Homemade Battery Packs

[Ypedal]

kinda like the 500w sticker on my Chaos !

[liveforphysics]

There are no LiMn 26650 size cells with 4Ah of capacity. They are either cobalt dioxide, or ~3Ah to maybe 3.5Ah if they really have awful impedance.

Maybe they are "creatively" labeled.

Most certainly.


Not quite as creative as the ultra-fire cell labelers though. Take 2-2.4Ah QC failed cells from dead packs or factory rejected cells from a MFG, and label them as 3.8Ah to lure suckers into buying them (which is fine for people running flashlights). They take the cake.

[DrkAngel]

In regard to charging Li-ion - Lipo battery packs:
Previously, I have always "recommended" - "highly recommended", the implementation of a PCB\PCM\BMS, recent trials with a dedicated Li-ion charger, seems to prove it, an unnecessary item! ... ?
(Tenergy 25.9v 2A charger - <$30 each, shipped, if buy 2.)

After I noted, that my homemade packs, were maintaining decent equalization of voltage between cells, others chimed in, agreeing that they have been recharging, without any form of balancing - equalization circuit. 2 claimed, that "good" cells, with varying degrees of monitoring, required no balancing circuit! Even after 100+ cycles!

The typical PCB\PCM\BMS monitors against over-charging pack, as well as of individual cells or banks of cells.
Secondary function prevents the over-discharge of pack, or cells.
The "optional" function is a balancing, or equalization, function.
This is normally accomplished by a "bleeding down", of the higher voltaged cells.
The normal equalization circuit is rated at between 5-10% of the charging voltage.
As example:
My iMax B8 balancing charger, charges at, up to, 7 amps, but the balancing circuit operates at a maximum 0.3 amps.
A PCB rated at 30 amps "balances" at a mere 60mA .06 amps. Sadly, this looks to be typical - meaning that "balancing", to be effective must be used on cells of "near balanced" state, or would require an extreme "equalization time".

After I tested and evaluated my recycled cells I took the acceptable, applied an initial balancing, assembled them into packs, and have been running-testing them for hundreds of miles, with a dozen+ recharges!
Packs have been tested for equalization after discharge and after recharge.
Results:
Both packs, Li-ion & Lipo, maintain within 1/100th volt of "full charge" 4.18v. (1 variance, might have been a mere few thousandths volt.)
Typically, I discharged to the 3.7- 3.8v range, where equalization was to, a less impressive, but very acceptable, 2/100th volt.

Packs seem "stable", very similar to my "recycled" packs, that I have been running for, 3 years, and thousands & thousands of miles.

Pack monitoring:
As previously mentioned, I monitor cell & pack voltage, pre- & post-charge.
Additionally:
While I have used an odometer - in conjunction with the oem voltage leds, I would recommend a voltage meter-low voltage alarm.
Cheap multi-featured one available, from China.
Nice little volt meter for 8 cells, or less!
Monitors, and displays pack voltage, then of each bank.
Low-voltage alarm is programmable from 2.7v to 3.8v, in 1/10v increments.
Meter & Low Voltage Alarm

1-8s.jpg (86.17 KiB) Viewed 2674 times

More than 8S?
Take 2 they're small! And cheap! $6.29 includes shipping!

Extension cable, from balance plug to voltmeter-alarm can place unit on your bars, for constant monitoring!

[Floont]

In regard to charging Li-ion - Lipo battery packs:
Previously, I have always "recommended" - "highly recommended", the implementation of a PCB\PCM\BMS, recent trials with a dedicated Li-ion charger, seems to prove it, an unnecessary item! ... ?
(Tenergy 25.9v 2A charger - <$30 each, shipped, if buy 2.)

Um, I just checked the Li-ion charger you recommended, and it has a negative rating, but I cannot read the review. So, I'm not sure if the web site shows ratings which do not require a review. Irregardless, its only 1 rating, although its poor. I know I wont be a guinea pig and find out. I never purchase products unless they have several good ratings.

FA

PS I am putting my 'shopping list' together for my switch to Lipo and stumbled on this thread. Caveat emptor.

[DrkAngel]

In regard to charging Li-ion - Lipo battery packs:
Previously, I have always "recommended" - "highly recommended", the implementation of a PCB\PCM\BMS, recent trials with a dedicated Li-ion charger, seems to prove it, an unnecessary item! ... ?
(Tenergy 25.9v 2A charger - <$30 each, shipped, if buy 2.)

Um, I just checked the Li-ion charger you recommended, and it has a negative rating, but I cannot read the review. So, I'm not sure if the web site shows ratings which do not require a review. Irregardless, its only 1 rating, although its poor. I know I wont be a guinea pig and find out. I never purchase products unless they have several good ratings.

FA

PS I am putting my 'shopping list' together for my switch to Lipo and stumbled on this thread. Caveat emptor.

