Cyclone Motor Mid-Drive Guide for IDIOTS Needed!

[KAZUALT]

Does this look like a cyclone to NuVinci Hub ?

http://farm4.static.flickr.com/3509/399 ... 6602_b.jpg

I really can't tell. It looks like a Nuvinci Hub. Very sturdy lookin frame, looks like that trike will go off road with no problems.

kentlim,
I will make sure I am understood. Even if the 24v works I still am going for the 36v just incase I want to up the volts.
\

KAZUALT

 

[boostjuice]

Boostjuice, I read your post about the Kelly controller, that Cyclone offered, limiting the RPM of the 1000w motor.
I run one of these motors with the standard Cyclone controller in my cruiser and am really happy with it.
I was considering ordering another 1000w motor and amping it up to get the 3000w for an offroad bike.
My questions are;
1) Does the standard 1000w controller have areas that can be beefed up for more "short term" amp handling. I have read your other posts about these controllers and recall that the body of the controller gets flooded with heat fairly quickly.

The standard controller does it's job reliably if used with a correctly geared motor (such as on your direct drive/internal hub cruiser). The problem is that Plug&Play Cyclone 1000W kits (nowadays "1500W" according to Cyclone ) are not geared down enough, and hence the warning listed on their webpage about "controller will burn if overload more than 30 secs", which is Cyclone’s poor explanation of a usage limitation due to poor kit design.
The issue is that unassuming customers buy these kits and often bolt them onto 26" wheeled bicycles. With a 6T motor sprocket driving a 44T chainring that’s a 7.33 reduction to the cranks/BB. The customer then thinks that when pedalling at his/her natural pedal cadence (~60>75RPM) that the motor and controller will be happy doing their job just fine, afterall that is what the kit's marketing suggests right? WRONG!
Under these circumstances the motor is spinning at only 440RPM>550RPM which is about ~30/35% efficient according to the dynometer chart. This is unsustainable to both the motor and the controller. Both heat up quickly and if the temperature sensors don't trip in or are un-calibrated (it seems they often are) then out comes the magic smoke. Most kits will survive if the motor is only loaded at low RPM for a short time whilst accelerating from a standstill and if the selected gear denies pedalling (keeping the motor RPM higher). However under continuous high loading at low speeds or in the wrong gear (gears that allow pedalling), the controller will inevitably blow once the thermal mass of the heatsink is swamped.
So without Cyclone advertising it, the current non-planetary Cyclone kits will only be reliable on bicycles that can't be effectively pedal assisted. 20” wheeled bicycles make things a bit easier due to the higher wheel RPM for a given speed, but as GGoodrum has stated in the past, the pedals are still effectively useless as an assist.
What Cyclone should do is start offering direct drive non-planetary motor kits that drive a large sprocket mounted next to a BMX freewheel on a Nuvinci/Internal hub. They do sell these components individually, but they don't yet offer a complete kit and most customers aren’t cluey enough to see the advantages of this setup over the standard kit.

Anyway, back to the controller.....
If the motor is gear reduced enough so that it runs within the more efficient part of its power-band, not only does the motor run cooler but it also demands less continuous current from the controller and due to the higher electrical RPM, the on-time duty cycle of the switching FET's decreases so they run cooler. (MOSFET's have far higher pulsed current ratings than continuous on current ratings. Their RDSon resistance increases exponentially with on-time)

In simple terms from a controller point of view;
Higher motor RPM => Higher electrical RPM => Lower phase current => stabalised RDSon (on resistance) => less heat => less chance of swamping the heat-sinking ability of the controller case => less chance of the FET junction temperatures reaching damaging levels => No dead controller

