MB-1-E Part Fifteen: Controller Upgrade

MB-1-E's picture

CONTROLLER UPGRADE:

For those of you who have been following my Mountain Bike build, I have decided to upgrade to an Alltrax controller for my Scott 3/4hp motor.

Although not listed on the Alltrax site, they do manufacture an Alltrax model AXE4824, Programmable, 24-48V, 200A Controller.
I found this one at http://www.electricvehiclesusa.com/product_p/co-axe4824.htm
Jeff Lindsey there was very helpful and let me upgrade from the Navitas to the Alltrax.

I had to spend a bit more, as I expected, but don't think I'll have any more controller problems.
The footprint is the same size as the Curtis 1204, so I'll need to find room on the bike for it.
I ordered a 150A, in-line, Mega fuse (and spare) to put between the battery and the controller. These are slow-blow type so they will handle some initial surge but should be about right to protect the controller.

I also ordered a USB to 9 pin RS-232 cable so I'll have the ability to program the Min/ Max voltages, ramp-up throttle speed and Maximum current output.
I would have purchased a 200A NPX if they had one but they only seem to make the 200A size in the AXE type.

TIMING BELT vs RATIO:

Yesterday I received my 5mm pitch by 15mm wide belt and pulleys. I got a 16T drive pulley and a 62T driven.
There is no way the 16T is going to stand being bored to 5/8" diameter so I went ahead and ordered a 20T instead. Even this will be close but I think a good machinist will be able to bore it out for me.
I will probably do as Eric Peltzer did and use a 1/8" roll pin to secure it. Sure wish I had a lathe to bore these out.
The belt sure seems small compared to my V-belt setup, but I guess synchronous belts are actually stronger than they first appear.
I can use the belt that I originally ordered since I have some room for adjustment of the shaft On-Center distance.
My reduction ratio will be comprimised to a degree but it will end up around 10.5:1 which may work fine with the higher amp controller.
I can always swap back to my current V-belt as an option if I want a 12:1 ratio.

I plan on swapping out my 60T rear chain sprocket with a 72T one that I have, but may try the current configuration first.

Well, I'm back to waiting for parts again ... rolleyes.gif

Until next time ...

Dave

before comments

Comments

echuckj5's picture

Dave,

Do you have a drill press and vise? What I did was drill a 1/4 inch hole offset 5/16" off center on my sprocket. Then, I drilled the centered 5/8 hole. For the key I filed the top edges of the key to fit in the half moon keyway created by the 1/4" hole. To hold the sprocket in the vise I drilled a hole in a block of dense wood using a hole saw the diameter of the outside of the sprocket. Then I cut the block of wood in half so I had two blocks of wood with a half moon cut in each half. I have what are called center dowels ( you could use a drill bit). They fit in the hole in the sprocket provided by the manufacturer which allows you to line up the spindle to the center the sprocket. Put the centering dowel in the chuck, put the sprocket on the dowel, line up the vise and clamp the vise tight against the sprocket, then clamp the vise down. Manually turn the spindle, you will feel if there is any runout. If the chuck spindle turns easily put in 1/2" drill bit and bore a hole, then put in a 5/8" bit and finish the hole. Good sharp drill bits and lubricant are required. Practice on an old sprocket or sheave if you can find one. I used a drill bit that was a thousanth over 5/8. Should have used a 5/8, I have to use locktite, that 1 thousanths was just a smidgeon to big.

Chuck

[b]AGM BATTERIES[/b]

MB-1-E's picture

Chuck,

I've got a radial drill-press that will take a 5/8" bit and I can easily clamp my vice to it.
The chuck speed is probably a little high but it should work if I get the feed rate right.
Like you said, a little practice might really help.

I never though of doing the key that way ... that's great ingenuity, I like it!
I can do this if I take my time and get the sprockets clamped right using a hardwood block. My drive sprocket (not the driven) has flanges but I can accomodate the flanges by cutting some relief for them in the wood block.

I'll get a new 5/8" bit.
I like your method of lining it up with the dowel (drill bit) first, making a pilot then using the 5/8" bit to pare out the last bit.
I know bees wax works well as a lubricant for cutting aluminum.

Did you use a Locking collar to hold the sprocket on the motor shaft?

Thanks for the tips ... now that I have a plan, I should be able to do this.

