IPS ZERO Review

[csmyers]

13 minutes ago, micro said:

Here some information on the ZERO-batteries. The manufacturer rates the NRH10 cell (ZERO-130/260) not as of 2.2, but 2.0Ah.
http://www.saftylipobattery.com/sell-2770756-18650nrh10-16s1p-60v-2000mah-lipo-battery-for-e-scooter.html

I tested one of these cells with a constant discharge current of 2.1A, the voltage dropped after 29min to 3.5V (I regard this is the limit for our EUC, that is 56V/2A for our 16 cells). That is almost exactly 1Ah. Compare this to the two batteries in this graph:
http://www.dampfakkus.de/akkuvergleich.php?akku1=141&akku2=491&akku3=&akku4=&akku5=&akku6=&a=2
The one is the Sony US18650NC1 cell which is used in the ZERO-340, the other is NCR18650B from Panasonic which I installed in my ZERO (see photo, it is now a ZERO-410 or so). The utilizable capacity (between full and 3.5V at 2A) is 1.5 Ah (Panasonic), 1.3Ah (Sony) and 1.0Ah (the unbranded 18650NRH10 cell in ZERO-130/260) respectively.
Internal resistances: 66mOhm (Panasonic), Sony seems to be comparable, NRH10 0.095mOhm (my own measurement). Obviously the NRH10 is not too bad.

My idea is, use either a 32-cell-battery with a capacity as large as possible (e.g. 2 x 3.5Ah), or, if weight matters, use a battery with a very low resistance (LG H2). The point is, if the resistance is not low, you will have much less utilizable capacity from the small battery and often lack of power (the "grinding noise" comes more often).

Fascinating research! I assume you assembled that battery pack yourself? I was hoping to do the same for my own Zero, at some point. Big upgrade from 260Wh to 400+!

[fearedbliss]

@PagsyWhere could I order one? I've been thinking of getting one primarily because of the weight, but now i have 4 unis .. I need to sell 2 once I make my decision on which one to sell off lol (TG-T3, E+, P, KS Mark 3).

[micro]

The review is updated now, see first page.

[playdad]

@micro

 

On 28/10/2015 at 5:49 PM, micro said:

The enclosure gives only little clearance to ground, jumping slowly from curbs or jumping up is not ideal.

Thanks for the update. Are you saying that the Zero doesn't suit jumping onto curbs? And even not coming off a curb?

I assume its because you feel that it would be too easy for the enclosure to hit the ground upon impact in both cases?

[micro]

In principle, everything is possible. As I said, I am a coward. I will jump down curbs with a height of 15cm, maybe more, but I do not like the idea to jump on curbs that are higher than the clearance of the enclosure (some 8cm).

[csmyers]

@playdad @micro 

I don't think the Zero can really be jumped up curbs. I've tried jumping on flat ground and I couldn't get it - the wheel is too small to get a grip on the sides with your calves, and the vertical plastic sides aren't very grippy against shoes.

However, riding down curbs is no problem, as long as you maintain consistent speed.

[playdad]

@csmyers

How about sticking some good "grabby" padding? Would that work?

Also, what height a curb would warrant jumping? VS just rolling over it? 4 inches? Surely, one should be able to roll over anything up to 3 inches? I have no experience hence the question!

Edited December 25, 2015 by playdad

[IPS zero driver]

On 10/28/2015 at 10:49 AM, micro said:

This review was updated by the following addendum on December 24 (Happy Christmas to all of you!). I did not change the first version (see below).

Available information:
Website: http://www.iamips.com
User's manual is attached.

Mechanical design:
The footrests are prone to scratches. However, with a can of glossy white paint it is easily touched up.
The semitransparent covers with the LED ribbons are fixed to the white body shells by means of fragile lids. It is not easy to remove the covers without breaking them. I have the bad attitude as to open my stuff too often. Consequently, four of these lids are broken.

