SRam Sparc -> how does it work (technically, two motors ?)? how in practical use

i have the opportunity to maybe get a used sram sparc for few money..

question:

 

how does it work ?

 

it is said to have 2 motors with belt-drive inside the internal gear hub..

 

what motors ? brushed or brushless ?

how are they rated..

i have read, that it is not a strong drive-train, more on the weak side

how noisy is it ?

 

do you feel a drag of the motor(s) when driving without motor-power ?

or is there a free-wheel unit integrated ?

 

are the electronics integrated (controller ?)

on the pics on the sram-homepage:

...::: POWERED BY SRAM :::... --> products and then SPARC

 

it looks so

if it is brushless, and there are two motors: is there one controller (and the phases of the motors synchronized) or are there two controllers.

(i would prefere to use my own controller)

 

how is it with giving some more than 16Volt to the motors.. would they servive ?

etc. etc.

 

does the motor use the gearing ? i think no, otherwise that would be a great feature and Sram would have not forgotten to mention that

 

has somebody more pics of the system..

 

iam realy interested in it !

 

 

thankx !!

Sorry I don't have any info Kraeuterbutter, except for a mention in the AtoB electric bike Buyer's Guide that you may have seen anyway: look for "Dahon Roo EL (SRAM Sparc power)" about 1/3 way down: this page was updated in April 2007, but that item refers to 2002 and 2005??

 

Stuart.

Be careful on this one Kraeuterbutter. The first generation Sparc was revised as it was very poor and gave trouble. The replacement is supposed to be more reliable, but it's still a low power system. That said, it is a good hill climber, but at low speeds, and has quite a good range with the standard batteries.

 

I don't have any figures, but that's the summary of past review information.

.

idoes the motor use the gearing ? i think no, otherwise that would be a great feature and Sram would have not forgotten to mention that

You're correct in that it's not a drive through the gears system and the motors are only connected to the hub through a compromise fixed gear ratio seems like a lost opportunity to me given the gears are already there in the hub. The Sparc has been around for ages now, I would have thought an all new replacement model can't be far away. Perhaps the next model might be sensible enough to drive through the gears, a bonus would be if the new unit incorporates a roller brake.

hmm.. how much would you pay for it..

 

i think i will go up to 150Euro.. if he wants more i will forget about it..

 

i liked the fact, it is said to be very light...

 

as i have seen, its powered by 16Volt ?

i would want to use a light battery (0.42kg light)

to have after conversion still a very light bike..

(i don´t need 20km range, so 18Volt and 4Ah would be enough for me))

 

last thing: do you feel the motor in power-offmode ?

does it has a resistance like hub-motors ?

or is there a free-spinning-unit integrated, and i can also drive without power ?

Thought this info might be of some interest to you...

 

If you go onto BIKE SHOP UK. Buy mountain bikes, road bicycles, cycle parts, bicycle store. Discount cycling bike shops London and enter SPARC into the search box, a whole load of relevant parts seem to be available, even some 5 speed motors at £450!

even some 5 speed motors at £450!

As long as people realise the 5 speeds only relate to the input sprocket gearing - from the pedals so in that regard the whole assembly has 5 gears but the motors, unfortunately only one fixed gear.

450 Pfund ?!?

wow..

 

well, than maybe 150 Euro would be not that bad of an deal..

maybe i should even pay more...

well.. bought it for 104 Euro

 

i think a very good price, isn´t it ?

 

i have now got the information,that you don´t feel it when pedaling without motor-assistance..

 

for weight:

its around 2.5kg for the hub-gear-unit

 

-> normal hub-gears without motor are often over 1kg in weight..

 

so: compared to this there are only about 1.5kg of added weight (without battery) compared to a normal bike..

 

QUESTION:

has somebody of yours already disassembled a hub-gear-drive..

is it very difficult ?

will all parts fall out of it when i unscrew it, and will i be unable to put it together again anymore ?

 

i would like to look at the motors and the controller..

i have seen a pic, and it seems that there are cheap canned motors are used..

if this is true, it should be doable to plant some after-market brushless-motors into it with

1.) higher efficience

2.) more power (2x 250Watt should be nicer)

 

or is it a no-no to disassamble a hub-gear by yourself ?!?

thx

(100watt)

The SRAM P5 hub gear part is easy enough kraeuterbutter, but I don't know about the motors that are fitted in that Sparc unit.

