Vectrix low battery blues

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theBaron
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Vectrix low battery blues

Hi all,
As a new Vectrix owner (6 weeks), I am still coming to grips with the range capability of this scooter.
My normal commute is a round trip of 42km, with about half of this being undulating 70km/h speed limit sections and the rest being reasonably level 60km/h limits (city traffic) with plenty of traffic lights.
Despite having religiously followed the handbook recommendation of five deep cycle discharges, I only just manage my commute on the single charge, despite trying very hard to limit my "lead-foot" tendancies
The confusing part of this whole exercise is that when the batteries are finally giving up the ghost, I get the red battery warning light illuminating, the top speed is limited to 60km/h (quickly reducing to 40km/h) but I can still have 6 bars showing on the battery level indicator??????
Is this normal?
Any advice/recommendations that you more experienced owners may provide will be greatly appreciated.

azvectrix
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Re: Vectrix low battery blues

I can't say for sure, but it sounds similar to a problem I've had occasionally:

http://visforvoltage.org/forum/4151-sudden-drop-half-charge-zero

Have you continued riding it to the point where the charge indicator drops to zero?

Mik
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Re: Vectrix low battery blues

Same problem with my Vectux.

Very similar commute, too.

And the same Vetrix distributor I believe....

Let me know how they fixed it if it can be fixed.

Mr. Mik

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There is always a way if there is no other way!

theBaron
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Re: Vectrix low battery blues

Thanks azvectrix.
I haven't had the opportunity of continuing the ride to see if the battery indicators keep disappearing (that's the problem of ending the commute at the workplace - they expect you to work when you get there!).
I will try a weekend ride to see what happens.

theBaron
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Re: Vectrix low battery blues

Thanks Mr Mik.
I will try and contact our mutual friend at Port Melbourne to see if he can offer any fix to this problem & will definitely let you know if there is any success.

Mik
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Re: Vectrix low battery blues

It might be better to not mention names...

You could use the edit function.

Mr. Mik

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cdragut
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Re: Vectrix low battery blues

trying to completely discharge the battery i've noticed this:
at two bars, and about 6 miles range the range drops to zero with no bars left... it still runs but no faster than about 15 m/h... i rode it to home, about half a mile... no idea how long you can ride it after it shows zero/range/bars...
i get about 45 miles on a charge on my regular commute: 6 miles one way with speed between 30 and 50 miles/hour on a flat terrain...
no complaints... it does the job!

CD

Vectrix-NH
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Re: Vectrix low battery blues

Hi
I had that happen to me . They said it was not sink or 0 out .
they said to discharge it completely and it would sink up . it would also charge the bartary more.
I did it and It did seam to help. How well did you discharge It? . When I did it I had to go more than 5 miles before it did not move . that take a while to go round and round at 5 or 10 MPH .

Happy riding , Herb

Hermes
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Re: Vectrix low battery blues

Since it doesn't sound such a straight forward and easy process for all, why aren't batteries conditioned by the dealer just before delivering the bike to the customer?

Vectrix-NH
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Re: Vectrix low battery blues

Hi
My battery were conditioned fine . Yes they did it before I got it . ( after the recall) They now have a setup to do it before they install the battery . I asume all new Bike will be shiped ready to go. but thay had a lot of bike out there.

It was to sink the charger . and diplay to the battery.
From what they said they do not just use volt to stop the chargeing it is part of the programing . so set point at the bottom is important.

Happy riding , Herb

Mik
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Re: Vectrix low battery blues

Here is a more precise Problem Description to avoid confusion:

The problem discussed in this thread is highly reproducible and largely independent of ambient temperature; in other words it happens each time and it was the same with my first Vectrix.

The last few bars displayed on the battery charge indicator hold no useful charge.

When the EST RANGE indicator shows something like 20km range left, and 4-5 bars are shown as remaining in the battery, the performance is already limited to about 60km/h on flat ground.
This will then very soon be followed by a sudden drop to 0 bars and 0 km range, usually on an uphill stretch with fully or almost fully open throttle.

