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Re: Homemade Battery Packs

Posted: Nov 25 2018 4:40pm
by DrkAngel
Index
DrkAngel wrote:
Nov 05 2017 7:55pm
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...
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.
Entering it's 2nd year, and Winter, these Samsung cells are performing excellently.
Most markedly, #1 build maintains equality within 2/100ths V at near empty discharge.
A testament to genuine Samsung icr18650-22p!

Tested at 14ºF and still outputs good Voltage-amperage.
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Re: Homemade Battery Packs

Posted: Nov 25 2018 7:47pm
by DrkAngel
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...
Updated Lithium Chemistry Chart
Li-Chemistries.jpg
Li-Chemistries.jpg (64.02 KiB) Viewed 2102 times

Link to full Article
- descriptions

Re: Homemade Battery Packs

Posted: Nov 26 2018 6:22am
by docware
DrkAngel ,
thank you for our yesterday´s conversation. I became interested in Li-ion cell just in summer 2017, so cells like Sanyo GA, LG MJ1, Samsung 30Q, … are for me really normal. Not realizing that in fact it is currently „state of the art“. So looking at these modern cells, I still didn´t uderstand, why recomended storage voltage is 3,8 V. After our discussion I have made conclusion that 3,8 V was valid few years ago and for mentioned modern cells we can use lower storage voltage 3,5 V. Just we have to know what cells are in our battery and use storage voltage accordingly. If we don´t know the cells type, then to be on the safe side, we should use storage voltage 3,7 – 3,8 V. Any comment about my conclusion ?

Re: Homemade Battery Packs

Posted: Nov 26 2018 8:55am
by DrkAngel
I mentioned storing my older cells @ 3.85V, 3.65V for my newer chemistry Samsung and determining optimal voltage range for any cell type and storing at the 20-50% capacity voltage.
Insuring , of course, that optimal (usable) voltage is determined at static voltage - Some manufacturers discharge graphs show discharging to 2.80V, however , this is during discharge and actual cell voltage recovers to, and is actually, 3.2V, 3.4V or even 3.6V+
Actually discharging any cell to a static 2.8V is damaging and dangerous!!!

How to determine optimal usable voltage and therefore reasonable storage voltage?
Manufactures specs - most reputable manufacturers produce a discharge graph, lowest rate discharge line usually demonstrates a cliff where voltage drops drastically, this indicates near minimal "usable" voltage.
Independent tests - Best Test Site!
Shipped voltage on new - law requires all cells-batteries to be shipped charged at 30% of capacity! - excepting batteries shipped with\in device. (measure voltage before 1st charge!) High, and low, voltages considered a danger risk!
"Safe" voltage for Unknown - 3.80V

Most recent RC LiPo purchases - voltages shipped at:
#1 batch shipped at 3.81-3.82V per cell
#2 batch shipped at 3.84V per cell
Indicates LiCo02 chemistry with ~ 4.20V - ±3.60V optimal usable voltages

"New" cells received with more than a minor variance in cell voltages should be considered "suspect" and in need of thorough testing or return.

Re: Homemade Battery Packs

Posted: Nov 26 2018 11:52am
by Philaphlous
For those of us that are using the 18650 battery spacers...are you gluing the cells into the spacers or just leaving the cells in loose?

Re: Homemade Battery Packs

Posted: Dec 06 2018 10:43pm
by Matador
FROM HOOVERBOARD PACKS of AlarmHookup.... Remasterized the cells...
Total cost 180 USD (including all, even the kapton tape, connection, cable, connectors, BMS, cell holders and cells...).
See whole build here (with casing) :https://endless-sphere.com/forums/viewt ... 5#p1412338
r.jpg
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s.jpg
s.jpg (441.54 KiB) Viewed 992 times
Specification are:
14S4P of Samsung MF1 (2150mAh, 10A);
Capacity : 8.6Ah
Max discharge : 40A (cell specs) ; 45A (BMS - continous rating)
Nominal voltage : 51.4V (3.67 V)
Max voltage: 58.8V - Min voltage : 38.5V (BMS LVC of 2.75V)
Chemistry : NMC - LiNiMnCoO2
Internal resistance : 125 mOhm DCIR measured (after the BMS when applying 12.8 amp load): Net equivalent of 36 mOhm per cells (including the effect of added BMS and connector resistance).
BMS: 45A continuous; 200A; balance current 60 mA
Cell connections: Through top grade pure 0.127mm thick copper sheet, soldered with 140W iron
Cell specification samsung MF1:
LG MF1 (hoverboard).pdf
(445.44 KiB) Downloaded 28 times
Matador.

