Generic OEM - Unicycle-A2

[esaj]

Hehe, looks like we cross-edit each other all the time... the cell capacity is 2200mAh, the chemistry is probably NMC (it says "NCM" in manufacturer pages), so LiNiMnCo) and at least the charge voltage (4.2V) seems pretty typical. The largest discharge ratio seems really low (1C = 2.2A), and the promised cycle life is the worst I've yet seen (80% at 300 cycles, usually that's 500-1000 cycles), although I haven't looked at chinese cells before, as I've heard they're pretty crappy...

So, I think you could be able to replace it with another NMC-cell with similar capacity, but can't say for certain. Probably best to find someone who knows about the cells and battery assembly, and can find & replace the cell for you. Or buy a whole new battery.

[dmethvin]

Maybe it's a long shot, but contact the manufacturer via Amazon and see if they will send you a new battery pack. If not, give them a bad review. You have done all the hard work in diagnosing this, it's not like they have to send you a whole new wheel so shipping should be much lower.

[esaj]

Maybe it's a long shot, but contact the manufacturer via Amazon and see if they will send you a new battery pack. If not, give them a bad review. You have done all the hard work in diagnosing this, it's not like they have to send you a whole new wheel so shipping should be much lower.

Good point about the warranty, I'm so used to thinking that everything has to be replaced by bought new parts, as my wheels are second hand and I have no warranty documents.

[cg]

I recommend to measure directly to the cells voltage. Then you will know whether they are ok.

 

It seems like they are glued into the overall compartment, should I just use a screwdriver between the batteries to loosen them?

Maybe it's a long shot, but contact the manufacturer via Amazon and see if they will send you a new battery pack. If not, give them a bad review. You have done all the hard work in diagnosing this, it's not like they have to send you a whole new wheel so shipping should be much lower.

Yeah, I actually informed them yesterday that I suspected a defect battery, and gave the wheel a bad review that I obviously will make better in case the battery is replaced...

And they did respond this morning that they would contact technical.

[KaleOsaurusRex]

Just gonna put this here: 

[cg]

Hehe, looks like we cross-edit each other all the time... the cell capacity is 2200mAh, the chemistry is probably NMC (it says "NCM" in manufacturer pages), so LiNiMnCo) and at least the charge voltage (4.2V) seems pretty typical. The largest discharge ratio seems really low (1C = 2.2A), and the promised cycle life is the worst I've yet seen (80% at 300 cycles, usually that's 500-1000 cycles), although I haven't looked at chinese cells before, as I've heard they're pretty crappy...

So, I think you could be able to replace it with another NMC-cell with similar capacity, but can't say for certain. Probably best to find someone who knows about the cells and battery assembly, and can find & replace the cell for you. Or buy a whole new battery.

yeah, I noticed the extra low cycle life also...

Just gonna put this here: 

and yeah, I know about that, that is why I haven't torn it completely apart already.

[esaj]

Just gonna put this here: 

This one's much better, the phone actually explodes... And nothing else needs to be done except try to insert head phones with wrong type of connector (too long) into an iPhone. In this case, the guy pokes a screwdriver through the headphone-jack and places the phone inside empty pants... the explosion is around 1:06.

 

Edit: Btw, sorry about the graphic image when the video isn't running, don't know why it comes there, I don't think it's in the video?

[dmethvin]

I'll keep that in mind the next time someone tries to stab my Firewheel with a knife, or jams a metal spike deep into my phone's headphone jack.

[EUC Extreme]

It would seem that one cell is broken. Will you be able to replace it, or someone your friend?
However, it can be difficult to figure out what kind of cell must be. If they can not find more accurate labeling.

 

[cg]

It would seem that one cell is broken. Will you be able to replace it, or someone your friend?
However, it can be difficult to figure out what kind of cell must be. If they can not find more accurate labeling.

 

Hmm, I guess replacing it might be more difficult than first anticipated, since it seems the batteries really are spot-welded.

[John Eucist]

 

Edit: Btw, sorry about the graphic image when the video isn't running, don't know why it comes there, I don't think it's in the video?