Charger:
My charger limits the voltage to 66.0V, that is 4.1V/cell. It charges with a more or less constant current. Charge current is 2.0 A when the battery is below 64V, the current drops with rising voltage, e.g. 1.4A at 65.5V and only 0.5A at 65.5V.
It is seems to be short-circuit protected.  

Connectors:
The charger uses a coaxial DC power connector  0.100"/1.42" (2.5/5.5mm) female connector. The counterpart is hidden behind one of the footrests.
Battery pack is connected via an XT60 connector, the balancer cables are divided into two JST SM connectors, 11 and 7 poles respectively.

Lighting:
Is Chinese bling-bling. It consists of four RGB dumb ribbons (you can have only one color at a time on the ribbon). They are connected by means of four six pole JST SM connectors. The ribbons are powered by a separate 5V power supply. If you do not like the fancy lighting, remove them and use the power supply for your own purposes. I myself took it for four bright red 70mA LEDs (2 x 2 in series with a resistor) and a Voltmeter.

Battery:
The ZERO-130/260 incorporates 18650 cells marked NRH10. The battery manufacturer rates the NRH10 cell not as of 2.2 (as imagined here sometimes), but of 2.0Ah capacity.
http://www.saftylipobattery.com/sell-2770756-18650nrh10-16s1p-60v-2000mah-lipo-battery-for-e-scooter.html
As reported here, in the ZERO-340 32 Sony US18650NC1 cells are installed.

I tested one of the ZERO-130/260 NRH10cells with a constant discharge current of 2.1A, the voltage dropped after 29min to 3.5V (I regard this is the limit for our EUC, that is 56V/2A for our 16 cells). That is almost exactly 1Ah.

Compare this to the two batteries in this graph:
http://www.dampfakkus.de/akkuvergleich.php?akku1=141&akku2=491&akku3=&akku4=&akku5=&akku6=&a=2
The one is the Sony US18650NC1 cell which is used in the ZERO-340, the other is NCR18650B from Panasonic which I installed in my own ZERO (it is now a ZERO-410 or so).

Constant current flow between full battery and 57V at 2A: After 2 x 1200 s (the time axis is divided in 2s-intervals) the Sony cell voltage drops to 3.55V. This corresponds to some 1.3Ah (2.6Ah for the 32 cell battery) which is the utilizable capacity (see table under the graph). The utilizable capacity (between full and 3.5V at 2A) is 1.5 Ah (Panasonic), 1.3Ah (Sony) and 1.0Ah (the unbranded 18650NRH10 cell in ZERO-130/260) respectively. The table also shows the utilizable amount of energy between full and 3.5V. The 32 cell Panasonic battery gives you some 32 x 5.7Wh = 180Wh (2A discharge cell current). When there are only 16 cells, the current is not only two times higher, the shutdown comes due to voltage dips earlier when the current is not absolutely constant. The 5A table could then serve for an estimation, it says 16 x 3.2Wh = 50Wh. A weaker battery than this Panasonic cell provides an even lower capacity.
My 7Ah Panasonic battery is empty after some 50 to 100 min depending on speed, acceleration and ambient temperature. 50 minutes would correspond to the 1500 tick of the time scale in the above mentioned graph. This battery is good for 16 ... 18km (at 10 °C) in town, with many stops & accelerations. Calculation and experience correspond to the difference of Paul's reported 4km (ZERO-130) and the range of my modified ZERO.

Internal resistances: 66mOhm (Panasonic), Sony seems to be comparable, NRH10 95mOhm (my own measurement). Obviously the NRH10 is not too bad.

My idea is, use either a 32-cell-battery with a capacity as large as possible (e.g. 2 x 3.5Ah), or, if weight matters, take a battery with a very low resistance (e.g. LG H2). The point is, if the resistance is not low, you will have much less utilizable capacity from the small battery and often lack of power (the "grinding noise" comes more often).

Recently IPS rates the batteries of 120 and 240Wh „capacity“. It is not clear whether they changed the supplier or are more honest now.

