Final Stages of Ebike Making : Where to put controller?

broloch

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May 10, 2008
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To the E-Spherers, I am writing for advice.
I have other threads with similar ideas, but am looking for one final closing answer.

I have had most of my parts and items and accessories come in now.

I am trying to finalize my set-up, and have gone over many ebikes that E-Spherers have built that look fantastic.

I am trying to figure out what I should do with my set-up. The concern is my controller.

I have a thick plastic, waterproof case.

The final step now is to put the controller in the case, and have the case permanently locked to the bike.
The case will house the controller and battery, and keep it protected from the rain. There will also be an air pipe to push air into the box.
(I may have to build an aluminum plate on the box, and hook up a heat sink to it.

But, another option is to mount the controller onto the bike frame, and have the case contain just the battery, then I can detach the case and take it with me.
Controller remains attached to the bike frame with wires, or something...not as secure.

In summary:

Option A: Put controller in plastic box.
==============================
Controller is permanently locked to case, case is permanently locked to rear rack of ebike
(The case itself will have a lock on it, or two padlocks)
Controller is protected from thieves (locked in case)
Controller is protected from rain and snow
Controller has moderate air (From air pipe inflow, and an air pipe exhaust)
Battery is placed with Controller in same box.
Battery comes with me when I leave the bike locked.
Box may attract attention, it is one of those Pelican style boxes (military grade plastic cases)

Option B: Mount controller on bike frame
=============================
Controller is exposed to rain, and snow, but better air flow
Controller is more visible to thieves
As a plus, the controller is not inside the case, so I can take the battery and case with me, but it may suck having to carry a case
There is more room in case for more batteries

What is best, Option A, or Option B? E-spherers, your thoughts and wisdom?
 
Option c is usually my choice, unless short wiring dictates a frame mount, usually on the downtube under the seat.

Option c is to mount outside the case on the front side of it, if it is mounted on a rear rack. This allows cooling, and rain is not a big problem for me here. Nor theft, since I never leave the bike in vulnerable places.

If rain or theft is an issue, then the best way is often some kind of removable battery box to take with you, and a very theft resistant permanent mount in a custom box for the controller on the bike, maybe in the triangle if there is one. Just concealing the controller may keep it safe, unless they take the whole bike of course. Theft of the bike may be covered by homeowners or renters insurance if you document the value of it.
 
I worry about someone stealing my controller about as much as i worry about someone stealing my seat.
or my mailbox.
They could.
But its not likely to happen, and preventing it is more of a hassle than the risk warrents for me.

So I submit Option D.
I water proofed mine and mounted it below the crank, half hidden by the chainring. its out of my way down there, and a carefull job of siliconing the seams wires and screws means it can handle roadspray andrain, but gets plenty of unubstructed air flow
 
The controller does need to be cooled. Mine is tie wrapped to the cross bar. The next will be in some out of the way place, and bolted. The bike will be stolen, before the controller. I take my $500 battery with me if i'm away from the bike for any amount of time.
 
Broloch, if you want to be secure, have you heard about those bolts that are theft proof kind. The ones they use on bathroom stalls? Might want to look into those. Not sure I've seen anyone do this but is it possible that you could mount your controller underneath your bike rack, to hide it real good?
 
Broloch, when I first made my e-bike, I was worried too. Mine isn't really expensive but I usually only stay inside the store for 20 min and I've never once had anyone come close to stealing it yet.
 
I'm with the others, don't put it in a box. You'll just fry it and be out a controller, which is far more likely than being stolen. Spend a few $ on water proofing it and be sure to incorporate drip loops if you expect to be in rain at all. I can't imagine even the stupidest of thieves to be after only a controller, and you can use special bolts to attach it anyway to avoid theft.

John
 
Thanks for the comments, I am considering what was posted about inside a case and not.

I was unable to get the security bolts since they are stringent about who they sell to (serious).

Will a LiFePO4 Ping battery have difficulty inside an airtight plastic case? I heard the BMS doesn't like getting to hot, cause it will get sick. :mrgreen:
 
i have an infineon 36v 20amp controller.... made a bracketout of 1/16 aluminum.... 2" longer and 1" wider than the controller... cut in the ends toleave a 1" by1" tab.... bend the sides up to fit the controller.... wrap tie the controller to the bracket and clamp the bracket upside down to top cross member with hose clamps has worked well fo over 1000 miles :D
 
What do I have to have done to sufficiently waterproof the controller?

