Is this the begining of the end for my Wisper battery?

[z0mb13e]

Last week and then again this am, the Wisper decided it wasn't going to play. I lost power and no amount of switching things off and on again or wiggling contacts made any difference. Then suddenly things started working again...

So last week I had completed my run into work and had finished work for the day and about to head home. I switched on the battery and everything looked ok, I turned the throttle and nothing happened. I noticed that the power level switch box green led had gone out (the little box on the left hand side that allows you to select high or low power modes) and the red light on the throttle was dim (the lights on the throttle are rarely above red these days - green and orange are lit when freshly charged or if left sitting all day I might get red and orange until I apply some load). Switching off the power on the handle bars and back on again, the green light on the power selector box would flicker on and then go off followed by the red light on the throttle going dim again.

Eventually after much faffing around checking contacts and measuring battery voltages (I can't remember what it was but I remember thinking it didn't seem low) checking fuses and reseating the battery a dozen times, I tried again and everything worked and got me home.

This morning on my way into work the same thing happened but while I was riding. After a bit of faffing I gave up and resigned myself to doing the last mile under just my own steam. I occasionally hit the power off and on and at one point it came back on, but then went off again after a minute of assistance.

I have yet to fire it up again to see if it will give me any assistance on the way home.

Anyone have any ideas?

I've also lost track of the exact mileage as my odo packed up and I haven't replaced it. So I think I'm over 8000 miles now. The battery is just over 2.5 years old.

 

[shemozzle999]

I would work this route: from the source of your power to the load, your motor.
The battery voltage after a full charge would be a good start point for your investigation.
It will eliminate any charger / battery problems first before delving into the electronics.

 

[z0mb13e]

I wish these things had data logging built in... it would make it much easier to figure out what is going on.

Will check the voltage tonight.

 

[flecc]

On the age and a lot of the characteristics it does seem to be the end. The LED indications and the cutoff when you apply a load are all consistent with end of working life. Working ok sometimes though is inconsistent, so it could be a well worn battery still with some life but with a connection problem.

 

[z0mb13e]

On the age and a lot of the characteristics it does seem to be the end. The LED indications and the cutoff when you apply a load are all consistent with end of working life. Working ok sometimes though is inconsistent, so it could be a well worn battery still with some life but with a connection problem.

Will check the connections thoroughly. I know the battery connections are well worn so I will pay extra attention there.

From what I had observed I got a nagging feeling that it was a cell dying or a cell with a flaky connection... still, start with the stuff I can see/measure...

 

[flecc]

I fear the same, but that inconsistency of working sometimes is at odds with a failing cell. Once one starts failing it's usually a one way trip.

 

[hech]

I have had similar problems with my 6 month old battery. The cells all read 4.22v after charging except for one which reads 3.88v. I thought about charging that cell individually with a balance charger but would need to solder up a special one cell connector I suppose and even then, might only be a temporary solution. Am sure I have lost considerable range due to one duff cell in ten.

 

[Scottyf]

Remove the dead cell cell and place a new one in its place. You'd need to cut the tab weld away from the other cells though.

THen you'd have to solder a new one in its place. Or just know that you've lost a little bit of range with the reduced amp hour in that bank of cells.

 

[z0mb13e]

The bike was dead this afternoon. I spent 45 minutes pulling all the controller connectors apart and checking them, there were a few signs of corrosion so I gave everything a liberal spray with electrical contact cleaner. That didn't make much of a difference.

I did the same on the junction box on the handle bars. Again a few signs of corrosion and sprayed with contact cleaner and then plugged in and disconnected a few times just to be sure.

Things sparked into life briefly but died again after trying the throttle.

One thing that I've never really paid attention to is the little box to select hi and low. It has never really worked. It defaulted to Hi a long time ago and doesn't let me change to low. Well I noticed the printed facia was peeling up in one corner so I tried lifitng it off and it came up far too easily. Through the holes in the housing I could see the circuit board was corroded so I gave it a blast with the electrical cleaner and after a power cycle things flicked into life again and I was able to select between hi and low.

However, trying the throttle and things died again.

I checked the power from the battery to the controller connector 37.4Volts. No power from the controller to the handle bars...

