Intermittent loss of power

[Kendodsdadsdog]

Hi, thanks for letting me join this excellent group. This is my first post so forgive me if I get some etiquette wrong.

I’m in my 60s and bought my Ebike about 8 years ago. Always been reasonably fit but spinal problems were preventing me from being able to get out of the saddle to cycle up hill. I bought a Haibike Sduro Hardseven, with Yamaha motor and it really helped.

I noticed a problem last year. Pedalling hard up hills the motor would suddenly cut-out for a second or so, then come back, then cut-out and so on. In the moments the motor loses power I notice the LCD display stops displaying speed. This only happens when I’m pedalling hard, up hill.

The place I bought the bike from has changed hands, I did call a couple of times and was told the tech-guy would contact me, but this never happened and they didn’t seem that interested.

Would anyone be able to point me in the right direction. I can’t believe I’m the only ebiker with this problem.

Thanks in advance

 

[fooferdoggie]

thats often a bad battery connection. one thing I use is this stuff on all my terminals

https://www.amazon.com/gp/product/B000P1C8UO/ref=ox_sc_saved_image_5?smid=A363BFUBCLUQU5&psc=1

 

[PSm]

Hi, thanks for letting me join this excellent group. This is my first post so forgive me if I get some etiquette wrong.

I’m in my 60s and bought my Ebike about 8 years ago. Always been reasonably fit but spinal problems were preventing me from being able to get out of the saddle to cycle up hill. I bought a Haibike Sduro Hardseven, with Yamaha motor and it really helped.

I noticed a problem last year. Pedalling hard up hills the motor would suddenly cut-out for a second or so, then come back, then cut-out and so on. In the moments the motor loses power I notice the LCD display stops displaying speed. This only happens when I’m pedalling hard, up hill.

The place I bought the bike from has changed hands, I did call a couple of times and was told the tech-guy would contact me, but this never happened and they didn’t seem that interested.

Would anyone be able to point me in the right direction. I can’t believe I’m the only ebiker with this problem.

Thanks in advance

Another possibility is that it’s “voltage lag.” For all of my e-bikes (3 each different brands), if I’m under very heavy load and the battery has been drained a bit, I had the power cut out due to a voltage drop under load. This is a fairly “normal” thing, depending on the model, power output, battery charge, and the capability of the controller. Could be getting some overheating, which could cause a dropout in power, until cooling back down.

If my battery is not drained to the lower range, and I choose a lower motor assist level, I typically never have that problem.

 

[Stefan Mikes]

Could be getting some overheating, which could cause a dropout in power, until cooling back down.

The same thought here. It could be the thermal protection of the motor taking its action.

 

[fooferdoggie]

How much effort does it take to overheat the motor? I had to hit 520 watts on my bosch just to hit the limit of what the motor could do. thats a lot of effort.

 

[Stefan Mikes]

How much effort does it take to overheat the motor? I had to hit 520 watts on my bosch just to hit the limit of what the motor could do. thats a lot of effort.

Is it the electrical or mechanical power?

I am in the convenient position to be able to measure the motor and battery temperature in my Specialized e-bikes. It is very easy to get at 60 C (140 F) in my e-bikes, especially at the maximum assistance and in the summer. My app classifies it as the "yellow card" situation. I had never measured the motor temperature at my extreme climbs (no time or inclination to do it), and the thermal protection on my stronger e-bike has never needed to kick in.

However, the thermal build-up takes time. If you climbed for several miles with a small chainring and big cassette cog in maximum assistance, the motor temperature could build up really high. We had several reports of EBR users about the intermittent power loss; it was often related to long climbs in "Turbo".

Now, you know it is doable to fry a hub motor on a significant climb. Mid-motors are bigger and can dissipate the heat easier; they have the thermal protection as well. I do not say it must be the overheat in the OP situation but it could be the reason.

 

[fooferdoggie]

I almost never use turbo on my bike. we use it on the tandem on steep climbs but we are both going at it too.
when i said 520 watts thats me thats what it takes to max out the performance speed gen 4 motor about 450 on the gen 2 motor. but thats only for a block or two at a time about all I can manage. buti t takes a steep ass hill to get to that level. or maybe going 28 on eco mode.

 

[PSm]

Is it the electrical or mechanical power?

I am in the convenient position to be able to measure the motor and battery temperature in my Specialized e-bikes. It is very easy to get at 60 C (140 F) in my e-bikes, especially at the maximum assistance and in the summer. My app classifies it as the "yellow card" situation. I had never measured the motor temperature at my extreme climbs (no time or inclination to do it), and the thermal protection on my stronger e-bike has never needed to kick in.

However, the thermal build-up takes time. If you climbed for several miles with a small chainring and big cassette cog in maximum assistance, the motor temperature could build up really high. We had several reports of EBR users about the intermittent power loss; it was often related to long climbs in "Turbo".

Now, you know it is doable to fry a hub motor on a significant climb. Mid-motors are bigger and can dissipate the heat easier; they have the thermal protection as well. I do not say it must be the overheat in the OP situation but it could be the reason.

I do a lot of climbing, and have gone up some really extreme grades, so have seen the problem with all three of my e-bikes (all different makes and models, 250, 350 and 500 watts peak power output). All depends on % grade, length of hill, duration and intensity of climbing, gearing, and specific motor & controller.

Didn’t happen that often, and rarely happens now that I’m in better shape and generally use much lower assist levels. If my battery is nearly drained, that’s a different story.

Then again, as mentioned, there could always be electrical issues, connector or wiring problems, too. Years ago, I had a wire shorting and failing.

 

[rich c]

You should definitely get some contact cleaner and clean all you can get at with an 8 year old eBike. Do you store the bike in a garage or house? Stored in a damp area would make the contact corrosion worse. There is no voltage sag in the Bosch Haibikes, but can't say for sure about the Yamahas.