YAMAHA EASY.. Old pedelec ebike but the 24v mid drive unit has potential

[Deleted member 4366]

A 1k resistor costs about 20p from Maplin or any electronics shop. While you're there, get a 10k one and a 100k one just in case the 1K doesn't work. The size/power doesn't matter: the smallest cheapest one will do. It's not a mod. You just hold it between the pink terminal and the black one, then check if the LED on the control panel stops flashing.

It has a high probability of working, then you make your battery and you'll be home and dry. Alternatively, you can last it out a lot longer and waste a lot more time exploring other solutions.

 

[Beach Thorncombe]

OK. Understood.

 

[Beach Thorncombe]

Though I must add ...

I usually regard these forum exchanges as enjoyable, entertaining nuggets of communication where I, for example, like to explore every angle, highlight every option or, (at the very least), provide information, (or tease out information), that might, just possibly, enlighten fellow readers / members who might come across a similar challenge or issue themselves in the future when searching these forum entries for enlightenment.

Impatiently inviting me to pursue an offered option, especially when written in such a condescending manner as "Alternatively, you can last it out a lot longer and waste a lot more time exploring other solutions.", is neither encouraging or friendly ... and such an outlook suggests I shouldn't pursue my own story in a fashion that suits my inquisitive nature, but, instead just complete the quest in some anodyne, emotionless or prescriptive fashion.

I write in a style as to present a story encompassing a beginning, a middle and an end ... with the aim of asking, (even) dumb questions on occasions, just so a body of knowledge might be built up for, (similar), readers like myself who might not always comprehend the full meaning or reason for a slice of wisdom being offered.

So ... we might ask ...

Will D8veh's suggestion work? Will the flashing LED cease flashing once the transistor is introduced across the pink wire / black wire divide ... and will the motor spring to life when the machine is tested?

Well ... the revelation of that answer might be premature ...

I had wanted to put flesh on the bones of why the original system had included a thermistor, what its purpose for existing had been, (past tense) ... and why, even though redundant in some revised lithium based battery replacement solution, there was even a need to trick the systems circuit by introducing a resistor across the, aforementioned, wires.

Put another way ... it is one thing for seasoned, knowledgable Pedelec members to offer advice, (gratefully received), but it is an entirely different discipline to deliver the gift of knowledge including a meaning or reason or logic or EXPLANATION of why such a potential solution is being offered.

Put a third way ... WHY ON EARTH, having located a fabled mid drive unit of significant worth, would I even consider 'shorting' two electrical connections with a transistor* ... from advice I got from a guy on the internet ... without first knowing why such a precedure was being suggested?

So ... let me continue the intrigue.

I have to anyway ... because, living in deepest Dorset, there are no Maplins, Tandy or similar electronic shops for 20 - 40 miles ... though my friend John H will be rooting around in his loft tonight, having promised to deliver me an assortment of transistors, (and accompanying colour coded chart), first thing tomorrow morning.

Perhaps, between now and then, dear reader, a learned Pedelec member will explain WHY, (an ever so simple?), procedure involving a 20p transistor is, (almost certain, it seems), able to solve the issue I have brought to this forum.

And I repeat ... most of us, no doubt, appreciate the free and fluid knowledge seasoned members provide us on occasions.

However, it would be really nice to see a little humility being exercised in the decanting of such precious information ... rather than it being spat at us as if we were lesser life forms.

*Of course it isn't really shorting but ... I'd expect a reader to see my point!

 

[Beach Thorncombe]

I acknowledge that D8veh did offer an explanation for 'shorting' the connections with a transistor, (and I said as much in an earlier reply to him), but ... I'd like to know what a pull up resistor is and how voltage floats when nothing is connected.

Such terms are meaningless to most of us and, while the information may be useful to some, it probably goes right over the heads of us mere mortals.

 

[D8ve]

I'm just theorising but a thermistor changes resistance with temperature.
So if cold it's one value and hot another. So a feed line with inbuilt resistance will float high until a low resistance to earth(0volts)is added at which point it drops to virtual zero volts. This change of voltage would let your controller know that the battery was to hot and switch off power to prevent damage.

