Battery now overheats when charging

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Bikemad
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Battery now overheats when charging

I have a 2007 VX-1 with only 3150 miles on the clock, but the range is now down to about 15 miles max. from a full charge, if I use the bike and top up the charge without fully discharging the battery I end up with even less range.

I found the only way I can achieve a reasonable range is by running it down until the battery light comes on, which resets the battery gauge and then allows a full charge to be taken. The last time I needed to use the bike for a longer trip I left it on charge overnight after being completely drained until the light came on the previous day. I noticed in the morning that the battery temperature was very high when I came to use it, but thought no more about it.

Today I went to use the bike which has been stood for a couple of weeks and the battery voltage was only reading 126V, even though the gauge showed the battery as being well over half full, so I decided to run it until the battery light came on and then monitor the charge process. I managed to just limp home after travelling less than a mile in total, and with the battery light on for the last 1/4 mile.

I put it on charge and took several readings as it was charging at different time intervals.

After about 40 minutes I noticed that the voltage had strangely dropped from 142V to 141V and did not alter over the next 40 minutes. I also noticed the temperature reading seemed to be stuck at 19°C as well, even though the battery capacity gauge was still filling up. At this point I switched if off at the mains and then switched it back on again to resume charging again, and the voltage had jumped from 141V to 145V, and the temperature had also jumped from 19°C to 24°C.

I continued to monitor the readings and noticed that the temperature began to increase quite quickly when the battery voltage reached 148V.
Within the 16 minutes it took to increase from 148V to 150V, the temperature had risen from 31°C to 40°C and I noticed that the battery light had also started flashing.
So after a total of 1 hour and 51 minutes I stopped the charge with just 11 bars filled out of the 17 on the battery gauge.
I put it straight back on the maximum delayed charge (8 hours 45 minutes) to allow the cooling fans to cool down the battery pack.

The fans eventually cut out and after four hours the battery temperature is now down to 24°C and the voltage is currently reading 138V with 12 bars showing on the battery gauge.

I have plotted a graph from the readings I recorded, but I had to delete the readings taken between 40 minutes and 1 hour 20 minutes when the voltage and temperature readout had frozen, because they upset the graph:

I presume the overheating is the result of several faulty cells (probably shorted out) which means the charger it is trying to overcharge the remaining good cells to achieve the set target voltage (153V).

I'm guessing I probably have at least four or five completely dead cells for it to start overheating at 148V, and it looks like I will be pulling my battery pack apart in the near future to hopefully find out for sure.

Has anyone else had a similar experience regarding the overheating problem and/or the frozen voltage and temperature readings?

I have also experienced some very unusual voltage readings in the past whilst charging which can be seen in this video clip.

Assuming it is just a few faulty cells, I am now looking at the following two options:

  1. Find some second hand NiMh cells that are still usable and repair my existing pack
  2. Find a supply of Leaf cells (18 modules) and replace the entire pack

I would ultimately like to perform a leaf cell conversion, but I think I may have to go for the poor man's option of simply replacing the faulty cells (assuming I can locate some suitable replacements) in order to keep the bike running for a little bit longer until I can afford to buy some of those lovely leaf cells.
In which case, does anyone in the UK have some usable NiMh cells that they no longer require? (ideally in the South West area)

If I can't find any NiMh cells, I might have to consider removing (or bypassing) 11 of the NiMh cells (including the faulty ones) and make up a 30Ah 4S6P LiPo pack to put in series with the Vectrix pack to provide the required pack voltage.

Alan

EDIT: Picture link repaired

Kocho
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Re: Battery now overheats when charging

150+ V is too high for the NiMh packs. When I had my battery taken apart to replace one bad cell, I had to balance charge the group it was in to match the rest of the pack. I used a variable power supply to charge the 8-cell pack as one module of 8 cells in series. I charged it until the individual cells were almost full, then reduced the current and continued to charge overnight at Constant Current of 1A. What I observed was that, with low constant current charge, the individual cells settled at 1.43 to 1.44V each and did not go higher. This translates to about 146V for the entire pack of 102 cells. My cells were cool until they reached that voltage, and only then began to warm-up gently. This tells me that this is their max voltage and trying to charge them to a higher voltage and with higher currents is simply overcharging and damaging them.

