePO4 battery.
12 hour LiFePO4 2A charge vs 3 hour Li-Co 5A charge!
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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armandd   10 W

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Re: Homemade Battery Packs

Post by armandd » Jul 13 2018 8:43pm

DrkAngel,

Are these packs for sale? Is it possible to ship to Malaysia? Thanks!

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DrkAngel   10 GW

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Cell Testing Methodology

Post by DrkAngel » Jul 15 2018 7:49am

copied post of easy cell testing procedure

Test cells the way I test used cells

1. self discharge
Charge all cells to same exact voltage
Let set several days
Discard any with noticeable voltage loss

2. IR (Internal resistance)

Comparative IR - identical cells under identical discharge will sag in voltage to the same voltage
With cells of identical voltage
Connect discharge device to cells, individually, in turn
check and note cell voltage at a specific time during discharge
Discard any with excessive voltage sag

3. Capacity
From full voltage, run a metered discharge
discard any with substantial capacity loss
or
after marking each cell with capacity, build banks of identical capacity

Bulk testing
After self-discharge test
String batches of 30s cells in series = ~120V
Discharge using 2x 60w light bulbs = 120w
Monitor all cells
Each hour of discharge = 1Ah of capacity
Stop discharge when any cell hits low voltage
3.40V - very safe discharge point, don't recommend below 3.00V
Label each cell with residual voltage
1hr = 1000mAh + 3.95V?
2hr = 2000mAh + 3.75?
3hr = 3000mAh + 3.45?

Bulk building
With all cells identically discharged
Sort all cells from best remaining voltage to worst
Sort into banks with best cells to worst
10s >> 1 2 3 4 5 6 7 8 9 10 10 9 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 9 10 etc
This will create banks of nearly identical capacity ... banks will safely balance if within ~.1V ... barring any cells of radically different voltage ...
Combine cells - since all cells are free of self-discharge and were identically discharged, simply bulk charge to full pack voltage
Good Lithium cells, discharged at moderate rate will bulk recharge right back to their starting voltage!
Should have good solid pack of reliable tested cells.
Best news ...
Should be good for bulk charging ... with no need for balance charging!

Oops! I forgot, good for bulk charging if pack of sufficient size for moderate discharge rate.
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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dirt huffer   100 mW

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Re: Homemade Battery Packs

Post by dirt huffer » Jul 18 2018 9:24am

Thanks for the awesome Wiki!
Quick question... what program do you guys use to determine size/shape/cell count/orientation of 18650 cell pack? I have a full suspension frame and need to get creative to pack as many cells in it as i can

.

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DrkAngel   10 GW

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Mapping Cell Placement

Post by DrkAngel » Jul 31 2018 7:02am

dirt huffer wrote:
Jul 18 2018 9:24am
Thanks for the awesome Wiki!
QuNick question... what program do you guys use to determine size/shape/cell count/orientation of 18650 cell pack? I have a full suspension frame and need to get creative to pack as many cells in it as i can

.
No known "programs"

Mapping Cell Placement

Measure and draw available space, to scale, on drawing paper.
Break open some rolls of pennies. (19mm penny is close to 18mm cell size)
Arrange into and tightly fill "available space".
Count pennies 120?, divide by desired voltage 48V = 13.
120/13=9.23 9x13=117 pennies-cells
Arrange into 13 piles of 9 pennies.
Mark each pile with a number (underline 9 to avoid confusion with 6)
Arrange into "space".
You should now have a plan-map.
Last edited by DrkAngel on Jul 31 2018 8:16am, edited 1 time in total.
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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pratikdas87   10 mW

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Re: Homemade Battery Packs

Post by pratikdas87 » Jul 31 2018 7:48am

Skalabala wrote:
Jul 18 2014 10:48am
stealthhack, buddy be careful with what you are doing.
I see you have 3.6V mixed with 3.7V cells. So the max voltage should not go higher than 4.05V and lowest 3.75V otherwise you will be looking for trouble with old cells!
Did you do a sag test on each bank while putting a 1C load on the whole pack?

Read a bit more in this thread :) As you have a really BIG bomb there! :lol:
Hey there,
I am following this thread for sometime. the point you are mentioning, mixing 3.6 cells with 3.7V cells, seems interesting. Why do youthink it's a problem? why the voltage limit of 4.05 to 3.75??