 

[Beach Thorncombe]

Hi D8ve,

Yes. My friend, John H, initially explained to me that a thermistor can cut out, (or deliver a value) when it detects heat, (EDIT - or realise a temperature has been reached), for example, when charging a battery, halting the process of charging, not necassarily when a battery is full but when it reaches a certain temperature. (That's my layman's language for decyphering John's words anyway).

THANK YOU for explaining the 'floating' scenario.

Yes. John also said that a thermistor can deliver those two opposing values and, he said, therefore, (in certain circumstances), a thermistor can perform different roles.

Your explanation helps me comprehend those points.

 

[flecc]

I had wanted to put flesh on the bones of why the original system had included a thermistor, what its purpose for existing had been,

To answer this question in a bit more detail, NiMh cells have very gradual change in voltage when nearing the end of charge, so a full charge cut-off at a certain voltage is very imprecise.

Therefore their cutoff is by temperature reached. An NTC (negative temperature coefficient) thermistor is placed against a cell within the battery pack to sense the temperature.

The accompanying NiMh charger has a low voltage circuit through the thermistor's resistance to ground, so this is able to signal to the charger when to stop the charge with the battery fully charged.
.

 

[flecc]

I have to anyway ... because, living in deepest Dorset, there are no Maplins, Tandy or similar electronic shops for 20 - 40 miles ... though my friend John H will be rooting around in his loft tonight, having promised to deliver me an assortment of transistors, (and accompanying colour coded chart), first thing tomorrow morning.

If you are anywhere near Dorchester, Dorchester Cycles have plenty of experience with the Giant Lafree which used NiMh batteries.

And if you'd mentioned your remoteness I would have immediately offered to first class post you the necessary resistors and details free of charge. D8veh would probably also have offered, since he has done similar and very much more for many forum members.

As for trusting advice seen here, just look to the left of the advice for when people joined and how many posts they've made. We wouldn't survive very long in a forum of this sort if we gave unreliable advice.
.

 

[Beach Thorncombe]

Thank you for the additional information ... and the offer of material support.

Your Dorchester comment addresses an earlier comment I made in post #40 when I asked; "Sure. The tech is 13+ years old but ... are there any contemporary style ebikes, (only half that age), that might still have spare parts / battery cases on a shelf somewhere?"

It's good to know that Dorchester cycles have experience regarding Lafree batteries and may be able to address related questions ... or offer support should I need specific nimh advice.

Of course I value and appreciate advice offered here, and said so by making sure I weaved such acknowledgement into my previous comments.

I don't intend to revisit my earlier frustration by adding additional comment other than to merely whisper, (less I ignite my own indignation), that I didn't appreciate the "wasting time" comment of the, otherwise, sterling advice I was offered.

I'm an inventor and wasting time is part of the job description!

I enjoy bathing, (up to my neck), in challenge, exploration and experiment so am never, ever, likely to take a well trodden path when there may be some, exciting, unexplored continent of a topic or conundrum to investigate.

That's the fun of it ...

I'll report back after the resistor procedure has been performed.

Thanks to all for the comments presented here so far. It is genuinely appreciated.

 

[flecc]

"Sure. The tech is 13+ years old but ... are there any contemporary style ebikes, (only half that age), that might still have spare parts / battery cases on a shelf somewhere?"

I did see this but didn't respond since there are no relevant spares that I know of and others have been seeking Lafree NiMh battery cases without any luck.

Basically e-bikes only started to appear in any numbers from 1999 and largely used two battery technologies to the mid 2000s, NiMh with the related NiCad, or SLA (sealed lead-acid). The relatively small sales during that era meant spares and service backup were often very poor, even non-existent.

Then from the mid 2000s, mainly 2007/2008, it was all change with the adoption of Lithium batteries, big advances in design of Crank Drive motors and greatly increased control sophistication of all motor systems.

So there's very little from the past that's relevant or available, and even knowledge of most of the older kit is sparse.
.

 

[Danidl]

I acknowledge that D8veh did offer an explanation for 'shorting' the connections with a transistor, (and I said as much in an earlier reply to him), but ... I'd like to know what a pull up resistor is and how voltage floats when nothing is connected.

Such terms are meaningless to most of us and, while the information may be useful to some, it probably goes right over the heads of us mere mortals.