You should try the Laird's software that only charges to 146V, not the 150V of the original Vectrix software that damages the pack every time it charges them "fully"... And avoid running it down to the red light - that kills (reverse charges) your lower capacity cells! Since you can't bottom-balance the cells while they are in your pack, your only option is to top-balance them via the equalization charge and never fully discharge them.

martinwinlow
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Re: Battery now overheats when charging

I have an unused pack in Herts. I could test a few if you like but too little time to offer them for free. How many do you think you need? Assuming I can find some with good capacity (I have a good tester and can provide printout of charge/discharge curves for each cell if you want) say, >25Ah (??) what would you be prepared to offer me for them? Obviously, postage won't be cheap but myHermes is my favourite courier at the moment - £10 for 15 kg. MW

Regards, Martin Winlow
Isle of Colonsay, Scotland
evalbum.com/2092

Kocho
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Re: Battery now overheats when charging

I presume the overheating is the result of several faulty cells (probably shorted out) which means the charger it is trying to overcharge the remaining good cells to achieve the set target voltage (153V).

I'm guessing I probably have at least four or five completely dead cells for it to start overheating at 148V, and it looks like I will be pulling my battery pack apart in the near future to hopefully find out for sure.
Alan

My suggestion is to first top-balance you pack so that all cells are full. You should do that at low amps ideally, 1A. Unfortunately, with the stock software and charger you can't do that... Then ride about to half-empty (around and a bit above 130V at 30mph on flat) and charge again. See if you still get the overheating.

The idea is that, when you rode to red light, what you did was completely empty the low capacity cells but not empty the higher capacity cells. Even if you do not have damaged cells, just cells with different capacity, what happens next during charging is that some cells get charged fully while others are still not full. And worst, the charger does not recognize some cells are full and pumps very high current through them. So, you get severe overheating even if all your cells are good, just started disbalanced (which is likely always the case when you ride in limp mode).

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Re: Battery now overheats when charging

150+ V is too high for the NiMh packs. When I had my battery taken apart to replace one bad cell, I had to balance charge the group it was in to match the rest of the pack. I used a variable power supply to charge the 8-cell pack as one module of 8 cells in series. I charged it until the individual cells were almost full, then reduced the current and continued to charge overnight at Constant Current of 1A. What I observed was that, with low constant current charge, the individual cells settled at 1.43 to 1.44V each and did not go higher. This translates to about 146V for the entire pack of 102 cells. My cells were cool until they reached that voltage, and only then began to warm-up gently. This tells me that this is their max voltage and trying to charge them to a higher voltage and with higher currents is simply overcharging and damaging them.

You should try the Laird's software that only charges to 146V, not the 150V of the original Vectrix software that damages the pack every time it charges them "fully"... And avoid running it down to the red light - that kills (reverse charges) your lower capacity cells! Since you can't bottom-balance the cells while they are in your pack, your only option is to top-balance them via the equalization charge and never fully discharge them.

Firstly, I don't have anything suitable for reprogramming, and secondly, I don't really want to lose my 69mph top speed.

From what you have said, the overheating could occur with just one cell failed and shorted out, but presumably any shorted cells would be easy to locate by measuring each of the 12 groups and comparing the total voltages of each 8 or 9 cell group.

I have an unused pack in Herts. I could test a few if you like but too little time to offer them for free. How many do you think you need? Assuming I can find some with good capacity (I have a good tester and can provide printout of charge/discharge curves for each cell if you want) say, >25Ah (??) what would you be prepared to offer me for them? Obviously, postage won't be cheap but myHermes is my favourite courier at the moment - £10 for 15 kg. MW

Hi Martin and thanks for the kind offer.

Unfortunately, I won't know how many cells I am likely to need until I check all 102 cells in the pack, and as I also have very little time to spare at the moment, further investigations may have to wait a while until I get some time (and a bit more space to work in the dry) to pull the pack apart.

I presume the overheating is the result of several faulty cells (probably shorted out) which means the charger it is trying to overcharge the remaining good cells to achieve the set target voltage (153V).