Thanks

pratikdas87   10 mW

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Re: Homemade Battery Packs

Post by pratikdas87 » Jul 31 2018 8:18am

DrkAngel wrote:
Jan 30 2015 5:52am
tomjasz wrote:I've got some new salvaged 18650 batteries from laptop packs the read 3.7v, 24 of them, the packs say they were 14.4 volts but that doesn't add up. 8X3.7=29.6. Huh? Also I have 18 from a 3M projector that rated the battery pack at 10.85 or 11.1v. They read 3.6v. That math pans out. Please explain. 18650 batts that are 3.6v not 4.2? How do I utilize them? I was hoping for 7s for replacement in my little Schwann scooters for the 24v SLA. How do I charge them? Build them into a 7s6p and use a Tenergy 2a 25.9 smart charger? Can a balance charger be used? Wouldn't that be better since you seem to say these should be charged a lower input? Confused but having fun at collecting the goods. Soon to have a new salvage source that may be very prolific. So I need to figure this charging thing out. Is there a BMS out there that will work? Is there a balance charger that can be used as well?
4s2p 4 x 3.6V = 14.4V

I would recommend against using 3.6V and 3.7V in the same pack ... unless you use an equal assortment in each bank and limit usable voltage between 3.7V and 4.10V?

Using the iMax B8 (will balance charge 7s) as an example, there are 2 LiCo charge settings.
Lion @ 3.6V for charging to ≤4.10V and Lipo @ 3.7V for charging to ≤4.20V

After removing any cells with self-discharge and capacity matching each bank, balance charging at every cycle becomes unnecessary.
I do recommend the cell level voltage meter-alarm as a pack monitor-safety device. see - eBike Toolbox
Hey DrKAngle, I have followed your post for a long time. They are very informative. I am building my pack. I have Li-ion cells from laptop batteries, 10.8V (3.6 nominal), 11.1V (3.7 nominal). as per your comment, i should not mix them? are the chemistry of these cells so different?

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DrkAngel   10 GW

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Re: Homemade Battery Packs

Post by DrkAngel » Jul 31 2018 8:48am

3.6V vs 3.7V rated cells are rated as the average discharge voltage over the entire discharge cycle at a specified discharge rate.
Factored are Internal Resistance (IR) and rated DOD
Not as the discharged "empty" voltage, more a coincidence than a "rule", with older LiCo cells.

Previously, not so important if equally distributed among banks.
Mixing old tech with new tech has become a much more important factor.
(Typically not a factor with Laptop cells.)

Older LiCo cells were effectively "empty" near 3.6-3.75V.
Newer tech cells drop this "empty" point to 3.4V or even 3.2V.
Mixing will either waste capacity on the newer cells or dangerously over discharge the older cells.

4.10V was recommended as optimal charged voltage due to observed optimal capacity vs enhanced cell life.
"Optimal" varies by cell "model" and requires mapping to determine ... but can often be estimated by looking at manufacturers discharge graph.

Just don't forget to test cells!
self discharge
IR
capacity
etc.
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?

pratikdas87   10 mW

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Re: 2015 - Cell Testing Methodology

Post by pratikdas87 » Jul 31 2018 10:21am

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.


how do you define, notably greater voltage sag?

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DrkAngel   10 GW

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Re: Homemade Battery Packs

Post by DrkAngel » Jul 31 2018 12:07pm

When testing same brand-model cells:
If 1 pair sags .10V and another sags .20V ... likely, one cell is bad.
Separate and test individually, either 1 cell is bad or both are poor.

Use of "comparative IR" is to compare cells against same brand-model.

"Cheap" IR meters seem inaccurate to ridiculously non-functional.
Proper IR meters, typically, test at 1C. ... IIRC
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! $

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pratikdas87   10 mW

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Re: Homemade Battery Packs

Post by pratikdas87 » Aug 03 2018 11:29pm

DrkAngel wrote:
Jul 31 2018 8:48am
3.6V vs 3.7V rated cells are rated as the average discharge voltage over the entire discharge cycle at a specified discharge rate.
Factored are Internal Resistance (IR) and rated DOD
Not as the discharged "empty" voltage, more a coincidence than a "rule", with older LiCo cells.