 

The P5 gear part uses a complete replaceable inner assembly and is effectively unrepairable now since no spares are available other than that.

 

Thanks for the information on free running and weight.

.

sorry.. my english my english..

 

what do you mean with:

The SRAM P5 hub gear part is easy enough kraeuterbutter

 

easy enough ?

easy to disassamble and re-assamble ?

 

effectively unrepairable

so, if a part fails i have to replace the complete unit ? (the gears, maybe not the motor + controller)

?!?

 

the bike-industrie is make me wonder more and more..

how can it be, that when i have a high-quality product (i think the sparc is more in the higher-price-region, so not a china-cheap-300US$-for-complete-electric-pedelec make)

 

so how can be there no spare-parts..

 

its like i buy a BMW or Audi, so not the cheapest cars, and when there fails something in the driveline i have to replace the complete motor + gears + clutch

Not the whole thing, just the hub gear part, the epicyclic gear core of which is available as a complete spare for around £100 in Britain. That sits inside the shell which is the hub on a bike with this 5 speed hub. This is the hub I speak of:

 

http://www.wiggle.co.uk/images/sram%20spectro%20p5%20hub%2004.jpg

 

The electric motors are outside that and inside the outer hub shell, and I've no idea on the spares situation for that. I would think there are spares for that, particularly the drive belt of course.

.

Edited June 13, 200718 yr by flecc

thx..

 

how likely is such a hub to fail ?!?

200Watts of the motor + my 300Watt from the legs (maybe 500Watt+ (leg-peaks)) ?

 

at least i have not seen a hub on the bikes in my neighbourhood fail after years..

hmm..

 

for the motor:

on the opended picture ont he sram-homepage:

...::: POWERED BY SRAM :::...

--> producte --> sparc

 

you can see part of the motor..

2 wires, so that are brushed motors

 

the length can not be that big, maybe 550 or 600er canned motors

(so 55m or 60mm long)

it looks on the picture like a cheap canned motor, you get for 10US$ each in rc-shops..

the power-rating - 100Watt - seems to be right for that too..

12-16V, most likeley 5-polemotors with best efficience in the region of 65-70% (but falling very fast under 50% )

 

if that is true it should be easy to replace it by a brushless-motor (i think about Lehner, because:

1.) sequmented neodym-magnets, so less eddy current looses at partial load

2.) very high efficience (including controllereff. up to 91%)

3.) i can get this motors in different sizes and each motor in 20-35 different windings... so its a pool of over 1000 motors i can select from

4.) one single motor would be enough (its difficult to run two brushless-motors from only one controller)

5.) power should not be a problem... (a single motor should have at least 2-3times the power of this 2 motors used there)

6.) there are a lot of power/efficience/torque diagramms on the Lehner-Homepage

7.) all motors can be used in Triangle AND Star-configuration...

 

well.. i think i will disassamble it before i install it to the bike and have a closer look, if i can use one of the lehners..

maybe, when removing the plastic innercase on the picture, its even possible to use a homebuild outrunner.. so i would be able to experiment with the count of windings until they fit my preferences...

The SRAM P5 is one of the strongest hubs and only the rider power is going through it in the Sparc, since the electric motors drive the hub directly. If anything it's much less likely to fail than a hub by itself.

 

I understood the motors that Sachs used in the Sparc were very similar to those used in rechargeable power tools at that time.

.

so that sounds not too bad for me..

iam not the strongest with my legs..

(ended some time ago at 330Wat on ergometer (every 3min watt were increased by 40watts)

for my power and weight (~71kg) the gears should hold

 

for the motor: if it are that kind of motors from power-tools (of the pre-liIon-area), than i know what power to expect from them.. not very much

 

so if i can fit it, i think it will become a lehner..

just a example:

http://www.lehner-motoren.com/diagramm/1940-20.18v_liste.txt

 

but when i replace the motors (i can not use the electronics than anyway, so i need a new controller as well)

i can even go up with voltage:

http://www.lehner-motoren.com/diagramm/1940-20.31v_liste.txt

 

the efficience was measured INCLUDING the controller efficience (controller with fixed timing to 15°, no hall-sensors

--> with automatic timing (controller varies timing of the motor depending on the load) the efficience can be even 1-2% higher)

 

well.. there are many other choices, will have to measure the speed of the brushed canned motors first to deside what is needed..

thx for your help..

will make some pictures and post them here when i open the unit

 

last one: just to compare the typical efficience-curve of canned cheap motors like you find in most power-tools

motor has a max. power of around 120Watt.. so it sounds similar from point of power to the sparc ones:

http://www.kraeuterbutter.at/Bilder2/sonstiges/Messwerte%20Mabuchi%20Lehner/Mabuchi%20RS-540SH-5045_Bild4.jpeg

 

not that nice when you compare it to the efficience-curve of the lehner !

http://www.lehner-motoren.com/diagramm/1940-20.31v_grafik.gif

(W stands for Wirkungsgrad and is the same like efficience, the red line)

Edited June 13, 200718 yr by kraeuterbutter

hmm...

when you look at this you can feel sorry..