I'm guessing I probably have at least four or five completely dead cells for it to start overheating at 148V, and it looks like I will be pulling my battery pack apart in the near future to hopefully find out for sure.
Alan

My suggestion is to first top-balance you pack so that all cells are full. You should do that at low amps ideally, 1A. Unfortunately, with the stock software and charger you can't do that... Then ride about to half-empty (around and a bit above 130V at 30mph on flat) and charge again. See if you still get the overheating.

The idea is that, when you rode to red light, what you did was completely empty the low capacity cells but not empty the higher capacity cells. Even if you do not have damaged cells, just cells with different capacity, what happens next during charging is that some cells get charged fully while others are still not full. And worst, the charger does not recognize some cells are full and pumps very high current through them. So, you get severe overheating even if all your cells are good, just started disbalanced (which is likely always the case when you ride in limp mode).

The range has always been pretty poor since I bought it 10 month ago, even after an equalization charge, so I'm assuming I definitely have some faulty cells.

I previously purchased some LED drivers with a view to making up a trickle charger, but I haven't had chance to wire them up to the pack yet.
Perhaps this should be my next step before pulling the pack apart.

I have four driver units which each have an output of 60-90VDC @320mA that I was going to wire up in series/parallel and have a rocker switch to select either 320mA or 640mA. My initial intention was to leave it on a very low trickle charge to compensate for the self-discharge and keep the battery fully topped up and ready to go, but I read somewhere that constant trickle charging is not recommended for NiMh cells.

I was originally thinking of fitting a simple jack plug socket on the bike with a diode on the positive feed connection to prevent the possibility of getting an electric shock from the socket, but I was then concerned about the high voltage (120-180V) on the end of the plug if it was pulled out while the charger was still turned on.

My solution to this problem will involve fitting the driver units inside the battery compartment and simply having a second (thinner) mains lead coiled up under the seat so that I would be able to easily use either charger at all charging locations.

As these drivers are completely isolated from the mains supply, it might even be possible to use both chargers simultaneously.

Alan

EDIT: Picture link repaired

R
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Re: Battery now overheats when charging

Hi Alan,

don't really want to lose my 69mph top speed.

Then you'll loose your nimh cells quite soon...

Forget the NIMH, don't waste your time and money, go for the lithium. If you can't afford leaf cells, there are other ways to build up a pack:

Good luck!

Anderson
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Re: Battery now overheats when charging

Since you can't bottom-balance the cells while they are in your pack

The laird had a bottom balance scheme ( Nimh battery only ) see http://visforvoltage.org/forum/10332-equalisation-difference that involved adding a resister to each cell the theory being that it's safe to fully discharge a battery cell to near zero volts. Maybe if the experimenter types weren't switching to lithium batteries there would be people reporting in there rusults of tring this out but as of yet there aren't any.

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Re: Battery now overheats when charging
Since you can't bottom-balance the cells while they are in your pack

The laird had a bottom balance scheme ( Nimh battery only ) see http://visforvoltage.org/forum/10332-equalisation-difference that involved adding a resister to each cell the theory being that it's safe to fully discharge a battery cell to near zero volts. Maybe if the experimenter types weren't switching to lithium batteries there would be people reporting in there rusults of tring this out but as of yet there aren't any.

One cannot guarantee that it is "safe" to fully charge the pack in series after it has been bottom-balanced. This is due to the fact that, in an aging NiMh pack, the individual cells have different capacitates. And, that at least a few cells will likely have substantially smaller capacity than the rest. This means that during charging, the "small capacity" cells will fill-up first, sooner than the rest. As soon as the "smallest capacity" cell is "full", it will begin to overcharge at high currents, because the fact it is full will be masked by the relative low voltage on most other cells. The charger simply has no way to know what the individual cell voltages are. Even with Laird's modified software, the current at that point will be too high and will heat-up any individual cells that are already full - it still pumps something like 6-7A at full power. Even 3A current heats-up the pack more than I think is necessary (and an individual cell sandwiched between other cells doesn't cool-off very well and heats-up the other cells around it and above it). A charging current of about 1A seems to just warm the cells up gently (I've tried 3A vs. 1A with a bench power supply while balancing individual cells when I repaired my own NiMh pack). So, that overcharging of the small capacity cell(s) will continue until enough of the "larger capacity" cells catch-up and fill-up. Only then will the charger software detect the overall pack voltage is high enough to throttle down the current to a safe level. By that time, significant overcharging/heating of the small capacity cells could have occurred.

