running without a controller

[nathan_jones]

I have search and searched this forum for something similiar but no luck.

soooo. i have a question

do any of you guys run without a controller?

how could you make this possible? the goal being a simplier design.

http://www.instructables.com/answers/How_to_run_a_DC_motor_on_electric_bicycle_without/

within this artilcle there is mention of a 555 relay how would this be used on a E bike?

i also found this:

http://www.theworkshop.ca/energy/picox/picox.htm

its a self made controller.

I dont like the idea of a "black box of magic tricks" :lol: and like to understand it all!

so what do you think?

 

[TylerDurden]

In the bad 'ol days, big relays (contactors) were used to switch power to the motor:

Low = two halves of the pack in parallel (half voltage), through a resistor
Med = two halves of the pack in parallel (half voltage), no resistor
High = full pack in series, full voltage

It works, but rather bluntly.

Variable speed controllers are a significant advance in drivability and efficiency.

Many of the members here are continually improving the design of controllers and other components. (for example, ES member FrankG is the pic-ox developer) Any mysteries about design or construction are easily revealed by searching these boards and asking about what you can't find.

 

[Link]

Yeah, and, generally, switches big enough to adequately handle the power a hub will try to draw won't be all that much cheaper than a basic brushed controller.

 

[Drunkskunk]

$40 for a good brushed controller, or $50 for a switch that can handle the high amps of a motor trying to start.
you could probably get a controller cheaper than that on ebay
or for realy cheap, jury rig an automotive starter relay up, buyt those thongs are still $25+

or be realy gheto cheap, and rig a contactor together out of some wood, a door hinge *(or duct tape) and some pennys.

or build your own PWM controller for $100 in parts

No one on here runs without a controller that i know of, but a few have designed and built there own. there are scematics floating around too, but mostly for the brushless motors.

 

[nathan_jones]

thanks for the response,

In my defense If you dont ask, you dont know.

can you recommend information regarding the benifits/use of the controller so i and others in my position can have a more informed discussion with the ....Masters.

the only general resource i have found so far is http://www.4qdtec.com/pwm-01.html#intro

here are a list a summised advantages.

pwm slowy turns the motor on.

stops the battery from discharging to a low level.

stops to high of current draws.

from experience what are the others?

basically i would just like to get a stysem i can understand. so without completely charging the thread of anyone who has built a controoller for a brushed motor which is what i have , i heard they are more simple.

Thanks for bearing with me, but we all have to start somewhere.

 

[nathan_jones]

ps thanks the relay does make sense now however, why are less efficent reletive to a controller?

 

[TylerDurden]

Contactor-based systems regularly have that resistor, which wastes power as heat... and having few speeds means frequently being in a power level not best suited for the speed desired.

Brushed controllers are simpler, since the motor is physically handling commutation (the switching of electromagnetic poles), but brushes need periodic replacement and armatures wear out eventually. Systems are more vulnerable to water ingress.

Brushless systems have no virtually no wear and can regenerate power during braking, but cost more.

 

[TylerDurden]

Here are some basic topics in the Reference section:

Series/Parallel: viewtopic.php?f=16&t=1312
Battery Basics: viewtopic.php?f=16&t=1403
Power needs: viewtopic.php?f=16&t=1499
Evaluate...: viewtopic.php?f=16&t=1763
Glossary: viewtopic.php?f=16&t=1216

more stuff here:
viewforum.php?f=16

 

[nathan_jones]

as a theoretical exercise,

let see how we can make a system as simple eg without a cnotroller, whilst effcient.

 

[Drunkskunk]

ok.. as simple as you can without a controller.

you need a sissy basket.. what we call one of those handlebar mounted baskets. drop a car battery in there. Duct tape it in place.. you know, for safety. Now use Jumper cables for your main wire. its thick, high strand, low resistance wire and cheap, plus simple connections. Now clip the positive side on the battery and duct tape it down.. you know, to keep it from shorting out. keep the negative aligator clamp clamped to the side of the basket. this is the Off position. You might also want to spray paint the negative clip and battery terminal green. you know, to make it user friiendly. Green means go!
Might also want to make a little tag that fits on the side of the bassket were you have the clamp clipped that says "Off".. you know, incase someone else wants to use the bike...


Now when you want to go, just reach over and unclamp the green clamp from the side of the basket (off position) and clamp the it on the green battery terminal (on position) and off you go! to stop, just reverse the process.

That seems totaly practicle and easy to me. Probably realy safe, too. You can't get much easier than that.

