IPS ZERO

esaj · November 16, 2015

Just now, Jason McNeil said:

I've been an IPS distributor for nearly 2 years & can say with absolutely certainty that the sustained motor rating of 1,000W is categorically wrong. IPS uses the same formula as Airwheel (and many of the others, KS excepted), where take the nameplate power output of the battery pack & adopt this as the 'motor power'. It's just wrong & causes a lot of unnecessary confusion.

Sometimes (many times) I just wish I had all the information and knowledge you've accumulated about these wheels over those years... The "cogging"-issue was something new to me (although I suspected it had something to do with the overpowering causing havoc in motor driving), as well as this.

houseofjob · November 16, 2015

8 hours ago, Jason McNeil said:

When I visited the factory last month, I couldn't believe that they didn't restrict the 130Wh model to a more conservative speed, I told them this was completely unrealistic and here we are....
Our Zeros will contain the LG HG2 cells, these have nearly half the internal resistance of the stock models & therefore vastly more resilient voltages under load, which means they will be much safer to operate.

The grinding noise is what's referred to as 'cogging'. In these situations when the voltage drops below the critical threshold (around 45v), the integrated BMS cuts the power to control-board, & the motor goes into power generation mode (but under no-load), which is what the sound you hear.

@Jason McNeil do all 340wh Zeros have this LG battery, or is this another special edition you are selling akin to your upcoming KS-14? If it is a special edition, will this be available in your new Miami Beach shop deliverable to the US? Thanks.

SlowMo · November 16, 2015

8 hours ago, esaj said:

The spec sheet on the first page of this topic lists the 340Wh version having 1000W motor vs. 800W on 130/260Wh -versions (this post, scroll down a bit: http://forum.electricunicycle.org/topic/748-ips-zero/?do=findComment&comment=8106 ). Don't know if it's true though.

I think the 1000w motor as tabulated in Tony's website is another marketing ploy. If you scroll down on the same page you will read:

"The IPS Zero is amongst the latest addition in the company’s product line. It is currently available in three different models, most of which containing

the same set of features. The Zero-130, Zero-260, and Zero-340 all have 800 watts of maximum power output".

Update: I got the official confirmation from IPS factory.

" No, it is 800w same as zero130 and zero260. "

Despite all this, me and my family really like the Zero. It's like having a beautiful toy to play around and show to everyone. Its much better looking and a lot lighter and more compact than my E+. The ride is so smooth the pedals are firm and wide and it's got a very thin profile. The lighting effects can be seen at all angles and the motor is very responsive. :wub:

Edited November 16, 2015 by SlowMo

SlowMo · November 16, 2015

4 hours ago, esaj said:

Sometimes (many times) I just wish I had all the information and knowledge you've accumulated about these wheels over those years... The "cogging"-issue was something new to me (although I suspected it had something to do with the overpowering causing havoc in motor driving), as well as this.

"Cogging" should be added to the Electric Unicycle Terminology thread.

playdad · November 16, 2015

Hello everyone!

I'm new to Unicycles and have been eyeballing the IPS Zero (and this thread) for a while. I can read/speak/write some BASIC Chinese as I'm an expat in Beijing, China. While I am not sure how much help I can be... I thought I'd point out the main sales sites of the IPS Zero range in China. Perhaps being located in China may prove to be of some use in the near future. IPS has basically been marketing the 130/260WH versions so far. I've not seen the 340WH material, where are you guys seeing it?

IPS own Official Taobao store ( known also as Tmall and is likely their main retail channel)

https://ipsyd.tmall.com

The ZERO itself (note only 130/260 variants)

https://detail.tmall.com/item.htm?spm=a1z10.1-b.w10805376-12178714206.3.Ot6rIm&id=523189141012&scene=taobao_shop&skuId=3114569203907

Interestingly, I spotted a ZERO selling on China's version of Amazon.com (who takes a chunk of commission) for 1000 CNY less. For some reason, this one's specs looked IDENTICAL except for one bit.. it said 240WH. It could be a typo or something else? Different versions for different merchants? Regardless, sales has just started and numbers are low at this point)

If you look at their Tmall store, the ZERO has only recently been launched and has had relatively low sales numbers or reviews. (I don't rely on Tmall reviews either - they can be rigged).

