Micargi Seattle SS

Diddler

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Joined
May 3, 2021
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Using the frame of a Micargi Seattle SS to design & build a super/fancy ebike. Desiring to use a 24" rear wheel with a Atlas white wall fat tire 4.25 inches wide.

It appears this won't work; too close to cross brace of the extending rods to rear drop-outs. Thus, anyone know of a quality extension kit whereby I can push wheel back one or two inches?

Any leads / advice appreciated. Thank you.
 
Hub motor or mid drive?
Retaining derailleur or single speed?
Retaining disc brake?

You have more fabrication options since it's a steel frame, but if you are looking for an off the shelf kit, then good luck.
 
Steel bike? If so cut your own and weld it on to the frame. Not all that hard, with a very cheap wire feed welder from Harbor Freight.
 
As a novice, working/developing an ebike, never had experience with a controller. Haven't yet determined which motor and controller. But, as it relates to my bike design, does a controller typically exhibit heat? At their peak heat, can one still touch it? Just trying to get a feel for how hot a typical controller gets. Thanks.
 
Controllers to heat up, but like motors, to varying degrees depending on the capacity, condition, usage. Most are mounted within an aluminum chassis that may or may not have heat dissipating fins to help. I have a fairly big controller mounted within a rigid tail box on my trike, and found that I needed to ventilate it and even added a silent fan to help with air flow, as we are experiencing near 100-degree temps where I live. You will find some conversion kits that are designed so the controller is contained in an enclosed pack or bag - not optimal for cooling of course.

These controllers are obviously intended to run in the open air stream, although some are better sealed against the elements. I'd estimate that if I push my controller hard in the heat of the day, the external case reached nearly 150f - hot enough you can touch but not really hold your hand on there long. Long term heatup can certainly stress the components and lead to failure. If you give them adequate airflow and don't over-push them, they should have no problem. I have only had experience with a few controllers, all in the 48v 25-40A category. There certainly must be some that run cooler than others. I think motor overheating is potentially a bigger issue, at least in part because they are costlier than controllers, in general.

I should mention, as a beginner you will find motors, especially mid-drives, where the controller is contained within the motor or drive housing, or other controllers that are small and can be contained within the battery pack etc. Most of the stories you read here around controller failure are only occasionally related to overheating, and even then, often brought on by aggressive current application. (which is fun but costly!)
 
Greetings. Would appreciate your wisdom, expertise and experience regarding the unusual placement of a 'Rack Battery' on a custom build ebike.

I am designing and building an ebike. I've purchased just the frame of a Micargi Seattle SS. Due to desired designing, I don't wish the 'Rack Battery' to be over the rear wheel which is typical regarding 'Rack Batteries.' Rather, I desire said battery to be underneath the bottom portion of frame that holds the sprocket. Yes, that makes a 'Rack Battery' close to the ground, but I have that worked out.

Here's why I'm seeking wise counsel and your expertise. Due to desires of design, I wish to flip the 'Rack Battery' up-side-down, thus having it hang from the securement harness (underneath the bicycle frame) verses how a 'Rack Battery' typically sits on top of the securement harness when it's over the rear wheel (hope I'm making myself clear - rather odd I know)

My question is this. Is it ill advised to flip a 'Rack Battery' up-side-down? Essentially, for those who are experts regarding how 'Rack Batteries" are put together, is there a problem flipping a typical 'Rack Battery' up-side-down?

I'm well into my creative design and someone suggested I'd better seek wisdom on this matter. I had assumed a 'Rack Battery' flipped up-side-down would not be an issue. However, it is acknowledged I'm a novice, at this stuff, and simply don't know.

Thanking you for your expertise and experience regarding this matter. Diddler
 
A battery in that location is subject to a lot more spray and debris than one mounted in a more customary location.

Some batteries do a pretty good job of draining away moisture when they're right side up, but pool and retain water when they're upside down. You'll have to evaluate the specific battery you want to use with that in mind.

Most battery packs intended for rack mounting are too wide to fit under the bottom bracket without fouling the cranks, kickstand, etc. Have you evaluated the width of the space available?
 
Any suggestions for a heavy duty, double prong kickstand for my Micargi Seattle SS frame? In addition to the rather wide rear drop out measurement, I am planning to place a 4" wide fat rim and tire on rear. Therefore, if anyone happens to know a kickstand with extremely wide prongs, would appreciate your suggestions. Diddler.
 
https://endless-sphere.com/forums/search.php?keywords=kickstand&terms=all&author=&sc=1&sf=titleonly&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search
 
I have the Ursis Jumbo on a dual suspension mtn e-bike https://ursus.it/shop/urban-city/kickstands/jumbo-evo-80/ . I like it. These double leg kickstands work best on a hard , flat , level surface . Otherwise bike is only supported by one leg and gets tippy. On my stretch cruiser e-bike I prefer 1 standard kickstand in front of the back wheel , and 1 rear kickstand that mounts to both the chain stay and the seat stay so that it does not slip and turn.
 
Folks, beginning to arrange components of my ebike. Noticed my controller has an exterior that's grooved heat sink designed. Question, from your experience how warm/hot could that controller become? My battery is a 52V connected to a 1500W rear hub motor.

Reason for asking this question. My preference for placement of the controller is in tight quarters (very tight). This would require virtually all the wires coming out of the controller to lay against the heat sink material. Is that a "no, no?" Asking as I don't have any experience with a controller.

Appreciate your wisdom / experiences on this matter.

Diddler
 
Diddler said:
Folks, beginning to arrange components of my ebike. Noticed my controller has an exterior that's grooved heat sink designed. Question, from your experience how warm/hot could that controller become? My battery is a 52V connected to a 1500W rear hub motor.

