Giant intermittent power loss

[atomicgreyhound]

Hi

I have a 2021 giant fathom 2 ebike with synch drive. Frustratingly as I pedal the power intermittently backs off. Its frequent and annoying as its rather hard to pedal as it happens. I cleaned the rear wheel sensor and magnet and I did a firm ware upgrade. No change. I suspect this has happened to others. I have no display screen so I don't get any fault codes. I figure I need to clean some contacts on the motor but need some help to confirm my next step. Many thanks, Paul, somerset, uk.

 

[TheEqualiser]

Are you sure you're not hitting the max speed cut off? Or just riding it on Auto which can sometimes feel a little jerky until you get used to it?

You should still get fault codes on the RideControl One:

 

[Coolbob]

@atomicgreyhound When you say backs off, does it quit abruptly or ease up over a period of time?

If the power assist fades away slowly, then it could be that you are slacking off on your peddling cadence. Giant/Momentum/Liv bikes are designed to be ride like a 'regular' bike that doesn't replace your effort, but adds assistance to your peddling efforts. Our legs operate more efficiently if we peddle at a medium/high cadence around 40-60 rpm and light/medium effort. If you peddle too slowly, and or with high effort, it's less efficient and harder on your knees and thighs. Giant bikes reward you with more assistance when your cadence is in the correct range, if your peddling slows down, the bike backs off on the assist, your cadence slows down more, the bike backs off more, etc. Shift to a lower gear if you need to and pick up the pace on your cadence and you will feel the bike perk up and help more.

If it's quitting abruptly, or if you are getting fault codes on your RideControl One then I'd recommend taking it to your local bike shop for diagnosis. If everything suddenly shuts off, including the RideControl One then your battery may be losing it's connection with the bike and Giant makes a shim kit to remedy that. If you're getting error codes, then the bike shop can use those codes to track down and repair the problem.

 

[atomicgreyhound]

@atomicgreyhound When you say backs off, does it quit abruptly or ease up over a period of time?

If the power assist fades away slowly, then it could be that you are slacking off on your peddling cadence. Giant/Momentum/Liv bikes are designed to be ride like a 'regular' bike that doesn't replace your effort, but adds assistance to your peddling efforts. Our legs operate more efficiently if we peddle at a medium/high cadence around 40-60 rpm and light/medium effort. If you peddle too slowly, and or with high effort, it's less efficient and harder on your knees and thighs. Giant bikes reward you with more assistance when your cadence is in the correct range, if your peddling slows down, the bike backs off on the assist, your cadence slows down more, the bike backs off more, etc. Shift to a lower gear if you need to and pick up the pace on your cadence and you will feel the bike perk up and help more.

If it's quitting abruptly, or if you are getting fault codes on your RideControl One then I'd recommend taking it to your local bike shop for diagnosis. If everything suddenly shuts off, including the RideControl One then your battery may be losing it's connection with the bike and Giant makes a shim kit to remedy that. If you're getting error codes, then the bike shop can use those codes to track down and repair the problem.

Ok.. Great responses which are appreciated. I'm certain something is wrong but also dont have fault codes. I've got time tomorrow to investigate. Maybe I need to tinker with the cadence setting on my app. It's definitely cutting out before 15 mph. I will update the forum soon if I work it out. Thanks

 

[rich c]

Check all connectors and especially the battery terminals. Does the interruptions have anything to do with bumps or rough terrain?

 

[tomjasz]

Check all connectors and especially the battery terminals. Does the interruptions have anything to do with bumps or rough terrain?

yup and what's the voltage doing?

 

[atomicgreyhound]

yup and what's the voltage doing?

Sorry.. Forgot to say its a abrupt loss of power. I've not spotted the display cutting out or any other side effects... Just need legs like swarznegger to make up the difference as it does it when I'm less than 15mph. Sadly it does it quite a lot.

 

[tomjasz]

Older battery? Voltages when dropping out?

 

[atomicgreyhound]

Older battery? Voltages when dropping out?

How do you see the voltages. I guess off my phone app? Cheers

 

[atomicgreyhound]

How do you see the voltages. I guess off my phone app? Cheers

I read the instructions to confirm I have no red light fault. I have noticed the light button is lit when I switch it on. I switch it off and it comes back on with the next power up.

I have always ridden the bike in manual mode. Tomorrow will try auto mode to see if its any different. I have attached a pici of my display when I switch it on. I recognise me battery is low on charge. Its charging up now.