 

a hub-motor weights something around 4kg, rated with 250Watt, 400Watt, 700Watt maybe even 1000Watt ??

 

this motor weights only 460g

44mm diameter

80mm long

 

http://www.lehner-motoren.com/diagramm/2240-17.33v_liste.txt

 

nevertheless it can put out 1850Watt

at 2000Watt input

efficience at that: ~ 92% including controller

 

and for short it can do even more (twice as much)...

 

of course its not that easy and only half the story (think alone about gearing)

 

 

this whole thing brings me to a question:

all the laws (200Watt, 250Watt, 400Watt) in the different countries..

are there input-powers meant (can be measured easily)

or are there output-powers meant (can not be measured that easily)

Edited June 13, 200718 yr by kraeuterbutter

Have I read that torque graph correctly kb? 95% efficiency @ 31V but 20A and 25708rpm!!!

 

for the motor: if it are that kind of motors from power-tools (of the pre-liIon-area), than i know what power to expect from them.. not very much

 

 

That's correct kraeuterbutter, I remember the reports that they were quite weak in power. The Lehner should be a very big improvement of it can be fitted.

.

 

this whole thing brings me to a question:

all the laws (200Watt, 250Watt, 400Watt) in the different countries..

are there input-powers meant (can be measured easily)

or are there output-powers meant (can not be measured that easily)

 

I think it's the mean (average) of the output power that is intended by the laws kraeuterbutter, as you say, not easy to measure or calculate. But that means it's not easy to measure for prosecution either!

 

The interpretations are very loose. For example, the Cycles Maximus goods and Taxi tricycles can have a Lynch motor legally rated at 200 watts, but it has a peak output of around 5kW. The power graph starts with this huge power peak which immediately drops almost to the baseline and continues, declining gradually to the end of the graph.

.

@flecc: thx..

so: when iam not going 40km/h with an e-bike without pedaling i should not get problems with the police (even when i use a stronger motor, for faster hill-climbs)

 

@coops:

yes i think you read it right way..

are you wondering about some datas ?

the rpm ? the motors in that size are capable to handle 50.000rpm without any harm to the rotor

in competition this smaller motors (less than 160g weight) are used even up to 100.000 - 110.000rpm at glider models.. thats enough to shoot a 2kg heavy model with 4000Watt Power and over 200km/h vertically into the sky *lol*

 

for power:

Lehner offers now the new 30er-series, for the big rc-planes and boats:

a example here:

http://www.lehner-motoren.com/motordaten/Motordaten%203080/3080-7.70V.xls

this little motor weights 1.6kg (so halfe the weight of many hub-motors)

nevertheless you can see on the data:

its able to handle 600A at 70V which are 42.000Watt (42kw !) Inputpower..

revolutions: ~52.000rpm

nevertheless: the efficience at that power-level is at 94,6%, so its not the limit of the motor !!!

 

with 40V the same sized motor still can handle 24.000Watts Input at 93,7% efficience

http://www.lehner-motoren.com/motordaten/Motordaten%203080/3080-6.40V.xls

 

this motors are used for big rc-boats or planes where normaly a 200-250ccm nitro-engine is working

 

well that was now offtopic, just wanted to show what power-density is possible

offtopic the second:

 

here just some real-world data of a motor i use myself and have measured myself:

 

its a Lehner 1930-8 in star-configuration

230g light

36mm motordiameter

56mm long

 

i think this motor may maybe fit into the sparc

 

 

here the data i measured myself within an rc-offroad buggy (~ 3,3kg heavy)

 

http://www.kraeuterbutter.at/Bilder2/CRONO/Crono_Messwerte/Bild1_5s_Prolite_W_rpm.jpg

 

http://www.kraeuterbutter.at/Bilder2/CRONO/Crono_Messwerte/Bild1_5s_Prolite_V_A_temp.jpg

