Advice required on a brompton conversion

NRG · May 27, 2012

benjy_a said:
This is basically correct, the controller limits the Max current that the motor can pull. Many of the controllers are programmable such as those from Edward Lyen and E-Crazyman. I have a Lyen controller and to change the Max current takes a few seconds using my laptop and a supplied USB cable. I can set it from 1-30A.

Alternatively just buy a controller that has a suitable Max current for your motor which for you will likely be 15-20A.

Ben

Yes, the motor windings are more or less a dead short if connected directly to a motor so the current has to be limited to preserve the windings and also if a its a geared motor the nylon drive gears.

It's also worth noting the controllers mentioned aren't that accurate When limiting current ...they can be up to 5amps out so peak battery draw could hit 20 amps with a 15 peak rated controller...

dingrpdl · May 27, 2012

slippa said:
I've ordered a cycle analyst which I understand I can use to limit the current.

Yes you can. But it will require extra wiring and soldering.

The Cycle Analyst limits the current by overriding the throttle signal. So the throttle signal has to be routed to the CA and then the modified signal routed to the controller. I believe you will have to do some soldering to the CA circuit board because the throttle signal input/output wiring harness is not provided. The manual shows how this is done.

Richard

jhruk · May 27, 2012

Thank you all for the explanations but I'm still a little unsure as to why the motor would get burnt with the more powerful controller. Is it because when the motor is under full load up a hill, it continues to pull as much current as it can and if the controller lets it pull too much, that's when it gets burnt?

Yes, the danger zone for these motors is when hill climbing. If the speed starts to drop off the motor will try to draw more power, but as it slows it also begins to lose efficiency and more of the power starts to go into heating the motor rather than driving it forward. If this carries on it will eventually overheat and fail. That’s why it’s important to keep the speed up, so that the motor operates in its most efficient range. If you can limit the current the motor can draw you will also limit, or at least delay, the degree of overheating.

The controller has a current limiter to protect both itself from supplying too much current and the motor from drawing too much current.

Is it possible to somehow limit the amount of current it can pull by modifying it?
Also, how do you determine how many amps a controller will deliver?

Most controllers have their set current limit on the label. As has been said some controllers can have their current limit programmed, others can by adjusted by modifying the shunt inside.

The KU63 supplied with my 36v Q85 has a current limit set at about 14amps, which give the motor a maximum draw of around 500watts. If you’re wanted to run the motor at 48v, and maintain the same maximum power, you’d need a current limit of 10.5amps. However, you can usually push these motors a little and I’d have thought a limit of 12-14amps should be ok if you’re careful with it.

I suggested using a different controller because the KU123 is rather large and might be difficult to place on a Brompton. The KU123 will work with the Q85, but unless you modify it to reduce its maximum current I think you’ll most likely overcook this little motor before long.

I've ordered a cycle analyst which I understand I can use to limit the current.

I haven’t any experience of the Cycle Analyst but it sounds as if it may do the job. Its other features are useful as well - I always keep a Watts Up meter connected on mine.

benjy_a · May 27, 2012

dingrpdl said:
Yes you can. But it will require extra wiring and soldering.

The Cycle Analyst limits the current by overriding the throttle signal. So the throttle signal has to be routed to the CA and then the modified signal routed to the controller. I believe you will have to do some soldering to the CA circuit board because the throttle signal input/output wiring harness is not provided. The manual shows how this is done.

Richard

This is not 100% true...what you are talking about is having a total current override (pre throttle) which the cycle analyst manual describes briefly. This does require soldering to the CA circuit board.

You can however limit the current and top speed on the Cycle Analyst without wiring and soldering but it takes some tweaking to get it reliable and not fluctuating around whatever level you have set. It also relies completely on having the cycle analyst set up correctly calibrated and displaying the correct current in the first place....as I have found myself its not that straightforward.

If I were in your position I would order a programmable controller, then you can play around with the levels gradually. When you are happy that nothing is overheating you can increase the peak current a little bit at a time. If you decide to go to 48v you can reduce peak current to protect the motor and wiring.

Ben.

banbury frank · May 27, 2012

Hi If you buy a controller with the infineon chip and the cycle annalist 6 pin connector like the link below

they make the cycle annalist just plug it in it powers off the controller

Now you can set away

Speed o meter put in diameter off Tyre it knows ever time the controller detects i rev from the hall sensors so very accurate

Set the max speed 15 MPH

set the max amps

http://www.ebikes.ca/store/photos/C3620-NC.jpg

http://www.ebikes.ca/store/photos/CA-LDP.jpg

Frank

benjy_a · May 27, 2012

banbury frank said:
Hi If you buy a controller with the infineon chip and the cycle annalist 6 pin connector like the link below

they make the cycle annalist just plug it in it powers off the controller

http://www.ebikes.ca/store/photos/C3620-NC.jpg

http://www.ebikes.ca/store/photos/CA-LDP.jpg

Frank

Hi Frank you are correct and they are great controllers. I have a 20A version which I've used for the last 18 months but its not programmable...but it was supplied with the exact values to set up the cycle analyst properly and easily.