As to my past comments on upgrading my Headline controller; I first looked at upgrading the FET’s to higher current, lower RDSon versions but soon realised that they were pretty darn good already -and expensive, $12 each! If they weren’t already large TO-247 package devices I might have upgraded from TO-220>TO-247 for the reduced junction to casing thermal resistance and higher current ratings, but of course there was nothing to gain here. Based on my guesstimate of the casing’s thermal mass and heat dissipation, the datasheet suggests the standard MOSFETS are capable of more pulsed current than the controller is rated for so what I did was lower the resistance of the power shunt from the standard 15milliohm down to 10milliohm resulting in a theoretical 50% increase in current switching. I did this by soldering a 30milliohm 5W resistor in parallel with the existing three. This tricks the microcontroller into thinking it hasn’t reached the maximum current limit which according to GGoodrum is 55A (I haven’t yet installed my Cycle Analyst so haven’t tested it myself). Together with this, I also flooded the enamel free sections of the power traces with solder to bolster their current carrying capacity. Visually, I considered these PCB traces the weakest link in terms of resistance between the battery pack and the motor. How much this is helping I don’t know, but I guess every little bit helps. Oh and I also swapped out the 10AWG wires (50A continuous rating) for 8AWG wire (75A continuous rating) that lead through the casing to the PCB. Theoretically it should now be a 82.5A controller but I will wait until i have some Cycle Analyst data before I start recommending this procedure to others.
By the seat of the pants, the motor now feels more powerful after the controller mods and I haven’t noticed substantially more heat from the casing judging only with my hand. I might even be able to extract more power by lowering the shunt resistance further, but without more sophisticated temperature logging I am reluctant to take the risk.

2) Is there a Kelly or other brushless controller that can be used to supply 100amps to this motor.
Thanks heaps for all your other great info.

The problem with most off-the-shelf powerful e-bike sensored controllers is that they are designed primarily for hub motor use. Although the majority of hub motors have high pole counts, they spin slow for an electric motor as they must of course match the wheel speed. However some hub motors have smaller higher speed motors within them that are geared down by internal planetary gears so as to decouple the motor speed from the wheel speed and achieve more efficient low speed/hill climbing performance. BMC makes a model like this, and Kelly controller recently released a modified version of their 72V/75A continous controller with a higher electrical RPM to enable use with these motors. I suspect they would be a worthy candidate for dumping more current into Cyclone motors.

http://www.newkellycontroller.com/product_info.php?cPath=24&products_id=624
With a 70000 electric RPM, on the 24 pole cyclone 1000w motor, it would be good for (70,000/24) = 2917 Mechanical RPM, probably just enough to use the best of the power-band, but you may loose a bit of top speed on your current setup as you only have 3 widely spaced gears.

Although these controllers allow higher than the intended 48V motor voltage, i would be inclined simply to use it for it's increased current capability which at 48V would be about 48V*75A continuous = 3.6kW continuous. Upping the voltage would spin the motor faster, drop efficiency and require a change of gearing.

 

[1000w]

Thanks boostjuice, great info and heaps of it.
I will open my controller up and see if I can work out where the resistors are that you mentioned.
Are 30milliohm 5W resistors easy to come by?
I currently get a max amp reading of 53amps on my wattsup so I will be able to see any change if I do the mods.
If it's no trouble to you, would you post a photo of the modded controller?
Cheers,
Matt.

 

[boostjuice]

This is the resistor i used;
http://au.farnell.com/vishay-dale/lvr-5-03-1-e73-e3/resistor-precision-0-03-ohm-1/dp/1108085
I see the minimum order quantity has gone up to 5 since i ordered them which is a pain.

My controller is weatherproofed with silicon so i can't dissassemble it without the headache of resealing it.

This is 'Rhyteeo3's' photos showing the standard shunt resistors;

They are mounted between the PCB and the bottom of the casing to take advantage of the thermal transfer/heatsinking which they really do need. To mount a 4th shunt resistor in parallel next to the existing shunt resistors requires an annoying dissassembly of all the clamped FETS and reapplication of thermal grease for reassembly. I did this, but in hindsight it might be easier to install a power resistor heatsinked somewhere convieniently to the side wall of the casing and then flywire high current leads between it and the shunt resistor solder pads (being through hole components they are accessable on both sides of the PCB).
One of these 30W TO-220 resistors would be more than adequate and save all the disassembly hassle.
http://au.farnell.com/bourns/pwr220-2far030g/thick-film-resistor/dp/1624518
http://www.bourns.com/data/global/pdfs/PWR220F.PDF