Hi do you have a rudimentary knowledge of electronics?
Even electronic engineers are mere mortal, I have yet to see one walk on water, and it is an area in which I have been teaching for decades.
If you measured 5.1v then you presumably had access to a multimeter and you measured across two connections as one can only measure voltage difference. Voltage is a meaningless term. Voltage difference has meaning
This voltage as measured on the meter may come from any number of sources including radio frequency interference. The input resistance of a typical multimeter is set at 10 megaohms, so even minute signal power can generate a measured voltage. The suggestions by my learned colleagues of putting a resistive load to ground of 10k 100k was first to eliminate this possibility. If the 5v remains present when this load is connected would prove that there was a voltage source present capable of driving 0.5mA. if a 1k resistance is used it would have to be capable of 5mA. . This first test would prove that the volt source was real and is part of the process of moving from fantasy to fact.

Many electronic circuits provide a voltage via a source resistance and if a current is drawn then an action results e.g pulling in the contacts of a relay . This is a typical action of A mechannical switch used with electronics is to feed one contact of the switch with the voltage via this source resistance and the other contact of the switch is connected to ground , closing the switch pulls current , the voltage on the live side of the switch drops to zero .

By selecting these resistance values, these colleagues were ensuring that the maximum current which would flow would remain at a safe level.

In the matter of thermistors in NiMh battery packs, the purpose is to protect the battery from overcharging. As the battery charged up, it's voltage increases towards a plateau. Close to full charge, the input energy is inefficien ly converted to chemical energy and progressively more is turned into heat. This causes the battery pack to warm up and the RATE of temperature rise is picked up by the thermistor embedded in the pack. This is used on a third wire, as a signal to disengage the charger . There would be no call for it to be used in the battery discharge mode

As a final aside,in my opinion, your comments about the assistance given to you by the experts within this forum was ungracious.

 

[Beach Thorncombe]

Is this online watering hole a public forum for all ... or a fiefdom ... for just a few?

I completed my electrical apprenticeship in 1976 while working as a contractor within the Westlands Group. (Now AgustaWestland). Obviously, now 60, I can't claim to have kept up with those regs but, yes, I have a rudimentary knowledge of electrical engineering and electronics.

You boast of your decades teaching so that, reasonably, allows me to boast a little also!

Aside from a career in Construction, (and Local Government), I've been International Inventor of the Year and International Engineering Inventor of the Year and won international awards and accolades for design ... and altruism!

Maybe that is why I find the "expert's within this forum", (your words), so intransigent in the manner and fashion they, sometimes, deliver their views. I mean; A little flair, charm and humanity accompanying their literary musings might knock the sharp edges off their, often, automated technical contributions.

The experts you highlight, are members on a niche interest, cycle based, website, not candidates for the Lucasian Chair of Mathematics.

And how many more times would you like me to write, (and repeat), how grateful and appreciative I have been for members suggestions, ideas and theories presented here?

As I have said, (above), I don't intend to revisit the subject but if ungracious is a demeanor parallel with uncompromising, forthright, frank, plain speaking, candid or direct then, sure, I'll accept your particular interpretation.

Thanks for the expansive and comprehensive explanation of points I had asked to be explained or clarified. I very much appreciate the time you took to, clearly, lay out the material you presented here. Thank you.

I shall now, graciously, remove myself from this post because, having read some very unfortunate remarks elsewhere on this site, I am keen to avoid being drawn into the sort of bitter online confrontation I have witnessed contributors of this very thread getting themselves involved in.

For those of you who enjoy any excuse to vent your spleen, please feel free to scold or chastise me further ... (for merely stating that I didn't appreciate one minor comment from one contributor here) ...

Be my guest ... but don't expect me to respond.

That would just encourage you further!

 

[flecc]

Maybe that is why I find the "expert's within this forum", (your words), so intransigent in the manner and fashion they, sometimes, deliver their views. I mean; A little flair, charm and humanity accompanying their literary musings might knock the sharp edges off their, often, automated technical contributions.

You came in asking for help and suggestions, but when you received a good suggestion you avoided trying it. You then explained you'd rather try things your own way in order to learn.

So why ask in the first place?

Little wonder that d8veh didn't return to the thread after your response.
.

 

[shemozzle999]

Here is the drive unit ... and here's an intriguing thought ...

