Magura Throttle 3 wire...

[unclejemima]

Oh, and is there different qualities of these things? I mean I see some for a few bucks each, and the another seller has the identical one for qty 20 for the same price or more.

http://www.ebay.com/itm/20pcs-3296W...321?pt=LH_DefaultDomain_0&hash=item3f2c91f3f1
$3.77 shipped for 20

http://www.ebay.com/itm/2x-3296-Pre...034?pt=LH_DefaultDomain_0&hash=item565a24516a
$4.27 shipped for 2. They are "precision"...but is it just the same stuff???

http://www.ebay.com/itm/Bourns-3006...942?pt=LH_DefaultDomain_0&hash=item5d3d6517d6

These look to fit the bill. 15 turn. What do you guys think?

 

[teklektik]

All good choices.
eBay pricing is largely a matter of what the market will bear and where and how many the supplier was able to get for stock. Bourns is a top tier manufacturer - you are seeing differences in the supply chain, not the cost/quality of construction.

When you adjust this, you will find interaction between the pots so you will need to go round and round a few times to get both set properly - annoying, but a one-time job.

I would recommend dialing the pots in to the resistance discussed earlier using a meter as a starting point or at least dial both to the midpoint or a guess at those resistances. Then put the bike on a stand and adjust using essentially the same technique laid out in an earlier post.

• First get a setting on the low pot where the motor just starts to run - then back off slightly to make sure it's OFF.
• Then adjust the top with the throttle at WOT, to where the motor runs as fast as possible and no further reduction in resistance will make it go faster - then decrease resistance a tad.
• Repeat, repeat, until both settings are good.

You should end up with a very very small 'dead zone' at each end - don't crop it in too tightly - parts will drift with temperature and age.

Good luck with your project.

 

[unclejemima]

teklektik, great! Thanks!

So, I'd imagine if I turn the pots counterclockwise I would get to 0K, and if I turn clockwise i would go up to 5K...correct?

 

[unclejemima]

Anyone know of a place to buy the Magura throttle in Canada by chance? I need 2 of them.

ebike.ca does not appear to have them...

Thanks!

 

[teklektik]

So, I'd imagine if I turn the pots counterclockwise I would get to 0K, and if I turn clockwise i would go up to 5K...correct?

Well - depends on which end of the resistive element to which you tie the center wiper. Not really important - whatever works - it'll be obvious if you are going the wrong way. This is a one time adjustment, so....

 

[teklektik]

Anyone know of a place to buy the Magura throttle in Canada by chance? I need 2 of them.

I buy mine from Holmes Hobbies - good price that may help offset your Customs hit.

JRH is a respected ES member - glad to give him a little business whenever possible....

EDIT - oops - he's out of stock. Well - if the price looks right, you might email/PM him as see about arrival of new stock...

 

[unclejemima]

So, I'd imagine if I turn the pots counterclockwise I would get to 0K, and if I turn clockwise i would go up to 5K...correct?

Well - depends on which end of the resistive element to which you tie the center wiper. Not really important - whatever works - it'll be obvious if you are going the wrong way. This is a one time adjustment, so....

Gotcha. Makes sense! Thanks!

 

[unclejemima]

Anyone know of a place to buy the Magura throttle in Canada by chance? I need 2 of them.

I buy mine from Holmes Hobbies - good price that may help offset your Customs hit.

JRH is a respected ES member - glad to give him a little business whenever possible....

EDIT - oops - he's out of stock. Well - if the price looks right, you might email/PM him as see about arrival of new stock...

I sent him a message to see when he's getting them back in stock. I can't seem to find any in Canada. The CAD is doing horrible against the USD right now...that's why I was trying to stay in Canada

But, your link was a $10 savings to what I've been seeing...for 2 throttles thats $20. Enough to make a difference!

teklektik, Thanks for staying through to the end of this thread. I'd say mission accomplished for now!

 

[Merlin]

can you please post his answer?
i need also 2 for Germany

 

[Doctorbass]

Anyone know of a place to buy the Magura throttle in Canada by chance? I need 2 of them.

I buy mine from Holmes Hobbies - good price that may help offset your Customs hit.

JRH is a respected ES member - glad to give him a little business whenever possible....

EDIT - oops - he's out of stock. Well - if the price looks right, you might email/PM him as see about arrival of new stock...

yeah but problem is that it is DIFFFICULT to reach!.. I have contacted him about 4 times to get two Magura without any answer except that the first time he said he only have one ad asked me how many i want.. than.. .no response...even 3 email or PM later... I never had any problem with him so I don't understand why he don't answer...