That is the “Resetting” of the battery empty point mentioned by others, I’ll call it “BaLPoR” = Battery Low Point Reset from now on.

Usually the battery telltale lights up in red and “buSVLt” is shown in the trip meter display before the remaining bars/17th disappear, but I am not yet sure if this is absolutely necessary for a BaLPoR to occur.
....................................................................................

I am currently developing a much better understanding of this problem:

After a range test on flat ground yesterday (more detailed report to follow) I only partially recharged the Vectux due to time constraints. The test drive had ended as described above, sudden drop from 5/17th to 0/17th and 0 EST RANGE. The partial recharge was less than 2 hours and the battery indicator was showing about ½ full when I started off again, which is usually insufficient for me to get home, because the last 4 bars are useless.

But because I knew that enough charging had occurred, I took off anyway and it worked fine.
So I headed home towards the hills, I made it there comfortably with full power whilst the bars disappeared one by one.
Once I was close to home I continued to test high load scenarios until the last bar disappeared. That means going up steep hills at full throttle, crossing through the 70km/h band where 100% amps flow, verified by the ReTAmpI.

Result: I got (almost) full power until the last bar had disappeared!

There was still full power with only 1/17th left.

I have gone through similar scenarios many times before, but never before did I only partially charge the battery after a “BaLPoR”.

It appears to me that the recharging after a BaLPoR cancels out the BaLPoR again and it possibly damages the battery, too.

Here is why and how:

After a few hours of cooling the battery with the ABCool to 22°C I plugged in again, (with 0/17th displayed but still almost full performance available).
The battery indicator started to slowly add bars from 0 upwards as the kWh’s moved from the grid into the battery.
After about 90min of charging the battery was shown as half full, 9/17 bars, having used up about 2.3kWh in the process. The battery temp stayed low at 22C during this, ambient temperature about 18 °C.
The battery voltage was 143V at that stage.
After about 2hrs 10min the battery voltage hit 151V and the charger changed to “tr” mode.
The battery was shown as 12/17th full at this stage. Battery temperature: 25 °C.
Power consumed until then: 3.5kwh.
The battery voltage dropped again to 148V during the “tr” which counts down for 15min. The charger then switched back to “CP” charging and that is where the problem begins.....
Battery temperature at the beginning of the second "CP" cycle (="CP2”): 26°C.

Within about 2min of CP2 mode the voltage rose back up to 151V, because the battery was in reality already full.

So the charger switched back to a second “tr” cycle (=”tr2”) of 15min duration.
Battery temp at beginning of “tr2”: 27 °C
At end of “tr2”: 28°C
At end of “CP3”: 28°C (again 2 min until voltage hits 151V and it goes back to "tr")
At the end of “tr3”: 30°C, 3.8kwh used. 13/17th full. Same at end of 2 min of “CP4”.
At end of “tr4”: 31°C, 13/17th displayed.
After "tr4" the charger changed to “CC 152” ; at this time 3.9kWh had been used, (This is the typical amount needed to recharge my Vectux fully from a point when it had just starting to show reduced performance.)

1hr 5min after start of the “CC” I turned the charger off to prevent it from wasting more energy and heat the battery further and undoing the effect of the BaLPoR.

The battery temperature had at this time risen to 36°C, the supposed fill level of the battery was still 14/17th, battery voltage still at 148V, and a total of 4.5kWh had been sucked out of the grid.

Despite the constant cooling the battery temperature had risen 18°C above the ambient temperature.

The charger - under these specific circumstances - attempts to push more charge into the batteries than it can accept, resulting in heating of the battery, ageing of the battery, and recreation of the erroneous 5/17th supposedly left in the battery.

The electronics appear to count the amount of Ah that have gone into the battery during charging, regardless of efficiency.
When the battery is already full, but the electronics believe that it is not full, (because the display says: “Hey, charger, 14/17th only so far, keep it coming!”), then the efficiency tends to go towards zero.
All the energy put into the battery at that stage is wasted as hot air coming out of the battery cooling exhaust.