Reason for asking this question. My preference for placement of the controller is in tight quarters (very tight). This would require virtually all the wires coming out of the controller to lay against the heat sink material. Is that a "no, no?" Asking as I don't have any experience with a controller.

Appreciate your wisdom / experiences on this matter.

Diddler
You should be fine as long as you don't put the controller inside of something the prevents air flow. If your controller gets hot enough to affect external wiring, then it's already fried by that point.
 
on one hand controller needs cooling on other hand it needs protection from rain.
of course your typical China brand controller is NOT rain proof.
I would try to transfer heat to bike frame through controller bracket.
 
Diddler said:
how warm/hot could that controller become?

Nobody can know since heat would be proportional to current. And current will be proportional to motor load.

Install it. Run it. Measure temperatures. Then go from there.
 
Diddler said:
Folks, beginning to arrange components of my ebike. Noticed my controller has an exterior that's grooved heat sink designed. Question, from your experience how warm/hot could that controller become? My battery is a 52V connected to a 1500W rear hub motor.

Reason for asking this question. My preference for placement of the controller is in tight quarters (very tight). This would require virtually all the wires coming out of the controller to lay against the heat sink material. Is that a "no, no?" Asking as I don't have any experience with a controller.

Appreciate your wisdom / experiences on this matter.

Diddler

i have a controller enclosed into the bike frame. from doing this, i am only able to run the controller effectively at 3/4 the max amp draw. can run all day like that with messing around and going on hills and everything. but as soon as I run the controller at full amps, it get's hot with in a mile or so on slight inclines and maybe 2 miles on flats/declines. have to pull over on the side for about 2 min to let it cool down before can engage the throttle again. so i say do this test :

1. run at full amps and test
2. if controller overheats/bike stalls, try next lower setting, wait 5 min for controller to cool down and repeat until you can run bike on slight hill at 10 mph without overheating.

after this, you should be fine playing with the throttle on most hills and only have to watch out for your motor to overheat. :thumb:
 
If its hot enough to melt the wires, somethings wrong with the controller IMO. Like running it hard with the wrong phase wire order, or you got it smothered .

But if you are that worried, it could be worth it to put some heat shrink tube over the wires where they touch the controller. At least heat shrink won't melt through easily.
 
dogman dan said:
At least heat shrink won't melt through easily.

If the outside of the controller case gets hot enough to melt anything except a chocolate bar everything inside the case will be toast pretty soon. It will have electrolytic capacitors inside and those don't last long at high temps for sure.

It's pretty much why all consumer residential LED lighting works for a few years and then croaks. The LED itself might go for 50K hours, but the driver circuitry is designed to last much less.
 
On my previous build, I ran a 1500w hub motor and 52V battery - I had the 45A KT controller enclosed in a tail box to keep it dry. I ended up cutting holes in the tailbox, and even using fans to ventilate the box. With heavy current draw, especially at high ambient temps in the summer, the thing would still get really hot.

As others have said earlier, best is to leave the controller out in the open and potentially in the airstream of the bike moving forward to help cool it. For me, it was fine when the ambient temps were cold, and also when I was going easy on the throttle.
 
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this is a kelly kls7212s inside a steel box frame (vector light). needed to be heatsinked to the frame to prevent overheating (error code 2,3). a basic controller would probably just cook itself
 
Here is my Kelly of 3.3kW on the bike. You can see the motor is much hotter than the controller. Controller is maybe 20* over ambient, and the motor is probally about 40* over ambient. This sees just about constant duty at 50A. I'll try to upload a better pic.
 

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99t4 said:
The rear tire looks to be as hot as the controller?

It is. It goes fast. Three miles up a hill at 40mph will do that.

Here is another. 1kW motor, 3.3kW controller, 85lb bike. Happy to show off thermal pictures. Lol.
 

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There are inexpensive 48V server fans (I'm told that servers are the computers that run large networks).

Install some diy ducting, then have one fan push air onto the controller, and the other fan pull air away from the controller.

For 72V systems, run three 24V server fans in series. Id prefer the fans with ball bearings.
 
Interesting how hot the tire gets.

I've melted a bike tire from the inside at the death race. Looked normal outside, but inside the cords were all detached from the tire. In that case, the tire got flat and I kept running by going fast enough to have it re inflate by spinning it. So it got much hotter than normal. But it shows how hot you can get a tire if its not inflated hard. It's why I scoff at guys who want to go 40 mph on a 10 psi fat bike tire. Better to go moped tire at that point for sure.

Best controller mount I ever had was on my cargo bikes. I put the controller under the deck where it would stay dry, between the deck and the fender. But just as good could be on top of a rear rack, with a U shaped cover over it that is open on both ends.

I also mounted controllers tucked tight under the seat, where my ass would cover it if riding in rain. My cheeks would just touch the controller, and when riding hard I could feel it get quite warm. But again, if your controller is melting wires, its not running right, or you are smothering it.
 
Building an ebike using frame of Micargi Seattle SS. Installing 48V, 1500W real hub motor coupled with a 52V 19.2 AH battery. Don't plan to use a chain nor front large sprocket; disregarding both. Plan to initiate start motion and achieve various speeds by throttle power only.
Question......given this planned design, I don't see a need to retain the rear freewheel. Thus, in your opinion can I simply disregard / eliminate the freewheel? Obviously there would be an approximate two inch space, along the axle, between housing of the motor face to edge of frame. However, the axle has that area whereby it's reduced in size where threads begin, thus holding the washer.
Seems I could simply not use the freewheel under circumstances herewith described. Friends, as noted before I'm a novice at this, thus simply don't know. Consequently would appreciate your wisdom / experience.
Thank you,
Diddler
 
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