For god knows what reason, Headline electric designed these controllers with stupidly high value shunt resistors (~10X higher than the standard 45A Cycle Analyst shunt). As a result, they dissipate a a$$load of heat and really do need to be heatsinked or the air cooled power dissipation rating would be exceeded.
Here's the maths for those who care;

EDIT: I have since discovered that this estimate of a 0.825V shunt threshold is wrong! I have now researched the BLDC controller chip datasheet to discover that it is either 0.5V or 1.23V depending on chip option used. Cyclone appear to use both options in different models of controllers. Either Hitachi ECN3031F or ECN3030F. The following calculations should be reworked with knowledge of chip option used

V = I x R (peak voltage accross the standard shunts = peak controller current x shunt resistance)
V = 55A x 0.015 Ohm = 0.825V across standard shunt resistors

P = I x V (peak dissipated power shared between parallel shunt resistors = peak controller current x shunt voltage)
P = 55A x 0.825V = 45W (each of the 3 standard shunt resistors are only rated at 5W each air cooled and what a waste of battery power :x )

I = V/R (new peak controller current = microcontroller peak shunt voltage threshold / new total shunt resistance)
I = 0.825V/0.010 Ohm = 82.5A

P = I x V (peak dissipated power shared between parallel shunt resistors = peak controller current x microcontroller shunt voltage threshold)
P = 82.5A x 0.825V = 68W

1/3rd of total shunt power is dissipated by the additional 30millOhm shunt resistor
68W/3 = 22.7W (additional 30millOhm shunt resistor must handle peaks of 22.7W)

 

[rhitee05]

boostjuice,

Thanks for the photo credit! :wink: Reading through your discussion about the shunts, I'm trying to understand something. Do I understand you correctly that the stock set of shunt resistors on the 55A controller are 15 milliohms? I would've expected them to be lower. The stock resistors on my controller, the 30A version, work out to be 16.7 milliohms. I would expect something around 10 milliohms for a 55A limit, so the shunt voltage remains constant. That would work out to be somewhat less power dissipation, too. Just curious.

 

[heathyoung]

Yep its a crazy high resistance for a shunt resistor ~ probably means they dont need so much gain for their opamp + better noise immunity.

 

[KAZUALT]

Ok I just ordered my 650watt motor with 2 freewheels. Gonna have to wait for the 36v external controller for a couple of weeks. In the mean time I am going to build a battery pack out of DeWalt a123 cells. As I understand it because of the output characteristic of these cells a 36v 10ah pack would run this setup nicely. Is this correct? If not, what would be best? I have 20 cells now with 10 more available if I need them. I know I asked the battery question before I was just wondering if there was a big difference using these batteries with the Cyclone 650watt Motor.

KAZUALT

 

[boostjuice]

boostjuice,

Thanks for the photo credit! :wink: Reading through your discussion about the shunts, I'm trying to understand something. Do I understand you correctly that the stock set of shunt resistors on the 55A controller are 15 milliohms? I would've expected them to be lower. The stock resistors on my controller, the 30A version, work out to be 16.7 milliohms. I would expect something around 10 milliohms for a 55A limit, so the shunt voltage remains constant. That would work out to be somewhat less power dissipation, too. Just curious.

Actually, a 16.7 milliOhm parallel value of shunt resistors within the 650W/720W 30A controllers makes sense mathematically if scaled with the 900W/1200W controllers. You must remember that the 900W/1200W controllers are lablelled as 35A on the casing sticker. This rating is probably for continuous current. Like most controllers, the peak current is a fair bit higher -in this case 53A~55A according to Matt and Gary's findings. The peak current for the 650W/720W controllers would be ~47A if scaled to the continous current rating by the same percentage.

Continous current - 30A : 35A = 1 : 1.17
Peak current - 47A : 55A = 1 : 1.17
15milliOhm : 16.7milliOhm = 1 : 1.11

As you can see the ratio's are pretty close for a 0.825V threshold accross the shunts;

EDIT: I have since discovered that this estimate of a 0.825V shunt threshold is wrong! I have now researched the BLDC controller chip datasheet to discover that it is either 0.5V or 1.23V depending on chip option used. Cyclone appear to use both options in different models of controllers. Either Hitachi ECN3031F or ECN3030F. The following calculations should be reworked with knowledge of chip option used

All this assumes that the max-current-shunt-threshold-voltage that the microcontroller triggers at is the same between both controller versions. It could easily be made different through different programming or different pre ADC Op-amp gain.