Unless one has a way to monitor the individual cell voltage on each cell, there is no "safe" way to charge nearly fully or to discharge nearly fully - individual cell's overcharge/over-discharge condition will be masked by a small number of higher capacity cells. So one has to leave a very big margin at the top end of the charge, representative of the capacity of the smallest cells in the pack.

Now, provided that all cells are very close in capacity (and that they remain so in use, which is unlikely as they heat-up differently when in use), it do agree that occasionally bottom-balancing them will minimize the stress individual cells will experience during the occasional top-balancing. And still allow nearly full charge and discharge safely. And, top balancing may not even be necessary - just stop short of full would be good enough. However, to say that bottom balancing is better for the cells vs. top balancing requires some sort of empirical proof. I have yet to see proof of some sort that bottom balancing to near 0V is more (or less) harmful than gentle top-balancing. If one proves that this type of bottom balancing is better (or worse) than top balancing over the same number of cycles (i.e., over many months and years of use), by all means - then we can make a conclusion and chose one wisely. Until then - it's anyone's guess because we do not know which is worse: doing the occasional top balance or the occasional bottom balance.

Sine just about all battery chargers are built around the idea use of gentle top balancing, I gather it can't be that bad, can it? Yes, harsh (high-current) top balancing is bad, but I am talking to doing it right. Plus, it is the only way to have a battery with different capacity cells "fully charged", which provides a more spirited performance for the first few miles of riding (higher overall pack voltage).

In that post the Laird makes a theoretically valid point that the resistors can naturally "self-balance" the cells: the higher-charged cells will discharge faster. But the delta in the discharge rate is very small - if one is using the bike regularly, it will probably not keep-up with the natural disbalances that are claimed to be occurring unavoidably in the Vectrix. Here is how small that delta is: say there is a 0.1V difference b/w two cells, which is a fairly significant difference as far as battery SoC near full is. That 0.1V over a 35Ohm resistor - that generates only 0.003A current! Given that in use the cells often work at 150A or more and that the cell capacity is rated at 30Ah, that 0.003A differential is a miniscule difference that will take forever to achieve any noticeable self-balance. And it will go even slower as it nears the balance point. As a reference, this is 100 time less than the typical 0.3A equalization current BMS systems use and which take hours to balance even slightly disbalanced cells. So this self-balancing with the resistor at near full voltages will take weeks provided no new disbalancing is occurring in the mean time at a rate bigger than the resistor's effect! So the argument about the so called "self-balancing" effect from these resistors due to faster discharging of the higher-charged cells vs. the slower discharging of the undercharged cells is very likely not practical, IMO. Bench-testing ignores the effect uneven heating when the cells are used as part of a complete battery pack inside an actual VX-1, where disbalances are claimed to be very significant in normal use.

One more thing to consider: the Runke chargers can be modified to charge at lower final currents than the ESD chargers - I hear that the ESD chargers do not like low currents (they get damaged). So, that is another alternative to do a gentle top balance in a factory setup, without the need to take the battery apart.

R
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Re: Battery now overheats when charging

Unless one has a way to monitor the individual cell voltage on each cell, there is no "safe" way to charge nearly fully or to discharge nearly fully

Kocho, I completely agree with you. The best way to keep a NIMH battery out of stress is to use a NIMH BMS,that would reduce charging intensity as soon as the weak cells get full. I'm afraid there's no NIMH BMS on the market..

bateria vectrix malmesa_0.jpg

Without anything to look after the cells, they get overcharged and undercharged on every deep cycle. At this phase, the entire battery begins to fail very quickly.

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Re: Battery now overheats when charging

Since the last overheating problem I have not been leaving the bike on charge unattended and I do dot allow it to reach the target charging voltage as I now stop the charging at 148V (unless it reaches 25°C first) as I do not want to cause any further damage by overcharging cells.

Today I was topping up the battery ready for use as it had been stood for several days since I last rode the bike.
It began the charge process at 129V with a temperature reading of 9°C. The battery gauge originally showed 6 bars but quickly dropped back to four bars within a few seconds.