1) Silicone conformal spray over the PCB and all the internal circuitry and exposed metal?
2) Seal all of the upper seams, and screws, but leave the lower parts exposed to allow drainage?
or do I completely seal it in? (Rain protection, and splash protection)
I read that sealing it in is actually a bad thing since the seal is never really 100% and once water gets in, it is hard to drain out if the controller is nearly completely sealed.
 
The thing about conformal coatings is they must be removed to do any repairs or modifications to the board.
Make sure yours can be removed with normal type solvents. Don't apply it too thick.

justin_le suggested clear fingernail polish. I should have taken his advice instead of springing for the MG Chemicals urethane stuff.
This second controller is a raw prototype from Kenny at Crystalite.
The capacitor mounting looks sketchy but I left it and have had no problems in 4100 km.

Drainage is a good Idea.

The batteries and controller both emit heat in operation. Keep 'em separated.

Finding the optimum spot for the controller is the first thing I did when planning le Béte.
The Xtracycle SnapDeck forms a nicely sheltered spot that still gets air and no road spray.
The controller is secured with two thick zip-ties and a small hose clamp.
There's a light, loose fitting, neoprene cover that fits over the top to help disguise it and shed any water that might make it to the controller.
It's mostly hidden from view so I've never worried about it.
 
I have used the MG Chemical stuff.

Will the battery need a lot of air flow as well? I was considering having an intake pipe, and an exhaust pipe, resistant to rain and water splash.

I am now leaning towards having the controller mounted outside of the case, and somewhere on the rack or on the bike frame.
 
broloch said:
I have used the MG Chemical stuff.

Will the battery need a lot of air flow as well? I was considering having an intake pipe, and an exhaust pipe, resistant to rain and water splash.

I am now leaning towards having the controller mounted outside of the case, and somewhere on the rack or on the bike frame.
The battery benefits from cooling in hot weather or being pre-warmed and insulated in cold weather.
It needs shock absorbtion plus physical protection from the elements and simple fall over type crashes all year.

Batteries are always a larger puzzle than controllers.

Digital 72V, 48 Amp, Crystalite controller on le Béte:
file.php


Infineon 35 Amp controller on EBII still in process:
file.php
 
One of the things I like about the metal toolbox for my battery, is I get a lot of cooling, without needing a lot of air flow. I worried more on the first one, and drilled a bunch of vent holes, and carried a plastic bag to cover it if it rains.

The second one, I just have a small hole to let air in, and let the wires out, and it worked fine all summer. Inside the box, is just a bit of air space around the bms, so it's not smothered in anything insulating. Any heat building up in there is quickly heat sinked to the metal box, and then it radiates into the air, even at 100F weather.

I have never seen my battery get above 105 F discharging, so I don't worry about the heat of discharging it. My c rate never makes em get so hot. My nicads are another story, they can get quite hot. The bms on a ping just needs some space around it, and a very small vent to let some air into a sealed plastic box, or insulated bag. In a cooler climate, just some air around the bms inside the battery box should be fine. But I'd want to open the box when charging since that is when a bms has the hottest fets.

I think a hole or two in the bottom of a battery box would let air in, and then one hole in the top, with a couple pvc elbows or a sheet metal hood over the top hole would let air convect while charging while keeping water out. If any got in, the bottom holes would let it drain.
 
le Béte

Zoot Katz, how fast is le Béte, running 72V and 48A on a Crystalyte controller?

dogman said:
One of the things I like about the metal toolbox for my battery, is I get a lot of cooling, without needing a lot of air flow. I worried more on the first one, and drilled a bunch of vent holes, and carried a plastic bag to cover it if it rains.

The second one, I just have a small hole to let air in, and let the wires out, and it worked fine all summer. Inside the box, is just a bit of air space around the bms, so it's not smothered in anything insulating. Any heat building up in there is quickly heat sinked to the metal box, and then it radiates into the air, even at 100F weather.