Remote Control Application:
It runs on Android from 4.4 on (not on FireOS) and iOS 8.0 or later. Compatible with most Android telephones and tablets; iPhone, iPad, and iPod touch. http://www.iamips.com/m/app.html
Useful items in the settings: Battery voltage and heat sink temperature, both values do not update, one has to leave the settings and return again to the setting in order to see the actual data.

You can connect your device during charging.

In the main screen there is something like battery percentage. That is misleading. I is just the voltage. It would be so easy to estimate the actual capacity...

Firmware update: 4.1.2 is the actual version. The update from 4.1.1 worked.

Some issues:
As soon as the wheel is switched of, even for a very short moment, the connection is lost and has to be reestablished which needs some time. The trip counter is then resetted to zero.

When the app scans the environment, it finds several other items and lists all the different MAC addresses.

One digit too much: 30.25°C or 64.83V is not really meaningful.

Quality:
The factory itself admitted that the first ZEROs like mine were assembled in a hurry.
Nevertheless, the design itself is well done, the body parts (the two shells and LED covers) fit precisely.

Speed and tilts:
As I am a coward, I do never drive faster than 22km/h or so. And even below this speed occasionally a very slight forward tilt occurs. When I first experienced it I was pretty sure to fall on to my old nose. I do not find too much about higher speeds here so I argue that my fellow drivers do not have so much experience so far, either. Please correct me if I am wrong.

When the battery is down to < 58V, the ZERO tilts back and forth to tell me it is the end of the trip. When I am waiting for some minutes and then ride very slowly I can do still another 1.5km (down to 57V).

Impressions:
I learned driving an EUC from this year's August on (Airwheel X3). In October, after I received my ZERO, I felt at first pretty uncomfortable on the ZERO. It is not very stiff, the legs do not touch the wheels' body, consequently there is no guidance and the wheel tilts easily to either side which results in an unsafe feeling. After some 200km I can say that riding the ZERO is in the beginning not very convincing, after a while a safer feeling comes up and today I dare to ride it rather fast.

The difference between low pressure (< 2 bar) and a higher pressure (> 3bar) bar is remarkable. With a low pressure it feels unsafe, but in fact the wheel forgives much more than with 3.5 bar. As it is not so easy to control the pressure I made this experience unintentionally.  

The ZERO is not designed to perform tricky things. Driving backwards or going back and forth waiting for green traffic light is not quite as easy than on stiffer EUCs.

The enclosure gives only little clearance to ground, jumping slowly from curbs or jumping up is not ideal.

The enclosure is very close to the tyre. There is a labyrinth on either opening to prevent splash water coming into the wheel, mud, sand and al other things are safely captured there. The ZERO is made for good conditions, you should not use it for trails in woods.
These are the costs of being beauty.

Due to the circular design the wheel looks bigger than other 14“ wheels. The small visible part of the tyre and its „illusory contour“ of the dark LED covers resembles a 16“ wheel. You can see that if you would see a ZERO and one of the older IPS designs side by side.

Possible modifications:
lighting (I do prefer a torch as head light)
voltmeter (100V type, powered by the 5V LED power supply, the instrument works also during charging)
2 x 3.5Ah batteries
tyre pressure control (the Bluetooth stuff for bikes)

Service:
Shanghai IPS Investment Co.Ltd (http://en.iamips.com/  and http://www.iamips.com ) is the manufacturer. E-mail-addresses: runrui.meng@iamips.com, Runrui is relatively new with IPS, but she is the person at the front, and she does a good job. For more specific technical questions ask sophie@iamips.com (Sophie is a traditional Chinese name :).
Shanghai IPS Investment Co.Ltd
Add: 102, 1/F, Yaojiang Internation Plaza, 308 Wusong Rd, Shanghai, China
Zip Code: 200080
Tel: 86-021-61728335
Mail: service@iamips.com

http://ipselectricunicycle.com/ is a reseller.

Orders are possible directly from the factory or through one of the resellers.
I would recommend to purchase fom IPS, it is probably more expensive, but the service is better, and there are friendly people.