So in conclusion, there's probably less than 500 Zero owners in China right now and you early adopters are right in there with the first round of testers. I thank you for your service and am eagerly awaiting more reviews. :lol:

My family is currently enjoying a 10-inch "hoverboard". It's awesome fun but useless around humps and bumps. Thus, I was planning on adding a Ninebot One C+. (There's no E+ readily available in China - weird huh?) But I'm keeping my eyes on this one now due to its much lower weight and the ninebot's recent risky software updates. The thing I do like about Ninebot though is their focus on a few models. IPS has way too many series. T-series, I-series, Zero and I even spotted a F-series. Confusing!

SlowMo · November 16, 2015

5 minutes ago, playdad said:

Hello everyone!

I'm new to Unicycles and have been eyeballing the IPS Zero (and this thread) for a while. I can read/speak/write some BASIC Chinese as I'm an expat in Beijing, China. While I am not sure how much help I can be... I thought I'd point out the main sales sites of the IPS Zero range in China. Perhaps being located in China may prove to be of some use in the near future. IPS has basically been marketing the 130/260WH versions so far. I've not seen the 340WH material, where are you guys seeing it?

You are absolutely right. The 340wh models are for overseas sales only.

Edited November 16, 2015 by SlowMo

Linnea Veteran · November 16, 2015

Correct, the 340wh model is for overseas sales. It will not public selling in China online shop.

micro · November 16, 2015

My personal conclusion from this discussion:

The main point is the voltage drop of the battery when high currents of 20A and more are drawn by the motor control.
The capacity in Ah or the storage capability in Wh give us the usable range, the safety as meant here is related to the internal resistance.

The 130Wh battery packs use cells with a rather high internal resistance. In case they would be replaced by the magic LG H2 cells, the internal resistance should be comparable to the 260Wh battery (half of the 130Wh pack) or even better.

The 340Wh is not safer. As long as we do not know the battery used in this pack we even cannot say that the internal resistance is as good as that of the 260Wh pack. Obviously designers cannot optimize capacity and internal resistance simultaneously.

Here
http://www.dampfakkus.de/akkuvergleich.php?akku1=561&akku2=128&akku3=&akku4=&akku5=&akku6=&a=5
an example. You can see that one battery has a higher capacity, the other (LG H2) a lower resistance. The LG H2 is even better than two in parallel of the examples I took for the comparison.

Nevertheless, the 130Wh battery could be used safely in case we are observing constantly the voltage. I would wish to have a meter (amps, volts, Ah) in all EUCs. It would be a safety feature. At least I myself would feel much better. I am working on a solution.

The indication by means of four LEDs (Airwheel & Co) or blinking (IPS non-zero) is not too bad. These LEDs do not show the state of charge or the remaining capacity (there is no Ah counter = ampere hour meter) but indicate four voltage levels. This is misunderstood here frequently. It is a voltmeter and thus you can see it go up as soon as the current is lowered or there is some energy recovering when driving downhill.

playdad · November 16, 2015

1 hour ago, micro said:

The 130Wh battery packs use cells with a rather high internal resistance. In case they would be replaced by the magic LG H2 cells, the internal resistance should be comparable to the 260Wh battery (half of the 130Wh pack) or even better.

The 340Wh is not safer. As long as we do not know the battery used in this pack we even cannot say that the internal resistance is as good as that of the 260Wh pack. Obviously designers cannot optimize capacity and internal resistance simultaneously.

Hi Micro,

Are you saying that the 260Wh batteries are actually better than the 130Wh? I had assumed from previous messages that the 260Wh simply had 2 packs of what the 130Wh had and thus was superior by having two concurrent sources.

micro · November 16, 2015

2 hours ago, playdad said:

Hi Micro,

Are you saying that the 260Wh batteries are actually better than the 130Wh? I had assumed from previous messages that the 260Wh simply had 2 packs of what the 130Wh had and thus was superior by having two concurrent sources.

When two identical cells are connected in parallel, the resistance is halved. That is why 260Wh is better.