But the electronics count these Ah as being added into the battery anyways, and then expect them to be available when the battery is being discharged.
Of course they are not available in the battery, because they float around as heat in the atmosphere, and so the circle closes and you get the vanishing 5 bars at full throttle crawling uphill again!
......................................................................................

What is needed is a Battery High Point Reset Procedure = “BatHPReP” that does not cook the battery and does not introduce virtual Ah that you cannot get back out of the battery.
........................................................................................

Possible explanations for this problem include:

A) Maybe the BatHPReP does exist but is not correctly performed by Vectrix Australia staff.

or

B) the software might be expecting a different battery with higher capacity; if there is a setting for LiPO battery instead of NiMH it might be set incorrectly; there are symbols on the instruments for fuel cell, Bluetooth and other future add-ons so I find it likely that higher battery capacity options are catered for, too!
The missing capacity is in the right order of magnitude – around 30% extra.

or

C) the battery is faulty in some way and has a lower than expected capacity.

or

D) they sold my old Vectrix to theBaron! Is it white???

Mr. Mik

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There is always a way if there is no other way!

Morrison
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Re: Vectrix low battery blues

Mik,
I understand most of what you described in your long explanation.

However, I have never experienced the core scenario of the last 4 or 5 bars being useless. I regularly use the final 4 or 5 bars and they disappear at the same rate and the others. When I have 4 or 5 bars remaining, I typically expect another 10 to 15 miles of range, depending on the speeds I am riding at.

So while I am very interested in what you are describing, I do not want to reproduce it and start having these issues.

So here is my question. in your opinion, what should we avoid doing so that this doesn't start happening? Avoid a partial charge when the battery is 100% empty?

AndY1
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Re: Vectrix low battery blues

Mik, could it be that you have one or more damaged cells or maybe imbalanced cells or maybe one or more cells with different capacity?
That could explain the issue you're having.

If they are connected into serial connection, that would explain a sudden drop before 0/17 bars. That would also explain the stop of charging before 17/17. Because the faulty cell is already full, when charging, not a lot of current is going in (because the faulty cell is preventing it (serial conenction)) and the charger thinks it has reached the end of charging.

This would also explain better bar accuracy when not fully recharged. Because is not fully recharged, the faulty cell is not being pushed over it's capacity and it actually performs better.

If I make a crude example:
Cells' capacity - fully charged:
C1: 1000mAh
C2: 800mAh
C3: 1000mAh
C4: 1000mAh
C5: 1000mAh

Until 4/17 bars, all the cells are being discharged until the C2 is fully discharged (lower capacity cell is being discharged more slowly than others):
C1: 100mAh
C2: 0mAh
C3: 100mAh
C4: 100mAh
C5: 100mAh

Because the C2 is suddenly fully empty, it won't let any current go through it anymore.

When you want to do a full charge, the C2 is fully charged earlier because it's capacity is only 800mAh and only 800mAh go into other batteries:
C1: 900mAh
C2: 800mAh <- this battery is full
C3: 900mAh
C4: 900mAh
C5: 900mAh

But because the C2 is already full, it wont let any more current go through her and the charger thinks that the battery is charged and start trickle charging until this:
C1: 1000mAh
C2: 800mAh
C3: 1000mAh
C4: 1000mAh
C5: 1000mAh

BUT, when you did a partial charge from full discharge the cells look like this:
C1: 700mAh
C2: 600mAh
C3: 700mAh
C4: 700mAh
C5: 700mAh

The capacity is more equalized and there's no C2 overcharging happening and no C2 current stopping making the charger think that the batteries are full.

I think the charger, looks for the cut-off current, the right LCD shows voltage, so there is a discreprency you're seeing. The charger thinks it has finished charging, because the current going in is low, but the actual voltage you're seeing on the battery charge bars is actually lower.