After 45 minutes of charging it had reached 145V and the temperature had risen slightly to 11°C. (Nothing to worry about there.)
After 55 minutes of charging it had reached 146V and the temperature had risen to 17°C. (A rise of 6° in 10 minutes is not unusual for my pack at this voltage.)

I left it charging but kept a very close watch on what was happening (via webcam) until this suddenly happened:

All three warning lights came on simultaneously, the Temperature light and Battery stayed on and the Spanner began to regularly flash on and off.
After 10-12 seconds the light all went off again and stayed off until I terminated the charge at 1:19 when it reached 148V (24°C).

I am puzzled as to why the lights have come on at such a low temperature (23°C) as the last time it happened it was just the battery light that started flashing at 40°C.

I know my poor old battery pack needs sorting, but it has been working fine for my short distance trips without any problem.

I think I must also have a problem somewhere with the voltage monitoring as I have experienced some very strange voltage readings during charging in the past.
Take a look at this video on YouTube to see exactly what I am talking about.

Unfortunately, I don't have the required hardware to plug it into a PC for diagnostic purposes, so I can't easily check the individual temperature readings to see what is actually going on inside the battery, but I would really like to know what might have triggered all three warning lights to come on instead of just the one battery warning light that started flashing when it reached 40°C last time.

Could it possibly be due to a poor plugin connection somewhere on one of the monitoring boards?

Alan

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Re: Battery now overheats when charging

Hi Alan,
Nice! Leaving a webcam recording the display is a smart way to log data without canbus cable, I tested this method to improve the specific version the laird wrote for my Vectrixs, and it was effective.

About the flashing lights, if I remember correctly, when there is a differential of 10 degrees between any of the temperature sensors, the warning lights start flashing. If you started to charge at 9ºCs and it ended at 24 degrees Celsius, it is quite plausible that these 10 degrees of difference took place inside your battery. If I were you, would not worry too much about these flashes, only for that massive temps rise.

Your charging pattern rises 15º C the temperature of the battery! That's not good, the end is nearing. If you don't want to mess up your Vectrix now with a battery upgrade, I suggest:

1- Buy peak canbus adapter
2- Install lastest scooterdiag on a laptop (download it from vecrix parts)
3- If you have Runke charger, Install extra features on scooterdiag, new menus appear(Pm me). Select the option to reduce charging power from 1700w to 800-1000w.
If you have ESD, Install the lairds firmware.
Additionally
4-Check that temperature sensors display correctly all temperatures inside scooterdiag
5- Apply a protective layer of ACRYLIC PROTECTIVE LACQUER on both temperature boards, put a plastic bag around them for extra protection.
6- Clean encoder with Spray cleaners for electronic and electrical components, apply ACRYLIC PROTECTIVE LACQUER, lift up rear wheel and recalibrate encoder with scooterdiag command as many times as necessary until the calibration number displayed each time is almost the same.
7- Consider adding some sort of cell monitor. You can use LIPO monitors to check 3 NIMH cells in series. If one cell's voltage drops near to 0V the alarm will be triggered. You'll know which group of 3 cells has a damaged cell and needs to be cycled or replaced.
This board http://www.chargery.com/cellsaver16s.asp can check 16 lipo cells, 48NImh cells in groups of 3, 2 boards can monitor 96 of the 102 cells.
This other board http://www.chargery.com/cellSaver12S.asp can check 36 cells, 3 can monitor the entire battery.
BS12V2.1.jpg

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Re: Battery now overheats when charging

Thanks for the comprehensive reply.

I have a Cell Log 8C which could be used to monitor (and even record) up to 24 cells at a time, but making up suitable wiring to cover all the cells in the battery pack would be quite an involved task.

I have just acquired another 2007 VX-1 with only 1159 miles on the clock and it is still running the old software, so perhaps I'd better start saving up for a Peak canbus adapter to allow me to update the software on the new addition and also to help diagnose the temperature problem on my current one.

Does anyone in the UK have a suitable USB canbus adapter that they no longer use and might be prepared to sell?

Alan

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Re: Battery overheats when charging and the display freezes

I went for a short run today and the battery light just came on as I arrived home.

I set up my webcam and started to record the charging process while I was busy doing other tasks on the computer.
After an hour and a half I noticed that the battery light started flashing so I quickly checked the temperature and voltage which did not seem high enough to warrant a flashing battery light.