Tomek · November 16, 2015

For me it's easier to think in terms of maximum discharge current. LG HG2 are rated for 20A continuous and 30A peak maximum discharge current. For a 60V (rounded up for clarity) cell of 16 batteries @3000mAh (180Wh total) this would mean that it can sustain output of 1200W with an occasional peak up to 1800W!). Now, for "normal" battery cells the max current can be typically calculated by multiplying their capacity by 2/h. For a 3000mAh battery that would give 6A max discharge current, giving it a max output of 360W (only!). I don't know what batteries IPS uses as default, but even if they are rated for 10A, or 15A, that's not enough (600W or 900W respectively) for a motor that can probably have a peak of 1000-2000W, and the battery BMS will likely shut the power down (=we face plant) if too much current is being drawn (unless it uses a smarter cell protection mechanism, which may result in a different kind of face plant).

Of course, parallel batteries deliver proportionally more amperes, e.g. 4 packs of the 6A-max batteries @60V would give 1440W max power. 4 packs of 30A-max batteries @60V would give a whopping 7200W max power!

(This is based on my superficial understanding of the issue, so please correct me if I'm wrong)

micro · November 16, 2015

It is not that simple. It is best to look at the discharge graphs as those from our Dampfakku-friends. The cells are all different. That is why I suspect that the 340Ah pack is less performing than the 260Wh pack.

If you would look into the data sheet of a certain cell you can find the resistance. In case of the Sony cells there is given 31.5mΩ. Applying Ohm's law this gives a voltage drop of R x I = 0.0315Ω x 20A = 0.63V or 10V for the 16 cell pack. For two packs 5V. The data sheets are also posted on dampfakkus.de

Edited November 16, 2015 by micro

Tomek · November 16, 2015

No doubt, some batteries will discharge (drop their voltage) differently than others, but my concern is the cut-off resulting by the motor trying to draw too much current that the battery/BMS can't handle.

I found a nice, short article explaining how max power delivered by a battery is inversely proportional to its internal resistance: http://farside.ph.utexas.edu/teaching/302l/lectures/node62.html

As an exercise: 57V²/(0.0314Ω x 16 x 4)=1617W (if correctly calculated, not toooo bad for a 16-pack of sony batteries you quote)

esaj · November 16, 2015

2 hours ago, Tomek said:

As an exercise: 57V²/(0.0314Ω x 16 x 4)=1617W (if correctly calculated, not toooo bad for a 16-pack of sony batteries you quote)

Hmm, just a couple of questions: is the external resistance (R) assumed to be 0 (ie. the batteries are short-circuited)? Where does the x 4 come from (if there are 4 battery packs in parallel, their internal resistances aren't summed)? Not saying that I couldn't have misunderstood the equations myself, but...

The equivalent resistance of the circuit is (since the load resistance is in series with the internal resistance), so the current flowing in the circuit is given by

$\begin{displaymath} I = \frac{{\cal E}}{r+R}. \end{displaymath}$

Assuming an external resistance R of 0 ohms (or near enough 0 to be insignificant, short-circuited battery), the current in the circuit with a single 16S-pack with internal resistance of 0.0314 ohms per cell would become

I = 57V / (0.0314 ohms * 16 + 0 ohms) = 113,455... A

The power output of the emf is simply

$\begin{displaymath} P_{\cal E} = {\cal E}\,I = \frac{{\cal E}^2}{r+R}. \end{displaymath}$

Power output would be 57V * 113.455A = 6 466,9...W. For four packs, the output would be quadrupled, so near 6467W * 4 = 25868W. The current flowing through also should quadruple, so 113.455A * 4 = 453.82A. Yeah, you shouldn't short-circuit batteries (although the BMS should prevent it anyway, unless shunted)

The power dissipated as heat by the internal resistance of the battery is

$\begin{displaymath} P_r = I^2\,r = \frac{ {\cal E}^2\,r}{(r+R)^2}. \end{displaymath}$

(113.455A)²* (0.0314 ohms * 16) = 6 466,9...W. As there is no external resistance, all the power is dissipated as heat by the battery. Not a good thing.

Likewise, the power transferred to the load is

$\begin{displaymath} P_R = I^2\,R = \frac{ {\cal E}^2\,R}{(r+R)^2}. \end{displaymath}$

(113.455A)²* 0 ohms = 0A. There's no external load (still in short-circuit).

Maybe more useful if actually calculated with an actual load resistance? Batteries will give huge currents if short circuited and there's no protection circuit to stop it. Just because a cell is rated to give out X amperes doesn't mean it won't give several magnitudes more when short circuited, the rated current is what it was designed to withstand...

