Crank

[ian slater]

Evening
Not sure if anyone might know what i could try next to resolve problem with my carrera vengeance e bike.I have had brand new display,brand new ecu,brand new battery holder,brand new crank sensor,tried a couple of working back wheels but problem still persists.Whats happening is i'm not getting full pedal assist,as i pedal the motor kicks in but for only a second or two.The only thing not tried which going to try tomorrow is remove crank to inspect magnets.Does anyone think this could be the problem or can anyone suggest what else i can try that i haven't alredy tried.
Thank you

 

[saneagle]

Evening
Not sure if anyone might know what i could try next to resolve problem with my carrera vengeance e bike.I have had brand new display,brand new ecu,brand new battery holder,brand new crank sensor,tried a couple of working back wheels but problem still persists.Whats happening is i'm not getting full pedal assist,as i pedal the motor kicks in but for only a second or two.The only thing not tried which going to try tomorrow is remove crank to inspect magnets.Does anyone think this could be the problem or can anyone suggest what else i can try that i haven't alredy tried.
Thank you

Normally, that happens when you have the incorrect speed sensor in the motor or the wrong setting for the speed sensor in the LCD. You haven't told us what stuff you have, so I can't help beyond that other than to suggest you change the number of magnets from 1 to 6 in the speed sensor setting.

 

[guerney]

Whats happening is i'm not getting full pedal assist,as i pedal the motor kicks in but for only a second or two.

That's what happened the other day uphill, when I was running down my battery to as low as possible, for a balance charge (subsequently charged to 42.1V, according to my reasonably accurate...

https://www.pedelecs.co.uk/forum/threads/checking-multimeter-calibration-at-home.45965/

... Neoteck DMM). Low voltage cutoff on my controller is 31V, pedal assist ceased then resumed for about a second or so when voltage recovered, ceased then recovered again etc. I had to switch off the "7800" Lumen lights I've soldered to my battery, to climb the hill to get to my uphill home.

brand new battery holder

Just a new holder, no new battery? I'm not suggesting you buy a new battery, but if appropriate, one of the battery boffins might perhaps suggest a check.

 

[ian slater]

Morning
I didn't need new battery,had it checked and was getting 39v so said that was fin,thank you for reply
Regards
Ian

 

[ian slater]

Normally, that happens when you have the incorrect speed sensor in the motor or the wrong setting for the speed sensor in the LCD. You haven't told us what stuff you have, so I can't help beyond that other than to suggest you change the number of magnets from 1 to 6 in the speed sensor setting.

Morning
I have just replaced everything like for like on original parts,i read that there has to be a 1mm-2mm gap between sensor and magnet.Just don't understand why anything in crank itself would have moved to disrupt this,thank you for reply
Regards
Ian

 

[Benjahmin]

If your 36v battery is coming off the charger at 39v then it is pluckered. A good 36v battery should be charging to 41.6/7v.
Charge the battery, when it has finished let it rest for around 10 minutes then measure the voltage.
You seem to have taken the very expensive route of replaceing parts on a theory without testing first. You need to say what kit it is that you have, with photos if poss.

 

[Ghost1951]

If your 36v battery is coming off the charger at 39v then it is pluckered. A good 36v battery should be charging to 41.6/7v.
Charge the battery, when it has finished let it rest for around 10 minutes then measure the voltage.

The battery is certainly not right, but not necessarily terminal.

Sometimes the serial connected cell groups get out of balance and charging is curtailed by one or more cell groups reaching 4.2 volts well before the others.

I am wondering if the bike has been left in a garage or shed for several months. The first winter I had mine, I checked the overall voltage about once a month and it was around 38 volts. What I had not realised was that one group had slipped down well below that, and when I came to use it in the better weather, it charged up (so I thought, because the red light went out) and then it shut down after being ridden two or three miles. One cell group was very low and was not being charged because others reached the terminating charge voltage of 4.2v, and the charger shut off while the dodgy group was still nearly empty.

The solution for me was to open the pack and measure all the cell group voltages.

I found the low group and soldered a red and blue wire to the positive and negative ends of the low group, and then charge that group up over a long period with a small lithium charger. It took a good while, best part of a day with the small slow charger, but two or more years later,I can still get 40 miles out of that 13Ahr pack. That groups still tries to go lower than the others unless I balance charge it now and then, but it works - Apollo 13 style (I have to manage it a bit).

If it is true that the battery came off charge at 39 volts, I would recommend charging it, then opening the battery case and measuring and recording the voltage of each cell group to see if it is badly out of balance.

However - saneagle's point has not been addressed by the OP. Has he changed the settings for number of magnets in the pedal sensor setup? I think on some bikes, button presses can get you into a programming condition and settings can be changed accidentally.

 

[flecc]

Ian's bike and battery are six years old if he's never replaced the battery, so that would be the first thing I'd suspect in this case. Very few pedelec batteries get to that age still working at all.
.

 

[ian slater]

The battery is certainly not right, but not necessarily terminal.

Sometimes the serial connected cell groups get out of balance and charging is curtailed by one or more cell groups reaching 4.2 volts well before the others.