Better now!

[Floont]

In regard to charging Li-ion - Lipo battery packs:
Previously, I have always "recommended" - "highly recommended", the implementation of a PCB\PCM\BMS, recent trials with a dedicated Li-ion charger, seems to prove it, an unnecessary item! ... ?
(Tenergy 25.9v 2A charger - <$30 each, shipped, if buy 2.)

...I am putting my 'shopping list' together for my switch to Lipo and stumbled on this thread. Caveat emptor.

Better now!

Yes. That is very impressive how 1 review had 8 five star ratings in just the last single hour, with no verbiage on any of those reviews. I strongly suspect that you have submitted false ratings in the last hour to make your recommendation appear to be a good one. Is all-battery.com your business which you are guiding people to under false pretenses? Or are you just trying to make your reputation here better? Either way, this stunt severely diminishes your reputation, stature, and recommendations here to absolutely nil.

From now on, I'll stick to the real expert's opinions and recommendations, now that you have performed this sham.

FA

[icecube57]

Ask Ambroseliao about the chargers I sent him with his bosch packs.... Atleast I think it was him. The chargers did what they were supposed to do. One thing I noticed is that they I had 3 charging in parallel and they all didnt terminate at the same time / voltage. One charger I had ... I had to beat on it sometimes to get the charger fan to run properly. When it did.. It ran very loud. They stopped charging a little shy of the intended voltage... the they oddly floated higher that the intended voltage so they stopped at around 41.7-41.8 and the floated to 42.1-2. For the price you get what you pay for. There are far better and more reliable options than these chargers.


All-battery gives you points that you can redeem for cash/discounts on your next order.

[DrkAngel]

Got me 4 more of the Tenergy 25.9v Li-ion chargers. Ganged 2 together for a 4amp charger. Now I can charge my 31.2ah pack, while I sleep! Worked great, last night!

Oh yeah. Floont pointed out that I hadn't left any rating on the web site, so I tacked on my 6 Positives!
Reviews not available for several days ... review by moderator ... standard procedure.

[neptronix]

Got me 4 more of the Tenergy 25.9v Li-ion chargers. Ganged 2 together for a 4amp charger. Now I can charge my 31.2ah pack, while I sleep! Worked great, last night!

Oh yeah. Floont pointed out that I hadn't left any rating on the web site, so I tacked on my 6 Positives!

That's a way better deal than those stupid 350w meanwells. Congrats on the steal, you shrewd shopper!

[DrkAngel]

Got me 4 more of the Tenergy 25.9v Li-ion chargers. Ganged 2 together for a 4amp charger. Now I can charge my 31.2ah pack, while I sleep! Worked great, last night!

Oh yeah. Floont pointed out that I hadn't left any rating on the web site, so I tacked on my 6 Positives!
Reviews not available for several days ... review by moderator ... standard procedure.

OH! Free Shipping on $75 order! With ... "THANKS" code!

Only $23.63 each ... shipped.
Light, and small enough, that it fits right in with my 31.2ah, "lunch bag" pack!

(Tenergy 25.9v 2A charger )
Other voltages & amperages available, haven't tested the recent models though.
I've purchased many from them, but alternate models have been for my older packs.

[DrkAngel]

Next up? ... RC Lithium-ion Polymer, stuffed into an EZip battery pack!

2 viable options:
25.9v - 22.8ah
4 banks of 7 cells.
2 - 2 cell packs, will be split, to provide 7th cells.

RC-Lipo_25.9v.JPG (55.15 KiB) Viewed 2001 times

37v - 17.1ah
3 Banks of 10 cells.
Each bank comprised of 3-3packs(9cells) plus a single cell of the 10th 3-pack.

RC-Lipo_37v.JPG (68.19 KiB) Viewed 1994 times

Sadly, my source has dried up, (shipping mah limitation on Lipo? ), and I only have enough for 1 pack.
So I might save my 11 3-packs + 2 2-packs for a more demanding project.

Packs are rated 20C surge:
456 amps from 25.9
or
342 amps from 37v

and:
15C continuous:
342 amps from 25.9
or
256.5 amps from 37v

[JoramsWeapon]

Next up? ... RC Lithium-ion Polymer, stuffed into an EZip battery pack!

2 viable options:
25.9v - 22.8ah
4 banks of 7 cells.
2 - 2 cell packs, will be split, to provide 7th cells.

RC-Lipo_25.9v.JPG

37v - 17.1ah
3 Banks of 10 cells.
Each bank comprised of 3-3packs(9cells) plus a single cell of the 10th 3-pack.

RC-Lipo_37v.JPG

Sadly, my source has dried up, (shipping mah limitation on Lipo? ), and I only have enough for 1 pack.
So I might save my 11 3-packs + 2 2-packs for a more demanding project.