 

[boostjuice]

Yep its a crazy high resistance for a shunt resistor ~ probably means they dont need so much gain for their opamp + better noise immunity.

Agreed. However it's no excuse for the circuit desinger. Other controllers manage fine with shunt values around 1milliOhm, and noise can always be integrated out. It doesn't have to be so fast in it's current throttling response that noise filtering is unallowable.

 

[rkosiorek]

ages ago there was a thread that has lots of pictures of the mechanical guts of the motors. including total dissassembly.

http://endless-sphere.com/forums/viewtopic.php?f=2&t=8621&start=0&hilit=cyclone+naked

the 500W motor with internal controller can be changed to one with an external controller by ditching the original controller and ordering a replacement sensor board from Cyclone -TW. cost is about $30USD.

i have used the 500W converted to external using the older Crystalyte V1 - 72V 40A Analog Controller. the old analog design does not have an RPM limitation and works well.

the newer V2 digital design controlers do have an RPM limit and limit the speed too much.

rick

 

[1000w]

Boostjuice, once again thanks for the info and photos.
I have ordered a 30w 30mohm resistor from farnell.
Cheers,
Matt.

 

[KAZUALT]

OK I need a few last pieces of advice.
I am 2 days from ordering my cyclone motor and have a question or two.
I am going with the 650watt motor with a 48v controller and 2 freewheels.
Has anyone tried the split chain setup? If so what are the pitfalls I should look for when installing?
Would you use a 36v battery or a 48v. From what my limited understanding is, the ah gives power while v gives ride longevity. What is the best v-ah combo that give me both. My battery budget is slim so 30ah batteries are not possible right now. What would you start out with, if you had a limited budget?
KAZUALT

 

[gunthn]

Kazault,

You may want to reconsider the 48v as they are out of stock. I was ordering a spare and was told that I can only get the 36 which is supposedly the same.

The power is determined by the c rating and the voltage. It really depends on the pack and the gearing. TO get good 48v power you need 48v gearing and less amperage than the 36v. To get good 36v power you need that gearing and more amps by either c rating or ah capactiy. They can be equal depending on the setup. 36v is easier to gear down and get good cadence with.

good luck
Gunther

 

[KAZUALT]

gunther,
THanks for the info. THat kinda $#@!s Well looks like the 36v controller for me. I sold the DeWalt Packs I had, going to invest the $ in a 36v 20ah LiFePO4. That should get me down the road nicely. I am placing my cyclone order in the AM. I am hoping to see it in 3-4 weeks. Only thing that bothers me a bit is that I have found no one that has tried the split chain configuration. Aligning everything is my worry. But with the help of the folks on this forum, I should be able to work it out. After waitin for 6 months to raise the money, I am ready to get goin.
KAZUALT

 

[gunthn]

Kazault,

Yes I think the cyclone is not to hard to line up things. People have done just about everything you can do with them here. When you get the motor, just post a build and you will get attention from those who have done it. Someone here has used the double I am sure. They just haven't seen your request. I am only slightly newer to this EP than you so I am speculating on some level but maybe informed speculatiion :wink:

Paco can be very helpful too if you can demystify his English. I think they fool around with those motors endlessly. On the battery front if you want I can try and get a good deal from Ecitypower.com They seem to have very good prices but they have a certain mysticism to their ways as well. Batteries advertised one minute gone the next. I ordered some high C rate cells from them and I will see how they are. If they are good then I can say from my perspective that they have the best price around. Much less than Ping for the same product. A 36v 20ah of a higher C rate should give you excellent power and reliability and still allow you to peddle with the motor. Most 48s just go too fast to peddle with.

Well thats the game from my angle !

Gunther

 

[1000w]

I received my resistor today.

I loaded all the large traces with extra solder.

The extra resistor is installed under the main board on the right hand side. The green rectangle is a soft spacer that keeps the resistor pressed against the body/heatsink.