I left it for a minute or so to see if the battery light would go off again like it has done before, but it kept on flashing.
I decided to stop the charging and restart it again to see what would happen, and I discovered that the Voltage and Temperature display must have frozen as the Temperature had jumped to 28°C and the Voltage went from 136V straight up to 148V.

Now the interesting part, I reviewed the video and it appears that the instrument display suddenly went slightly darker after just 12 minutes of charging.

I plotted a graph using the data taken from the readings displayed on the instrument panel in the video and here is the graph:

//www.arhservices.co.uk/GoldenMotor/Vectrix/Charging%20frozen_zps9bi2r4an.JPG)

It appears that the voltage reading and the temperature reading stopped moving around the same time as the display dimmed slightly, but the charging current displayed on the speedometer and the bars on the battery gauge continued to update normally.

I am puzzled as to why the voltage and temperature stopped updating yet the current and capacity continued as normal. Are these controlled by different components, ie charger and motor controller, and if so which of them is responsible for the frozen display.

If I hadn't have been using the webcam to record the display I would not have noticed the change in brightness, but it is very obvious when I watch the video playback.

From completely empty, the battery gauge had filled 8 bars and the voltage had risen from 128V to 148V which is about where I try to terminate the charge nowadays with my suspect battery pack and the temperature had risen 12° from 16°C to 28°C.

When I resumed the charging at 148V the battery light also resumed flashing again even though the temperature was only reading 28°C.

I haven't been able to dismantle the battery pack or check the temperature control boards as yet, but I don't suppose my suspect battery is responsible for the display freezing, although I suspect that it may be responsible for the battery light flashing.

If I get chance, I will post the section of video that shows the dimming of the gauges when the voltage and temperature reading froze.

Alan

EDIT: Picture link repaired

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Re: Battery overheats when charging and the display freezes

You may have experienced one of the infamous "charger freeze" conditions, where the charger keeps charging and doesn't recognize the battery is full. I've seen it happen several times on my ESD NiMh bike (with original and with Laird's firmware versioned as of a year or so ago). So, best to use a timer that will stop the charge after a predefined time. Can also use it to start the charge at night so you have the bike ready in the morning.

With some observations, you will figure out how long it takes to charge from various starting voltages... I use a fairly inexpensive ($20 or so) programmable electronic timer and it has worked great for that purpose. I also use that same timer during the winter months to automatically add some charge to the battery every few weeks to make sure it does not go flat.

Though with my Li upgrade and a Runke charger, this winter I observed that I barely got any voltage drop while not riding the bike - for the entire winter it would have lost only a couple of volts if that (I rode it perhaps 2 times in 4 months, so I charged once or twice during this time, but I was monitoring the voltage between these and it was stable). With NiMh it will self-discharge much faster...

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Re: Battery now overheats when charging

Wow, the charger,s freeze program effect srikes again! Lucky man, how fortunate you could manually disconnect the battery charger before the battery got fried!

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Re: Battery now overheats when charging

My computer is in my little office which is right next to the garage where the scooter is charging.
I have a webcam clipped to the screen pointing at the gauges and use iSpy to record the whole process, which makes it a lot easier to gather data.

I also have the scooter plugged in to a remote controlled mains socket so I can turn the charging on and off without having to leave my warm office and go out into the cold garage.

I have a dual screen setup on the computer so I am able to work on one screen and simultaneously monitor the charging on the other. I tried using my tablet to monitor the video from other rooms in the house via my wireless network, but it was not very successful as the streaming was a bit hit and miss.

Here's a short video showing the frozen voltage and temperature readout, but you can clearly see that the elapsed time, charging current and battery capacity are still being correctly updated.

As I don't use the light in my garage when I'm not in there, I could clearly see from the video that the headlamp did not come on when I switched off the charger while the Voltage and Temperature display was frozen, but you can clearly see it come on as normal when I turn the charger off for the second time at the end of the video.

I mentioned before that the instruments dimmed slightly around the time when the freezing started, but while watching the video again I noticed that the speedometer suddenly brightened up more than the other two gauges after 1 hour and 1 minute of charging.

I don't know whether the dimming of the instruments is actually related to the freezing of the display, but I think it could well be.