My contact to IPS:
Meanwhile I had some discussions with the IPS people. They read the first version of this review, and there where some reactions:
„Hi, pls note the euc shouldn't be lifted if it is turned on, the fast spinning of the tyre would not be safe to the person. and so far we didn't receive any information mentioning that the tyre is not balanced.
Since you first buy it from Tony in Oct (I guess he ordered from fund raising) and we didn't start to sell it internationally then, all orders from fund raising are manufactured in a rush, that's why what you received is not as good as expected.
All orders shipped from us are now well packaged, the same issues will not exist.“

I addressed the battery shipment issue. They agreed in a shipment of ZEROs without battery in order to install the battery by a distributor or end customer.

IPS is willing to sell the ZERO without batteries.

Unanswered Questions:
(Today I got a letter that I might expect some answers later.)

How is the shutdown issue handled?
(low battery, temperature, current)

BMS battery cut out (over discharge): Voltage and delay
Cut in seems to be at around 58V

The temperature value In the application settings:
Is this the heat sink temperature? What is the maximum?
What happens when the maximum is reached?

The power rating in the spec sheet is 800W. What is that? Rated motor input power, output power, surge power, something else?
I have seen in Tony's list 800W for ZERO 130/260, and 1000W for the 340.
Is there really a difference?

In our forum is some confusion as meanwhile there are 120 and 240Wh in your specifications instead of 130/260Wh.
Is IPS really using another battery? In the beginning, was "Safty" the supplier? Today?

Is there any difference between the firmware versions for the different models?
Is it possible as to program the 32cell version of the firmware in a Zero which has been modified this way?

In the manual there is the firmware version 4.3 mentioned. In my ZERO I do have there was 4.1.1, now updated to 4.1.2. What is correct?

There is no CE mark on the ZERO. It could cause a problem with customs.

 

======================================================================================================================

 

I am trying to bring in this review all relevant information together about the IPS Zero. Many is to be found in this thread: http://forum.electricunicycle.org/topic/748-ips-zero

Available information:

IPS seems to be regarded as one of the more serious manufacturers. On their website http://ipselectricunicycle.com/
there is a tab „electric unicycle“ and another „IPS ZERO“. IPS probably expects that it has a bigger potential than the older products.

A Chinese sales brochure is posted here (it was a fund raising program) : http://forum.electricunicycle.org/topic/748-ips-zero/?page=1
The weight (see 7th image) is not 8.6/9.3 kg as claimed but 9.4/10.3 kg.
You can find an „explosion view“ (8th image) where the different enclosure components are to be seen.

The data sheet shows three models, the first ZERO-130 and -260 had been shipped by mid october, the ZERO-340 seems to be available from now on. I guess the batteries for the latter will be of the 3 Ah capacity (the weight is the same as for the ZERO-260, where else the other two are using the standard 2 Ah - cells. In my opinion the ZERO-260 makes not much sense if the ZERO-340 does not weigh more. In the spec sheet there is a difference in the power (1000W vs. 800W). See screenshot here http://forum.electricunicycle.org/topic/748-ips-zero/?page=2

Csmyers' well documented  teardown: http://imgur.com/a/AVqN9

There is no user's manual so far.

Mechanical design:

The weight of my ZERO-130 is 9.42 kg, not 9.2 as claimed in the spec sheet. You can bring the weight down to less than 9.1kg by leaving off the LED covers. Then there is no more fancy blinking... The Zero is not really light. Airwheel X3 (which is of the widespread old design) weighs with the same battery 9.8 kg.

Footrests are slightly inwards tilted, height with 3.5 bar tyre pressure and 75 kg driver is110mm.
The ground clearance is better than of some others, narrow turns are possible.
The footrests are long, the rubber cover is 185mm. The grip is pretty good.

