Wisper 905se. Quick or slow?

[dickndoris]

I have had my Wisper now since June/July and overall I’m pleased with it but recently it is getting a little slow. I do a minimum of 30 miles most days and up to 45miles on a pleasant day. It did used to go at the 19mph that is quoted in the specs (19.5mph in specs) but now I’m lucky if I can get 17mph out of it and that’s with a gentle pedal. This is all with the throttle and derestricted button. Does anyone know of any testing I can do on the speed controller or battery pack? That 2-3 mph is missed.

It will sit at 15mph all day long in pedal assist that’s with the pot turned fully that is in the little compartment. I rarely just use the throttle only its nearly always helped along with my chicken George legsJ

I have checked with all six of my GPS’s and my flight computer along with the Speedo that all read the same within .5 mph so I reckon pretty accurate.

Any ideas would be appreciated.

I weigh in at 11stone and 5’11 so not too heavy, with the panniers when going to work around 10-15kg max. It’s all lubricated with free running wheels and all brakes free from any binding, tyre pressure at 60psi.

 

[frank9755]

That's about the speed my Wisper goes at when unrestricted - 15 mph pedelec and 17-18 with throttle and moderate pedal effort. It gives some assist perhaps to 19 mph but beyond that the rider is doing the work.

 

[the_killjoy]

I agree, even with deristrict I think you will be unlikely to get any assistance beyond about 17 mph. I get the impression from the postings that the latest batch of which mine is (july on) are a little slower than the previous shipments.

It would be interesting if any one quoting a top speed said how old the bike is.

 

[dodgyal]

I expected that 17-18 was what this bike would be capable of with my weight (110kg) and assistance, the 19.5 quoted is with a 70kg person.

Are you sure that the sweet spot on your battery has now leveled to what you should have been getting in the first place?

Put a 70kg person on it and see what it does!

 

[flecc]

Put a 70kg person on it and see what it does!

Whoops! Dickndoris at 11 stones is exactly 70 kilos.
.

 

[dickndoris]

Depending how much red wine and curry, I am 70-75kg wet ie out of the shower
Doug at Wisper bikes is on the case so we will see if anything can be done. Will keep you all upto date. Thanks for the replies so far.

Rich

 

[The Maestro]

If they are using the Bafang motor designed for a 26" wheel it will give 16ish on throttle and assist up to about 18. Motor will spin up to 19.5 unloaded i.e. wheel in the air but won't give any meaningful assistance in the real world above around 18. This is my experience on a number of similarly set up bikes.

 

[Mandy]

I have had my Wisper now since June/July and overall I’m pleased with it but recently it is getting a little slow. I do a minimum of 30 miles most days and up to 45miles on a pleasant day. It did used to go at the 19mph that is quoted in the specs (19.5mph in specs) but now I’m lucky if I can get 17mph out of it and that’s with a gentle pedal. This is all with the throttle and derestricted button. Does anyone know of any testing I can do on the speed controller or battery pack? That 2-3 mph is missed.

It will sit at 15mph all day long in pedal assist that’s with the pot turned fully that is in the little compartment. I rarely just use the throttle only its nearly always helped along with my chicken George legsJ

I have checked with all six of my GPS’s and my flight computer along with the Speedo that all read the same within .5 mph so I reckon pretty accurate.

Any ideas would be appreciated.

I weigh in at 11stone and 5’11 so not too heavy, with the panniers when going to work around 10-15kg max. It’s all lubricated with free running wheels and all brakes free from any binding, tyre pressure at 60psi.

Hi There Dickndoris

I think it is funny you should say this as I thought I may be going a little mad
I love my Wisper bought from Germany in January but I am convinced it has got a little slower? Don't get me wrong I love the bike and have had the same cycle computer since February but over the last couple of weeks I don't seem to be getting the same speeds?
I was easily doing 17 to 18 on power only and over 20 with pedelec.
I am now losing around 2mph over all pedelec and motor.
As I have the German Bike I thought I had knocked the red button which changes it from restrict to de-restrict but I haven't so I don't know why this has happened but I can definitely feel the power has decreased a bit as opposed to what it used to do when handling the bike.
Don't get me wrong as I still love my Wisper but I am a little puzzled by this as it is effecting my journey time too and from work a little?
Any ideas why this may happen? I have had it approx 7 months.
I am a little over 8 stone but carry a heavy handbag weighing 2 stone (only kidding)

Regards

 

[Mandy]

Are you sure that the sweet spot on your battery has now leveled to what you should have been getting in the first place?