I had to buy 2 of them from EVDRIVE at 55$ each + shipping + UPS customs and...... total about 160$ !! DAMN !! few month ago I sold mine for about 30$ I had form the salvaged Zero...

If John would have answered me I would have pay probably twice less.....

holmeshobbies.com still display OUT OF STOCK for month.. even for years...

Doc

 

[unclejemima]

I got a reply from him and he said that there should be a whole bunch coming in at end of this week. I'm going to email him again thursday/friday to see if they show up. I hope they do!

 

[scorpionice]

Noob question: I wanted to put three speed switch with my build, is it still necessary if this setup can modulate properly? Thanks

 

[unclejemima]

Just ordered 2 today. They are back in stock. Excellent service and communication. A1!

Only now they dont come with grips.

 

[Merlin]

perfekt that they dont come with this hard-ugly grips...

i have ordered 3 also.....to germany....will tell when they arrive....

 

[unclejemima]

perfekt that they dont come with this hard-ugly grips...

i have ordered 3 also.....to germany....will tell when they arrive....

Cool I just got a bike from Germany delivered to Canada!

You got more than one project on the go to I guess, lol.

 

[GUI13]

i have 3 magura throttle by it's not 5Kohm i mesured 10Kohm i try teklektik resistance calculator ( i found 4500 and 3800ohm for Rhi and Rlo )
but it doesn't work ....

i bought here :http://www.1977mopeds.com/magura-electric-throttle-assembly.html

 

[teklektik]

i have 3 magura throttle by it's not 5Kohm i mesured 10Kohm i try teklektik resistance calculator ( i found 4500 and 3800ohm for Rhi and Rlo )
but it doesn't work ....

Ya - Magura apparently makes variations, I've seen the 10K version in the past. It's unfortunate the website didn't specify the resistance.

Exactly what doesn't work and what resistor values did you actually use?

Does the throttle work (more or less) without the resistors? If everything is wired properly the bare throttle should activate the controller, although there will be large dead zones at either end, and (depending on the controller) full throttle may force a controller input fault and stop the motor. That would be an easy check to see if the throttle wiring is correct: Blu=+5v, Blk=Gnd, Brn=Sense.

 

[GUI13]

connections are correct Blu=+5v, Blk=Gnd, Brn=Sense.

i put on blue 2,8kOhm
on black 2,2kOhm

result : 1,2V on Brn and 2,2v full throttle ( without resistor = 2,35V and 4,5v full throttel motor stop , normal )

 

[teklektik]

without resistor = 2,35V and 4,5v full throttel motor stop , normal

Unfortunately, it looks like you have this type or similar:

http://www.ebay.com/itm/Magura-Electric-Bicycle-Twist-Grip-Throttle-Black-7-8-22mm-0026473-/360735571315

which claims to have a 4K range on a 10K pot. From what you describe, this seems to effectively be a 4K pot with one leg to +5v and the other in series with a 6K resistor to Gnd (although it actually is constructed as a kind of strange pot w/o the separate resistor). There isn't a way to get the desired 0.8-4.1v spread from this unit.

This is perfectly usable if you are driving a Cycle Analyst V3 because you can adjust the CA throttle range to match, but in your case you have fixed controller input voltage requirements - which are out of range.

This is really too bad - I'm sure this was a a long wait coming from the States, but I think you will need to return these or sell them off to V3 users in Europe.

• You might investigate this further by measuring the Brn-to-Blk resistance at ZERO and WOT then repeat for Brn-to-Blu, but I don't think the result will be materially different than in that eBay unit (e.g. something like 6K-to-10K and 4K-to-0K).

 

[GUI13]

ok thanks , someboby have adress to buy 5k magura throttle in europe ?

 

[teklektik]

Hey GUI13-
Thinking about this, I believe you may be able to salvage those wacky 10K Magura throttles with a couple of extra parts. The idea is to add a diode to introduce a .75v drop in the throttle output to get everything down to a passable working range, then add a pulldown resistor to overcome the built-in 6K pulldown inherent in the pot construction. I posted up about this elsewhere as a trick to get a non-linear curve for CA V3 throttles, and the result will be similar here - you might even decide this non-linear throttle curve is an advantage.

So, we have an modified circuit and some example values here:


The bottom plot shows the % voltage range OUT vs the % throttle rotation IN for a typical linear Magura (dotted green line) and the new curve for this circuit (red). This gives better control at low throttle and worse control at high throttle - which may or may not be Good.

Anyhow - in this example R2 is the internal 6K Magura fixed resistance and R1, R3, and D1 are extra parts. Even though this is a bit of a PITA, this might be an acceptable way out of your predicament.