Alan

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Re: Battery now overheats when charging

If your battery pack is anything like mine was, you probably have one or two bad cells that overheat while the rest are not getting hot. That causes the temp. reading at and near them to be higher, while the temperature in the rest of the battery is low. If that difference is more than something like about 10C (or was it 5?), you get the lights and the charge should stop. Luckily, these bad cells are usually bulged visibly, so you can identify them if you take the battery pack apart. If you replace them with good cells, likely you will gain 5-10 miles of range.

It is easiest to see if one bank of cells overheats more than the rest with ScooterDiag. But, you can measure the resistance of each of the temperature sensors without taking the battery apart and without scooter diag. and without CANBus adapters. You need to gain access to the two temperature control boards: one in the front and one in the rear of the battery compartment. You need to take them out from where they are mounted and find the solder points where the wires go to the batteries. Alternatively, to not have to take the boards out (especially the front one can be a bit tricky to take out from where it is), you can tap each of the wires that go from these boards and measure the resistance between pairs of these wires. Taps are cheap to buy at automotive stores and easy to use - just clamp on the wires with regular pliers: they are used to install hitch harnesses for example (to get electricity from the wires that go to the turn and stop lights). You will be measuring the resistance of each of the temp. sensors. At room temperature, around 21C, all should read something like 10kOhm. Look-up the thread on this site to find a temp. vs. resistance chart for these sensors to see what measurements to expect at different temperatures. If towards the end of the charging one of these sensors' resistance changes more than the rest, you either have a defective sensor or the temp. of the cells near it has changed differently from the rest of the pack. You can tell which of the two is the case by measuring these values when the whole pack is at the same temperature: once on a warm day and once on a cold day after several hours or a day following a charge, so all cells are at approximately the same temperature. If all sensors measure close to the same value when cold and close to another value when hot, then it's not the sensors.

Of course, doing these measurements exposes you to the risk of electrocuting yourself and your equipment, so be careful or don't do it!

antiscab
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Re: Battery now overheats when charging

the display dimming slightly at the same time the charger locks up suggests you are onto something here

we still do not know the cause of the charger lock up, but slightly dimmed display could mean the 12v has dipped slightly for some reason...very interesting

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst 2 x TC Charger & MC
conversion

Bikemad
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Re: Battery now overheats when charging

Matt, is it possible that the charger provides the signal output for the voltage and temperature display but not the battery gauge, charging current and elapsed time?

I'm puzzled as to why only some parts of the display freezes. If all of the display data was being output from the charger and the software locked up, I would expect everything associated with the charger to stop updating too. Is there a flow chart of some sort that explains how the electrical components interact across the CAN bus?
I'm still wondering whether the Motor Controller or the Interface Control Module could have something to do with it.

Also, does this freezing problem only occur with the ESD chargers or is it a problem with the Runke chargers too?

Alan

antiscab
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Re: Battery now overheats when charging

Matt, is it possible that the charger provides the signal output for the voltage and temperature display but not the battery gauge, charging current and elapsed time?

I'm puzzled as to why only some parts of the display freezes. If all of the display data was being output from the charger and the software locked up, I would expect everything associated with the charger to stop updating too. Is there a flow chart of some sort that explains how the electrical components interact across the CAN bus?

The charger actually has at least two processors, only one locks up.

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst 2 x TC Charger & MC
conversion

Bikemad
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Re: Battery now overheats when charging

Your charging pattern rises 15º C the temperature of the battery! That's not good, the end is nearing. If you don't want to mess up your Vectrix now with a battery upgrade, I suggest:

1- Buy peak canbus adapter
2- Install lastest scooterdiag on a laptop (download it from vecrix parts)
3- If you have Runke charger, Install extra features on scooterdiag, new menus appear(Pm me). Select the option to reduce charging power from 1700w to 800-1000w.
If you have ESD, Install the lairds firmware.
Additionally
4-Check that temperature sensors display correctly all temperatures inside scooterdiag

I have the ESD charger but I am a bit reluctant to install different firmware at the moment, but at least I now know that I have some definite problems with the battery cells, and one of the temperature sensors is obviously faulty too:

//www.arhservices.co.uk/GoldenMotor/Vectrix/Before_zpsxuythpmp.PNG)

//www.arhservices.co.uk/GoldenMotor/Vectrix/After_zps0zba4rrb.PNG)

I charged the battery from 127V up to 146V and used the data from the above screenshots to produce this graph which clearly illustrates the actual temperature rise for each of the battery modules:

//www.arhservices.co.uk/GoldenMotor/Vectrix/Temperature%20rise_zpsu7f8wsud.JPG)

It looks like it might take a bit more than just a change of firmware to cure this battery pack.
//www.arhservices.co.uk/GoldenMotor/emoticons/everyday_sad_230608.GIF)

Alan

P.S. If anyone wants some nicer looking desktop icons for their Diagnostic program short-cut I have created these:
//www.arhservices.co.uk/GoldenMotor/Vectrix/Vectrix%20icon%20eliptical_zpsph3lpvef.PNG)
//www.arhservices.co.uk/GoldenMotor/Vectrix/Vectrix%20icon%20round_zpsq37xhkd8.PNG)
(Simply click the one you prefer to download the associated .ico file from my Dropbox and then customise your desktop icons and folders. )

EDIT: Picture link repaired

R
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Re: Battery now overheats when charging

Nice Desktop Icons, thanks!

About your temps sensors, you may buy entire temps replacement, front or rear pack:
http://shop.vectrixparts.com/wire-battery-temperature-rear.html
http://shop.vectrixparts.com/wire-battery-temperature-front.html
Or you may find the damaged sensor and bring to electronic repair shop to fix it.

It looks like it might take a bit more than just a change of firmware to cure this battery pack.

of Course, the lairds firmware will not cure nothing, but it will stop/reduce cell degradation.
About the 6 4D rise, yes, the sensor is placed close to a damaged cell. The end is nearing. It is imperative to reduce charging intensity, don't hesitate to upgrade firmware if you want to stop cell degradation. with ESD, your best choice is The laird Firm.
You'll have to open the battery to install/repair temps sensor. You should also cycle the strings of 8-9 cells and find the damaged cells, and replace de faulty ones. You'll recover up to 50-60 km of range.
Or you can start looking for lithium replacement...
Bikemad
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Re: Battery no longer overheats when charging

Of Course, the lairds firmware will not cure nothing, but it will stop/reduce cell degradation.

Since I recently installed The Laird's modified firmware on both of my VX-1s his firmware has completely cured the irritating flashing battery and temperature warning lights on my other bike that started when I had to disconnect both of the temperature sensor boards in order to rectify the charging problem, and it has also cured the excessive temperature rise I was getting with a full charge on this bike, so at least I can now set it charging and it will actually complete a full charging cycle at the lower current without overheating:

//www.arhservices.co.uk/GoldenMotor/Vectrix/Sandys%20firmware_zpslclh6iw8.JPG)

The graph clearly illustrates how much less heat is being generated within the battery during the 6 Amp charging process compared to the higher charging current that the original Vectrix firmware allowed.
My dodgy battery pack still gets warmer than it should (11.1°C increase on the worst module) but it's a lot better than the 27+°C increase I witnessed before when I had to manually terminate the charging process when it reached 40°C, so the temperature rise problem has definitely been reduced by a significant amount.

You'll have to open the battery to install/repair temps sensor. You should also cycle the strings of 8-9 cells and find the damaged cells, and replace de faulty ones. You'll recover up to 50-60 km of range.
Or you can start looking for lithium replacement...

With the Laird's firmware I am no longer concerned about overheating of the battery so the sensors are not so important.
I intend to upgrade one of the battery packs to leaf modules (when/if I can eventually get hold of some at an affordable price) and then I will hopefully use the best cells from both packs to make one good NiMH pack, provided I still have 102 good cells available to use.
//www.arhservices.co.uk/GoldenMotor/emoticons/fingerscrossed.GIF)

I might replace the one faulty temperature sensor using a good one from the other pack, but I'm not sure whether it's worth the additional hassle of refitting the temperature sensor system at all. I will make that decision at a later date (Leaf modules permitting).

For the time being I will use this Red bike with the dodgy battery for short rips and the other Blue bike with the much better battery on longer runs.

Alan

EDIT: Picture link repaired

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