The results are great.
Peak amps have gone from 53 to 76
Peak watts have gone from 2500 to 3600.
I have done two 4ah/8.2km rides and the controller was bearly warm (cool evening approx 15C)
The power is awesome, the bike hits 60kmh in no time and hill climbing is unstoppable.
Thanks again boostjuice, your expertise is much appreciated. I'm stoked that such a simple mod can make such a big difference.
Cheers,
Matt.P.

 

[gunthn]

Matt,

As most controllers have not survived well when I have had internal contact with them(I am like the surgeon who leaves a staff infection, 1 week later and you're dead ), could you in more detail describe what, where and how you made this resistor mod happen? I know that boostjuice had the idea, but I can find little detail enough for this electronics neophyte.

Thanks,
Gunther

 

[KAZUALT]

Gunther,
Any help on getting the right battery for my setup would be greatly appreciated. It will take me about 2 weeks to raise the money for the battery. When I have the cash together I will PM you. I emailed cyclone today with what I want, hopefully I will hear back on the firm price later today. Since it will take a couple of weeks to get here, I have some time to do some research into split chain configuration. I might post a split drive topic to see if I can get more info. Trust me, as much help as this forum has been, when I do this setup I will be posting it from start to finish.
KAZUALT

 

[kentlim26]

as for a Single piece of crank, the aligment is bit difficult , but it can get it right. (clock wise is okay), as for using a 3 piece of crank,, that one (3 piece of crank) 100% no worry.. sure correct one. The chain tensioner,,, try to get a roller one.. it is better in anyway. not the 8teeth gear use for chain tensioner.

cheers
kentlim

 

[boostjuice]

Matt,
Nice innovative mounting solution for the additional shunt resistor
Nice and cheap mod eh. Its like upping the boost on a turbo car. Taking advantage of the manufacturers conservative headroom/tolerances :lol:

Unfortunately, from your photos i just realised i gave you the Farnell link for a slightly different resistor package to the one i intended (surface mount TO-220 rather than the easier to mount through-hole TO-221) but i see you managed to come up with an innovative way of clamping it to the casing without a small bolt/screw.

For others who may follow your graphic example, it would be easier to install a PWR221-2FCR030G rather than PWR221-2FAR030G.
i.e. this one http://au.farnell.com/bourns/pwr221-2fcr030g/thick-film-resistor/dp/1616339
This single letter difference denotes the difference in package type.

76 Amps peak is pretty close to the theoretical increase of 82A peak. Being that my calculations were based off Gary's 55A standard peak measurement and yours read 53A its actually quite close allowing for the scaling. The small resistance in the leads to the extra shunt may also be increasing the effective resistance enough to lower the real-world increase. Let me know what sort of temperatures you feel the casing get to during summer. Ive been waiting until the hot parts of the year to see what sort of temps it gets to on a 40 degree scorcher. If it doesnt feel critically hot i might consider replacing my 5W 30milliohm throughhole shunt with a 15>20milliohm TO-221 version. See if i can get over 100amps out of the sucker

Im glad to see you went the whole way and bolstered the power traces with solder, as you can tell by their enamel free design, they were intended by the circuit designer to be flooded with solder, but like so many competitive asian manufacturers they likely avoid doing it to save a skeric of $ on manufacturing costs.
You probably also noticed that several options on the PCB are unpopulated such as the motor direction external switch and the power disconnect relay. Again, likely cost savings.

Although iv'e had this mod running reliably for about 6 months, i have been reluctant to advertise the instructions due to the high likelihood of someone with inadequate skills stuffing up and blaming post-modified inoperation on my instructions rather than their own bad work. Many people dont realise how easy it is to kill Electrostatic sensitive parts like FET's and hence end up with unworking circuits, not knowing what they've killed and hence which part to replace.

So for others who may attempt this mod.
-Only attempt this if you are patient and precise when working with small fiddly parts
-Can solder adequately (Im pretty sure these boards are built with Lead-free solder. Do not mix Lead-free and Lead solder)
-Use an anti-static strap whenever handling the PCB/components
-reapply thermal grease in correct quantity to the right areas if removing the PCB from the case for power trace bolstering

If your cool with all this then GOOD LUCK!