I hope you understand what I'm trying to say.

If this is true, than the problem you're having is only going to get worse. The bad cell is going to be overcharged with each charge and over discharged with each discharge.

This might also explain your low range. One or more bad cells are preventing the whole pack from discharging fully and getting the whole mileage.

azvectrix
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Re: Vectrix low battery blues

Mik,

Thanks for the interesting analysis. In your opinion, then, I can't rely on my Kill A Watt meter to tell me if a full charge has gone into the battery, right, because some of that juice may not have resulted in further charging?

I guess the only real proof is in the putting...or something like that.

Thanks,
Ron

Mik
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Re: Vectrix low battery blues

Mik, could it be that you have one or more damaged cells or maybe imbalanced cells or maybe one or more cells with different capacity?
That could explain the issue you're having.
............
This might also explain your low range. One or more bad cells are preventing the whole pack from discharging fully and getting the whole mileage.

Thank you very much! Most interesting!

I'm mulling and pondering it....

Mr. Mik

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There is always a way if there is no other way!

Mik
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Re: Vectrix low battery blues

Mik,

Thanks for the interesting analysis. In your opinion, then, I can't rely on my Kill A Watt meter to tell me if a full charge has gone into the battery, right, because some of that juice may not have resulted in further charging?

Thanks,
Ron

No, in my opinion, having a meter helps under those circumstances, too!
(Go, go, go metric!!!)

If the charge went well, as it seems to do for most Vectrix riders most of the time, then a certain amount of energy is used in the process. You learn what that amount is, spot the difference when/if it happens, then teach others.

If charging stops early, less energy was used. You can spot it with the meter, or push, your choice...

If charging continues to heat the planet by pushing excited electrons into a full battery, producing hot air, then the power consumption will be increased. You spot it with the meter, figure out what the heck it means, then tell us all! (please)

Either way, you will be better off if you know that something different from the usual has happened.

Mr. Mik

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There is always a way if there is no other way!

theBaron
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Re: Vectrix low battery blues

Hi all,
Firstly, I am somewhat humbled by the effort & generosity of you forum members in offering your knowledge & experience in solving one members problem. Heartfelt gratitude to all who have assisted!

I have used the weekend to explore the limit of both range & speed following the display of the red battery indicator & the buSVLt indication.
Test commenced with trip meter indicating 21km since full charge & 10 bars remaining.
Some hard riding in hilly terrain soon caused the now familiar red battery & buSVLt to display (5 bars remaining) at 35km on the trip meter.
Speed was initially limited to 60km, but was below 40km within 0.5km & all bars had now disappeared & range meter indicated a big 0.
I am very restricted on where I can test the bike, as I live in a quite hilly area with no access to level areas where I can do this testing (in the vicinity of the all important power outlet!).
Using my residential street (I would estimate street gradient around 1:50) to do the final discharge, I was lucky to achieve walking pace for the next 1km or so & I called it a day at 39km on the trip meter.

I will be reporting the above findings to the Technical Manager at the Australian Distributors, who has mentioned that he wishes to forward this on to the American office for their investigations in these particular issues.

To Mr Mik regarding (d); my bike is silver & was purchased in mid-June, so your white model is not the culprit this time!

In conclusion, despite my range difficulties I have not regretted the purchase of the V at any stage & I get a real buzz from knowing that it is the right mode of transport going forward.

Mik
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Re: Vectrix low battery blues

Mik, could it be that you have one or more damaged cells or maybe imbalanced cells or maybe one or more cells with different capacity?
That could explain the issue you're having.

If they are connected into serial connection, that would explain a sudden drop before 0/17 bars.

Yes, they are connected in series, 102 cells.
Here I have posted more details about the Vectux battery.

That would also explain the stop of charging before 17/17. Because the faulty cell is already full, when charging, not a lot of current is going in (because the faulty cell is preventing it (serial conenction)) and the charger thinks it has reached the end of charging.