After lots more faffing - turning things on and off and trying various combinations of power settings I was able to get the motor to run but as soon as there is any load it cuts out and the red led on the throttle goes dim.

So I set off home and again tried the on/off button a few times and noticed that the pedelec sensor was firing up the motor a tiny bit, just pulses. The sensor hasn't worked for ages... possibly the corrosion... however it wasn't supplying constant power, but the power lights was staying bright (with green dropping out on each pulse of the motor). Full throttle killed everything and required a power cycle.

I gingerly applied throttle and the power held. I was able to get some assist this way for a few miles and after a little longer I was able to use full throttle on high power even up hills without the power cutting out. However there was very little power pulling away from a stop when using throttle.

I wonder if the controller is corroded or if a capacitor has failed?

So now I am charging the battery which was registering 37.4v.

I will report back when the charger thinks it is full... (39.2v presently)

 

[rog_london]

Long-term notes:

I've got a Wisper and it and its battery are now approaching three years four months old. It doesn't have the same zip it had when new but it's never cut out on a hill or any other place and as of last October when for the first time I managed to run it flat after a longish (35 mile) ride it was still good for a decent range. My mileage is probably similar to or maybe more than yours.

The green and yellow lights disappear as soon as any power is drawn. This would not have happened when the battery was new, but I can't complain after this amount of time.

I suppose much depends on how much effort you put in and your weight, as both will affect the battery on a day to day riding basis. Also I always use the throttle and the 'off road' button is permanently engaged. Off road mode gets me to around 18-19 mph before the motor is fully disconnected. It's easy to tell just by keeping an eye on the yellow light - when it comes back on, I know the controller has disconnected the motor power.

I use a wattmeter to record the power taken during a charge (among other things) and recorded some 0.45 kWh following running it flat - so even allowing for the fact that you don't quite get out what you put in I feel reasonably happy that approaching three years old it still had some 80% of its original capacity.

Finally - never a problem right from new beyond needing to replace the gear selector on the handlebar damaged in transit and replaced immediately and without question by E-Bikes Direct. So, one entirely satisfied customer.

Rog.

 

[shemozzle999]

Make a note of the final battery voltage after charging this evening, then re-test in the morning,
If there is hardly any difference in the two readings I think you can eliminate the battery and charger.
If the drop is significant it could indicate a bad cell pulling the others down.
The handlebar controller is the central hub for deciding power delivery to the motor if you think there has been water ingress it could be worth looking into obtaining a replacement as from my experience of laptop repair liquid spills on motherboards it invariably meant they had to be scrapped as the fine copper circuits were burnt away.

 

[z0mb13e]

Long-term notes:

I've got a Wisper and it and its battery are now approaching three years four months old. It doesn't have the same zip it had when new but it's never cut out on a hill or any other place and as of last October when for the first time I managed to run it flat after a longish (35 mile) ride it was still good for a decent range. My mileage is probably similar to or maybe more than yours.

The green and yellow lights disappear as soon as any power is drawn. This would not have happened when the battery was new, but I can't complain after this amount of time.

I suppose much depends on how much effort you put in and your weight, as both will affect the battery on a day to day riding basis. Also I always use the throttle and the 'off road' button is permanently engaged. Off road mode gets me to around 18-19 mph before the motor is fully disconnected. It's easy to tell just by keeping an eye on the yellow light - when it comes back on, I know the controller has disconnected the motor power.

I use a wattmeter to record the power taken during a charge (among other things) and recorded some 0.45 kWh following running it flat - so even allowing for the fact that you don't quite get out what you put in I feel reasonably happy that approaching three years old it still had some 80% of its original capacity.

Finally - never a problem right from new beyond needing to replace the gear selector on the handlebar damaged in transit and replaced immediately and without question by E-Bikes Direct. So, one entirely satisfied customer.

Rog.

That's impressive and gives me hope that my battery is ok and the problem lies elsewhere. Interesting that you are still getting 18-19 with off road mode. I've had off road mode permanently engaged for the past 6 months or so, just so I can maintain assist up to 15-16 mph...

 

[rog_london]

That's impressive and gives me hope that my battery is ok and the problem lies elsewhere. Interesting that you are still getting 18-19 with off road mode. I've had off road mode permanently engaged for the past 6 months or so, just so I can maintain assist up to 15-16 mph...