Edited November 16, 2015 by esaj

Tomek · November 16, 2015

Oh, wow @esaj, didn't expect to start such an in-depth discussion. As I said, I'm no expert, so just thinking along for fun, possibly in a completely wrong direction...

If you'd short circuit a battery pack without a BMS, like in your example, would reach for a split second over 113 amperes, and probably after that it would overheat and blow up (that's why we're not allowed to take big batteries on planes, and that's why BMS' have overload protection that makes us face plant to save the battery).

As I understand the example given in the link, external resistance is not assumed to be 0, it's just eventually removed from the equation. Number four comes from the analysis of the function relating all remaining parameters. But I'm not actually sure if I've interpreted Pmax in this example correctly. Actually it may have nothing to do with how much Watt the battery can deliver, just what would be theoretically the most efficient power transfer - a battery may very well not be able to withstand such current being drawn due to it's physical characteristics.

Anyhow, the maximum power/current a battery can deliver is limited. if it's exceeded the BMS will shut down, or the battery will overheat and blow up. This shouldn't be possible to happen on a unicycle, but it seems to happen all to often, so we need better batteries.

I'm not sure what's the exact relationship that the internal resistance has with the maximum power/current of the battery. From what I saw in the technical sheets of batteries, max current is the usual parameter that's almost always provided if it exceeds the typical 2*capacity/h, while internal resistance is pretty hard to find...

...perhaps this thread has not been the right place for this discussion, but anyways, it's interesting to look into those things.

claycase · November 18, 2015

On 11/16/2015, 1:59:19, esaj said:

Hmm, just a couple of questions: is the external resistance (R) assumed to be 0 (ie. the batteries are short-circuited)? Where does the x 4 come from (if there are 4 battery packs in parallel, their internal resistances aren't summed)? Not saying that I couldn't have misunderstood the equations myself, but...

The equivalent resistance of the circuit is (since the load resistance is in series with the internal resistance), so the current flowing in the circuit is given by

$\begin{displaymath} I = \frac{{\cal E}}{r+R}. \end{displaymath}$

Assuming an external resistance R of 0 ohms (or near enough 0 to be insignificant, short-circuited battery), the current in the circuit with a single 16S-pack with internal resistance of 0.0314 ohms per cell would become

I = 57V / (0.0314 ohms * 16 + 0 ohms) = 113,455... A

The power output of the emf is simply

$\begin{displaymath} P_{\cal E} = {\cal E}\,I = \frac{{\cal E}^2}{r+R}. \end{displaymath}$

Power output would be 57V * 113.455A = 6 466,9...W. For four packs, the output would be quadrupled, so near 6467W * 4 = 25868W. The current flowing through also should quadruple, so 113.455A * 4 = 453.82A. Yeah, you shouldn't short-circuit batteries (although the BMS should prevent it anyway, unless shunted)

The power dissipated as heat by the internal resistance of the battery is

$\begin{displaymath} P_r = I^2\,r = \frac{ {\cal E}^2\,r}{(r+R)^2}. \end{displaymath}$

(113.455A)²* (0.0314 ohms * 16) = 6 466,9...W. As there is no external resistance, all the power is dissipated as heat by the battery. Not a good thing.

Likewise, the power transferred to the load is

$\begin{displaymath} P_R = I^2\,R = \frac{ {\cal E}^2\,R}{(r+R)^2}. \end{displaymath}$

(113.455A)²* 0 ohms = 0A. There's no external load (still in short-circuit).

Maybe more useful if actually calculated with an actual load resistance? Batteries will give huge currents if short circuited and there's no protection circuit to stop it. Just because a cell is rated to give out X amperes doesn't mean it won't give several magnitudes more when short circuited, the rated current is what it was designed to withstand...

Wow! I've been away for a while. I didn't know there would be a test.

micro · November 18, 2015

The short circuit current is lower than that of a good capacitor (could be much smaller than our battery).

The amount of dissipated energy is small, it compares to the heating value of a very small to medium glass of sunflower oil.

So we are pretty off-topic and nobody dares to tell something new on our beloved ZERO.

csmyers · November 18, 2015

Well, I unlocked the 30km/h top speed and it's absolutely fantastic. Tiltback begins at around 28km/h, but most of the time I find myself cruising at around 25.

At stop signs, sometimes cars will actually let me go first, even if they were there first. EUCs are very new to California!