My new Lyen Infineon programmable controller also has a cycle analyst direct plug in connector and is in my opinion (owning both) the better controller as it is physically smaller and can supply up to 30A as well as being fully programable. I cannot yet compare reliability as I have only just started using the Lyen.

I sound like an Ed Lyen salesman but as I own both discussed controllers I feel in a good position to comment. The support offered me by both Justin at ebikes.ca and Ed Lyen has been outstanding. On paper I just feel the ability to program ones controller wins hands down.

My only (slight) gripe is that the Lyen controller was supplied without an exact, measured Rshunt value which you absolutely need to get the cycle analyst calibrated. So...I am still tinkering to get it set up properly.

I would say if you want direct plug in and go, not bothered about programming the controller then go for ebikes.ca (I have a 20A if want to buy it from me! ) but....if you want smaller and more powerful with the ability to program...contact Edward Lyen through the endless sphere forum but be prepared to have to calibrate things yourself.

Good luck whatever you decide.

Ben

dingrpdl · May 28, 2012

benjy_a said:
This is not 100% true...what you are talking about is having a total current override (pre throttle) which the cycle analyst manual describes briefly. This does require soldering to the CA circuit board.

Ben.

I should have been more specific. I was referring to the method method he would have to use on the Cycle Analyst with his KU123 controller as the KU123 does not have a direct plug-in port.

Another mod others have done with the KU123 to limit the current is to cut one of the two current shunts on the board. This will reduce the current limit to about half of what it currently is. However, it is a lot of work as you will have to tin or shave the second shunt to get the current limit you want. If you are not comfortable with working on circuit boards, then it might be easier to just buy another controller.

Richard

benjy_a · May 28, 2012

dingrpdl said:
I should have been more specific. I was referring to the method method he would have to use on the Cycle Analyst with his KU123 controller as the KU123 does not have a direct plug-in port.

Another mod others have done with the KU123 to limit the current is to cut one of the two current shunts on the board. This will reduce the current limit to about half of what it currently is. However, it is a lot of work as you will have to tin or shave the second shunt to get the current limit you want. If you are not comfortable with working on circuit boards, then it might be easier to just buy another controller.

Richard

Ah ok yes I see what you mean...I wasn't thinking about the controller with no CA connector.

Ben

benjy_a · May 28, 2012

slippa said:
ok - I've requested the KU123 controller be removed from my order and I've asked Edward Lyen for a quote on a 6x4110 Mini Monster Programmable Controller LYEN Edition shipped to the UK.

The costs are certainly adding up now but its less than a Nano I suppose and I'll have a more flexible kit.

Thank you for all the advice so far. I'll no doubt struggle with connecting it all up too so may need some more advice in a week or two.

Cheers
Slippa

I think you have made a good decision...if you have a look at my thread on my electric Brompton build you will see where I have fitted my lyen controller.

Make sure you order the correct one for your motor... ie sensored or non sensored. I can't recall if your motor has sensors or not. Also you will need to specify the cycle analyst connector.

Ben

NRG · May 29, 2012

Dont bother faffing about with ttl adapters, get the cable of e-crazyman which has the ttl and switch to program inbuilt, you may have to contact him if its not listed on ebay:

I also recommend his controllers, essentially the non modified versions of Lyens...you need to add the programming port header yourself but its no big deal..

benjy_a · May 29, 2012

slippa said:
Actually - I think I can get the USB-TTL programming adapter for a bit less on ebay:

usb to ttl adapter | eBay

I'm not sure if the E-crazyman controllers come with a Cycle Analyst connector but if they do then it would be cheaper than the Lyen. I would personally recommend getting everything from the same supplier for compatibility whichever you decide to go with. You would be better off with Ed Lyens (modified) software for programming his controller if that's what you go for. The lead that Ed Lyen supplies looks exactly the same as the E-crazyman depicted by NRG above. Just install the software, plug it in and go...no faffing around required; for $15 I wouldn't mess around with other leads which may not work.

I have tried other controller programming software with my Lyen controller (for fun) and cannot get it to work properly. I'm sure if you are more technical than me and good with programming etc then you could get it to work. For me I like to make it as easy as possible!
Ben

benjy_a · May 29, 2012

Good choice...mine all works very nicely; good luck with putting it all together when you have all the bits.
Ben

jerrysimon · May 29, 2012

slippa said:
I'm pi$$ed off with BMSBattery at the moment as I ordered last week (23rd) and now they are saying that my order won't be shipped until this Friday taking at least a week to get to the UK. That is also with me contacting them and complaining over their chat system as they sent me an email message today saying my order wouldn't be shipped until next week! Something to keep in mind when ordering from bmsbattery - you will be waiting 2-3 weeks to receive your order.

To be honest I have found this to be the case with nearly all my orders direct to China. Even if you get them to confirm items are in stock and ready to send, they will pretty much say anything to get the sale.

I have found patience is the only answer when dealing directly with suppliers from China. They always come through, just often delayed.

Regards

Jerry

Advice required on a brompton conversion

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