The unit looks very bespoked ... and the actual bike has a weird frame, (certainly not like a regular familiar frame) SO ... until I were to dismantle it, I'm of the opinion that it is unlikely that the unit could be removed and installed on some newer, more traditional frame ... though I might be wrong and, perhaps, by rotating it and making use of some, currently, unused spare threaded lugs, (covered with rubber bungs at present), it might just make itself a portable mid drive I could use elsewhere.

View attachment 16824 BELOW are the three lugs or pins or blades ...

Is this setup an industry standard ... or was it ... in the days of Nimh batteries?

View attachment 16825 And here, (below), we can peek inside the empty key barrel assembly and spot the heavy duty black and red cables in the foreground ... and the other thinner cable beyond. (Unless I can crack / resolve / complete this simple looking puzzle, I can't easily test the motor).

Frustrating, eh? All I need to know, (based on building a replacement 24v lithium battery), is what voltage goes to what pin?

I read elsewhere online that, possibly, the red wire takes + 24v, the black takes the earth / negative - and the little wire takes 12v, (The arrangement sounds similar to what D8ve stated re delivering voltage to the controller / box), but the info was written so ambiguously, I wouldn't dare try that unless I got some consensus here.

View attachment 16826 OK. She's not a looker, (below) but ... allegedly, while a basic workhorse running on only 24v, she can climb walls with that efficient, clever, mid drive unit. (I say clever but that is only true if we assume she has got a torque sensor). In any event, she only cost me £35 at auction.

View attachment 16827

This one up for sale - has spare battery and charger - may sell separately if contacted - might even have manuals as owned from new - contactable via email or telephone.

http://www.freeads.co.uk/uk/buy-sell/leisure-hobbies/sports-equipment/bicycles/electric-bikes/32020755/yamaha-easy/view

 

[Beach Thorncombe]

Wow!

Well spotted, Shemozzle.

You are right. It is worth me contacting them.

Thanks. x

 

[Beach Thorncombe]

Email sent.

I've enquired as to the possibility of the seller selling me their spare battery on its own. (And I've asked about the manual).

I am still planning to build a modern lithium pack for my machine but an original battery would, obviously, be ideal to return the Yamaha to 100% complete status. (I could even replace the original battery packs nimh's with 18650 if I aquired such a pack and felt the urge to upgrade it).

Nice.

 

[shemozzle999]

If the seller does not want to split the sale up it would be handy to know the resistance of the NTC thermistor @ room temperature by measuring it across the negative and thin wire terminals.

With a known value you can purchase a replacement and permanently hook it up between the terminals thus simulating the original battery characteristics.

 

[Danidl]

Is this online watering hole a public forum for all ... or a fiefdom ... for just a few?

I completed my electrical apprenticeship in 1976 while working as a contractor within the Westlands Group. (Now AgustaWestland). Obviously, now 60, I can't claim to have kept up with those regs but, yes, I have a rudimentary knowledge of electrical engineering and electronics.

You boast of your decades teaching so that, reasonably, allows me to boast a little also!

Aside from a career in Construction, (and Local Government), I've been International Inventor of the Year and International Engineering Inventor of the Year and won international awards and accolades for design ... and altruism!

Maybe that is why I find the "expert's within this forum", (your words), so intransigent in the manner and fashion they, sometimes, deliver their views. I mean; A little flair, charm and humanity accompanying their literary musings might knock the sharp edges off their, often, automated technical contributions.

The experts you highlight, are members on a niche interest, cycle based, website, not candidates for the Lucasian Chair of Mathematics.

And how many more times would you like me to write, (and repeat), how grateful and appreciative I have been for members suggestions, ideas and theories presented here?

As I have said, (above), I don't intend to revisit the subject but if ungracious is a demeanor parallel with uncompromising, forthright, frank, plain speaking, candid or direct then, sure, I'll accept your particular interpretation.

Thanks for the expansive and comprehensive explanation of points I had asked to be explained or clarified. I very much appreciate the time you took to, clearly, lay out the material you presented here. Thank you.

I shall now, graciously, remove myself from this post because, having read some very unfortunate remarks elsewhere on this site, I am keen to avoid being drawn into the sort of bitter online confrontation I have witnessed contributors of this very thread getting themselves involved in.