Previously, not so important if equally distributed among banks.
Mixing old tech with new tech has become a much more important factor.
(Typically not a factor with Laptop cells.)

Older LiCo cells were effectively "empty" near 3.6-3.75V.
Newer tech cells drop this "empty" point to 3.4V or even 3.2V.
Mixing will either waste capacity on the newer cells or dangerously over discharge the older cells.

4.10V was recommended as optimal charged voltage due to observed optimal capacity vs enhanced cell life.
"Optimal" varies by cell "model" and requires mapping to determine ... but can often be estimated by looking at manufacturers discharge graph.

Just don't forget to test cells!
self discharge
IR
capacity
etc.

Thank you so much for the valuable comments. I am doing the IR, SD and apacity tests. I just want to understand, when you say Older LiCo cells and new ones, which year of manufacturing you are talking about? (i mean for old and for new).

Thanks

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DrkAngel   10 GW

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Re: Homemade Battery Packs

Post by DrkAngel » Aug 04 2018 5:02am

Only in the past 2 years have I noticed any of the lower voltage cells in any laptop packs. Most are still "standard " LiCo. Mixing together, a few, has no determent except not taking full advantage of full capacity of, the "few".
Just maintain a universally safe ≥3.70V static discharged voltage, measured after throttle released.
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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DrkAngel   10 GW

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Location: Upstate-Western-Southern Tier NY. USA

Hoverboard 36V 4.4Ah Bargain

Post by DrkAngel » Aug 23 2018 8:39am

.
...
Cheap "new" 36V 4.4Ah hoverboard batteries.

Just had offer accepted for "Random 36V 4.4Ah hoverboard battery packs (new) Samsung or LG" @ 4 for $100, $25 each.
"Guaranteed delivery" by Monday.
Will post up info as soon as delivered, link and recommendation as soon as preliminarily tested.

Update - Tracking shows Saturday delivery.
Last edited by DrkAngel on Sep 02 2018 5:11pm, edited 1 time in total.
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?

User avatar
DrkAngel   10 GW

10 GW
Posts: 4983
Joined: Dec 15 2010 11:14am
Location: Upstate-Western-Southern Tier NY. USA

Re: Hoverboard 36V 4.4Ah Bargain

Post by DrkAngel » Aug 24 2018 7:05pm

DrkAngel wrote:
Aug 23 2018 8:39am
Just had offer accepted for "Random 36V 4.4Ah hoverboard battery packs (new) Samsung or LG" @ 4 for $100, $25 each.
"Guaranteed delivery" by Monday.
Will post up info as soon as delivered, link and recommendation as soon as preliminarily tested.

Update - Tracking shows Saturday delivery.
Received the 4 packs.
All labeled 36V 4.4Ah
2 labeled with Samsung, other 2 of no known manufacturer.
Only 1 charges to near 4.20V!
Discharged all below 3.40V and doing metered charge on each. Will have results tomorrow.
Have not broken open double shrink wrapped packs yet, will after charge results tomorrow.

Not charging to full voltage is typically the result of a low capacity cell, or cells, which will charge higher triggering the high cell voltage safety-disconnect.
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?

User avatar
DrkAngel   10 GW

10 GW
Posts: 4983
Joined: Dec 15 2010 11:14am
Location: Upstate-Western-Southern Tier NY. USA

Re: Hoverboard 36V 4.4Ah Bargain

Post by DrkAngel » Aug 29 2018 8:21am

DrkAngel wrote:
Aug 24 2018 7:05pm
DrkAngel wrote:
Aug 23 2018 8:39am
Just had offer accepted for "Random 36V 4.4Ah hoverboard battery packs (new) Samsung or LG" @ 4 for $100, $25 each.
"Guaranteed delivery" by Monday.
Will post up info as soon as delivered, link and recommendation as soon as preliminarily tested.

Update - Tracking shows Saturday delivery.
Received the 4 packs.
All labeled 36V 4.4Ah
2 labeled with Samsung, other 2 of no known manufacturer.
Only 1 charges to near 4.20V!
Discharged all below 3.40V and doing metered charge on each. Will have results tomorrow.
Have not broken open double shrink wrapped packs yet, will after charge results tomorrow.