 

[nathan_jones]

it was einstein that said "any intelligent fool can make something bigg, more complex, [however] it takes a touch of genius and great courage to step in the oppersite direction" ... you know :lol:

heres my entry.

entries of simple self made electronics are also welcome

the problem that i see with controllers is that if one thing fails generally the whole thing falls this system could be improved by a series of more simple indepenadant parts. what do you think?

let this forum be the garden for ideas to grow, and never stamp on even weeds as who are you to say they are not as beautiful as flowers. basically i know tha controlless system might not work now but just give it some time ant thought.

 

[TylerDurden]

Mechanical switching is prone to rapid degradation. There is also the risk of switches closing at the same time, causing a short-circuit.

Electronic switching allows safe, reliable management of power.

 

[nathan_jones]

thanks td i knew it wasent perfect so what would be the simplist means of electronically swithing power and how would you make such a device?

 

[TylerDurden]

Personally, I'm generally not in favor of re-inventing what is servicable and readily available. To be sure, most things can be improved, but that is for people more talented than I am. There are lots of those people here at ES.

To see a high-power pack mechanical switching setup, you can see Doc's: viewtopic.php?f=2&t=7170 Keep in mind, the relays (contactors) cost more than a decent controller. Doc's setup still uses a controller, but halves the pack voltage for more range.

 

[Link]

thanks td i knew it wasent perfect so what would be the simplist means of electronically swithing power and how would you make such a device?

With a large FET, driven by a chip switching it on and off as fast as the FET can go at about 18kHz. Effectively, what a brushed controller already is.

Technically, you could even control the FET with something as basic as an astable flip-flop circuit, though that might blow it if you can't get the circuit to switch states quickly enough. And I haven't managed to get one going faster than about 180Hz (or was it 360...), which wouldn't be all that great for efficiency.

 

[nathan_jones]

"With a large FET, driven by a chip switching it on and off as fast as the FET can go at about 18kHz."

could you show me a circuit diagram.... preety please

ps for those not a smart as link etc here is good link to a e-book im reading

http://books.google.co.uk/books?id=edqTZb9PbLQC&pg=PA141&lpg=PA141&dq=brushed+controllers+explained&source=bl&ots=yv80xNlC1N&sig=Jc1wKlaKt36PI_388jaxBh4KOYk&hl=en&ei=9RS-SbPIIqSLjAf71PSnCA&sa=X&oi=book_result&resnum=2&ct=result#PPA157,M1

 

[dogman dan]

Not to stamp on weeds, but , controllers for brushed are pretty dang cheap. But I have to admit, a good solid 36v on off switch would work fine the way I ride. It's just that it might cost more than a cheap controller and throttle. Add the fact that a controller will help your batteies last.....

Of course that doesn't take into consideration the FUN of inventing stuff, that's priceless!

 

[docnjoj]

Hey nathan_jones! Brett White at his old solarbbq website had just the ticket in a simple circuit for a 24 volt start then switch to 36 volts by another button! Contact him and see if the old site is still up. Tons of good info there!
otherDoc

 

[TylerDurden]

KC4mts just posted a simple controller:

http://endless-sphere.com/forums/viewtopic.php?f=2&t=278&start=330

 

[nathan_jones]

the cost of a new heinzmann controller 160£

the cost of a new scooter controller 20£

the cost of putting together little bits and bobs that works....PRICLESS i agree dogmann

docnjoj thanks for the advice however i coulndnt find his wibsite i have sent him a email though.

http://www.users.bigpond.com/solarbbq/

Tyler. we have a saying in england. everyday is a school day, however this is a bit more university the elementry. but thanks i have to learn sometime. As i believe " if you cant fix it, dont buy it".

 

[monster]

to be fair, you can run small brushed motors fairly well with just a switch on the handle bars. most ebike motors are so weedy that you only need full power or nothing. its only the people on this forum that have the uber powerfull motors that need to be controlled.

 

[regmeister]

deleted

 

[chet]

I read through and don't think any body stated clearly, modern brush-less motors need a controller to modify the current.
Brushed motors. (starter motors hobby motors seat motors wiper motors and such) can work well with on off switches, relays feeding from
multiple batteries, or even resistance pots. The first electric bicycle I made was in the mid sixties. A volks wagon DC generator hung
with bailing wire to ride the pulley on the front tire. A large 12 V battery hung from the cross frame, and a battery jumper clamp for GO.
I don't remember the speed now, but it made 3 to 4 miles to town and returned with a six pack on one charge.

 

[torker]

If a guy could scavenge parts from junk cars could you use a ford type solenoid and maybe a headlight relay and a switch to power the solenoid? Put this in a trailer with a starter motor or reworked alternator.

 

[monster]

these rocker switches work fine for 200 watt european ebikes http://www.maplin.co.uk/Module.aspx?ModuleNo=11918 . have two in series incase one of them decides to weld itself closed