Lithiumization or Ni-Cd Rejuvination?

Posted: Dec 23 2018 7:40am
by DrkAngel
Almost embarrassed to note, here ...
Sorting through my piles of garage sale cordless tools, looking for items worthy of lithium upgrades. Found Ryobi 14.4V VSR drill and light (Blue - old models) in large plastic case. Both Ni-Cd batteries at empty and would not charge.
So, decided to "shock them up" as a rejuvenation method, figured not worthy of Lithiumization ...
Standard recommendation is shocking at 200% rated voltage, closest I have are my 36V hoverboard packs, so I paralleled a pair and and sparked 41V voltage into the Ni-Cd battery terminals. Several brief contacts then a single 2-3 second contact. Supposedly melting-burning dendrites that short cells or cause self-discharge.

1 week later, cells are maintaining good voltage and I have a good drill and light set that I will never use ... damn it all!
16.8V 2A Lithium charger - $3.89

6-24V 3w LED -$2.98

Similar 12V Ryobi set
Shocked with 24V SLA and successfully rejuvenated 1, of 2, battery packs.
Drill and light look like new, so might Lithiumize. Will integrate 3s 2A charger into oem charger body.
12.6V 2A Lithium Charger -$3.98
Will go LED upgrade on light.
4-12V 3w Flashlight bulb - $2.73

Re: Homemade Battery Packs

Posted: Mar 09 2019 11:27am
by DrkAngel
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Spring?

Time to get ready for Spring!
I have about 5 batteries and a couple+ bikes to get ready for "the road".

Batteries
Summer weight (Laptop cells)
Test and balance check
25.9V 25.92Ah (2014 build - laptop lipo)
33.3V 31.2Ah MaxCell 1kWh (NOS HP laptop cells)
10.8V 25.9.Ah Wheelbarrel battery (will add 12V (3s) 40A continuous BMS)
25.9V 34.56Ah Mower battery needs 1 bank replaced ... the last add-in bank from lesser cells ... :oops: ...
(May add 20A continuous 50A cut-off BMS ... and will monitor for BMS parasitic draw!)

HO (High Output) 36V 4.4Ah Hoverboard batteries and various builds therefrom ...
25.9V 2.64Ah eZip build
cordless power tools 18V 4.4Ah Lithium rebuilds from Ni-Cd packs etc

Will also build 7.2V & 10.8V Laptop Lipo for 6V and 12V Florescent lanterns. (not worth converting to LED)

Bikes
Still need to correct motor wheel spoke holes on 2 eco-ride eZips. Spoke holes too small-tight forcing nipples to be straight >> which causes a severe bend of spoke at nipple >> causing excessive stress >> causing spoke breakage!
Will wrap 22ga insulated wire around spoke intersections to stabilize, remove all nipples, re-drill all rim holes slightly larger, re-insert hub and spoke assembly back into rim, tighten and true!
Front forks are Disc brake capable, so will outfit, at least 1 with Disc brake and may upgrade controller for ≤ 50V battery.

Clean-lube-tune-up, new pedal chain and, possibly, new quiet motor from eco-ride, for my 2013 Comfort Cruiser (near 12,000 miles ... so far)

Better get started!

Oh! Bought an eBikeling 500w geared front hub for a 24spd mountain bike last Summer and never took it out of the box ... better do something with that?

Re: Homemade Battery Packs

Posted: Mar 09 2019 2:08pm
by LeftieBiker
If you want a sharp-looking ride I can make you a deal on my black diamond frame Trailz. Only about 2k miles on it, and quite a few accessories, plus a 20AH Ping pack. See my post in the Trailz topic.

Re: Homemade Battery Packs

Posted: Mar 09 2019 5:19pm
by DrkAngel
LeftieBiker wrote:
Mar 09 2019 2:08pm
If you want a sharp-looking ride I can make you a deal on my black diamond frame Trailz. Only about 2k miles on it, and quite a few accessories, plus a 20AH Ping pack. See my post in the Trailz topic.
Got 2 of 'em already.
eZips
2 - Black Diamond frames
2 - Blue Diamond frames
1 - Silver Diamond frame
2 - Red Diamond frames
1 - Blue Step-through frame
iZip
1 - Mountain Trailz AL

+ 3 Hub Motored ...

Re: Homemade Battery Packs

Posted: Mar 09 2019 6:38pm
by LeftieBiker
DrkAngel wrote:
Mar 09 2019 5:19pm
LeftieBiker wrote:
Mar 09 2019 2:08pm
If you want a sharp-looking ride I can make you a deal on my black diamond frame Trailz. Only about 2k miles on it, and quite a few accessories, plus a 20AH Ping pack. See my post in the Trailz topic.
Got 2 of 'em already.
I have four. ;-) Plus two new bikes that I actually ride.