Not charging to full voltage is typically the result of a low capacity cell, or cells, which will charge higher triggering the high cell voltage safety-disconnect.
3 of 4 packs defective!
Discharged below 34V then metered charge with 3 of a metered capacity below 2.0Ah and will not accept 42V charge.
Indicates old(?) cells of differing voltage that hit cell low and/or high BMS voltage cutoffs.
Disassembled 1 pack and manually balanced cell voltages and will cycle again to note high and low voltage balances and capacity.
Already complained to seller and awaiting reply.
Not willing to recommend until response received.
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?

User avatar
DrkAngel   10 GW

10 GW
Posts: 4983
Joined: Dec 15 2010 11:14am
Location: Upstate-Western-Southern Tier NY. USA

Re: Hoverboard 36V 4.4Ah Bargain

Post by DrkAngel » Sep 01 2018 9:30pm

DrkAngel wrote:
Aug 29 2018 8:21am
DrkAngel wrote:
Aug 24 2018 7:05pm
DrkAngel wrote:
Aug 23 2018 8:39am
Just had offer accepted for "Random 36V 4.4Ah hoverboard battery packs (new) Samsung or LG" @ 4 for $100, $25 each.
"Guaranteed delivery" by Monday.
Will post up info as soon as delivered, link and recommendation as soon as preliminarily tested.

Update - Tracking shows Saturday delivery.
Received the 4 packs.
All labeled 36V 4.4Ah
2 labeled with Samsung, other 2 of no known manufacturer.
Only 1 charges to near 4.20V!
Discharged all below 3.40V and doing metered charge on each. Will have results tomorrow.
Have not broken open double shrink wrapped packs yet, will after charge results tomorrow.

Not charging to full voltage is typically the result of a low capacity cell, or cells, which will charge higher triggering the high cell voltage safety-disconnect.
3 of 4 packs defective!
Discharged below 34V then metered charge with 3 of a metered capacity below 2.0Ah and will not accept 42V charge.
Indicates old(?) cells of differing voltage that hit cell low and/or high BMS voltage cutoffs.
Disassembled 1 pack and manually balanced cell voltages and will cycle again to note high and low voltage balances and capacity.
Already complained to seller and awaiting reply.
Not willing to recommend until response received.
Packs appear to be bulk rejects ... seller sending 3 replacement packs.
"Repaired" 2 packs:
replaced 1 low capacity pair,
Replaced 2 low capacity pairs ... then noticed both removed pairs were never banded together ... cheap-unskilled labor.
3rd poor pack has no repair possible. Well, it does have "Samsung" cells, some dead "Samsung" cells ...
10 no brand generic blue cells and 10 "Samsung" cells none of which (Samsungs) were connected, with 0V ... for weight or to claim "Samsung" ???
Will post up pictures.

Can't really recommend this auction!
But will post up link ... Only for the DIYer!
Cell salvage?
Oops, sale ended anyhow...
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?

User avatar
DrkAngel   10 GW

10 GW
Posts: 4983
Joined: Dec 15 2010 11:14am
Location: Upstate-Western-Southern Tier NY. USA

Re: Homemade Battery Packs

Post by DrkAngel » Sep 02 2018 2:33pm

.
...
"36V 4.4Ah Hoverboard Samsung Battery"

Wow! Samsung cells!

IMG_9320.jpg
IMG_9320.jpg (121.93 KiB) Viewed 924 times

Whaa?

IMG_9321.jpg
IMG_9321.jpg (104.88 KiB) Viewed 924 times

What the hell!!!

IMG_9323.jpg
IMG_9323.jpg (114.88 KiB) Viewed 924 times

All "Samsung" cells dead with 0V, and yes, not even connected.

.
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?

User avatar
DrkAngel   10 GW

10 GW
Posts: 4983
Joined: Dec 15 2010 11:14am
Location: Upstate-Western-Southern Tier NY. USA

Re: Homemade Battery Packs

Post by DrkAngel » Sep 02 2018 8:53pm

Battery repair success.
3 of 4 defective batteries now metered at 4Ah+.
Got 3 more replacements, likely defective too, scheduled for delivery next week.
Could be as many as 6 good batteries for $100 ... and some work. 36V 26.4Ah .733kWh

Hoverboard batteries, typically, do not have the balance function with their BMS.
Opening the pack and manually balancing recommended, if usable capacity drops, or fails to fully charge to 4.20V.
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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