Topic: Mobility scooter design (Diseño de scooter)

[piersdad]

 Mobility scooter design.
my designtheirs  

Most of today’s mobility scooters are built and sold by large multi-corporation.  Businesses.
The design of them  varies from atrocious rip offs designed by a perambulator engineer to  ones designed by a formula one  engineer.
and one thing in common is a very high price for what you get

my concept is made from scrap materials so not as flash but a lot better design

So have they actually asked the users about what they want from a mobility scooter.

Good points-

They have made  very nice seats that swivel  and can be removed to make transport easier.
They have mobility scooters that dismantle to small parts.

There are fast ones and slow ones and even off road 4 wheel drive mobility scooters.
The gearbox design   is  generally good enough for the purpose but not to my knowledge any where near the standard of a cheap motorbike gear box  system.

They also all have one standard feature.
A adjustable steering column that can be moved  back and forward to assist the driver to get in and out of the scooter.
When up right the steering is just like a push bike and very nice  but it means that any thing on the handle bars has to move with the steering so limiting  any load here.

Moving the steering column towards the rider converts it to tiller steering and the very few people I have seen using this mode  find it very disconcerting and uncomfortable.

For goodness sake!  Tiller steering went out in automobiles in 1906.

Have not the designers of mobility scooters gone past this error yet.

The sensible way to go is a light weight frame in the front that supports the top of the steering handle bars and has an adjustable clamp that allows the steering column to move back and forwards to the convenient position to suit the disablement of the driver.
This makes the handle bars so much   sturdier
  for some one using them to pull themselves up on or off the mobility scooter.

As well the lightweight frame will enable many different sorts of attachments  that are not limited to the weight restrictions of a moving handle bar.

Attachments that would then be able to be used are.

Large grocery carrier.
Walking stick holder
Any other heavy disability items even a light weight wheel chair.
Special clip on windshield and other weather protection.
Pet carrier.
Even on the larger ones a grand child carrier.


With this sort of frame there is no limit to the accessories that could be attached to the front of the scooter and as well they are in full view of the driver.

So here is my design of the scooter of the future

(please note i am on a pension and have to build my projects from scrap materials)

It opens the way for not only disabled people using them but also able bodied people will enjoy them as well due to the appearance being more that just a disabled persons transport

    
 It is no bigger than a large scooter and would fit through any supermarket entrance or maneuver in the narrow isles.
Groceries can be carried in the front  where the lid opens forward to form a large carrying space

the motor is mounted on the wheel assembly and swung from the chassis.
each side is independent and instead of a roll bar i have used a syatem in the front suspension to limit the roll this works well as undulations in the road seem to be evened out and the ride is very comfortable.



  

 
later construction with a motorbike clear windshield set up right


the rear part rebuilt to look a lot better
note there are just a pin and a bolt to remove and the entire wheel assembly can be removed  for repair


BATTERIES
i am looking at using LiFeP04 batteries as wit a potential of 3000 plus cycles i will for what today is a very good tradesman's weeks wages get a battery that will possibly  last me for the next 10-15 years
so here is a site that sells them.

THE ELECTRIC BICYCLE CO

 


another design adapted from a standard  scooter frame and motor the windshield not on yet

here is my scooter at a local musem open day with a tram conductor who borrowed it for the day


Further links to other  information on scooters  on this site
initial stages of the above scooter

 
rebuilding a scooter transmission from scrap motors cycle gears

electric fuel cell  powered scooter

making an adult tricycle

future development of electric cars

electric cars and batteries(lease them or not)

just has a trial with the new lifepo4 battery
the one i am trialing has a 10 amp hour rating but has the range of a 30 amp hour lead acid battery
this is because there is no loss of capacity even if it is discharged at 10 times the rating
ie 10 amp hour will give 100 amps and still get 10 amp hours from it
the life is 3000 cycles three thousand
and at this great age has still 95% capacity left
so i have the lend of this battery for a few weeks as a trial.
the car club meet the other day the warrick stevens car has a set of these batteries and they should last him at least 10 years or more and 100 km range.
the batteries are extremely stable and have a battery management system with them that lets the charger charge till 95% charge and then the system  charges each individual cell to its full capacity so that no cell gets out of  sync with the other

  the size of it is not much bigger than a ladies purse looks lost in my battery compartment
my first distance was 8 km at 12 kmph and as the voltmeter was showing its first tiny drop i used discretion to return home and get a new charge
the lighter load dropped the running current from 12 to 11 amps
cost of this battery and charger is $1080
life 3000 cycles
cost of gell cell lead acid of equivalent performance $500
life equivalent is about 400 cycles (if you are lucky some last 90 cycles)
3000/400 = 7.5 time longer life
 1080 /7.5 =$144
about 3.5 time cheaper and still have a limited range of the battery