The axis of the footrest is fixed in the axial position by a little headless screw, it has not to be tightly fixed as the axis has to turn around freely. The footrest holds in the park position by means of two magnets, one in the footrest and the other behind the enclosure. This solution is also found on other brands and works fine, but the screw should be secured by Loctite.

The handle would suit a suitcase better than this fancy appearance. I would have formed it as a part of the enclosure.

The tyre is not balanced, the origin of the imbalance seems to be the Kenda tyre. When the EUC is being lifted, it wobbles before the shutdown.

The tyre comes very close to several parts of the enclosure. If not everything is correctly aligned, a grinding noise comes from the touching tyre. It is not easy to reassemble the enclosure. Pump up the tyre to 4 bar before you try to align all enclosure components.
Take care that the lid of the internal black cover fits the white outer part correctly. This provides some protection against water and dirt.
No doubt that somebody did a remarkable effort on the enclosure design. It is not only pretty but also truly convincing in most details. The LEDs may be seen as an expression of bad taste, however, it is simple to disconnect them so that you can be regarded as semi-serious. The drawback of the design is that it is not so easy to dismantle the wheel in order to fix a problem or to repair the tyre.

Electrical design:

As csmyers showed on several photos, it is a spaghetti monster and an application for hot glue producers. As there are no fixation provisions in the enclosure shells I do not believe IPS will change that.
Control box. Have a look at the attached photo of csmyers (mine looks very similar).
The fixation points of the enclosure do not fit the counterparts of the box. The brave mechanic forced the alignment. Consequently, the covers of these box are open, a slit is visible. This is true for either side. The cover strips are very weak, and there are no fixations in the middle. In no way waterproof. The box with the electronics is of the type water comes in but not out. I regard this as potentially unsafe. Next time I will seal the box on either side.
The aluminum enclosure serves as a heat sink, the FETs are tightly fixed by four screws onto it. The plastic cover where this box is mounted on has a big rectangular opening in the rear side for better cooling. Thus the box is exposed to the wheel to splash water as well as to dirt.
I am not an expert in electronics nor did I examine the circuit very long. What I did see:
The component that was burnt in csmyers' ZERO seems to be a transient voltage suppressor 82 volts from ON Semiconductor. I did not find the data sheet, maybe it is customized item. However, on other types of this manufacturer the marking 82A is to be read as 82 volt, minimum 80.
There is a 30 amps fuse at the input, it is rated 32 volts. The fuse will blow only when there is something wrong on the board (burnt FET or voltage suppressor in this case). This fuse serves only to contain the fire when something bad happens. You should never try to replace it.
The MOSFETs are P75NF75 from ST (75 volts max). I am not sure whether this will not pose a problem. I think IPS inserted the voltage suppressor as the FET max voltage is pretty low. (Normally designers do not use voltage suppressors in power electronics as e.g. inverters.)
The Cypress cy8c4247lqi-bl483 controller is stuck on the back side of the pcb (see photo :).
Power supply for the control circuit is provided by a LM5576 step down converter. (If you would like to have a low voltage source you can take one of these converters with an on-off switch at the input. There are tiny boards available.)
Charger:
The EUC is coming with a charger 67.2V/1.75A which uses a coaxial power connector 5.5/2.5mm.
(others use a three-pole round connector). I have little doubt that this connection is not specified for 70V/2A. The opening for the plug (male) is hidden behind the footrest. It is not covered outside of the enclosure, but the plug together with the buzzer has its own little enclosure mounted with three screws on to the inner enclosure part. This is well done and there is no need for an external cover. On the photo the little box had been removed.

The charger weighs 502 g with cables. I would prefer a built-in charger 1 A or so which should not add more than 200 g to the weight. (But everybody is happy with her ultra thin laptop which comes with a bulky power supply.)

Safety:

How does IPS handle shutdowns? The BAMAS is in the control box, this is not an issue.
IPS is still in the "less dangerous" category here: http://forum.electricunicycle.org/topic/478-brands-with-without-unexpected-shutdowns-new-buyers-look-here/
Why?
Here is often stated that more battery capacity means more safety. I do know the arguments. But is it true?

