How many miles left in the battery?

[Bigbee]

Can any electric bike tell you how many miles are left in the battery?It would be far better than just having the lights go out one by one.I mean like a modern car informs you how many miles are left with the present amount of petrol

 

[Mussels]

You know how innacurate a car trip computer is, couple that with it being harder to measure energy left in a battery than the volume of petrol and it will be incredibly vague.
That said you can probably buy an add on if you really want it.

 

[flecc]

Batteries are chemical devices so it's impossible to accurately measure their content electrically. Our battery meters measure the voltage and as is declines they roughly equate that to how much is left. That isn't remotely accurate enough to give mileage left.

Devices like the Cycle Analyst measure the usage and from that can give predictions for subsequent trips, but that isn't measuring the content of course.

If we ever get fuel cells instead of batteries we will be able to do it like cars, because we'll be dealing with fuel volume.
.

 

[Bigbee]

Ok thanks.I borrowed an e-bike for the Weekend and picked it up with only one light out of four lit.I did not know how many miles were left in the tank so only rode it for a bit near to my house in case it ran out.The last light eventually started flashing at me so I turned for home on eco mode immediatley!I assume the flashing light means the battery is nearly flat?

 

[flecc]

That's correct. You'd picked it up with only around one fifth charge so it quickly diminished to the warning flashing, indication thaat cut out could be imminent.
.

 

[joab]

Cycle Analyst

The cycle analyst will give you a good indication how much is left in the battery.

Regards,
Jo

 

[Patrick]

If we ever get fuel cells instead of batteries we will be able to do it like cars, because we'll be dealing with fuel volume.

But even if a system knew exactly how much energy was available for the motor it would still be unable to predict accurately how many miles are left without also taking into account things like how hard you will pedal and what hills you'll be riding over. If it tried to make a prediction without that info then you could end up with a number of miles that's almost as arbitrary as the number of lights showing on a battery meter.

 

[flecc]

Quite right Patrick, but of course the same applies to cars, so the result would still be comparable in answer to Bigbee's above inquiry using cars as an example. How I drive a car can easily make a 30% or more difference to mpg.
.

 

[Patrick]

Can any electric bike tell you how many miles are left in the battery?It would be far better than just having the lights go out one by one.I mean like a modern car informs you how many miles are left with the present amount of petrol

I just found out in the latest edition of A-to-B magazone that a German company, Daum http://www.daum-electronic.de , makes bikes which tell you how many miles are left in your batery, as well as lots of other things.

Here are the features of their premium dashboard according to their Pedelec Catalouge

Dashboard functions

• 3.7“ grey scale display with backlight and brightness sensor
• Card slot for SD card, integrated SD/SDHC memory card reader
• Interference free digital heart rate receiver
• Integrated buzzer
• Storage of the heart rate, speed, distance and travel time on the SD card
• Incline adjusted pedalling assistance
• Barometric height measurement
• GSM module with GPS for enhanced documentation of biking tours, transmission of position data via SMS or internet (requires SIM card)
• Theft protection per SMS notification (requires SIM card)
• Gear recommendation for optimal travel range
• Software update via SD card

Dashboard display values

• Assistance mode
• Display of remaining battery charge
• Speed
• Average speed
• Maximum speed
• Trip distance
• Total trip distance
• Daily travel time
• Total travel time
• Clock
• Date
• Heart rate (requires chest belt)
• Average heart rate (requires chest belt)
• Temperature
• Incline
• Height above sea level
• Gear recommendation
• GPS coordinates

 

[Bigbee]

It shows how much charge is left in your battery,which is different and fairly common on most current ebikes.Its their own central crank motor,made in Germany,interesting.I wonder how much one of these babies is gonna cost?

 

[flecc]

It shows how much charge is left in your battery,which is different and fairly common on most current ebikes.

And as I've remarked above, this sort of measurement isn't accurate, chemical capacity cannot be measured electrically in a simple fashion.

At least the Daum e-bike has at last got gradient sensing to vary power according to the climb steepness, something I've been suggesting for years would be an advantage for both economy and hill climb reasons. One Chinese e-bike manufacturer also claim to be developing a bike with this but I've seen no evidence of it yet.
.