Apparently they can choose whatever still image they want even if it's not in the video.  This was in the YouTube comments for the video:

Patrick Graham 1 week ago
how low do you have to be to use the boston marathon bombing photos as a thumbnail?

[EUC Extreme]

The new sensor can also be soldered into place. It is not necessary to weld.

[cg]

The new sensor can also be soldered into place. It is not necessary to weld.

By 'sensor', do you mean the battery cells themself?

In this photo, you can see the small welding signs.

 

But if they can be soldered, it should be possible for me.

 

[EUC Extreme]

I refer to the exchange of the cell. It can be soldered. Disconnecting the welded metal sheets as gently as possible, that will remain intact.
If the sheet metal is broken, you can replace solder a piece of wire.
It would be good to have a 60W soldering iron.

[dmethvin]

My concern with soldering would be that you might overheat the cell in getting it up to temperature. I'm pretty sure that's why they use the spot welds because it limits the heating and reduces the chances of damaging the battery. So if you are going to try it use a high-wattage iron like vee73 says and apply it just long enough to melt the solder.

[EUC Extreme]

Powerful soldering iron because, fast touch soldered to suffice. And it does not have time to over-heat the cell itself.
Gladly first tin in both the contact point. Then, rapid heating to combine them.

[cg]

Ok, I think I have isolated the problem to to one battery. Would your recommend using a soldering iron to loosen the spot welded points also? or should use something like a knife to pry it off ?

[EUC Extreme]

Careful some vetsellä, for example, twisted sheet metal out of it.
Soldering does not help any spot welding disconnecting.
But be careful, especially at the other end with the + and - are close to each other. You do not short-circuit them.

Get the first new cell. And only then remove the old out.

[cg]

Careful some vetsellä, for example, twisted sheet metal out of it.
Soldering does not help any spot welding disconnecting.
But be careful, especially at the other end with the + and - are close to each other. You do not short-circuit them.

Get the first new cell. And only then remove the old out.

Got you about waiting and taking care, but I am not sure what you mean be 'vetsellä' google gives me the Finish flag as a cake .

But I do measure 4.2V over the batteries, that seems like pretty much. If I find a 4.2V battery, how important is it that the cell has identical chemistry?

I mean, is it turning into a bomb if the batteries are different chemistry, or will i just give them shorter life?

[esaj]

Got you about waiting and taking care, but I am not sure what you mean be 'vetsellä' google gives me the Finish flag as a cake .

But I do measure 4.2V over the batteries, that seems like pretty much. If I find a 4.2V battery, how important is it that the cell has identical chemistry?

I mean, is it turning into a bomb if the batteries are different chemistry, or will i just give them shorter life?

"vetsellä" = typoed "veitsellä" (meaning "with a knife"), and Google translate has left it there. Vee writes most of his messages in Finnish and then translates them to english.

4.2V is the MAXIMUM voltage of most Li-Ion -chemistries, ie. that's the voltage when the cell is fully charged. The usual nominal voltage is around 3.6-3.7V depending on chemistry (and lower at least for LiFePo). Mixing different chemistries with different capabilities is probably not a good idea, but not sure. I'd go with as similar cell as the others as possible. Also might be a good idea to get the new cell charged to as close to the same voltage as the others, to prevent current rushing from other cells to the new one (or vice versa) due to voltage (potential) difference when it's connected. But I'm no expert on this issue, vee probably knows better.

[hobby16]

 I guess this mean that shunting the battery is not the right right sollution,

Indeed, shunting the battery won't save your dead cell(s) but it will save you from a faceplant. With a shunt, all you will have when a cell dies out (it happened once, no reason it won't in the future, like in any ageing pack) is a decrease in power instead of a brutal shutdown.

Do it now, it's so peasy easy on your BMS (red line in the picture, same principle : connect B-  and P-). You'll see the difference, even with a dead cell, you can still ride without risking a faceplant.

For the spare cell, see here (and the following page) : http://trottinetteselectriques.heberg-forum.fr/sutra22704_solution-probleme-bms.html#22704

Maybe it will inspire you on how to buy and repair, the battery pack is not so hard to deal with and it's good to have modders de-mystify it somewhat.

Ok, I think I have isolated the problem to to one battery. Would your recommend using a soldering iron to loosen the spot welded points also? or should use something like a knife to pry it off ?