I thought it might help if you knew what you might expect under favourable conditions. From what I've heard from others the Wisper battery is generally pretty good, and most problems have come down to loose connections, dodgy fuse holders, and such like.

Rog.

 

[z0mb13e]

Battery voltage after charge 41.5V

I will leave the battery sitting for today and see if there is much change.

 

[shemozzle999]

I would expect the overall battery voltage to drop if you have a failing cell in one of the serially connected blocks of cells.
When these blocks are connected together in parallel they will try to normalize to the lowest voltage level.
If your handlebar controller is open to the elements I would seriously look to replace it if it can't be sealed again.
If it displays battery voltage level you could have a feed coming directly from the battery only protected by the main battery fuse which is far too highly rated for the fine wiring of the control cabling. If a short occurs in the control box serious damage could occur before the fuse blows.
This supply to drive the display really should be fused independently as a spur, especially for those who are thinking of putting on additional monitoring displays by tapping into this feed.

I would advise anyone with battery monitoring to trace the feed wire back and if there is no low current protection device to retro fit one.

Could you take a photo of the controls on your handlebar setup as I don't seem to be able to find any relating to the 2009 model on the web.
Does your model have lighting if so how is it turned on and off.

 

[z0mb13e]

I would expect the overall battery voltage to drop if you have a failing cell in one of the serially connected blocks of cells.
When these blocks are connected together in parallel they will try to normalize to the lowest voltage level.
If your handlebar controller is open to the elements I would seriously look to replace it if it can't be sealed again.
If it displays battery voltage level you could have a feed coming directly from the battery only protected by the main battery fuse which is far too highly rated for the fine wiring of the control cabling. If a short occurs in the control box serious damage could occur before the fuse blows.
This supply to drive the display really should be fused independently as a spur, especially for those who are thinking of putting on additional monitoring displays by tapping into this feed.

I would advise anyone with battery monitoring to trace the feed wire back and if there is no low current protection device to retro fit one.

Could you take a photo of the controls on your handlebar setup as I don't seem to be able to find any relating to the 2009 model on the web.
Does your model have lighting if so how is it turned on and off.

I don't have any photos handy but you can get a good idea from page 4 of the Wisper manual for the 2009 905 SE Sport. This bike has no built in road lights or display (other than the leds) or any electrical mods beyond the off-road button.

I should be able to reseal the power level selector box, I figured I would just tape it up as it only worked for the first few months and I've never really paid much attention to it so I don't really need it!

If the battery holds steady I will turn my attention to the controller... when I figure out how to physically remove it from the bike that is! (Even with all the access panels and connectors out of the way the box jams against the mounting brackets. The only thing left to remove is the connecting pins for the battery)

 

[shemozzle999]

I looked at the manual and from what I can see you have a standard type throttle with combined battery monitor/stop switch together with a separate illuminated power level selection unit, which you say operates intermittently.

The battery level leds should give a true reflection of the state battery voltage and will vary on and off when the real level exceeds or not the predetermined levels set for each led.

I think the controller may be OK as you have said you have occasionally had the bike running.

I would turn your attention to the power level selector box as I am guessing that it feeds the result of the button selection back to the controller, if the switches are sticking it could be sending back conflicting signals back to the controller, confusing it's operation, resulting in your problems.

I have a 705eco and was hoping it had the same system as yours so I could make some comparisons, but mine has a standalone throttle and a single control box containing all your other functions.

I would now contact Wisper support with your findings and see if they can offer further help as they have first hand knowledge of the system.

 

[z0mb13e]

Battery is now showing 41.3v (it has been switched on at the key and connected to a high resistance load (multimeter) all day).

41.5v to 41.3v in 14 hours doesn't sound too bad too me.

 

[z0mb13e]

Battery is now showing 41.3v (it has been switched on at the key and connected to a high resistance load (multimeter) all day).

41.5v to 41.3v in 14 hours doesn't sound too bad too me.

Another 10 hours or so and voltage is 41.1v

 

[flecc]

That looks good, just the BMS current drain and normal early stage settling.

So it looks like it's back to either a cell collapsing under applied load or a weak connection, bike or battery, also failing under load.