I am wondering if the bike has been left in a garage or shed for several months. The first winter I had mine, I checked the overall voltage about once a month and it was around 38 volts. What I had not realised was that one group had slipped down well below that, and when I came to use it in the better weather, it charged up (so I thought, because the red light went out) and then it shut down after being ridden two or three miles. One cell group was very low and was not being charged because others reached the terminating charge voltage of 4.2v, and the charger shut off while the dodgy group was still nearly empty.

The solution for me was to open the pack and measure all the cell group voltages.

I found the low group and soldered a red and blue wire to the positive and negative ends of the low group, and then charge that group up over a long period with a small lithium charger. It took a good while, best part of a day with the small slow charger, but two or more years later,I can still get 40 miles out of that 13Ahr pack. That groups still tries to go lower than the others unless I balance charge it now and then, but it works - Apollo 13 style (I have to manage it a bit).

If it is true that the battery came off charge at 39 volts, I would recommend charging it, then opening the battery case and measuring and recording the voltage of each cell group to see if it is badly out of balance.

However - saneagle's point has not been addressed by the OP. Has he changed the settings for number of magnets in the pedal sensor setup? I think on some bikes, button presses can get you into a programming condition and settings can be changed accidentally.

Morning
Thank you for a positive response and am now starting to think it does point to battery thats the problem and the only component i have'nt replaced
Regards
Ian

 

[ian slater]

Ian's bike and battery are six years old if he's never replaced the battery, so that would be the first thing I'd suspect in this case. Very few pedelec batteries get to that age still working at all.
.

Morning
Thank you for sending reply and am thinking you are correct in what your saying,with it being the only part i have'nt replaced it's got a chance ofbeing the battery
Regards
Ian

 

[Ghost1951]

Morning
Thank you for a positive response and am now starting to think it does point to battery thats the problem and the only component i have'nt replaced
Regards
Ian

Test the battery rather than replacing it Ian. I assume you have a multi meter. Mine are the cheapest and most used tools in my collection. I keep one in the car so I have one wherever I am. Last used it on Saturday when one of my sons found his car was shutting down when the air con was on. He had a dodgy bad earth connection on the car battery and when the alternator could not supply the roaring aircon and the ecu, the car just shut down. How the car ever started I do not know, but there we are.

 

[sjpt]

Very few pedelec batteries get to that age still working at all.

My limited experience of two is that the Bosch one (8 years) and HL/Samsung/Woosh one (6 years) were still working fine but with significantly reduced capacity (???60%??? guestimate) and a bit more voltage sag.

 

[ian slater]

Hi
Yes i will test the battery first,if it is not firing on all cylinders as they say can i do anything to get it back up to the 42v it should be at
Thank you

 

[Ghost1951]

IF it is out of balance, you can do something about it. I explained what I did in my post above this morning.

It is also true that the battery is quite old, so it may just be done in. IF YOU ARE CONFIDENT in your ability to safely open the battery and measure the cell group voltages, it will cost you nothing to do that. It might just save you some money, but the battery is old and could need replacement. Mine is just an idea to test that might save you spending any more money right now.

There is another way to re-establish balance in the cell groups. It involves lowering the voltage of the high groups by putting a sensible load on them to drain them down to the same voltage as the low group, or groups. People sometimes use high wattage security light bulbs with leads soldered onto them. Since my problem was just one group being low and all the others being near as dammit at 4.2, I charged up my low group with a small wall wart type single cell lithium charger.

 

[ian slater]

Hi
Not that confident in doing as you suggested but have a electric/mechanical maintenance person where i work so will take battery in tomorrow for him to look at
Thank you

 

[Ghost1951]

Ask him to measure and record the voltage of each parallel cell group. He will probably need to lift the capton tape so he can get at the nickle strips.

Good luck. It is worth a try. They should all be about the same voltage. Any big deviation is indicative of being badly out of balance which could give the symptom you described.

 

[guerney]

The reason why I was running down the voltage of my battery to low cutoff, was because I'd not used my bike for over 2 months - had kept it at 35V, and was concerned that some variation in cell chemistry had resulted in a lower fully charged voltage than normal, which had always more than 42V, not just 42V. Plan worked. Whatever the diferences were, they weren't large enough to stop the BMS doing a full balance charge.

Hi
Not that confident in doing as you suggested but have a electric/mechanical maintenance person where i work so will take battery in tomorrow for him to look at
Thank you

Hope that maintenance guy knows his stuff. The last time I measured cell bank voltages, unlike this dude, I measured at the tiny connector peering at needle probes through a big illuminated magnifying glass.

 

[ian slater]

Hi
Would like to thank all those who have messaged and offered their support in me trying to sort problem with my bike and the battery issue seems the obvious error.One last question,if i am getting the 39v instead of 42v out my 36v battery this can be fixed rather than new battery
Thank you
Ian

 

[saneagle]

Hi
Would like to thank all those who have messaged and offered their support in me trying to sort problem with my bike and the battery issue seems the obvious error.One last question,if i am getting the 39v instead of 42v out my 36v battery this can be fixed rather than new battery
Thank you
Ian

Try leaving it on charge for several hours after the green light and see if it improves. If it does improve, keep doing it until it maxes out, hopefully at 42.0v, which is what it should be. If it doesn't improve from 39v, it's knackered, but don't forget to measure the voltage on your charger jack in case it's a charger problem.

 

[ian slater]

Yes will do,my battery has 4 blue lights so should i continue past the max 4 blue lights while on charge