It would be good if you could do a few tests to be sure we understand the odd 10K Magura:

1. Measure the resistance BLU to BLK
2. Measure the resistance BRN to BLK at ZERO throttle
3. Measure the resistance BRN to BLK at FULL throttle
4. Measure the resistance BRN to BLU at ZERO throttle
5. Measure the resistance BRN to BLU at FULL throttle
6. Measure the actual controller throttle +5v level.

If you can post up these values, I'll verify the spread has all the necessary elements and post it back for you to mess with.

 

[GUI13]

Measure the resistance BLU to BLK 10KOhm
Measure the resistance BRN to BLK at ZERO throttle 7,1KOhm
Measure the resistance BRN to BLK at FULL throttle 9,84KOhm
Measure the resistance BRN to BLU at ZERO throttle 3,7KOhm
Measure the resistance BRN to BLU at FULL throttle 0,4 Ohm
Measure the actual controller throttle +5v level. 4,98V

 

[teklektik]

Hey GUI13-
I don't doubt that you measured accurately, but the values don't quite add up - I'm thinking it's because the internal pot may have a wide wiper that may give different readings depending on which end of the element is used as the measuring point.

For generality I added a few extra resistors to the circuit and represented the Magura with a pot (Rm) and a couple of fixed resistors (Rmhi, Rmlo) at either end to represent the portions of the pot that are out of reach. To eliminate a resistor set it to 0 or 99999999 appropriately.

• The illustrated (Rm, Rmhi, Rmlo) values seem to be about correct for the wonky 10K Magura
• To make this handle a regular 5K magura, set Rm = 5500, Rmhi = Rmlo = 0 (not present/shorted), R1 = R2 = 9999999 (removed), Vf = 0v (no D1).

In any case, the 400ohms at the top of the Magura range is a problem (Rmhi = BRN to BLU at WOT). This pretty much makes it impossible to achieve the needed voltage range. I have never done it myself, but others have opened the throttle and slipped the gears a tooth or so to try to manage the dead zones. That might work here, but don't know and don't wish to lead you down a Bad Path - but something to try to minimize Rmhi if you are up for it.

As you can see, in this example R3 and R4 are not present (shorted) while R1 is completely removed. The diode (D1) is any small signal diode (1N914, 1N4148 or even a 1N4001 rectifier) - the current is tiny and you are just looking for an appropriate voltage drop.

If you tinker with your throttle to eliminate or reduce the Rmhi value to less than the present 400ohms, this spreadsheet may help you to select other values. Hope this helps.

 

[unclejemima]

Hi Guys. Thanks for all the epic help. This forum has very knowledgeable members on it!

I finally finished my setup last night and have it working. Only I ran into a few issues with drive-ability.

To set the throttle off and WOT, I did not use a meter. Rather I turned the trimpot for the OFF throttle wire until the power came on...then I turned back 1/4 turn.
Then at WOT I would turn the trimpot on the WOT wire until I could hear a reduction in power...then I turned it a 1/4 turn more (back to WOT).

All is well with no dead zone at the bottom or top...but what I do have now (with 2 throttles that I converted) is low power when I start twisting the grip...then I can twist for a 1/2 turn more and the power remains the same! then at about 3/4 throttle to full it is linear (more I turn, more power I get)

Whats up with the zone at the bottom of the throttle band where I've actually got power...but nothing happens when I turn? I thought dead zone was no throttle at all (at WOT or full off positions)

Let me know

 

[spisska]

Noob question: I wanted to put three speed switch with my build, is it still necessary if this setup can modulate properly? Thanks

The 3-speed switch is an On-Off-On type. The second position is Off, and assuming you're configured for 50%, 75%, and 100%, will give you 75%.

In other words, if you disconnect the switch entirely, you'll leave it in second position. The circuit itself is made up of two hot wires and a ground. One of the wires has around 1.2V while the other has around 3.7V. If you cross the 1.2V line with ground, you can lock in position one, while crossing the 3.7V line will give position three.

It's not a 'speed' in the traditional sense of gearing. What the switch regulates is the maximum amount of power your controller sends to the battery. Using 100 percent of available draw rather than 75 percent will only make the bike a couple mph faster. Instead, it will give more torque throughout its operating range at the cost of draining the battery more quickly.

I'm planning on building a control panel with the three-speed switch on it, but for now I can't say I miss it that much. I've rigged a jumper to give me full power when I want it, but mostly I just leave it off -- longer range and less stress on the motor.

If you still want the ability to switch, you'll have to rig up an on-off-on type toggle or rocker switch.