For those of you who enjoy any excuse to vent your spleen, please feel free to scold or chastise me further ... (for merely stating that I didn't appreciate one minor comment from one contributor here) ...

Be my guest ... but don't expect me to respond.

That would just encourage you further!

Hi
I suspect that we have differing opinions as to what constitutes grace.That topic I will not address further.

However to technical matters.

1. You have not indidated the source by which you achieved 24v to apply across thick red and black cables . This matters as the motor and electronics will expect to draw up to 20amp on initially starting up. If you are using car or mobility scooter batteries these will be ok, but smaller sources will not supply sufficient current.
2. If you decide to replace or install Li ion batteries be sure to use an appropriate charger, preferably supplied by the vendor who has supplied the battery. There will be slightly different chemistry from different vendors and what one considers full charge might be excessive on a different battery.

3. In the matter of the third wire and the missing barrel switch, my instinct is that it is was intended to control power flow. There is no logical reason for having a single wire going back to the switch area, unless there was a lamp there.
The barrel switch would have likely had the following positions
open ... Allowing the battery pack to be removed the key could be removed
closed ... Locking the battery pack in place but no ignition. The key could be removed
Ignition .... Locking the battery pack in place and energising the power circuits . The key locked in place.
This would have allowed the designer to use a cheaper low current switch, than one rated with 30amp DC contacts.
I think that in one of his early posts, dv8 suggested that possibility.

The fact that you got a pulsating led light is very good news because it indicates that electronics are functioning. ... It needs intelligence to periodically turn on and off a circuit. Were it on constantly it just means that power is present.

What component is used to control the power inside the controller cannot be determined without either a circuit diagram or opening the unit up. However because it uses 5v I suspect that it is controlling a digital logic gate and connecting it to ground via a resistance, will start the process.

I have no further interest in assisting you further.

 

[Beach Thorncombe]

Season of good will. (As they say).

I apologise, D8veh …

I might reflect … NO. I do reflect, (and admit), I should not have been so pedantic in reading too much into your ‘wasting time’ comment … and should have just appreciated the sentiment of your observation regarding the simple task of, (hopefully), just getting the job done …

And … forum experts?

Sure. I was posting on the technical forum so should have appreciated that, unlike some social forums I am used to, it would be quite normal to expect ‘matter of fact’ advice, (delivered in a practical way), rather than in emotive, expressive prose!

Yes. I conceed, it was ungracious of me to be so prickly.

I’m sorry …

I must have got out of bed on the wrong side!

John H is yet to furnish me with any resistors and, in another flashback of hindsight, I might have just ordered a few online … because John’s busy schedule has meant he was unable to get to me over the, (past), weekend.

No matter.

I imagine the resolution of the motor test, (either by using forum suggestions or other means), may not happen for a few days but I will report back any progress. (or success), as soon as I have any news to offer. (For the benefit of anyone else addressing similar issues in the future).

I’ve taken on board all the additional suggestions and thoughts posted in the last day or so and the collective mass of that information will, hopefully, eventually get the issue(s) resolved.

I don’t wish to fall out with anyone, (more than I already have), and will endeavour to try my best not to be so precious in the future.

Regards,

Beach x

P.S

Shemozzle. Yes. It would be useful to gain such info re the resistor spec but I'm not sure I'd be brave enough to milk that seller for such information or request they perform such a test!

Danidl. An excellent addition to the thread, especially the positive 'good news' deducing, (hopefully), that the system appears to be healthy in working well enough to even have the LED flashing.

I've absorbed the other points you have raised ... and welcome them.

... and I understand / acknowledge your final sentence.

Like Scrooge, (in a Christmas Carol), I think I have had time to reflect on the error of my ways!

EDIT. Oh. Forgot to add. I used two, (fully charged),12v, deep cycle, SLA's, (in series), to perform the 24v test so would anticipate they were adequate in replicating the power required to emulate the original, (missing) nimh cells. (Battery).

 

[flecc]

John H is yet to furnish me with any resistors and, in another flashback of hindsight, I might have just ordered a few online … because John’s busy schedule has meant he was unable to get to me over the, (past), weekend.

If you email an address to me I'll pop 1k, 10k and 100k resistors (identified for you) in first class post, no charge of course:

ebike@flecc.uk
.