I am not sure this is correct. The problem during recharging after a BaLPoR is that the charger continues to charge and heat the battery.

This would also explain better bar accuracy when not fully recharged. Because is not fully recharged, the faulty cell is not being pushed over it's capacity and it actually performs better.

Not sure if the poor cell performs better (if a bad cell is indeed behind this whole thing). But if charging stops when or before the bad cell/s have reached their maximum capacity (due to a partial recharge), then the charge indicator would remain accurate regarding the "empty point". And further damage to the bad cell/s might be reduced if charging stops early so there is no repeated over-charging.

If I make a crude example:
Cells' capacity - fully charged:
C1: 1000mAh
C2: 800mAh
C3: 1000mAh
C4: 1000mAh
C5: 1000mAh

Until 4/17 bars, all the cells are being discharged until the C2 is fully discharged (lower capacity cell is being discharged more slowly than others):
C1: 100mAh
C2: 0mAh
C3: 100mAh
C4: 100mAh
C5: 100mAh

Because the C2 is suddenly fully empty, it won't let any current go through it anymore.

That is one of the things I do not quite understand yet. How do Ni-MH batteries in a string behave? Does it really not let power through any more? What is and how does cell reversal work?

When you want to do a full charge, the C2 is fully charged earlier because it's capacity is only 800mAh and only 800mAh go into other batteries:
C1: 900mAh
C2: 800mAh <- this battery is full
C3: 900mAh
C4: 900mAh
C5: 900mAh

I agree with this part.

But because the C2 is already full, it wont let any more current go through her and the charger thinks that the battery is charged and start trickle charging until this:
C1: 1000mAh
C2: 800mAh
C3: 1000mAh
C4: 1000mAh
C5: 1000mAh

As I said above, the charger does not sense the battery as full and continues to go back to the high-power "CP" stage repeatedly.
But then again, maybe that is what is needed to equalize the cells. Maybe I need to do this repeatedly. I am unsure if it would make the problem worse or better.

BUT, when you did a partial charge from full discharge the cells look like this:
C1: 700mAh
C2: 600mAh
C3: 700mAh
C4: 700mAh
C5: 700mAh

The capacity is more equalized and there's no C2 overcharging happening and no C2 current stopping making the charger think that the batteries are full.

I think the charger, looks for the cut-off current, the right LCD shows voltage, so there is a discreprency you're seeing. The charger thinks it has finished charging, because the current going in is low, but the actual voltage you're seeing on the battery charge bars is actually lower.

I hope you understand what I'm trying to say.

I understand parts of it, but this part makes no sense to me so far.
My incomplete understanding is that the most likely signals used for a "full battery" assessment by a Ni-MH charger would be "negative delta V", or the gradient of the temperature curve.
The display on the right, the 17 bars, appear to be an interpretation that the Vectux electronics come up with somehow, like the EST RANGE indicator. Both can be TOTALLY out. But the Voltage display on the left (during charging) and the battery temp display on the left (also only during charging) appear to be actual measurements.

If this is true, than the problem you're having is only going to get worse. The bad cell is going to be overcharged with each charge and over discharged with each discharge.

But the Vectux' range appears to get better over time, rather than reducing. This is hard to be sure of though, because I do now recharge at work to avoid daily deep-ish discharges. I did a range test on mainly flat terrain the other day, babying it as much as possible, limiting the top speed to 50km/h and I got 67km total. This is the maximum I can tickle out of the Vectux, but it is not really "Real World" range, because I did turn at lights in whichever direction was green, just to keep momentum, go the longest, slowest, flattest rout I could etc etc. All under pretty much perfect conditions.

This might also explain your low range. One or more bad cells are preventing the whole pack from discharging fully and getting the whole mileage.

I am not sure if the Vectux' range is really much lower than other Vectrix' range, if at all; with 110kg on board and high speed, moderately to steeply undulating terrain with much stop-and go and a very steep driveway at the end many do not go further than 45km on a charge!

