Ole Grundsøe wrote:
> Hej gruppe
> I hvilken gruppe finder jeg gode råd om køb af elcykel - er det denne
> ellers send mig venligst videre.
>
>
> Kh Ole
Hej Ole
1. Cyklen skal leveres med LiFePO4-akkumulatorer (
http://da.wikipedia.org/wiki/Lithium-jern-fosfat-akkumulator ) og
kompatibel lader - helst A123-Systems, da de regner med mindst 1000
fulde af/opladninger. Deres test vist på hjemmesiden er indtil videre
oppe på 7300 fulde af/opladninger.
Test accelereret forældelse tyder på at A123-Systems akkumulatorer burde
holde ladningskapacitet (80%) og lav indre modstand i ca. 15år.
LiFePO4-akkumulatorer er langt sikrere end traditionelle
LiIon-akkumulatorer.
Lithium Iron Phosphate Batteries:
http://www.iloveebikes.com/batteries.html
September 21, 2008 LiFePO4 Batteries: A Breakthrough For Electric Vehicles:
http://www.metaefficient.com/rechargeable-batteries/innovative-lifepo4-batteries-electric-vehicles.html
Følgende LiFePO4-akkumulator forbedring er ikke i handlen endnu:
12. mar 2009, Gennembrud i batteriforskning giver lynopladning på få
sekunder:
http://ing.dk/artikel/96999
Citat: "...
Derfor valgte de at arbejde videre på en anden type, nemlig
lithium-jern-fosfat blandingen, som har langt bedre termiske egenskaber
og derfor kan belastes hårdt. Desuden er den billigere og mere miljøvenlig.
......
Forskerne fandt frem til en metode, der øgede batterimaterialets
ledningsevne med 10 millioner gange. Samtidig er batteriets holdbarhed
forbedret, så det tåler flere op- og afladninger, før det bliver slidt.
Det skete ved at overtrække batterimaterialet med en glaslignende
lithium-fosfat blanding, som gav en langt mere porøs overflade.
......"
March 11, 2009, A Better Battery? The Lithium Ion Cell Gets Supercharged:
http://www.scientificamerican.com/article.cfm?id=better-battery-lithium-ion-cell-gets-supercharged
Citat: "..."We took a basically great material called lithium iron
phosphate [LiFePO4] and we tried to improve it further," says study
author Byoungwoo Kang, a graduate student in M.I.T.'s Department of
Materials Science and Engineering..."
Standard blyakkumulatorer holder kun til 50-100 fulde af/opladninger:
http://www.electricrider.com/batteries/index.htm
Citat: "...
The cycle life of sealed lead-acid is directly related to the depth of
discharge. The typical number of discharge/charge cycles at 25°C (77°F)
with respect to the depth of discharge is:
* 50 - 100 cycles with 100% depth of discharge (full discharge)
* 150 - 250 cycles with 70% depth of discharge (deep discharge)
* 300 - 500 cycles with 50% depth of discharge (partial discharge)
* 800 and more cycles with 30% depth of discharge (shallow discharge)
......"
-
2. Det elektriske system (controlleren, regulatoren) bør have
regenerativ bremsning, hvilket vil sige at bremseenergi fyldes i tilbage
i akkumulatoren (dog med tab). Fordelen er at man ikke behøver at skifte
bremseklodser så tit.
Regenerative Braking:
http://www.diyelectriccar.com/forums/showthread.php?t=8848
Test af elcykler:
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=7891
Citat: "...
You can see that there is a pretty wide range from about 6 amps to 12
amps of regen current where half of the original kinetic energy was
recovered. I was rather surprised that the result was this high and over
such a broad range, and 6-12 amps
......"
-
3. Motoren bør være børsteløs (brushless). Det burde være mere effektivt
og holdbart og bedre egnet til regenerativ bremsning. Børsteløse motorer
fås også til RC-fly og helikoptere:
http://uk.youtube.com/watch?v=uU7AYKx-7RQ&feature=related
Nogle vigtige detaljer - som selvfølgelig også gælder elbiler:
* Jo større effekt elhjulet kan klare, jo hurtigere kan det bremse.