I have never seen my battery get above 105 F discharging, so I don't worry about the heat of discharging it. My c rate never makes em get so hot. My nicads are another story, they can get quite hot. The bms on a ping just needs some space around it, and a very small vent to let some air into a sealed plastic box, or insulated bag. In a cooler climate, just some air around the bms inside the battery box should be fine. But I'd want to open the box when charging since that is when a bms has the hottest fets.

I think a hole or two in the bottom of a battery box would let air in, and then one hole in the top, with a couple pvc elbows or a sheet metal hood over the top hole would let air convect while charging while keeping water out. If any got in, the bottom holes would let it drain.

Because of this, I am considering separating the controller from the battery, mounting the controller onto the rack or somewhere on the frame. As well, I am considering putting an aluminum plate on it to help conduct heat out of the case for the battery.
 
maybe one of those racks that hook onto the seat post would work because they usually are raised much higher than the wheel which would give you space underneath to hide the controller. Maybe you could look online for a rack like that and get it as the same color as the controller or spray paint the whole thing the same color. No one will even know what it is. They'll think it's part of the bike rack.
 
something like this. And if you are a tall person and have the seat up high, that would give you lots of clearance between the rack and the wheel.
put the controller underneath it
31Z0QP8GYQL._SL500_AA280_.jpg
 
broloch said:
le Béte

Zoot Katz, how fast is le Béte, running 72V and 48A on a Crystalyte controller?
I wish I knew!
The controller can handle 72V but my wallet could only handle forty-eight.

The bike will do ~43 kmh on the level or ~47 if I get off the saddle and onto the SnapDeck.
 
Yeah, I will look to getting air flow for the battery in the box.
Still working on the aluminum plate though.

Thanks for the tip about the bike rack, but I will stick to the current one. I came up with an idea to mount the controller in the bike triangle.
It will require the bottle rack holes. I want to put an L-bracket on to see if it will hold.

Too bad about the security bolts. The closest thing available is Pitlock.

40km/h plus is plenty. Sounds good.
 
Broloch, will you show us some pictures of your e-bike once you are ready to show it.
 
Option X,

1.) Put a smallish handlebar bag on the front of your eBike...
2.) Insert a small piece of hobby wood (1/4 - 1/8" thick) into the bottom of the bag
3.) Drill a 1/2 - 1 1/2" hole (as needed) in the bottom of the bar bag to allow wiring harness from Controller to pass into bag.
4.) Screw controller into the underside (upside down) of the handlebar bag
5.) Run wiring harness through the hole you drilled earlier

Now you have a semi weather-proof installation (don't ride in a pool) which protects the controller and more importantly the WIRING from accidental shorts and such. Since your wiring is contained within this bag, a small application of the spray water proofing you use on new shoes would be a good idea (it's what I did) and finally to be really clean, run some velcro around the inside of the bottom of the bag then fashion a nylon cover for the wiring harness plugs with a velcro seal (like a rear rack bag compartment barrier) to keep it in place at the bottom. Now you even have useable storage space on the bars.

I usually mount my controllers fets facing forward. I do use a snap-on fender durring rain or wet riding (mud, etc) to protect me more than the controller but it serves both purposes... Finally... keep a T-Shirt style plastic bag or a large elastic / nylon shower cap in the handlebar bag, when it rains... pop it over the bag and controller for instant (and fool proof) weather resistance in the worst downpours.

Just my .02 for what it's worth.

-Mike
 
Yes morph999, I will post when I get the bike ready. I hope so soon. I have a means of securing the controller with a Pitlock. That is difficult to breach.
It will be attached by a "mending plate". Mending plates are easy to find. Just a sheet of metal shaped like a ruler that has holes in it.
The mending plate can be bent to suit your needs.

g005.jpg

woodandplate.jpg


The controller currently has silicone coating over the insides, but I will seal the top part of the controller, and all screws. The bottom will be partly sealed, the lowest edge,
and corners will not be sealed to allow for draining. Where the pitlock bolts onto the top part of the mending plate, there will be a bonded sealed washer. I may line

Here is a simple schematic:

sb7oec.jpg


You can have one more mending plate added to the side of the controller to hold it in place, and prevent the controller from "swaying" left to right...but the front water bottle cage mending plate should be enough to prevent swaying anyway.

OPTIONAL PLATE:
rk1z0w.jpg
 
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