8/09/2009
today i drove the scooter till it had flattened the battery
12kmph average speed and at 7 km the voltage began to sag a little so turned for home.
the last km was slowing down and the voltage meter indicated  exhausted battery.
so i had only a 1 km warning if the battery was going to die.
the surprise was that a small squeak came from the sealed battery pack to indicate it was seriously flat.
 
 
 article on new breakthrough shows insight to lifep04 battery

from the ping battery company is revealed the life cycle of their battery so after 3000 cycles you have to factual in the future anticipated range of your scooter powered by these batteries

Lifecycle of the whole pack: >85% capacity after 1000 cycles. Lifecycle of single cell: >85% capacity after 1500 cycles, >70% capacity after 3000 cycles. (<1C discharge rate and <1C charge rate)[/i]

1 c discharge rate  means a 10 amp/hr battery discharged at 10 amps
my batteries are rated at 10 c which means 100 amps for a short burst of power

so my scooter with a 10 amp/hr battery will have a range in 10 years time of 7 km
this would still be enough for my daily commuting

a new test this time with the battery recharged and it appears it is new and just waking up as this time i drove for 1 hour  and got 10.3 km before the battery sagged for the last 1/2 km.
a second test the next day and i got10.89 km before the battery was definitely flat
again i got about 1/2 km warning that the scooter was slowing and the voltage was sagging.
this is not the sort of treatment i should be giving the battery as in every day use it will only need to go 1/2 that distance between charges
this should give me at least 10 years or longer with this battery.
its small size means i can drastically redesign the scooter  to a much better design with the battery in the front of the scooter perhaps

[piersdad]

Having a wheelchair is great for mobility, but getting from your bed to one isn't exactly something most wheelchair users can do autonomously.  The Rodem is a next-generation wheelchair that aims to make sliding into it something that everyone can perform all by themselves.

rodem wheel chair

well at last the wheel chair that has advanced design from the 100 year old concept
the batteries are in the front with the wheels and the passenger balances the rear wheels.
the rear part is open to all sorts of devises that can assist the rider onto it.
winches,rotating chairs,any sort of support frame can be hung from the rear part  there is no end of innovations to suit the disability of the rider.
this is a hybrid between the scooter and the chair.
often i see partially disabled people with wheel chairs that ideally would more suit a scooter with the modem design.

and at last  some bright spark has put a frontal bib from which all sorts of attachments and even luggage holders or wind screens  and do away with th eugly wire basket in the front, a remanent of 100 years ago


 

as can be seen here there is ample frame work in the rear to accommodate any devise that will assist or hold a disabled person to get on and remain in the seat

must get to my work shop soon and try this design out

[piersdad]

At last after shifting 3 times and developing my section and building 2 granny flats i have a decent workshop again. it is heated and has the sun all day--woopee-
the scooter has a complete overhaull and a special motor from the 1980s had 4 poles of permanent magnets each pole has 2 magnets glued to the stator.
the winding are such that it is really two motors in one with a diameter that has the same circumference as two ordinary 360 watt dc motors.
 the result is a very gutsy motor with the losses of one motor and  the torque and back emf of two.
so with discarding one transmission and installing the restored motor i get a free running current of 2 amps and a 10 km speed  with current of 8 amps on smooth flat ground.
with cog belt drive and chain the drive is almost inaudible and heaps of acceleration.
when i throttle off to 6 km the current drops to 6 amps and a potential range of 30 plus km.
am now investigating the use of new lifepo4 batteries that were used on the mars explorers and with the right choice of battery could potentially last me for the next 20 years.
the price of between $1000 and $2000 with charger etc is a lot cheaper than buying new $500 batteries every 2 years

the electric bike NZ christchurch

so today i am off to find out more about these new batteries

[piersdad]

 
fault finding  with lithium iron phosphate batteries

trying out a 24v pack
this has 8 cells in series and a battery management system.
at first two tries it was ok but started to give off alarms  when used both in charging and discharging.
so with a bit of trepidation i opened up the seals and looked in
 
there were some electronics and a set of 8 round cells  linked together.
so i set up a 6 amp discharge  for the batteries and monitored each individual cell as well as the main voltage.
eventually on cell seemed to be the culprit as it would start off at 3.4 volts and gradually drop  to 3.1
 volts while all the rest stayed at 3.4 volts dropping to 3.2 volts
on charge from flat  this cell showed 2.2 volts and climbed to 3.9 volts where it set off the battery management systems alarm.

the batteries are secured with 6mm metric bolts and i noticed what appeared a loose nut and tried it and that was the cause of the alarms.
that super intelligent battery management system had told me that a cell interconnection was loose.
a quick tighten of that cell and check on all the other cells and the battery seems to be back to
normal