Homemade Battery Packs

[DrkAngel]

The 10S charger would be great if you ever wanted to break into the 10S zone eventually.

Been running my 37v, recycled 18650 cell, 20.8ah pack, for 3 years - 3500 miles.
Last build ... when I built the:
Li-ion 25.9v 31.2ah pack
and the
Lipo 25.9v 26ah
I also built:
Lipo 37v 26ah, in a fabric 6-pack cooler = .96kwh!

The reason I play at 25.9v, is that it works so nicely with the Currie EZip-IZip bikes, and keeps it 20mph "legal", if you run the battery down and let some air out of the tires. .
Combined with my other mods, it can turn a base model, budget ebike, into a really decent machine!
I have 5, 4 different models, all with various modifications. (1 is geared for torque, then bumped to 37v, w/homemade studded tires! Ran it through 2 Winters!) Latest project is adding a standardized "Deans" T-Plug connector at the motors. This will make possible a 5 minute, tube replacement, rear wheel swap, etc., previous time, 1/2hour, or longer.

My next voltage upgrade will be 44.4v* on an AmpedBikes front hub, then, I will probably push it to, the newly capable 60v.

* 44.4v is extremely simple, from my supply of 11.1v 6packs of Lipo. I have 11.1v 500ah+ Lipo stockpiled (1/2 are SONY matched cells!). All charge to full, and maintain voltage.
55.5v is easier than 48.1v, but uneven, for my saddlebag design plan.

[neptronix]

If you're going to do 12s later on, get the 48v meanwell and do the shunt clip mod i did ( see the last pages of my trek build ), the amperage is perfect for 12s.

The 48v meanwell can adjust to 50v, with the shunt clip it is putting out 6.675 amps for me, that's ~330 watts which is just a bit under it's max rating and i reckon that would be perfect for you.

Or you can do the resistor mod, it doesn't matter.

And an ampedbikes DD hub at 44v nominal should do upper 20mph.. go for it.. it will be a massive improvement over your fleet of eZips even at the stock amperage.

Look into the cell_man kit though, it consists of the same parts. And is dirt cheap in comparison, should be under $250 shipped to the east coast.

Hey, look at you now.. lipo.. direct drive hubs.. hang out in a barber shop long enough and you're gonna get a haircut..

[DrkAngel]

I've been equalization testing my Li-ion & Lipo homemade packs for a couple weeks now.
My preliminary testing was solely for non-pedal assist range.
Results:
Li-ion 25.9v - 31.2 ah 50miles+ at 18mph average level cruising pace.
Lipo 25.9v - 26 ah 40miles+ at 18mph average level cruising pace.

Equaliziation - monitored charging, (w/Tenergy Li-ion-Lipo charger $23.62), 10 cycles, (5 cycles each)
All cells, both packs remained within about 1/100v of 4.18v!

Equalization testing has been done with my normal pedal assist mode.
For the Li-ion, (18650 cells), I typically recharge every 30-35 miles.
For the Lipo, I typically recharge every 25-30 miles.

Of course, I tend to cruise at 20mph+, But attack hills, and sprint ahead of traffic - motor and pedal combined gives me almost a block, from a red light, till traffic catches up.
Sprints on the level are starting to give me an endorphin rush!
I get up to near 30mph, impressive, since motor assist fades at 23mph, and ends at 25mph.
I try to, daily, get my 5 block "rush", maybe 1/2 mile. (potholed side streets make main drag advisable!)

Finally getting back in shape, after my "range trials".

I feel that eaBikes" Electric Assist Bikes", are best used to enhance my biking ability ... not replace it!

[Ypedal]

you keep using the term equilization with that tenergy charger, and this is fundamentally wrong, readers of this thread need to understand that your charger is not equilazing or ballancing or doing any of that.... it simply charges the whole pack to a set voltage.. that's it...

Luke has tried to explain this to you, many times over, and you insist on testing something that is already known, nothing wrong with you enjoying your pack, and reporting findings, but let's be clear on something.. your tenergy charger is not ballancing the pack

[DrkAngel]

you keep using the term equilization with that tenergy charger, and this is fundamentally wrong, readers of this thread need to understand that your charger is not equilazing or ballancing or doing any of that.... it simply charges the whole pack to a set voltage.. that's it...

Luke has tried to explain this to you, many times over, and you insist on testing something that is already known, nothing wrong with you enjoying your pack, and reporting findings, but let's be clear on something.. your tenergy charger is not ballancing the pack

Never claimed it was "ballancing"!
Merely pointed out, that it was - maintaining equalization!
Without a BMS/PCB/PCM, or, balancing charger.

In fact, I clearly state that it is not a perfect balance and is not improving!
Which would mean, that I am not even, implying, that it is a balancing charger!