Quality:

My ZERO arrived in a poor condition. Painting peeled off from the footrest, footrest not aligned, the glossy surface of the semi-transparent LED covers blind, even scratches on them, tyre touched the enclosure, wheel imbalanced, inside lots of glue, poor cabling, control box not tight, packaging provisionally, no manual.

Impressions:

Jason McNeil:  http://forum.electricunicycle.org/topic/748-ips-zero/?page=11
1. Motor feels powerful, but I think they dispensed with a number of poles to reduce motor component weight. The consequence is that while riding, it's not quite as perfectly smooth as existing designs—I doubt most people will notice this
2. Mature/sophisticated App: Speed, battery capacity, power (in A), mood lighting (very similar to Ninebot), headlight (not great), ride mode (hard/soft)
3. Perhaps the biggest oversight is the design of the charging port: at the moment, it's on the side near the pedal, with no cover to protect it from the elements. They say it will be improved...
Remarks:
1. Everybody feels that. For me this is the main disadvantage of the ZERO.
2. That is not the application that we do have right now. The actual application does not provide too many informations or options. The battery voltage is hidden in the preferences. Most of the information is useless or „not yet available“ as the suppression of the blinking.
3. This is not a really an issue. See above and photo.

My own impressions: Vibrations, loud, feels a bit weak in narrow corners, tilt back is not aggressive, leg-friendly (cushions from the accessories are not really useful), fancy appearance without the LED gimmick, technically no step ahead.

Service:

Here are many remarks on the wonderful communication with the person with the pseudo „Tony“ to be found. I got best wishes from some of you for my attempts to get anything useful or at least a friendly word. For instance, in case you have the feeling that something is not as it should be, the answer could be: „we did not agree ! unless you send me the video of unboxing like this one.“
https://www.youtube.com/watch?v=VbiBjobG__0
Whenever you are touching a IPS product you should have a camera at hand.

Shanghai IPS Investment Co.Ltd (http://en.iamips.com/  and http://www.iamips.com ) seems to be the manufacturer

There are two E-mail-addresses, the one does not work, on the other (suka@iamips.com.cn) I got no response so far.

http://ipselectricunicycle.com/ is a reseller. This would explain our "Tony"-adventures. „Tony Lee“: manager@ipselectricunicycle.com

http://www.ipsunicycle.com/ And what is this?

I have sent a copy of this to IPS, I invited them to comment on possibly wrong statements.

Please contribute to this review, I would like to get it better and more complete.

User manual for Zero.pdf

I agree entirely with your remarks. My IPS zero 340 shut down suddenly and i fell backwards I was cruising at  15 km/h so not speeding. I still wonder what (technically) happened ?

[LorenW]

Wow... The level of product knowledge here is pretty staggering, and really impressive. I'm really blown away!

I have been interested in a light-weight EUC for a while after having a Ninebot e+ for quite a while.

The IPS Zero 340 has been tops on my list for a while, and I have been thinking of finally pulling the trigger.

I was curious about the "real world" range that folks were seeing for the 340 model. I know range depends greatly on terrain, rider weight, and riding style, but I still wondered what you all have been experiencing.

Thank you!

BTW, I am about 90kg (approx 200lbs). Which I have come to understand is heavy in EUC terms! I get about 16km/10mi of range on the Ninebot e+ in my area, riding just under the beep warning. Much slower riding appears to extend the range hugely (although I haven't precisely measured this yet). Manufacturer claims a range of 10 to 35km. So my experience falls in there... On the lower end. :-)

[SlowMo]

3 hours ago, LorenW said:

Wow... The level of product knowledge here is pretty staggering, and really impressive. I'm really blown away!

I have been interested in a light-weight EUC for a while after having a Ninebot e+ for quite a while.

The IPS Zero 340 has been tops on my list for a while, and I have been thinking of finally pulling the trigger.

I was curious about the "real world" range that folks were seeing for the 340 model. I know range depends greatly on terrain, rider weight, and riding style, but I still wondered what you all have been experiencing.

