Accuracy of the battery telltale (and of the gauge)

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Le Concombre Masqué
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Accuracy of the battery telltale (and of the gauge)

This morning, I think I've reach the limit of the battery telltale safety system during my commuting : after 35 kms of travelling on the highway, I still had 7 bars left but, as I'm used to now with NiMh chemistry, the power available began already to decrease (my former scooter was based on LiFePo chemistry that gives almost full power during 90% of the discharge). Unfortunately, I needed then to pass a truck, I was riding at about 85 kph and I asked full power for half a minute. This peak of power lowered the voltage under the low battery voltage threshold for a short time, and the battery telltale lit on.

I thougt it would be harmless, because I knew I had a lot juice left : I checked my battery voltage as soon as I left the highway, that appeared to be as high as 128 volts. Of course, the 7 bars left and the autonomy (I call this display RNG : Random Number Generator ...) disappeared as soon as I switched off - switched on the bike. The problem occured when I plugged the bike : the charging process though, because of no bar left, that the battery was empty, and run the CP stage until the battery reach the high voltage threshold (CP 151). There was still five bars missing. It was then followed by a TR stage for 15 minutes, and then again a CP stage (with a threshold of 150), because the charger though that the battery was not yet full because of the inaccuracy of the gauge, despite the high voltage. Of course, in reality the battery was full, and all this power was only used to heat the battery (it reached 40 C°, the ambient temperature was 18 C°). I had to left the bike then, but I supposed that this cycle followed on until the gauge was full, heating uselessly the battery.

My hope is that is harmless for the battery, because the voltage and the temperature never reached a dangerous level, but I understand now why, in the software upgrade notice, Vectrix advice to discharge the battery until the scooter couldn't reach 15 mph. That's the only way to realy calibrate the gauge. I never did it because I'm reluctant to lower as much the voltage. Has anyone an advice about the pertinence of this process ?

Mik
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Re: Accuracy of the battery telltale (and of the gauge)

When you get back to your Vectrix you will find that it stopped charging and the gauge shows about 15/17th.

And it will get hotter, because it repeates the CP stage 4 times (at least with the older software) before it gives up and heats it some more by CC charging.

What your Vectrix is going through is a "Recharge after BALPOR".

BALPOR stands for Battery Low Point Reset.

Have a read of this for a start: http://visforvoltage.org/book/ev-collaborative-hand-books/7145

This information may be used entirely at your own risk.

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

AndY1
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Re: Accuracy of the battery telltale (and of the gauge)

This morning, I think I've reach the limit of the battery telltale safety system during my commuting : after 35 kms of travelling on the highway, I still had 7 bars left but, as I'm used to now with NiMh chemistry, the power available began already to decrease (my former scooter was based on LiFePo chemistry that gives almost full power during 90% of the discharge). Unfortunately, I needed then to pass a truck, I was riding at about 85 kph and I asked full power for half a minute. This peak of power lowered the voltage under the low battery voltage threshold for a short time, and the battery telltale lit on.

I thougt it would be harmless, because I knew I had a lot juice left : I checked my battery voltage as soon as I left the highway, that appeared to be as high as 128 volts. Of course, the 7 bars left and the autonomy (I call this display RNG : Random Number Generator ...) disappeared as soon as I switched off - switched on the bike. The problem occured when I plugged the bike : the charging process though, because of no bar left, that the battery was empty, and run the CP stage until the battery reach the high voltage threshold (CP 151). There was still five bars missing. It was then followed by a TR stage for 15 minutes, and then again a CP stage (with a threshold of 150), because the charger though that the battery was not yet full because of the inaccuracy of the gauge, despite the high voltage. Of course, in reality the battery was full, and all this power was only used to heat the battery (it reached 40 C°, the ambient temperature was 18 C°). I had to left the bike then, but I supposed that this cycle followed on until the gauge was full, heating uselessly the battery.

My hope is that is harmless for the battery, because the voltage and the temperature never reached a dangerous level, but I understand now why, in the software upgrade notice, Vectrix advice to discharge the battery until the scooter couldn't reach 15 mph. That's the only way to realy calibrate the gauge. I never did it because I'm reluctant to lower as much the voltage. Has anyone an advice about the pertinence of this process ?

In this kind of event, after you turned off and on again (or after the red battery telltale was gone), you should have ridden the bike until the real red battery telltale with gentle driving (up to 70km/h) and only then let the bike do a complete charge.
It wasn't very healthy, for the battery, to let it overcharge this way. 40°C is quite high temperature for NiMH charging, meaning it was being overcharged.

Le Concombre Masqué
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Re: Accuracy of the battery telltale (and of the gauge)

Another way could be to stop the charge as soon as the battery reach the high voltage level threshold, and to live with the gauge inaccuracy until I have the opportunity to ride until the battery is really empty. Is it healthy for the battery to ride, for time to time, until the bike cannot reach 15 mph, as adviced by Vectrix ?

I don't understand why the software is not designed to stop the charge and to calibrate the gauge on high voltage level threshold, as do every laptop computer around the world. Basically, the programers are pouring gasoline on their feet, trying to fill a full tank because the gauge is out of synch !

This bike is really not ready for ordinary users. As long as it needs a so complicated care, only geeks as us could be enough motivated to stand this !

April 2010 Vectrix VX-1, 2004 Prius (feeded with E85), Giant Suede (electric bicycle)

Mik
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Re: Accuracy of the battery telltale (and of the gauge)

Another way could be to stop the charge as soon as the battery reach the high voltage level threshold, and to live with the gauge inaccuracy until I have the opportunity to ride until the battery is really empty. Is it healthy for the battery to ride, for time to time, until the bike cannot reach 15 mph, as adviced by Vectrix ?

I don't understand why the software is not designed to stop the charge and to calibrate the gauge on high voltage level threshold, as do every laptop computer around the world. Basically, the programers are pouring gasoline on their feet, trying to fill a full tank because the gauge is out of synch !

This bike is really not ready for ordinary users. As long as it needs a so complicated care, only geeks as us could be enough motivated to stand this !

Amen to that!

That's why I don't like discussing the bike with interested "people on the streets" or at green fairs etc.

An honest report will put almost everyone off!

I don't think it is EVER good for the Vectrix to be driven when it cannot maintain good speed and acceleration. It is not safe, it is not a roadworthy vehicle in that condition, and someone will get hurt and someone will get sued over it sooner or later!

The gauge may be actually much more accurate if the display is stopped at less than 17/17th. This is the case when you have damaged cells in the pack, with reduced capacity. These damaged cells will then be full at the same time as the others, and they will be empty at the same time as the others. If you fill the good cells by over charging the weak ones, and filling the gauge to 17/17th, then the weak cells get reverse charged and damaged further, particularly during "deep discharges".

This information may be used entirely at your own risk.

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

AndY1
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Re: Accuracy of the battery telltale (and of the gauge)

Is it healthy for the battery to ride, for time to time, until the bike cannot reach 15 mph, as adviced by Vectrix ?

I don't practice that. You never know how imbalanced cells are. One of them may already be completely emptied, being reverse charged, thus destroying it.

I don't even practice driving until the red battery telltale, because occasional EQ charging already does the sync (at the top of the gauge instead of at the bottom if you drive it until the red battery telltale) with slow overcharging, which also balances the cells.
But if I had to, I'd only do it up to the red battery telltale moment, no further.

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