Mr. Mik

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There is always a way if there is no other way!

cdragut
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Re: Vectrix low battery blues

well, i had the 5 bar "syndrome" for the first time today... with a 15 miles range and 5 bars left, on a slightly steep road at about 50 m/h the power was suddenly limited (with red light and that bus... thing displayed), and at 4 bars left, the bars disappeared, and 0 range displayed... i manage to make the rest of about 1.5 miles at an embarrassing 15 m/h on a 45 m/h speed limit road...

to mr. mik: should i fully charge, or partially charge, and ride to discharge again?

thank you.

CD

cdragut
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Re: Vectrix low battery blues

see my previous post... after getting home i plugged it in... after about an hour i had 5 bars showing... i decided to take it for a spin... it showed a 17 miles range when i left... rode it at 35 to 55 m/h for about 13.5 miles... until all bars disappeared... when i got home, no bars left and still showing a range of 2 miles left!... all the time having full power!... and no battery red light!...oh, and all this in a 30 degrees celsius florida heat!

go figure!... can someone explain this?

i am not an engineer, but i am a computer programmer... and i suspect it is a software problem...

CD

HCT
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Re: Vectrix low battery blues

Hi Mik

Read your excellent postings regarding the Vectrix battery , find them very interesting and informative,would like to make some comments that maybe useful for all the Vectrix and other EV owner .

Several years ago ,designed and deliver a 150W/H power pack for a Middle East application,with a BMS and internal charger in a sealed case , 21 NiMh D cells Panasonic HHR650D those are 6.5 A/H with extremely low impedance 2 milliohms , although the charge and discharge initial specification was mild at C/3 and up to 4 hours to recharge , we had to meet a 55C ambient charging

Those cells are identical to the ones used by the Prius except in a standard "D " case.

Been told by Panasonic that the NiMh cell do not like to charged at high temperature,the charging efficiency dropped very fast . A very big understatement ! .

Using a environmental chamber testing we discovered that each 5 C rise in ambient temperature,the charging efficiency dropped by about 10-15% . Starting at 25 C being 92%, at 40 C we where down about to 50% efficiency , at 50 C we where down to less than 25% ,we where dissipating 75% of the charging power into the case ,it was a big problem ! ! ! .

Aggravating the situation was the sealed case and inability to use air cooling .Finally the specs and software where changed to prohibit charging if the pack temperature was above 30 C( took almost a year to convince the customer that it could not be done otherwise ) Image the required cooling time from a full discharge state at a 50 C ambient ! ! .

Those very low impedance cell and C/3 load was great benefit,had we use a different NiMh cell with higher impedance we would been unable to designed and produce it .

In summary the NiMh cells are very temperature sensitive and not easily charged without thermal management ( I do not mean temperature sensor but cooling of cells )and easily damaged ( raising of impedance )

Looking at your pictures and comments ,I suspect that you may have cells in your 120 Volt pack that are lower in capacity and high impedance which create all the heat( loss)that you noticed ,do not believe that the majority of the cells are overcharged just a few are the culprits , which ones that is the question that has to be answered ! ,

You may want to get you hand on a milliohmmeter such as HP4328A (used by a lot of battery manufacturer ) and measure each cells impedance and posted it on the site .

It would be very helpful for everyone that has a Vectrix and suspect problem with their batteries .

In addition you may want to replace any cells with are 20% or higher than the average impedance (taken in fully charged state and allowed to cool down or fan cooled)

Trying to convince the world that heat generation and loss is directly related to impedance. Zero impedance equate to Zero Loss

MVC-009F.jpg

HEAT & LOSS & INEFFICIENCY RELATED DIRECTLY to IMPEDANCE

Mik
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Re: Vectrix low battery blues

see my previous post... after getting home i plugged it in... after about an hour i had 5 bars showing... i decided to take it for a spin... it showed a 17 miles range when i left... rode it at 35 to 55 m/h for about 13.5 miles... until all bars disappeared... when i got home, no bars left and still showing a range of 2 miles left!... all the time having full power!... and no battery red light!...oh, and all this in a 30 degrees celsius florida heat!

go figure!... can someone explain this?

i am not an engineer, but i am a computer programmer... and i suspect it is a software problem...