Packs are rated 20C surge:
456 amps from 25.9
or
342 amps from 37v

and:
15C continuous:
342 amps from 25.9
or
256.5 amps from 37v

I've used that brand of cell before bought from China and a pretty good price at the time. Terrible experience. They were rated for 20C sure but when put to the test they barely pumped out 10amps without heating up quickly. I put 12 of them in a 10S6P setup and they overheated very quickly under 35amp draw and had that tell-tale smell of cooked Lipo. I hope your experience turns out differently.

[DrkAngel]

I've used that brand of cell before bought from China and a pretty good price at the time. Terrible experience. They were rated for 20C sure but when put to the test they barely pumped out 10amps without heating up quickly. I put 12 of them in a 10S6P setup and they overheated very quickly under 35amp draw and had that tell-tale smell of cooked Lipo. I hope your experience turns out differently.

A few questions:
12 - 11.1v (3 cell) packs would be 36 cells, would not a 10S6P pack be made of 60 cells? 12 - 18.5v (5 cell) packs?

Were your packs the older, copper wire, or the newer, silicone wire, type?

"They barely pumped out 10amps without heating up quickly", "35 amp draw and had that tell-tale smell of cooked Lipo," - from a 5.7ah pack?

[JoramsWeapon]

I've used that brand of cell before bought from China and a pretty good price at the time. Terrible experience. They were rated for 20C sure but when put to the test they barely pumped out 10amps without heating up quickly. I put 12 of them in a 10S6P setup and they overheated very quickly under 35amp draw and had that tell-tale smell of cooked Lipo. I hope your experience turns out differently.

A few questions:
12 - 11.1v (3 cell) packs would be 36 cells, would not a 10S6P pack be made of 60 cells? 12 - 18.5v (5 cell) packs?

Were your packs the older, copper wire, or the newer, silicone wire, type?

"They barely pumped out 10amps without heating up quickly", "35 amp draw and had that tell-tale smell of cooked Lipo," - from a 5.7ah pack?

The packs I had used silicone wire at 14ga. Each brick was 5S 5.7ah 20C, 12 of those bricks were arranged as 10S6P. I'm counting by lipo brick not cell, but yes 60 individual cells total. Each brick had trouble delivering 10amps, I got about 3/4 capacity on the discharge but the amount of heat generated was alarming. Even so I figured that in 6P configuration the bricks would hold together fairly well under ebike conditions, failed miserably. I actually did the same thing you're doing now by stuffing them into an Ezip case, everything was cool until I hit the throttle .
The batteries that managed to survive that quick run now power my laptop for many hours, a much more sensible application i think .

[DrkAngel]

The packs I had used silicone wire at 14ga. Each brick was 5S 5.7ah 20C, 12 of those bricks were arranged as 10S6P. I'm counting by lipo brick not cell, but yes 60 individual cells total. Each brick had trouble delivering 10amps, I got about 3/4 capacity on the discharge but the amount of heat generated was alarming. Even so I figured that in 6P configuration the bricks would hold together fairly well under ebike conditions, failed miserably. I actually did the same thing you're doing now by stuffing them into an Ezip case, everything was cool until I hit the throttle .
The batteries that managed to survive that quick run now power my laptop for many hours, a much more sensible application i think .

Big question!
How did you manage to fit 60 cells into an Ezip case, when I can barely squeeze in 30, of the same size cells?

[JoramsWeapon]

The packs I had used silicone wire at 14ga. Each brick was 5S 5.7ah 20C, 12 of those bricks were arranged as 10S6P. I'm counting by lipo brick not cell, but yes 60 individual cells total. Each brick had trouble delivering 10amps, I got about 3/4 capacity on the discharge but the amount of heat generated was alarming. Even so I figured that in 6P configuration the bricks would hold together fairly well under ebike conditions, failed miserably. I actually did the same thing you're doing now by stuffing them into an Ezip case, everything was cool until I hit the throttle .
The batteries that managed to survive that quick run now power my laptop for many hours, a much more sensible application i think .

Big question!
How did you manage to fit 60 cells into an Ezip case, when I can barely squeeze in 30, of the same size cells?

Easy! Two cases . Was a real tight fit though, barely had room for a little foam padding. I also sliced the cases' innards up quite a bit by getting rid of that middle portion and its attached threads with a rotary tool, the pack was so much lighter than the SLA's I didn't think I'd need all 5 screws. I had removed the SLA charging port and ran the charging leads and balance wires out that exit. If I had the opportunity to do it again I'd fill the case with LiMn Konions, you could easily cram over a hundred cells in there and still have some room to spare and you'd save the hassle of having to solder in balance wires.