 

you can see:

peaks around 50A

voltage: it was a 400g light 5s Lipo used

rpms: up to 30.000rpm

Watt: up to 950Watt peak, average was 180Watt

not that bad for such a small motor, its enough to outperforme the nitro-buggies at our field

 

so i think this motor should work ok in the sparc.. maybe too fast spinning ?

but there are 30 other windings available for that motor

Edited June 14, 200718 yr by kraeuterbutter

It certainly looks promising kraeuterbutter. Were you still intending to use two motors? I'm not sure if just one is possible due to the belt drive outside the gear hub, but you may be able to have just an idler pulley in place of one of them.

.

the problem with two motors is, that i would need two controllers..

 

i use brushless SENSORLESS controllers from Kontronik

 

here the specs of the KOntronik JAZZ 80-6-18

(for up to 6s lipos)

or the JAZZ 55-10-32 (for up to 10s Lipos)

Jazz - Drehzahlsteller für sensorlose Brushless Motoren, Jatt - Speed controllers without Sensors for brushless motors

 

the controller works without sensors, does not need hall-sensors, etc. etc.

it has features like:

BEC short circuit protection, Auto Programming Mode, Automatic Power Consumption APC (Governor-mode), Proportional brake (i would not want to use that in an heavy electric-bike because of overheating of the controller), Reverse polarity protction, Short circuit protection, False start protection, Current limiting, Overtemp. protection, Undervoltage cutoff, Active free wheeling circuit, and a frequenzy which adjust itself from 6 up to 32 khz, auto timing for best efficience at all circumstances, ....

 

so you see: even it is "only" a rc-hobby-controller (rc-cars-helis-planes-boats) there is lot of technics/hightech and knowhow inside that controllers..

its also programmable in different modes (how fast it spins up, when it cut offs, how strong the brake is, ...) and with a programmable card

 

but two motors: its doable, but the motors must be syncronized because the controller sees only one motor, not two !

so, when the motors are not syncronized it will not know how the rotor(s) are standing and can not power it...

baddest case -> controller gets destroyed

 

for that: i would realy prefere a single-motor-solution, or i would need two controller which is expensive..

Edited June 14, 200718 yr by kraeuterbutter

Sram Sparc, the true story

 

I have only just come across this thread and even at a cursory glance find quite a bit of misinformation in it. I would suggest a look at http://www.sram.com/_media/pdf/sram/dealers/TM_GHS_MY06_E.pdf

where, straight from the horse's mouth, everyone will find accurate technical details of the SRAM sparc system with illustrations.

 

This is the latest 16.8 volt version which definitely does not use ex-power tool motors, or a drive belt. It is a very sophisticated set-up with the 5 speed gear hub (all metal), the motors (brushless), together with the electronics which note wheel speed and cut the motors at 15mph, and provide motor power in direct proportion to pedal speed, all enclosed in the steel hub casing. There are therefor only three external parts: the gear shifter and the on/econ/off switch on the handlebars, and the battery on the rear rack. The motor power is transmitted to the gear hub within the casing by means of nylon toothed gears (one of which runs round the internal circumference). I have never heard any reports of these stripping, an unlikely event, given the well controlled motor output.

 

I have found that the system provides power more or less equal to what I put in myself, and I assume that like most average cyclists I produce somewhere between 50 and 100 watts. Any cyclist who can produce 200 or 300 watts does not need an electric assister!

Thanks for this up to date information rooel.

 

But where is this "quite a lot of misinformation" you mention? No-one said they were power tool motors or that they were the same, only that the original ones were similar to power tool designs,which they were.

 

kraeuterbutter bought his cheaply second hand, so the latest information has only limited application since it was considerably improved after being received very badly when first released. His could well be the first version.

 

I also disagree about cyclist power and the need for electric assist, and suspect you don't have to ride up very steep hills where you are. If you live in a constantly hilly area and have to ride up long hills of between 14% and 20%, with some a mile or more in length, 200 watts will mean a miserably slow rate of progress. If you carry shopping or other items with weight regularly in such conditions, the need for assistance becomes even more apparent.

 

I wouldn't regard any assist system that could only match 50 to 100 watts of rider power as adequate at all, or even worth purchasing, and neither would any experienced reviewer. Even one of the most popular which was limited to equalling rider power, the Giant Twist series, could give up to 390 watts of power.

.

Edited June 14, 200718 yr by flecc