Exactly the scenario I am trying to figure out.

Sorry to hear it is affecting others now, but also kind of glad because together we might figure it out!

Did you notice any unusual charging behaviour when you let it complete a full charge after this BaLPoR?

Mr. Mik

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There is always a way if there is no other way!

Mik
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Re: Vectrix low battery blues

Problem solved!

Now, that was not so hard, was it now?

An accurate fuel gauge after all:

Photobucket ...............

Mr. Mik

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There is always a way if there is no other way!

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Re: Vectrix low battery blues

Thats how you fix analog Gages . bend the neetle.
or make new lines ,fast an easy .

Happy riding

Mik
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Re: Vectrix low battery blues

I will be reporting the above findings to the Technical Manager at the Australian Distributors, who has mentioned that he wishes to forward this on to the American office for their investigations in these particular issues.

I hope he has some sucess. I have been pointing this problem out since before I put 500km on my first Vectrix in 2007:
After traveling at 40km/h for 2.1km the EST RANGE indicator suddenly dropped to zero and the battery indicator did the same.
It happened on one of the uphill stretches.

They never looked into it, then the fuse blew and they replaced it with a worse scooter...

Mr. Mik

This information may be used entirely at your own risk.

There is always a way if there is no other way!

HCT
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Re: Vectrix low battery blues

Mik

Happen to reread one of your previous posting,this statement got my eyes .

Until 4/17 bars, all the cells are being discharged until the C2 is fully discharged (lower capacity cell is being discharged more slowly than others):
C1: 100mAh
C2: 0mAh
C3: 100mAh
C4: 100mAh
C5: 100mAh

Because the C2 is suddenly fully empty, it won't let any current go through it anymore.

That is one of the things I do not quite understand yet. How do Ni-MH batteries in a string behave? Does it really not let power through any more? What is and how does cell reversal work?

When a cell in a multi cell pack is depleted (discharged,emptied),with the load remaining on, current will flow through that empty cell,being forced by the other good cells.This current going through that depleted cell is reversed (with the net effect that it subtracts from the overall pack voltage ),

This is what is meant by reversed charge .

Reverse charging any cell chemistries is a absolute no-no (some chemistries react more violently than other), the first most obvious result is heat , impedance raising , capacity drop.

In past experience have seem depleted cell impedance climb at a such rate that a 24 volt pack (19 good cells and one depleted cell ) that the load voltage was almost zero , the entire voltage was dropping across that reversed charged cell ,tremendous heat and the cell burst.

In summary a depleted cell WILL NOT stop current through it ,it will be reverse charged,heat up,its impedance will rise rapidly ,very likely result in a explosion .

A impedance measurement will tell you which cell has been abused since it will have a much higher reading (will have a much lower capacity).

HEAT & LOSS & INEFFICIENCY RELATED DIRECTLY to IMPEDANCE

cdragut
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Re: Vectrix low battery blues

sorry for the late reply mr.mik!

yes, as posted earlier, when i plugged it in it showed 2 miles range and zero bars...after a few hours we decided to go to the beach... it is a 30 miles round trip, flat terrain...i unplugged it without finishing the whole cycle... it showed all the bars, CC150, and about 147 on the left gauge... counting down the clock...
the scoot made it but!!!... all the time it showed 2 miles range (as when i plugged it in)... i got home with about 4 bars left, and no other incidents...
after a full overnight charge, the next morning the range was normal - about 56 miles, and all the bars... all this happened last sunday...

today i had to do several short trips at 45-50 miles/h...after about 30 miles, with about 11 miles range, and 4 bars left, it happened again... lost power, and zero range, and zero bars... i managed to go home (about 2 miles) at about 15-20 miles/h...
the outside temperature is pretty high: 36-37 grade celsius...