* Jo større effekt elhjulet kan klare, jo mere energi kan indvindes ved
(evt. hård) regenerativ bremsning.
-
4. Cyklen bør kunne tåle dansk "saltvandsklima".
-
Det nærmeste jeg er kommet er (men uden LiFePO4-akkus!):
http://www.electricrider.com/
http://www.electricrider.com/crystalyte/phoenix.htm
Citat: "...
Phoenix Brute
Use the Brute when you have extreme hills, pull a trailer, or do not
want the speed of the Cruiser. With the 4840 controller, it reaches its
top speed of 25 MPH [40-50km/t] in 11 seconds
......"
http://da.wikipedia.org/wiki/Mil
Det ser ud som om 25km/t (ca.=16mph) nås efter 4-5 sekunder ved 48V
(4840 controller).
Der er vist noget med at el-motoren skal slå fra over hastigheder på
25km/t (undersøg det selv). Denne begrænsning skal være sat i
controlleren. Regenerativ bremsning må vel godt fungere ved højere
hastigheder.
http://www.electricrider.com/crystalyte/roadrunner.htm
Citat: "...
RoadRunner electric bike kits are brushless, meaning the energy is
transferred to the motor in a more sophisticated and efficient way.
RoadRunner motors have no brushes to wear out, but brushes last a long
time. The main advantage that the brushless motor is more efficient,
meaning you get more miles per charge.
......"
Det ser ud som om 25km/t (ca.=16mph) nås efter 10-11 sekunder ved 48V
(4825 controller).
-
http://www.electricrider.com/parts/controllers.htm
-
http://www.google.dk/search?q=regenerative+braking+controller
Det er ikke sikkert at kelly-controlleren er kompatibel med
electricrider.com el-hjulene. Det skal undersøges.
Ved ikke hvor gode eller dårlige disse controllere er, men de skriver at
controlleren har regenerativ bremsning [•Brake Switch for regeneration.
•Analog Brake Input for continuous variable regeneration.] og Synchronos
rectification, ultra low drop, fast PWM to achieve very high efficiency:
http://www.kellycontroller.com/mot/Brushless-DC-Motor-Controller.html
http://www.kellycontroller.com/mot/KellyKBLUserManual.pdf
Citat: "...3.2.1 Front Panel of BLDC [=børsteløs!] Motor Controller..."
-
Professional 120
4 Quadrant 12v, 24v, 36v & 48v Vehicle controller:
http://www.4qd.co.uk/prod/pro.html
http://www.4qd.co.uk/fea/regen.html
Citat: "...
It is best treated as braking (which just happens to feed the braking
energy back to the battery) rather than a means of saving lots of
energy. This is because most motors and drive systems are inefficient
and you won't save a lot of battery! However there are applications -
such as Go-Karts with the Lynch motor - where the energy re-generated
can make a significant difference to the battery life.
......
It is actually the battery which is doing the braking, not the
controller, since the braking energy gets dumped into the battery. For
this reason regen braking should not be considered as a safety or
emergency braking system. A properly designed vehicle will also have an
adequate mechanical brake, for emergencies.
......
Can I vary the regen braking?
Regen braking is indeed variable. In the same way as you adjust the
acceleration (power to the motor) by advancing the speed control, you
adjust the braking (power from the motor) by reducing the speed.
......"
-
Pedelec Forums - Electric Bike Forum
http://www.pedelecs.co.uk/forum/
http://www.diyelectriccar.com/forums/
http://www.endless-sphere.com/forums/
-
Kig på disse sites og se hvad de kan:
http://www.fantombike.dk/
http://www.trialaction.dk/elcykel/index.html
http://www.go-one.de/
http://www.ligfiets.net/
SCO viper
http://www.hybridcykel.dk/
http://www.cykellet.dk/
/Glenn