Thank you!

BTW, I am about 90kg (approx 200lbs). Which I have come to understand is heavy in EUC terms! I get about 16km/10mi of range on the Ninebot e+ in my area, riding just under the beep warning. Much slower riding appears to extend the range hugely (although I haven't precisely measured this yet). Manufacturer claims a range of 10 to 35km. So my experience falls in there... On the lower end. :-)

You might try to consider having the MCM4-HS. It has an 800w motor and efficient power handling for almost the same price as the IPS Zero. 

Being accustomed to the handling of my resurrected Ninebot which I am riding for almost 2 weeks now, I took my MCM4-HS for a spin and was surprised with the very smooth acceleration and speed that it provided.

Edited March 23, 2016 by SlowMo

[DS]

1 hour ago, SlowMo said:

I took my MCM4-HS

Hey @SlowMo, may I ask you where did you buy it from?

[SlowMo]

7 minutes ago, DS said:

Hey @SlowMo, may I ask you where did you buy it from?

I bought it from Mr. Chen @unicycle distribution .

Edited March 23, 2016 by SlowMo

[DS]

Thank you @SlowMo,

I'll send you PM, not to mess this thread.

[who_the]

I am about 165 lbs (75kg) and yesterday got 10.2 miles (16.4 km) on a 340wh IPS Zero along a mixed (not flat) paved route here in San Francisco averaging around 20 kph and peaking just below 30 kph. Did the same ride at a slower speed a few weeks ago and had more life left in the cells. So speed kills. (Your battery.) .

Bought mine from xiaoq-cn on eBay (on this board as Linneaunicycles).

[Chris Westland]

Thanks for the great reviews!   I just purchased one, and should receive it Friday.  I'm looking forward to trying it out!

[matt]

Hello,

I wondering, if one can use 2 x 32 cells, is it possible to use any multiple of the 32-cell battery, say 3 x 32 cells?

[Esper]

11 hours ago, matt said:

Hello,

I wondering, if one can use 2 x 32 cells, is it possible to use any multiple of the 32-cell battery, say 3 x 32 cells?

What a revival of such an old thread. May I suggest starting a new one? 

[matt]

Well, my first thought was not to mess an informative thread... But I don't understand the need of making a new one because of age. It's about expending information from the first post here (at least the edited version of it).

[Chriull]

11 hours ago, matt said:

Hello,

I wondering, if one can use 2 x 32 cells, is it possible to use any multiple of the 32-cell battery, say 3 x 32 cells?

Theoretically yes. Practicly maybe.

Many people expanded their wheels battery capacity like this. The BMS has to stand the higher burdens as the wheel itself, cell balancing could be a bit limited (pfff.. have to think about this statement a bit more in detail...) and connecting li ion cells can easily degrade the cells and could "make them hazardous", if not done right..

Most likely people who have to ask such questions lack the experience and knowledge of performing such work in a non dangerous way... High Capacity LiIon packs can be very dangerous

 

3 minutes ago, Esper said:

What a revival of such an old thread. May I suggest starting a new one? 

Sounds like a good idea. Is more of a mod question and till now no relation to an IPS Zero to be seen but the topic title.

[matt]

5 minutes ago, Chriull said:

Sounds like a good idea. Is more of a mod question and till now no relation to an IPS Zero to be seen but the topic title.

I meant could it be done in IPS Zero, like the author did in his, but, as I said, on multiple basis. That was obvious to me since the thread started as IPS Zero review. (I've had one with a dead battery for quite some time.)

And you're right about the lack of knowledge btw . I just wanted some basic information for the beginning, to asses if my Zero has any potential for me, if it's worth to even think about that.

Edited May 13, 2019 by matt

[Chriull]

8 minutes ago, matt said:

I meant could it be done in IPS Zero, like the author did in his, but, as I said, on multiple basis.

If there is enough space. And it has to be done in multiple of 16 cells. The ips zero uses a 67.2v pack?

