¿Repair "disappearing bars" with software upgrade?

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mpregal
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¿Repair "disappearing bars" with software upgrade?

Hi!

I would like your opinion about this:
My Li+ has the "disappearing bars" problem: I start with full charge (pack: 139v, Hi: 3.49v, Lo: 3.30v) and as soon as I drive for 40-45km (more or less 50% of the charge burned), the "red battery" turns on. At this point I read "Lo Cell", "Est Range" shows "0" and all the charge bars disappear.
If I drive in "debug mode" (so I can read pack voltage, hi & lo, etc while driving) I can confirm that Hi is 3.10v and Lo is 2.65v just before the error. I think that at least one cell is damaged.

I told about this with the dealer, and I was requested to take the Li+ to the workshop so they can make some tests. If necessary they will replace the battery pack (it's the second one installed in the bike, and still under warranty).

Today (8 days after they began with the testing procedure), they phoned me to say that after a complete firmware upgrade and some tests everything is ok. No battery replacement was necessary. ????????????????????????
The question is...is it possible to solve the referred issue just with a software upgrade? Sincerely it sounds to me like "Sci-Fi"...

Thanks for your opinion.

PS: Tomorrow I will take the bike and check with the ScooterDiag.

R
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Re: ¿Repair "disappearing bars" with software upgrade?

My brother is having a similar experience.
His lithium battery is having problems, giving pretty short range: the red battery light lits on after only 20km. Hopefully the dealer has been very helpful. It has recently installed "that" new firmware, which is supposed to solve many battery problems.
However first tests have been quite disappointing:
Range has been doubled, increased to only 40 km. The Vectrix was left 6 days plugged in, performing an ever lasting equalization that never ends. Now the Spanish dealer is going to take that Vectrix in their facility to make further tests. We want to congratulate them, they are giving their best. In my opinion, it's just the GP cells, they're simply bad. I wish the vectrix Factory could make a wide range of battery packs (20Ah, 40Ah and 60Ah) with A123 prismatic Pouch cells...

Some Nimh vectrix users may think that 40 km is the "normal" range of a 30Ah battery.
My personal experience with the Cycle Analyst: 32Ah are good for a 85km trip. My brother's battery is a 30Ah LI GP. Assuming a 10% of safety margins, effective charge may hang around 27 Ah, good for a 72 km trip.
When that Li GP battery was new, it could nearly hit 80 km. This makes me suspect that there weren't any safety margins at all in the firmware (if the battery provider says 2.5 volts low limit, BMS limit is set to 2.5 volts?.
And, of course! 70 km is the range that can be obtained from the original NIMH batteries... you just need a bunch of 102 cells in perfect, balanced shape!.

Mpregal, I'm really interested in knowing if the problem of your V is solved, keep us informed.

mpregal
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Re: ¿Repair "disappearing bars" with software upgrade?

Hi R!

I completely agree with your opinion.

BTW I am writting here LINK a short "logbook". There is also another Li+ user (JPrates) with a very interesting logbook (I have learned a lot from him).

I will keep you updated!

Thanks!

antiscab
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Re: ¿Repair "disappearing bars" with software upgrade?

My Li+ has the "disappearing bars" problem: I start with full charge (pack: 139v, Hi: 3.49v, Lo: 3.30v) and as soon as I drive for 40-45km (more or less 50% of the charge burned), the "red battery" turns on. At this point I read "Lo Cell", "Est Range" shows "0" and all the charge bars disappear.

your problem is your lowest cell is not fully charged when the rest of the battery is - 3.30v is far from fully charged

most likely they just manually fully charged each cell individually

With a variation that large, it would indeed take days for the bike to balance itself out on charge
*but* letting the bike do it means the remaining cells get overcharged (long story short you can't hold a LiFePO4 above 3.45v continuously without overcharging it, an hour or two once in a while is ok, but not several hours every day, and definitely not days on end)
basic design flaw but there you go

personally I would buy a single cell charger, and individually charge each cell, then go for a ride.
that way you can see what the capacity of the smallest cell is

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km

mpregal
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Re: ¿Repair "disappearing bars" with software upgrade?

Thanks Matt for your advice.

I think I have identified two "lazy" cells in the scooterdiag monitor (you can check in the pictures shown in my logbook HERE).
The idea of "single charging" each cell seems the best way to make an initial approach.

I have this power source:

Power.jpg

Do you think I can use it to make the job?
If not...which charger would you use?

Thanks!
Manuel

R
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Re: ¿Repair "disappearing bars" with software upgrade?

