Wisper 705SE problems

[Howard Hill]

I recently bought a red step-over Wisper 705SE. I just noticed that at around 12-13mph and above the power starts to come and go every few seconds (power drop for a fraction of a second then surge back to normal). I can feel it and I can see the power loss on the current display. At first I thought it was just the 15.5mph threshold being reached, but it’s too erratic for that. The start assist throttle doesn’t stop this happening if activated and held on while pedalling. Any ideas?

 

[vfr400]

Has it always done it since you've had the bike, or are you saying that it's just started doing it?

There are a few versions of that bike. Which one do you have?

 

[Howard Hill]

Has it always done it since you've had the bike, or are you saying that it's just started doing it?

There are a few versions of that bike. Which one do you have?

The Wisper is a 705 SE step-through in red with 26” wheels and was bought new November 2018. It doesn’t have front suspension and the battery is horizontal on the rear rack. It has 7 speed Shimano derailleur gears and rear hub motor.

I bought it second hand on Thursday (4 days ago) but only noticed the problem the following day once back home. I suspect I didn’t test it fully when buying, but I can’t be sure. So maybe it was faulty when I bought it or maybe something happened while the bike was being taken home in my car. I wish I knew.

 

[Howard Hill]

I’ve just been out and waggled each cable/wire I could see and the bike is now performing to spec. My conclusion is that it took a hit of some sort during the 1.5 hour journey in the back of my car after purchase, even though I was very careful loading and unloading. Nothing was actually loose, so I don’t know which connection was the source of the problem, but I’m very happy it’s working.

Now for some cycling!

 

[vfr400]

Intermittent connections on an electric bike are very bad, not so much that they're annoying and difficult to find, but they can lead to serious consequential damage. The three things you should check are:
1. That the motor connector located near the motor inside or under the righthand chainstay is in ALL THE WAY TO THE MARKED LINE, not just in tight.
2. That there is no damage to the motor cable, especially where it comes out of the axle.
3. That any motor connectors at the controller end are tight. For that, you have to look inside the compartment at the front of the battery, which is where all the connectors normally are. You can check the others while you're there because any could cause your problem, but it's only the motor ones that can do damage.

Some Wisper versions don't have the motor main connector at the rear. Instead, it's somewhere near the controller so that they don't have to have additional connectors at the controller.

 

[Howard Hill]

Intermittent connections on an electric bike are very bad, not so much that they're annoying and difficult to find, but they can lead to serious consequential damage. The three things you should check are:
1. That the motor connector located near the motor inside or under the righthand chainstay is in ALL THE WAY TO THE MARKED LINE, not just in tight.
2. That there is no damage to the motor cable, especially where it comes out of the axle.
3. That any motor connectors at the controller end are tight. For that, you have to look inside the compartment at the front of the battery, which is where all the connectors normally are. You can check the others while you're there because any could cause your problem, but it's only the motor ones that can do damage.

Some Wisper versions don't have the motor main connector at the rear. Instead, it's somewhere near the controller so that they don't have to have additional connectors at the controller.

That's good advice. I'll be sure to check as you have advised. Many thanks!

 

[Llandudno Wisperer]

I have the same bike. To me it looks as if the motor is cutting out as it reaches near the top speed of 15mph when it should cut out. I'm sure David from Wisper will be able to help you. Get in touch if they don't answer on this post. In my opinion, their customer service is excellent.

 

[Howard Hill]

I have the same bike. To me it looks as if the motor is cutting out as it reaches near the top speed of 15mph when it should cut out. I'm sure David from Wisper will be able to help you. Get in touch if they don't answer on this post. In my opinion, their customer service is excellent.

Interesting. I did half suspect this (see my original post) but because it happened at various speeds above around 12mph (not just 15mph) then I thought maybe not. I’m wondering if the 15mph threshold varies with battery condition, load etc etc. In which case, that may be the answer. I would describe the effect as a kind of pulse (power drop/rise cycle). It behaves fine at lower speeds. I’m going to test and estimate the battery life next. Maybe it’s a bit knackered and struggles with high demand. Trouble is, new batteries ain’t available right now (I already asked Wisper).

 

[Tim@Wisper]

Hello,
feel free to contact us directly through support@wisperbikes.com if you have any further issues. we should be getting a stock batteries in soon. We have a large stock of 575 batteries.
All the best