Put a 70kg person on it and see what it does!

Hi Dodgyal

Excuse my ignorance but what is a sweet spot on the battery? It isn't so sweet if it go's slower
Is it like it gets run in like a car engine? But that would be a motor in this case wouldn't it
I confess I don't know a lot about batteies apart from how to charge them? lol.
My old Powabyke was consistent (consistently slower than the Wisper) But it never wavered on power although that was a L acid battery I guess.

Regards

 

[Blew it]

Natural ageing?

It's a demonstrated fact that large capacity lithium batteries are more able to maintain a constant voltage under maximum demand than smaller arrays. Is it possible that the ageing process of your batteries is allowing the open contact voltage to sag under maximum demand enough to lower your maximum speed?.

This reduction in capacity might not readily show in the demonstrated range, unless you run the machine to low voltage cutout.

To give you an idea, today, when returning from a ride, I took the quick route home along the northern section of route 45. This route is on the old permanent way with a gentle upslope. It's 1.5 miles long but I easily held my new Wisper 905 at a constant 19.5 MPH with reasonable input on the pedals.

The ultimate speed that any machine can achieve is a correlation of several factors:

The motor coil windings
The internal gearing of the hub motor
The open contact voltage of the battery under load
The wheel diameter

The slightest change to any of these parameters will result in an equal change of the maximum speed possible. Only two of these parameters are likely to change.

The open contact voltage of the battery when under maximum demand.
The wheel diameter.

The latter is unlikely, which brings us back to the ability of an ageing battery to hold it's working voltage under maximum amps demand at the same value as it did when new.

hope this makes sense

Bob

 

[dickndoris]

No idea yet Mandy.
Doug at Wisper would like me to send the bike back for tests but me been in York and Wisper down south and no packing box sounds like a pain to do but we will see Might be a day out in car wi whippet n flat cap t see Queen.

Rich

 

[Rod Tibbs]

Gawd! What is open contact voltage and when does it occur? I have a Mistral and everything you are saying about the Whisper seems to apply to that. I think both are 36 volt systems.

 

[the_killjoy]

dickanddoris

I look forward to hearing the outcome of Doug's investigation as my bike is the same.

When I recieved it the restrict/destrict was about 12/17 mph. I have adjusted the resricted screw so I now get 17 on both so that I don't have to worry about whether I have pressed the button ~ but would have liked another couple of miles per hour.

 

[The Maestro]

I'm pretty sure that the 19.5 mph quoted by Wisper will be the no load maximum (i.e. wheel lifted in the air). As far as i'm aware its a Bafang motor internally geared for 26" wheel with a 36V battery. I see no reason why it would go faster on a Wisper than every other bike that uses this set-up. Some people are saying that they get over 20 though so maybe I'm wrong but I suspect their cycle computers are wrongly calibrated.

 

[frank9755]

Guys,

I don't think there is anything wrong with your Wispers or their batteries - they are going at the speed that they are geared to operate at. Have a look at this thread where Stuart (Coops) and I compared riding speeds and unloaded max speeds of Wisper and Torq 1. It became clear that the Torq was quite a lot more highly geared (helping to explain why the Wisper is slower but better on hills and range).

Others seem to be getting the same speeds as I get now and was getting back in February when my battery was pretty new.

Frank

 

[dickndoris]

Cheers Frank9755 interesting reading.
If I pedal real hard, like real real leg burning hard I get 20mph with or without motor. in fact it is easier with the motor switched off as it seems to have less drag. It seems Doug at Wisper seems to think it is ilegal to sell a higher power motor?! OPTIBIKE!! I will get the Wisper bike sorted out and then build my own as the bike I would like is real expensive. Could be a good winter project. 500w motor 48v li?? brakes that work;-) I know , I know its ilegal--on the road!;-)