The latest Vectrix Firmware does the following approach. (please correct me if anything explained is wrong) When the first cell hits Hi voltage, it does not end the charge. It starts an Equalization mode, which continues to charge the battery at 0.3A. The BMS's 0,3A shunt resistors from the "Hi voltage cells" start to dissipate energy into heat, allowing the unbalanced cells to charge and catch the rest. If a cell needs a 9A balancing, the process will take up to 30 hours to fill that cell.
First tests resulted in equalizations that lasted over 6 days.
As antiscab Points out, this program tend to overcharge the Hi cells. The solution would be to apply a safety margins on the BMS's shunt triggering point. In my case, Max voltage of the GBS cells is 3,8 Volts. My BMS starts dissipating energy at 3.55v, and cuts charge if any cell reaches 3.65V. I,m not sure at all, but these conservative margins should give me a healthy battery for at least two or three years.

About the power source, it is not programable? it never ends the charge? I recommend RC chargers, such as Imax B8. You can program intensity and top voltage, and it automatically ends the charge, avoiding overcharging the cell for unnecessary periods.
Have a look: http://www.hobbyking.com/hobbyking/store/__5606__genuine_imax_b8plus_charger_discharger_1_8_cells.html

Archi13
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Re: ¿Repair "disappearing bars" with software upgrade?

Hi,
2x.

Archi13
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Re: ¿Repair "disappearing bars" with software upgrade?

Hello R,
The problem with lithium is thé nominal voltage, when you charge thé battery to 3,65 or 3,55 volts after a few times thé battery want return near thé nominal voltage and go down, and your bms switch again a full battery to charge, and on the long time (not very long pereaps) you finish to destroy the good cell. The best for me , is better not use a bad bms.
Hello Mperegal,
Can you send me your scooter diag revision. Thank you very much in advance.

mpregal
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Re: ¿Repair "disappearing bars" with software upgrade?

There are some interesting news.

As I told in the first post, my bike's firmware was updated, and I was told that with the upgrade my problems will disappear....
I checked with scooterdiag that the firmware was new:
Firmware +13h.png

I also checked that cells number 3 (bank 0) and 5 (bank 3) had differences with the others in the pack (although the bike had been charging for 24h at the warehouse).
Baterias +13h.png

I was requested to charge the bike at home until it stopped (they told me it could take several days, even more than one week).
I know that long equalizations are not safe for healthy cells, but I still have some warranty left, so...why not to try?
After 57h charging (plus the 24h in the workshop) I get this:
Baterias +57h.png

Cell 35 seems to be "revived", and cell 03 is vey-very lazy....
Temperatures are into reasonable limits, so I will continue with the test.

I will update more results in a few hours.

R
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Re: ¿Repair "disappearing bars" with software upgrade?

Thanks for sharing, Mpregal.
I can see in the pictures ( very low resolution, I can't read many numbers!)that the BMS shunts energy at 3.50 Volts(6.65 in old EQ firm) , and during EQ the cells don't hit 3.55V). Archi points out that A BMS programmed to turn on the charger as soon as the voltage drops will destroy the god cells. True. But vectrix Official Firm does an Equalization once per charge. When that charge ends, the charger never turns on again unless you replug the Vectrix.

mpregal
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Re: ¿Repair "disappearing bars" with software upgrade?

Just to upgrade the impressive results obtained after a few recharges.

In my last visit to the workshop, bike's firmware was upgraded:
Battery Charger: R8010-42
Motor Controller: R2042-04
ICM: DIY 1708
BMS: BMS R54

With these modifications and some recharges the "missing bars" problem should disappear.

I followed step-by-step what they told me to do (let the bike charging until it finished eq), but after more than 80h charging... some cells were not able to equalize (they were frozen around 3.34v).
So I decided to follow what JPrates did (http://prius-pt.com/cafe/forums/127.aspx). Basically drive until 50% of the charge was consumed and then recharge.
Just two attempts later, all the cells got equalized!

I still continue making tests and checking what happens with the cells. Now I can verify that cells go better on each cycle completed.
Another "improvement" was setting the charger power to 850w (this makes charging g slower, what means -I think- less stress to the cells).

At this moment I can drive for 70km (uphill and downhill) at reasonable speeds (over 70km/h) and still keep 4 bars.

I am planning to make a test drive to check what is the real "full range", but I think that over 90km (may be more than 100 if I drive in a flat road).

I will update with more results.

R
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Re: ¿Repair "disappearing bars" with software upgrade?

Good. Nice the cells are getting balanced without overcharge.
Interesting, you had installed ICM: DIY 1708...;-)

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