Re: Homemade Battery Packs

Posted: Mar 10 2019 9:19am
by DrkAngel
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...
Expounded
DrkAngel wrote:
Mar 09 2019 11:27am
.
...
Spring?

Time to get ready for Spring!
I have about 5 batteries and a couple+ bikes to get ready for "the road".

Batteries
Summer weight (Laptop cells)

Test and balance check

25.9V 25.92Ah- (2014 build - laptop lipo) One of my most durable-reliable builds, built from NOS Dell Media Bay battery LiPo cells of 2008 vintage. Used for 5 years and thousands and thousands of miles ... so far. Did add, tacked on 1 18650 cell to slightly weaker bank. Nope, no BMS!

33.3V 31.2Ah MaxCell 1kWh (NOS HP laptop cells) - Barely used 2018 build. 36V Hoverboard batteries made this nearly obsolete. but will use for a bit of extra speed (23mph±) or extended cruising at partial throttle. (estimated range 40 miles+ @ 20mph ... 60 miles+ @ 15mph)

10.8V 25.9.Ah Wheelbarrel battery (will add 12V (3s) 40A continuous BMS) - Unregulated usage from different users results in intermittent-negligent charging, making BMS protection a near necessity.

25.9V 34.56Ah Mower battery needs 1 bank replaced ... the last add-in bank from lesser cells ... :oops: ...
(May add 20A continuous 50A cut-off BMS ... and will monitor for BMS parasitic draw!)

HO (High Output) 36V 4.4Ah Hoverboard batteries and various builds therefrom ... - Snow Beast uses 3 x 36V paralleled for 13.2Ah. Vintage WE 600w front hub build alternates between 2 x 36V for 8.8Ah and 4 x 36V for 17.6Ah (will likely transfer WE front hub to Mountain bike with dual brakes of drop to 25.9V Lipo and put on trike or rebuild into 20" and mount on rear of BMX, removing crank and adding foot pegs and full seat ... for the smaller grandkids, think I have a 24" disc brake wheel-fork I can add.)

25.9V 2.64Ah eZip build - great Samsung-22p cell build that ran great last year and during clear road Winter. Does good in the cold, but great when kept warmer.

cordless power tools 18V 4.4Ah Lithium rebuilds from Ni-Cd packs etc - will just test for maintained good balance

Will also build 7.2V & 10.8V Laptop Lipo for 6V and 12V Florescent lanterns. (not worth converting to LED) - yes, 6V Florescent lanterns run just fine and seem durable running at 7.2-8.4V Lithium. (2 examples)
Decided to explain a bit more-better.

Miles per Kilowatt hour at various speeds

Posted: Mar 14 2019 10:20pm
by DrkAngel
Hit 60ºF+ today and was testing batteries\bikes, Tried 33.3V on my 25.9V Comfort Cruiser ... "cruised" up to an exhilarating 25mph. At 1kWh will provide 60 miles @ 15mph, 40 miles @ 20 mph and 30 miles @ 25mph.

EBike Simulator rates 1kWh battery at:
15 mph = 76 miles
20 mph = 51 miles
25 mph = 35 miles
30mph = 20 miles (reapportioned battery, higher volts-lower amps)

Re: Homemade Battery Packs

Posted: Mar 17 2019 12:31pm
by DrkAngel
Oh boy! ...
Found 3 more boxes of Dell Laptop LiPo.
10.8V 4.32Ah from 3s2p packs. Hundreds of packs should provide good 1000+ cells. (All packs that would not maintain good charge were discarded years ago.)

Need to finish off the rest of this last batch, Lawnmower batt repair, fluorescent lanterns, maybe inverter or auxiliary UPS pack?
Image

Set aside a 15 pcs pile of NOS for 25.9V 25.92Ah eZip build.
Will need to test and rate them all ... next lousy weather project? I have 4 x 4 bay chargers for the oem Dell packs.
Charge them all up
Open and test all for full and equal voltage - label
Let set several days - test for any self-discharge, set aside failures!
Run a discharge and meter for voltage sag of pack and cells , set aside any with uneven or excessive IR
Gang cells as 30s for discharge test through 2 x 60w = 120w light bulbs for a 1 Ah per hour discharge
Discharge for 2 hours (2Ah) and label each cell pair with residual voltage
Build batteries with banks of best-equal residual voltage

Save good, but lesser capacity, cells for large bulk packs etc.
Separate and individually test cells from packs that failed self-discharge or unequal voltage, for ... ?