CD

AndY1
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Re: Vectrix low battery blues

Looks like high temperatures (35'C+) really stress the NiMH battery. Especially when they are close to depletion.

Mik
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Re: Vectrix low battery blues

Looks like high temperatures (35'C+) really stress the NiMH battery. Especially when they are close to depletion.

But it also happens at 20°C ambient, just the same...

Mr. Mik

This information may be used entirely at your own risk.

There is always a way if there is no other way!

Morrison
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Re: Vectrix low battery blues

Looks like high temperatures (35'C+) really stress the NiMH battery. Especially when they are close to depletion.

The Vectrix fan system is really good at keeping the battery below that temp.
When I have plugged in, my battery temp is typically between 33 C to 36 C. Once plugged in it drops quickly to 30 C within 15 minutes.

Mik
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Re: Vectrix low battery blues

Hi Mik

Have you been able to get your hand on Milliohmmeter like the HP4328A ?

I am very sure that you have weak or defective cells from looking at your postings .

Very surprised that everyone does not seem to accept that a " weak ", "low capacity ", "depleted cell" DOES NOT STOP THE CURRENT THROUGH IT ( a open cell is another story).
When in the discharge mode,this cell will be reverse charged,in the charge mode the cell will exhibit a much higher voltage across it( due to it high impedance ) .
Mik , if there is one thing that I know for SURE , a low impedance cell in series connected pack , will most likely have the highest capacity ( amp/Hours), by the same token a high impedance cell will have a low capacity .

The only exception is when a cell has a internal short ,then in the charge mode will a lower voltage reading across it .In the discharge mode will either have a very low voltage and when depleted , will show reversed voltage across it.

Mik please get yourself a milliohmmeter and within 10 minutes you will be able to determine the state of all your 102 cells , you do not have to disconnect anything at all .

I believe that you are very dedicated to resolve all the problem with the battery performance , but without a impedance measurement of the pack and the cells , you are not taken the one measurement that create loss = heat into account " IMPEDANCE " .

Maybe I am making myself a pain in the neck on this web site , but cannot over emphasize everything is related to impedance . the lower the better since it lessen loss = heat .

Regards

Hi HCT,

thanks for you PM. I'll reproduce it here partially so I can answer including photos.

You are not a pain, I think you are probably right about the impedance importance, otherwise you would have gotten some "flak" from more experienced V members than myself by now.

I'd love to use a milliohm meter, but it's mainly a cost issue at this stage. Those things are seriously expensive!
But I will probably need a milliohm meter again and again if this new hobby of mine continues!

It also takes a lot of time to dismantle the Vectrix battery.
About one hour to get the batteries out of the frame, the same to get them in again.
It involves lifting of 47kg at a very awkward angle in close proximity to the motor controller board. One wrong move and the Vectux is history - or my back!
The second battery weighs 43kg and is a little easier to lift out because the first one is gone by then, making some space.

Photobucket Click here for a higher resolution picture.

Photobucket Click here for a higher resolution picture.

Photobucket Click here for a higher resolution picture.

And then there is the battery disassembly itself: As far as I can see there are three layers of cells, and the cells need to be dismantled one by one to get to the lower layers.
And then re-assembled with correct torque settings, which I do not know yet.
Photobucket Click here for a higher resolution picture.

Once the battery is in pieces I would like to install a real time monitoring system like the PakTrakr or greenBMS, but I do not yet know if this is feasible.
I do not want to take it apart twice if I can avoid it. It needs careful planning!

Overall, due to the dangerous voltages and the need to go slow and carefully it will be at least a weekend job, not 10 minutes to do this impedance measurement!

I am also still hoping that the Vectrix riders with the same problem and an intact warranty manage to get an answer out of Vectrix, and maybe a fix for the problem. That might help to narrow down the options to tackle the problem.

Mr. Mik

This information may be used entirely at your own risk.

There is always a way if there is no other way!

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