 

[gunthn]

Thank you for this info boostjuice.

Two things:

That resistor appears to be out of stock. edit: in stock in US only
You really haven't left any instruction whatsoever that I am aware of. Clearly Matt has found some guidance somewhere, but for the rest of us could you leave a link?
Edit again: I see what you are talking about and it makes sense and don't worry I won't blame you when its dead.
Not all of us have real world electronics experience so we must learn as we go. I tend more towards mechanical things.

On blame:
Would anyone hear be fool hearty enough to blame another member for an experimental mod gone wrong?

I know I can be a little self deprecating but that's just my way of dealing with my own shortcomings as a hacker. :wink:
I am sure that we can all benefit from your wisdom if you would allow. edit: in more detail

Question: is the cyclone a 60 degree motor or 120?

Super work Matt!
G

 

[boostjuice]

Below are my earlier posts on the previous page of this thread. I know this isn't as detailed as it could be but with the controller in your hands as a reference it should make sense what to do.

PS: Farnell is the sister company to the USA mothership Newark. The same product can be ordered through Newark and will be an entirely US transaction.
http://www.newark.com/bourns/pwr221-2fcr030g/thick-film-resistor/dp/64M0626 ......oh and look its half the bloody price compared to buying through Farnell (even though ATM 1AU$ buys US$0.93 - Typical Australian monopolising importer markup BS :x )

As to my past comments on upgrading my Headline controller; I first looked at upgrading the FET’s to higher current, lower RDSon versions but soon realised that they were pretty darn good already -and expensive, $12 each! If they weren’t already large TO-247 package devices I might have upgraded from TO-220>TO-247 for the reduced junction to casing thermal resistance and higher current ratings, but of course there was nothing to gain here. Based on my guesstimate of the casing’s thermal mass and heat dissipation, the datasheet suggests the standard MOSFETS are capable of more pulsed current than the controller is rated for so what I did was lower the resistance of the power shunt from the standard 15milliohm down to 10milliohm resulting in a theoretical 50% increase in current switching. I did this by soldering a 30milliohm 5W resistor in parallel with the existing three. This tricks the microcontroller into thinking it hasn’t reached the maximum current limit which according to GGoodrum is 55A (I haven’t yet installed my Cycle Analyst so haven’t measured it myself). Together with this, I also flooded the enamel free sections of the power traces with solder to bolster their current carrying capacity. Visually, I considered these PCB traces the weakest link in terms of resistance between the battery pack and the motor. How much this is helping I don’t know, but I guess every little bit helps. Oh and I also swapped out the 10AWG wires (50A continuous rating) for 8AWG wire (75A continuous rating) that lead through the casing to the PCB. Theoretically it should now be a 82.5A controller but I will wait until i have some Cycle Analyst data before I start recommending this procedure to others.
By the seat of the pants, the motor now feels more powerful after the controller mods and I haven’t noticed substantially more heat from the casing judging only with my hand. I might even be able to extract more power by lowering the shunt resistance further, but without more sophisticated temperature logging I am reluctant to take the risk.

The standard shunts are mounted between the PCB and the bottom of the casing to take advantage of the thermal transfer/heatsinking which they really do need. To mount a 4th shunt resistor in parallel next to the existing shunt resistors requires an annoying dissassembly of all the clamped FETS and reapplication of thermal grease for reassembly. I did this, but in hindsight it might be easier to install a power resistor heatsinked somewhere convieniently to the side wall of the casing and then flywire high current leads between it and the shunt resistor solder pads (being through hole components they are accessable on both sides of the PCB). However if you want to bolster the PCB traces with solder then you will need to dissassemble everything anyway.