Unfortunately you can't ride too far if you sustain such high speeds, but that's to be expected. I managed to get back home with 40-50% battery after riding 8-10 km (I'm 180cm and about 77kg or 5'11" and 170lbs). Voltage sag was definitely a factor: sustaining high speeds made the app read as low as 35% battery when I knew it was around 50%. High speed voltage sag seemed to bottom out at around 40%.

Kinda random, but there were no signs of overheating.

In the future (maybe in a year or two) I might try building my own 32 cell battery pack for the Zero, might be a fun experiment or a terrible mistake.

Jurgen · November 18, 2015

I have the IPS Lhotz 340Kw (previous version max 20KmH), same here

I weigh +100kg

I believe the grinding noise is the BMS that cuts in for a split second.

This happens when I try to accelerate or brake too fast, or when reaching close to the max speed and riding in a pit or going over a bump

The experience of a triple forward judo roll at maybe around 15KmH, makes me hesitant to buy the IPS191 or the IPS ZERO to do it over again but this time at 30KmH

I'm afraid that the torque at higher speed might not be enough to cope with my mass.

micro · November 19, 2015

We are discussing here batteries. There are some hints that point rather to the motor and its control.

Experiences so far tell that the "grinding noise" happens no matter whether the batteries are full or partly discharged. There seems not to be a difference between the three models 130/260/340 in this respect.

It cannot imagine that the BMS cuts out during a voltage drop for less than a second. There is simply no need for it and designers are not always dumb. Even less probable is a cut-in in less than one second, as there is no voltage recovery that quickly. Unfortunately it is not easy to test this idea.

Let us concentrate on the motor control. I do know almost nothing about it. However, in a proper design the current rise during the ON state of the MOSFET is observed and when the limit is reach, the MOSFET will be driven into the OFF state (for a particular cycle). This will happen not as regularly as the normal control, so it is audible. In this mode the power output is at its maximum. In case this is the origin of the noise, there is no problem. That is why I am comparing it with a blocked drilling machine.

It is still unclear whether there could happen any unexpected shut down in this control. Reasons could be: Average current too high, MOSFET or motor temperature too high, and maybe others.

Any ideas?

Trailseeker · November 19, 2015

HELP: Can someone tell me how to install the XIMA app on my SGS2?
When I try to install the app I get the message Error while Parsing.

App: XIMA-ver1.1.3-201508141542.akp

Rooted SGS2 with Android 4.1.2

Thanks for your help

Micha

Jason McNeil · November 19, 2015

7 hours ago, micro said:

It cannot imagine that the BMS cuts out during a voltage drop for less than a second. There is simply no need for it and designers are not always dumb. Even less probable is a cut-in in less than one second, as there is no voltage recovery that quickly. Unfortunately it is not easy to test this idea.

The evidence would suggest otherwise: this is a datalog under some pretty hard acceleration with the 340Wh XIMA, the moment the power output reaches 1,500W & the voltage drops to 54v the power cuts-out. Recovery is nearly instantaneous.

micro · November 19, 2015

2 hours ago, Jason McNeil said:

The evidence would suggest otherwise: this is a datalog under some pretty hard acceleration with the 340Wh XIMA, the moment the power output reaches 1,500W & the voltage drops to 54v the power cuts-out. Recovery is nearly instantaneous.

Concerning the battery voltage recovery I agree. But is there an instantaneous cut-in?

What is responsible for the cut-out? BMS or motor drive? In case it is the BMS, why? And in your plot there seems to be no instant cut-in, so the "grinding noise" is not due to the BMS cut-out/cut-in, right?

Jason McNeil · November 19, 2015

BMS cut-off to prevent the batteries from going under-voltage (not saying this is smart or correct). Try to think of the eWheel system in supply/demand analogy, when the demand (motor) outstrips the available supply (battery), you run into a power shortage. Causes of the grinding noise were discussed earlier in the thread.

micro · November 19, 2015

I am trying to think. It is not always easy.

It is not reasonable to cut the battery when there is a transient. I cannot believe in it. Regarding the grinding noise I do see mainly my ideas in this thread.

Sign In

IPS ZERO

Recommended Posts

Link to comment

Share on other sites

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

Jason McNeil

csmyers

Jason McNeil

Posted Images

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Join the conversation