# Carrera crosscity pedal assist fault



## Rhysr123 (22 Apr 2022)

Hi I have a carrera cross city pedal assis bike. When I get on it turns on but the assist won’t kick in and the mode light is flashing on high power it I’ve tried taking the battery out and cleaning the ports still not working. I’m clueless with electrics anyone have any advice please. Thanks


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## ebikeerwidnes (23 Apr 2022)

Try the walk assist - if that works then it is basically OK

Also - on ours I have noticed that it is easy to bend the connectors that link the rear part of teh frame to the battery in the front part as the bike is folded
check they look OK

Finally - is it new - if it is still under guarantee take it back to the shop. If there is a battery or motor fault it could be expensive to fix and you need to get the shop to acknowledge the fault as soon as possible


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## classic33 (24 Apr 2022)

Manual available here
https://www.manualslib.com/manual/2138210/Carrera-Crosscity-E.html

For their e-assist bike. As far as I'm aware they don't do pedal assist bicycles.


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## ebikeerwidnes (24 Apr 2022)

classic33 said:


> Manual available here
> https://www.manualslib.com/manual/2138210/Carrera-Crosscity-E.html
> 
> For their e-assist bike. As far as I'm aware they don't do pedal assist bicycles.



that bike is pedal assist
if you pedal it assists you


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## classic33 (24 Apr 2022)

ebikeerwidnes said:


> that bike is pedal assist
> if you pedal it assists you


Don't pedal and you go nowhere, unless going downhill.


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## Rusty Nails (8 Jun 2022)

Just as an aside, I volunteer at a community bike workshop where we renovate donated bikes and sell them on.

Last week a couple came in and donated two Crosscity E bikes. They look like new but the couple said they have been unused for a couple of years and the batteries are dead. The boss is not sure whether to try to fix them or de-electrify them and sell them as manual bikes.


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## ebikeerwidnes (9 Jun 2022)

Rusty Nails said:


> Just as an aside, I volunteer at a community bike workshop where we renovate donated bikes and sell them on.
> 
> Last week a couple came in and donated two Crosscity E bikes. They look like new but the couple said they have been unused for a couple of years and the batteries are dead. The boss is not sure whether to try to fix them or de-electrify them and sell them as manual bikes.



See if you can borrow a battery from someone and see if they work
Less work and more value if you can sell them as working ebikes - although the batteries are expensive

I presume you don;t live near me (widnes) but if you do then I would help out to see if they work


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## Rusty Nails (9 Jun 2022)

ebikeerwidnes said:


> See if you can borrow a battery from someone and see if they work
> Less work and more value if you can sell them as working ebikes - although the batteries are expensive
> 
> I presume you don;t live near me (widnes) but if you do then I would help out to see if they work



No. Down in Cardiff, but thanks.

I understand there are companies that will renew old batteries, but I don't know how effective this is as a solution.


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## ebikeerwidnes (9 Jun 2022)

That would work well - I did it to mine on my old bike and recently on my wife's crosscity

only problem if that it costs - so you really need to be sure the rest of the bike works before you do it

As far as I can see there are , on mine which is the old bafang motor system, there are 2 simple connections from the battery into the rest of the bike - does anyone know enough to know if you could attach a different battery to the system using a couple of wires
Just to test the motor actually turns the wheels


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## Rusty Nails (9 Jun 2022)

ebikeerwidnes said:


> That would work well - I did it to mine on my old bike and recently on my wife's crosscity
> Only problem is that it costs - so you really need to be sure the rest of the bike works before you do it
> As far as I can see there are , on mine which is the old bafang motor system, there are 2 simple connections from the battery into the rest of the bike - *does anyone know enough to know if you could attach a different battery to the system using a couple of wires*
> Just to test the motor actually turns the wheels



That is something we will be looking at.


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## bonzobanana (10 Jun 2022)

Cadence sensors can give issues, move out of position or the cable can have poor connections etc. That is probably the first thing to look at as its one of the mechanical aspects of the bike. There are also fuses I'm sure in the battery and components in the controller that can fail like the mosfets. Normally the wheel will do something if its given power so its more likely to be a fault prior to that. 

I think the Crosscity is a fully open non-proprietary ebike system however the battery fitting inside the downtube of the frame makes it difficult to replace at a reasonable price but presumably if you didn't mind a battery on a rear rack or somewhere else you could fit a cheaper battery. It's 313Wh. You could probably pick up a plastic wrapped battery to the same spec for less than £90 delivered on aliexpress but the official replacement battery probably costs over £200 maybe £300 or more.

A quick look shows a 36V battery pack capable of 20A output, not quite the same overall capacity but small enough to fit into a saddle bag and provides 245Wh at about £60 delivered. The 36V 6800mAh battery.

https://www.aliexpress.com/item/4001009534335.html

How long do batteries last without any charge at all. Normally they protect themselves so won't discharge beyond 20% capacity and that 20% capacity will take many months to fully discharge and end up destroying the cells I would estimate 9 months to perhaps 18 months but always worth trying to recharge the pack at any point. Bosch batteries self-brick, as the battery becomes discharged as soon as the BMS has too low a voltage the BMS will stop working permanently as a protection method for their highly proprietary batteries, this prevents you changing the cells yourself or re-using the BMS so those batteries can self-brick very easily perhaps in 6 months or more of not being charged. Of course Bosch batteries are extremely expensive for their capacity. The only good thing is the BMS dies long before the cells so if you catch it at the right time you can strip the battery pack of the cells to use in another non-proprietary ebike battery pack and the Bosch battery packs always use good cells.

Also batteries with bluetooth circuits. The bluetooth circuit is permanently enabled so this creates a additional drain that can kill the battery in a shorter period of time perhaps 3 to 6 months. It needs a tiny amount of current but on for 24/7 it will kill a battery.


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