[DrkAngel]

Sorry ... I never posted my Laptop Lipo recycled pack. (EZip 10ah SLA original case)
84 - 2160mah lipo cells, oem configured in 11.1v "6-packs".
7S12P 3.7v - 7Series 12Parallel
25.9v - 25.92ah pack

Laptop Lipo.JPG (52.89 KiB) Viewed 3416 times

On the side, are 12 separated cells, which make up the 7th bank.
Balance-equalization plug sets flush to side, but extends, when needed.
Black plastic "shelves" were cut from a plastic tub, and were added to support-protect cells.

Clear "boxing" tape used to keep "unruly" wires, "in their place".

[DrkAngel]

Also built a 37V 25.92Ah Pack (.96Kwh)
And packed it into an innocuous 6pack cooler.

37v1kw_2.JPG (86.4 KiB) Viewed 2824 times

Since I have no 10S balance charger, pack is connected, and charged, through a 37V PCB, via my old style connector.
Connected to controller by standard 2 prong AC connector.

37v1kw_3.JPG (87.55 KiB) Viewed 2824 times

Pack is made up of 120 - 2.160mAh Lithium-ion Polymer cells.

37v1kw_4.JPG (83.97 KiB) Viewed 2823 times

Cells on the right, under black tape, are 12 cells connected in parallel to add 10th bank.
Black tube, on bottom contains a moderate 30amp fuse.
Cells are stabilized with a 7/16 waferboard base, and surrounded by a fairly solid cardboard, which allows easier insertion-removal from 6pack bag.
Tinned copper braid works excellently with these cells.

[TonyReynolds]

"Cool Cell"

What a wonderful visual pun!

Tony

[justadad1957]

the tinned copped braid looks like it can take some amps
keep your tire pressure gauge outta there

[DrkAngel]

the tinned copped braid looks like it can take some amps
keep your tire pressure gauge outta there

Folding cardboard closed, protects wiring nicely.
But, my pressure gauge, CO2 pump, patch kit etc. all have non-conductive surfaces.
Plenty of room inside for charger & tool bag etc.
Also, the lower zipper "expands" the bag to add an extra couple inches, for more storage space.
(Fake lunch items ... etc.)
Total weight about 13lb.

Bonus:
NY & PA (USA)
Valu Home Center - a chain of hardware stores - has a nice allen wrench set for $1!
It covers all the EZip-IZip allen fittings.
It has a blue plastic body.

[Starson]

Wouln't a 6 pack cooler bag be insulated and trap any heat generated and ruin the batteries? Also, it may look inoccuous, but I'd be worried that instead of someone looking to steal batteries, kids & cops would be looking for the beer, except for Yogi Bear of course, who likes to steal the "picinic baskets".

Gary

[DrkAngel]

Wouln't a 6 pack cooler bag be insulated and trap any heat generated and ruin the batteries? Also, it may look inoccuous, but I'd be worried that instead of someone looking to steal batteries, kids & cops would be looking for the beer, except for Yogi Bear of course, who likes to steal the "picinic baskets".

Gary

I've never had any heat problems with Lipo or Li-ion.
Of course I rarely exceed 1C, more common is .3 - .5C.

Li-ion Lipo seem not to heat, during charge or discharge, unless "pushed" beyond, "recommended".
I've run this 37v pack for a steady 2 hours, and felt no noticeable heat.
Oddly, Lipo and Li-ion seem to output better when warmer. However, warmer while charging is bad!
Bag is nice for Winter, Li-ion - Lipo, are degraded by the cold, retaining ambient heat is a nice plus.

[DrkAngel]

Wouln't a 6 pack cooler bag be insulated and trap any heat generated and ruin the batteries? Also, it may look inoccuous, but I'd be worried that instead of someone looking to steal batteries, kids & cops would be looking for the beer, except for Yogi Bear of course, who likes to steal the "picinic baskets".

Gary

If I use my "6-Packer" on a front hub bike, I'll mount it between the bars and suspension fork.
No long wires to be broken , or spotted!

Of course I might have a partial, clear, water bottle, sticking out the edge.
As camo ...

[DrkAngel]

Great new price on, 1-8S Lipo Battery Tester Low Voltage Buzzer Alarm. $3.29 w/shipping
Half the price of previous best price! I ordered another 5.

Displays total voltage and well as that of individual cell-bank.
Programmable low voltage alarm, audio-visual. (2.7-3.8v)

1-8S Lipo Battery Tester Low Voltage Buzzer Alarm RC 1S - $3.29 w/shipping

1S-8S.JPG (149.24 KiB) Viewed 1135 times

$3.29
Note: Claims accurate to within 1/100th Volt, actual, from several, is a few 100ths.
Total voltage accurate, cell accuracy varies.

I use one as an "on bar" volt-fuel gauge. Rigged into throttle, (voltage to battery level leds).
Up to 30v 1S meter, just attach to neg - pin 1 and pin 2.
Use multiple to monitor, larger than, 8S packs.