[icecube57]

Everybody Calm Down.

[neptronix]

you keep using the term equilization with that tenergy charger, and this is fundamentally wrong, readers of this thread need to understand that your charger is not equilazing or ballancing or doing any of that.... it simply charges the whole pack to a set voltage.. that's it...

Luke has tried to explain this to you, many times over, and you insist on testing something that is already known, nothing wrong with you enjoying your pack, and reporting findings, but let's be clear on something.. your tenergy charger is not ballancing the pack

+1, that's the reason i jumped on here.

According to merriam-webster.com:

Definition of EQUALIZE

transitive verb
1 : to make equal
2 : to compensate for

Synonyms: balance, equate, even, level

Equalizing sounds a lot like balancing to me.

Might indicate a balancing algorithm?
Charge-discharge-charge-discharge - cycles every 2-3 seconds.
Premise 1 - A lower voltage cell will accept charge more easily than one with a higher voltage.
Premise 2 - A higher voltage cell will expend energy more easily, (faster), than lower voltage cell.
Given these 2 reasonable premises, then the chargers, charge-discharge pulsing, would tend to equalize, (balance), Li-ion cells!

Immediately after you said this,. we jumped on you and you resisted the idea that your charger isn't capable of doing any sort of balancing, or uhh, equalizing.

Lithium-ion Polymer 25.9v, 26ah pack charged nicely, also!
All banks of cells charged tightly within 1/100th of a volt, of the median 4.18v!

Previously described, "off balance" pack test, scheduled for Tuesday, when I'm back in the shop.

But you didn't go through with it because it sounds like you may have learned that your charger won't do what you thought..

Immediately after you said this, this thread was created by someone excited about your newfound cheap balancing charger:

http://endless-sphere.com/forums/viewtopic.php?f=14&t=28496

This is why we ding people for posting incorrect info. Happens to the best of us.. myself included. It's ok to correct yourself and move on. I haven't seen anyone be eternally hated on this board for being wrong once. Just sayin.

[DrkAngel]

Tenergy 25.9v Li-ion charger report:
I decide that the most relevant test would be the maintenance of voltage equalization after repeated deep cycles.
Packs are discharged into the 3.7*v range. (3.5v under moderate throttle)
Further tests will follow.

Most important, real world application test, not completed yet.

[DrkAngel]

+1, that's the reason i jumped on here.

According to merriam-webster.com:

Definition of EQUALIZE

transitive verb
1 : to make equal
2 : to compensate for

Synonyms: balance, equate, even, level

Equalizing sounds a lot like balancing to me.

My lipo cells come out equalized after dozens of non-balance charges too, only because they a set of matched cells in the first place.

OOPS! ... Can you say ... hypocrite?

[neptronix]

Oh my god...

I see we are not getting anywhere here, so i'm going to step out for now.

[DrkAngel]

I see we are not getting anywhere here, so i'm going to step out for now.

Don't go away mad ...

Hypocrite - would be someone who criticizes another for an action, then does the exact same thing!
or, who holds anothers actions words etc. to a different standard than they hold there own.
Hypocrisy - the action of a hypocrite.
Hypocrite

Neptronix claims that when I use the term equalized, I mean balancing. (Wrong!)
but when he uses the same term, in the same context ... it must mean something different! ... ???

My lipo cells come out equalized after dozens of non-balance charges too, only because they a set of matched cells in the first place.

[mihai_atanasiu]

guys,

maybe with http://www.bmsbattery.com/li-ion-cell/12-4ah-3c-c-rate-26650-g-limn2o4-cylindrical-battery-cells.html this kind of Li ion cell;

they make packs with these cells; which is why we can not ? the cells are rated 2C discharge; the packs that they sell have 12AH with max continues discharge current 10 A
http://www.bmsbattery.com/36v/337-36v-lithium-ion-little-frog-abs-shell-ebike-battery-pack.html

[DrkAngel]

The individual cells don't look bad, but, "3. Capacity: 3Ah~4Ah." looks "curious"?

The pack is limited to 10 amp output.
Might run a kid's toy car, but not much else.
Maybe a 200w assist motor?

[liveforphysics]

guys,

maybe with http://www.bmsbattery.com/li-ion-cell/12-4ah-3c-c-rate-26650-g-limn2o4-cylindrical-battery-cells.html this kind of Li ion cell;

they make packs with these cells; which is why we can not ? the cells are rated 2C discharge; the packs that they sell have 12AH with max continues discharge current 10 A
http://www.bmsbattery.com/36v/337-36v-lithium-ion-little-frog-abs-shell-ebike-battery-pack.html

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.

[stanz]

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.

[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 2659 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.