But the more cells in parallel the higher the possible burden for the motor drivers and BMS protection. So this addition could overload some mosfets sometime...

8 minutes ago, matt said:

And you're right about the lack of knowledge btw . I just wanted some basic information for the beginning, to asses if my Zero has any potential for me, if it's worth to even think about that.

Theoretically i should know how to do such work - but getting the right equipment, putting in the effort and taking the risk of doing a work one is not experienced with would be nothing for me, personally. Taking the possible worst case hazards into account ...

Also from my readings so far the sustainability (life time, performance) of such li ion packs is mostly dependend on perfect cell matching - something that cannot be achieved by customers...

[matt]

If it's about space, that would be no issue. I was thinking about changing my Zero dimensionally and, I would say, mechanically (more ergonomically spaced and shaped pedals among other things). I was thinking of getting rid of the original casing completely. The original cells are supposed to be Panasonic NCR18650PF 2900mAh - 10A.

I know about the danger involved with high capacity cells, obviously. I was hoping that maybe "cloning" the dead pack and adding a second and possibly even a third one would be relatively easy. You know, just "copy and paste" I also thought I would learn new things in the process, there's no rush, you know, a spare time thing.

I thought having cells from one batch was all one would need. The perfect matching sounds like a deal breaker.

Edited May 13, 2019 by matt
forgot about the question about cells

[Chriull]

7 hours ago, matt said:

I thought having cells from one batch was all one would need. The perfect matching sounds like a deal breaker.

I don't have any idea how closely matched one could get cells from one batch. Some more knowledge about matching:

https://batteryuniversity.com/index.php/learn/article/bu_803a_cell_mismatch_balancing

This was one nice article about battery pack making:

https://www.electricbike.com/introduction-battery-design-2/

 

[matt]

Thanks, I'll dig into it.

13 hours ago, Chriull said:

The BMS has to stand the higher burdens as the wheel itself, cell balancing could be a bit limited (pfff.. have to think about this statement a bit more in detail...)

So, I'm guessing, for the BMS and the rest of the EUC it's better to have a smaller number of higher capacity cells rather then vice versa, despite the worse price/capacity ratio?

Edited May 14, 2019 by matt
to avoid multiplying post

[Chriull]

4 hours ago, matt said:

Thanks, I'll dig into it.

So, I'm guessing, for the BMS and the rest of the EUC it's better to have a smaller number of higher capacity cells rather then vice versa, despite the worse price/capacity ratio?

I don't know if the Zero has a seperate BMS/everything realized on the mainboard? The Zero knows the individual cell voltages?

But either way normally there are mosfets at the charge and discharge site, that can cut off (overcurrent, cell over/undervoltage). They have to be designed to withstand the current, which presumably will not render a problem.

But the normal maximum current is limited by the internal resistance of the batteries, the motor, the connections, wires, copper traces and the mosfets of the motor driver (inverter/h-bridge).

Increasing the overall battery capacity works by putting more cells in parallel. This lessens the internal resistance and by this increases the maximum possible system current.

The system current is limited by the BMS overcurrent cut off (if implemented) and by the cpu (measuring the motor current via a shunt and then reducing the pwm duty cycle or directly shutting off the driver mosfets). This cpu overcurrent control could be too slow so the weakest link in this chain gets destroyed. Or at each burden there flows a bit more current than "normally" (till the cpu decides to reduce) and by this overheats the weakest part "slowly".

... Or just everything is fine and nothing special happens  ...

Regarding which cell to choose: higher capacity cells have their real advandage with "low" burdens. The more current one takes out, the less capacity advantage is left...

So its up to you to design your system performance/space/cost wise... And you're not really limited to 18650s, if you do it yourself. If you can add your own BMS for the new cells (or discard the old cells).

If you have to stay with the current BMS(s?) and cells you should maybe stay with the currently used cells, depending on how you decide in regard to cell matching. Which will be difficult to impossible with already used cells?!