EDIT: I have since discovered that this estimate of a 0.825V shunt threshold is wrong! I have now researched the BLDC controller chip datasheet to discover that it is either 0.5V or 1.23V depending on chip option used. Cyclone appear to use both options in different models of controllers. Either Hitachi ECN3031F or ECN3030F. The following calculations should be reworked with knowledge of chip option used

V = I x R (peak voltage accross the standard shunts = peak controller current x shunt resistance)
V = 55A x 0.015 Ohm = 0.825V across standard shunt resistors

P = I x V (peak dissipated power shared between parallel shunt resistors = peak controller current x shunt voltage)
P = 55A x 0.825V = 45W (each of the 3 standard shunt resistors are only rated at 5W each air cooled and what a waste of battery power :x )

I = V/R (new peak controller current = microcontroller peak shunt voltage threshold / new total shunt resistance)
I = 0.825V/0.010 Ohm = 82.5A

P = I x V (peak dissipated power shared between parallel shunt resistors = peak controller current x microcontroller shunt voltage threshold)
P = 82.5A x 0.825V = 68W (the newly installed 30milliOhm shunt resistor in parallel with the existing three must dissipate 1/3rd of this power (68W/3 = 22.7W - Hence the need for a high power heatsinkable package)

 

[1000w]

That resistor appears to be out of stock. edit: in stock in US only

I ordered even though it was out of stock locally (Australia), they emailed me after I ordered, saying it was out of stock, then it arrived on my door step 1 week later. Excellent service.

You really haven't left any instruction whatsoever that I am aware of. Clearly Matt has found some guidance somewhere, but for the rest of us could you leave a link?

As boostjuice says on page 4; Attach 2 wires to the resistor so it can be mounted elsewhere ie attached to the body for heat sink reasons and solder these wires one at each end of the 3 round resistors ie conected in parallel. If you look at and follow the solder traces running off each end of the 3 round resistors, you will see that there is loads of points where you can soilder in these "flywires" that run to the new resistor.

The only small problem I had with the flooding of the traces with extra solder was that. I had to slightly lift (move away from the board) the 3 round resistors as one of the traces runs right underneath them. This caused the board to sit high, away from the little brass mounting point. I used a sightly longer screw and a nut as a spacer to solve the problem. See the hexagonal brass post on the right of the photo below.

Also the body of the big black capacitor has to be carefully unstuck (gentally lever off the board at the oposite end from the pins), not unsoldered, so that some of the trace can be accessed for extra solder. This cap should be reglued after so that it doesn't move. Vibrations and bumps will fatuge the pins if a large component like this is not stuck down.

-Can solder adequately (Im pretty sure these boards are built with Lead-free solder. Do not mix Lead-free and Lead solder)
-Use an anti-static strap whenever handling the PCB/components

I didnt know about this solder issue. I have used lead solder. Is this alright?
I am a cowboy I guess when it comes to anti-static straps, I didn't know about that either.
Thanks again joostjuice.
Good luck to anyone who does this mod, be gental and patient.
Cheers,
Matt.P.

 

[gunthn]

Thank you both

You know I will eventually do this. But for now there is no way in hell that my battery will sustain that sort of amperage.

I believe that on a 48v you would be pulling about 4500 watts.

That's about 6hp through a bike chain which is already not dealing well with the 2500-3000 that is being thrown at it.

I believe this work will be a catalyst for some great things to come as your ideas have been in the past.

G

 

[boostjuice]

Thank you both

I believe that on a 48v you would be pulling about 4500 watts.

G

Both Matt and I have the 48V "1200W" version of these controllers (same power circuitry as the 36V 900W) and are powering them at 48V so their is no upscaling from 36V>48V as i think you may be suggesting here. I understand you have the 36V-720W version (same power circuitry as the 24V 650W) with the IRF IRFP064V FETs yes? You may want a slightly different upgrade shunt value depending on the level of risk/stress you want to attempt with a raised current adjustment mod. You'll be in unexplored territory though as your controller has higher RDSon FET's which will dissipate greater heat for every extra amp you demand of the controller. Still well worth doing. Im sure they are also conservatively setup the same as our versions. It would be good to see what you can get out of the other versions.

I didnt know about this solder issue. I have used lead solder. Is this alright?

Matt, when lead and lead-free solder mix they form a new alloy that is more resistive than either in independance. This is due to microcrystaline fractures forming under non-eutectic compositions (a bunch of physics/engineering technicality not worth trying to understand). It's not worth worrying about for bolstering power traces as their is so much volume that it will still be a dramatic improvement over the bare traces. It's mainly a concern in complex low value precision resistor networks when doing repair work. Still..it's good to avoid if you can.