Do your best to avoid heating a battery : buy battery with tabs, solder at the tip of the tab instead of near the battery, use a powerfull soldering flux to decrease soldering time (look up "goot flux", used for soldering stainless steel).

Disclaimer : those are extra-ultra-theoretical precautions required by PhDs in whitecoat from their chemistry labs. Ordinary people should be fine soldering as usual, that's what I do all the time with my RC batteries .

[cg]

Thanks @hobby16, I will shunt.

I have good quality equipment at my work, I am just not the usually user, but our electronic engineer is on vacation :/.

Regarding replacing the cells, I am a bit in doubt if I can get a matching cell, This is from what seems to be the batteries I have (source: http://m.en.lishen.com.cn/products_detail/&productId=22&pmcId=15.html )

• The anode material：NCM
• Capacity (mAh)：2200
• Maximum charge voltage (V)：4.20
• Largest discharge ratio (C)：1.0

I have contacted the factory, but I do not know I they will get back for selling one battery :),

Now, everybody is talking about that its bad to mix different kind of batteries, but if I get something like this CGR18650, what would happen if I just added this one?

[esaj]

Now, everybody is talking about that its bad to mix different kind of batteries, but if I get something like this CGR18650, what would happen if I just added this one?

I'm not sure if it affects that one of the cells is much higher capacity (3400mAh) vs. the rest (2200mAh). Just to be on the safe(r) side, I'd personally go with same capacity & chemistry, but am not sure if it even really matters...

You could try looking here:  http://www.dampfakkus.de/akku_liste-nach-groesse.php?size=18650

I ordered them by capacity, and this is the list of 2200-2300mAh NMC's (sorry, it looks a bit messy):

 

Marke	Bezeichnung	Form	Kap. lt. Hersteller	Real Kap. (2A bis 3V)	Max A	Chemie	Protected	Top	Maße in mm	Bild
Basen	BS186Z 18650 2200 60A	18650	2200mAh	1956mAh	35.0	NMC	Nein	Flat
Efan (EH)	IMR 18650-2200 ButtonTop	18650	2200mAh			NMC	Nein	Button
Joyetech / JOYE (OEM)	DESAY 18650EC (IMR) (ego-T Mod)	18650	2200mAh	2102mAh	3.5	NMC	Nein	Flat	18.1*64.9	ja
Keeppower	18650 2200mAh protected (Sanyo)	18650	2200mAh		4.3	NMC	Ja (10A)	Button
LG	ICR18650S3	18650	2200mAh	2171mAh	4.4	NMC	Nein	Flat	18.0*64.7	ja
MOLICEL / EMOLI	IHR18650BN	18650	2200mAh		10.0	NMC	Nein	Flat
Totally Wicked (OEM)	18650 "IMR" 2200mAh schwarz/rot	18650	2200mAh			NMC	Nein	Flat
Vapage (OEM)	VP-18650 2200mAh protected	18650	2200mAh			NMC	Ja	Button
XC (Xinchi)	CRN18650 (IMR)	18650	2200mAh		3.0	NMC	Nein	Flat
Yiklik (YLE)	INR18650-A220 (unprotected)	18650	2200mAh	2151mAh	4.4	NMC	Nein	Flat	18.1*65.0	ja
BAK	B18650CA (IMR)	18650	2250mAh		6.0	NMC	Nein	Flat
BAK	B18650CC (IMR)	18650	2250mAh	2047mAh	6.0	NMC	Nein	Flat	18.1*64.9	ja
Efan (EH)	IMR 18650-2250 (Panasonic) FlatTop	18650	2250mAh		10.0	NMC	Nein	Flat
EFest	IMR 18650-2250 (Panasonic) ButtonTop	18650	2250mAh		10.0	NMC	Nein	Button
EFest	IMR 18650-2250 (Panasonic) FlatTop	18650	2250mAh		10.0	NMC	Nein	Flat
ENERdan (OEM)	Panasonic CGR18650CH (IMR) ButtonTop	18650	2250mAh		10.0	NMC	Nein	Button
ENERdan ENERPOWER	+ 18650 2250mAh / 4C protected (blau)	18650	2250mAh		10.0	NMC	Ja	Button
Keeppower	IMR 18650 2250mAh	18650	2250mAh	2169mAh	10.0	NMC	Nein	Button
Noname	Panasonic CGR18650CH (IMR) BtnTop	18650	2250mAh		10.0	NMC	Nein	Button		ja
Noname	Panasonic CGR18650CH protected	18650	2250mAh		4.0	NMC	Ja (4A)	Button
Orbtronic	Panasonic CGR18650CH	18650	2250mAh	2179mAh	10.0	NMC	Nein	Button	18.2*66.8	ja
Panasonic	CGR18650CG (IMR)	18650	2250mAh	2284mAh	4.3	NMC	Nein	Flat	18.2*65.1	ja
Panasonic	CGR18650CH (IMR)	18650	2250mAh	2237mAh	10.0	NMC	Nein	Flat	18.1*65.0	ja
Sanyo	UR18650A	18650	2250mAh	2148mAh	4.3	NMC	Nein	Flat	18.0*64.7	ja
Sanyo	UR18650AY (IMR)	18650	2250mAh		4.3	NMC	Nein	Flat
Sony	US18650V3 (IMR)	18650	2250mAh	2163mAh	10.0	NMC	Nein	Flat	18.0*64.8	ja
WEISS	18650 2250mAh protected	18650	2250mAh	2252mAh	4.3	NMC	Ja (6A)	Button	18.5*68.6	ja