 

[daniel.weck]

That looks like a nice machine (I have my reservations about the gigantic electronic display, but I could live with it...).

I wonder why the battery is so big, given that it's not LiFePo4 (500 charging cycles only) and not very high capacity either (9.5 Ah, 36 Volt). As a result, it has to be attached on the rack which raises the center of gravity (yet the frame seems to have been designed with extra space behind the seat post / above the crank unit).

I just found out in the latest edition of A-to-B magazone that a German company, Daum http://www.daum-electronic.de , makes bikes which tell you how many miles are left in your batery, as well as lots of other things.

Here are the features of their premium dashboard according to their Pedelec Catalouge

Dashboard functions

• 3.7“ grey scale display with backlight and brightness sensor
• Card slot for SD card, integrated SD/SDHC memory card reader
• Interference free digital heart rate receiver
• Integrated buzzer
• Storage of the heart rate, speed, distance and travel time on the SD card
• Incline adjusted pedalling assistance
• Barometric height measurement
• GSM module with GPS for enhanced documentation of biking tours, transmission of position data via SMS or internet (requires SIM card)
• Theft protection per SMS notification (requires SIM card)
• Gear recommendation for optimal travel range
• Software update via SD card

Dashboard display values

• Assistance mode
• Display of remaining battery charge
• Speed
• Average speed
• Maximum speed
• Trip distance
• Total trip distance
• Daily travel time
• Total travel time
• Clock
• Date
• Heart rate (requires chest belt)
• Average heart rate (requires chest belt)
• Temperature
• Incline
• Height above sea level
• Gear recommendation
• GPS coordinates

 

[daniel.weck]

At least the Daum e-bike has at last got gradient sensing to vary power according to the climb steepness, something I've been suggesting for years would be an advantage for both economy and hill climb reasons. One Chinese e-bike manufacturer also claim to be developing a bike with this but I've seen no evidence of it yet.
.

Wow, crank torque sensor + tilt sensor ! This must feel so great to ride ! I wonder about the price.

 

[flecc]

Wow, crank torque sensor + tilt sensor ! This must feel so great to ride ! I wonder about the price.

I nearly included gradient sensing in my Q-bike design, but it's so powerful a hill climber* I didn't bother in the end. I still hope to see it commonly on the better commercial hub motor e-bikes one day.

*Standing start on 1 in 7 (14%) without any pedalling and 9 mph climbing 14%.
.

 

[Velospeed]

Daum pedelecs

Hi all

Rather late to this party, but just to let you know that we'll be showing the Daum Pedelecs range at Presteigne next weekend - 8/9 May 2010. We're the UK importer and are launching the bikes on the UK market. We're really very impressed by them but you must come and see for yourselves, if you can make it to the event.

Cheers
John

Velospeed

 

[Geebee]

This one is I suspect a lot cheaper, is accurate and will give you a very good idea (much more so than the average E-bike gauge) of how much power you have used and thus how much is left.
HobbyKing Online R/C Hobby Store : Turnigy Watt Meter and power Analyzer $23.95

Spec.
Operating voltage: 4.8~60V (0V with optional auxiliary battery)
Measures;
0~130A, resolution 0.01A
0~60V, resolution 0.01V
0~6554W, resolution 0.1W
0~65Ah, resolution 0.001Ah
0~6554Wh, resolution 0.1Wh
Screen: 16x2, backlit LCD display
Size: 85x42x25mm
Weight: 82g

 

[lemmy]

I've found with my Kalkhoff that experience in conjunction with a trip computer tells me how much juice the battery has left just as accurately as any meter could.

This is helped by the fact that I generally know the route I will be taking and the old grey matter makes allowances automatically. If I don't know the route, the grey matter can't predict - but neither can a meter. A look at a map would help, though.

 

[flecc]

That's my method too Lemmy. No meter can tell what is in a battery since they don't contain electricity, ony chemical potential to produce electricity, and that cannot be measured electrically in situ.
.

 

[Yamaha1]

If anyone is considering the Turnigy Watt Meter, here is a link to the "manual" for it.

http://boydhobby.com/Documents/Turnigy Watt Meter.pdf

Mike