[hobby16]

 

Now, everybody is talking about that its bad to mix different kind of batteries, but if I get something like this CGR18650, what would happen if I just added this one?

Adding a not paired cell is not "bad" in itself. The problem is that the BMS will try to equilibrate it to oher cells so it will balance the capacity of all cells to the cell of lowest capacity.

On most BMS, the balancing process is "top balancing", ie triggered once the cells are charged over 4.1V (about 90% capacity). So if you don't charge to 100% too often (which is a good thing since it's recommanded to charge only to 80%, when possible, to extend the battery's life), the balancing is not triggered and your repaired cell would not cause much trouble. You can charge to 100% to trigger balancing only once every 10 or 20 charges, your battery won't complaint, on the contrary, that's what we do in the RC world. How to charge to 80% ? Use a voltmeter- amperemeter, or a Charge Doctor, if there is any suspicious change in capacity, you will know it immediatly.

BTW, what's the response of Lightinbox so far ? You've done the right thing buying from a big reseller (with eBay, Alibaba or even an Amazon's reseller, once you have given them evaluation, most of times, you can say adios to the customer support). Some wheelers buying from Banggod have had problems with the battery too, and its response has always been to send them a brand new battery.

You are probably be the first one to make a "BMSectomy" before getting a replacement approval from the vendor . Let's hope it won't cause problem with the Lightinbox's customer service ! Fingers crossed.

 

 

[cg]

@esaj, @hobby16, thanks a-lot for your input, I am really holding myself back trying not to mangle to much with the battery before I have a grand plan ...

I was reading through the French forum thread @hobby16 suggested (translated), and i found this much better prices Sony US18650V3, so I might bye some of those.

BTW, what's the response of Lightinbox so far ? You've done the right thing buying from a big reseller (with eBay, Alibaba or even an Amazon's reseller, once you have given them evaluation, most of times, you can say adios to the customer support). Some wheelers buying from Banggod have had problems with the battery too, and its response has always been to send them a brand new battery.

You are probably be the first one to make a "BMSectomy" before getting a replacement approval from the vendor . Let's hope it won't cause problem with the Lightinbox's customer service ! Fingers crossed.

Wee, good to be first for once

It is very interesting what is going to happen. The only thing I heard from lightinthebox was the initial response, (Thursday morning), that the issue would be passed to a more technical co-worker... I guess I will give them until Tuesday to give me a response. (By the way, I made the order via amazon.co.uk with the seller 'lightinthebox europe', since I trust amazon would return the money in case nothing showed up)

 

now I have to prepare Barbeque for quests, but I have my soldering iron near the barbequeu, so I might shunt while cooking

Ohh, by the way, the only charger I have is the one that came with unicycle..