Dave

MB-1-E
Electric - Bridgestone MB-1 Mountain Bike
Icon Photo of lighning striking Eiffel Tower Jun 3, 1902, taken by MG Loppe'

Dave B

MB-1-E
<a href="http://visforvoltage.org/book-page/996-mountain-bike-conversion-24v-3-4h... - Bridgestone MB-1 Mountain Bike</a>

echuckj5's picture

Dave,

Slow down, Don't drill that until I think about this. My motor drive sprocket is steel. You just said your's is aluminum. Rarely would you need lubricant on aluminum. High speed won't hurt on aluminum. I have been up since 5 am, thought I would check this site before I hit the hay. Aluminum will some times drill larger than the bit by a couple of thousanths, steel actually develops ridges when drilling which can make the hole about a few 10,000 thousanths smaller than the drill bit. A lot of the aluminum sprockets that I have come across are cast out of unknown properties. Some cast pulleys don't peel like steel, they powder. The dust from drllling these can make the hole size quite a bit larger. You can minimize your chuck runout with the bit that you buy. Visual sighting will suffice, use all three holes to tighten the drill bit, run the drill press, retighten all three holes if there is any visual runout. Use a digital caliper and measure the shaft on the scott motor before you buy your drill bit. Drill into some aluminum after you set the drill press up and try a fit before you drill the sprocket. Some of this is easy for me, I have chunks of all kinds of metal laying around. Aluminum is usually easy to identify by color, match the colors of two pieces of aluminum and they will usually machine the same. Aluminum machines very easily, drilling aluminum is not truly machining, runout is critical when drilling aluminum.

If you bought an alumimum sprocket from a top of the line manufacturer, I would not be so concerned, but, a lot of cheap sprockets are cast from aluminum and don't perform well. Also, with a good fit after boring, aluminum exands, so I would recommend locktite even on a perfect fit.

chuck

[b]AGM BATTERIES[/b]

echuckj5's picture

Dave,

Another comment,
No and yes I used a locking collar. I drilled a hole and used a hand tap to use a set screw to lock the sprocket to the motor shaft above the key. If you can remember, my sprocket drifted while I was riding which wore my belt enough that my belt started jumping. The sprocket drifted because of that 1 thousands over bore so I put a couple of collars on temporarily. Then, later on, I used blue loctite on the sprocket, will use red when I finalize my drive.

chuck

[b]AGM BATTERIES[/b]

MB-1-E's picture

Chuck,

One of the sprockets is from SPD and the other is from Gates.

I had another Gates that I drilled to 1/2" and it pealed and chipped out. There were a few curly-ques and some small triangular chips about an eight of an inch long and a thirty-second of an inch wide. No Powder.

The motor shaft is right at 0.6250
The 1/2" test hole in the same aluminum alloy came out 0.5000 +/- 0.001 and that was without taking the time to get things set up right.

I think it will work, I just need to get everything rock solid, perpendicular and concentric.
My drill press is ok but probably the biggest variable. It works but takes extra care to get it adjusted right. I can't depend on the indexes but once I get it set and clamped, it won't move.

I've never met him but there's a guy nearby that has CNC shop. I may stop in to see if I can interest him in doing it. I'll ride the ebike down there, maybe that will spark his interest, ya never know.

At any rate I won't be doing it for a while, I'm pretty busy right now and still waiting on the controller so it'll be a week or two.

Dave

MB-1-E
Electric - Bridgestone MB-1 Mountain Bike
Icon Photo of lighning striking Eiffel Tower Jun 3, 1902, taken by MG Loppe'

Dave B

MB-1-E
<a href="http://visforvoltage.org/book-page/996-mountain-bike-conversion-24v-3-4h... - Bridgestone MB-1 Mountain Bike</a>

echuckj5's picture

Dave,

Great!

Most machine shops want aluminum because it machines so well. Hope you drill this yourself. Usually my bores are better than the machine shops.. Just gotta check those tolerances before your final bore. Where I live here in Richardson TX, machine shops have $600,000 dollar minimum CNC machines, make parts for military and the electronics industry. No local small shops would bore this for less than $50.00.

I like aluminum sprockets if they are made well. There was a time I swore off aluminum. Belts slipped on cheap ones, the powder would act similar to a graphite and I would have to overtighten belts to overcome this. I did not think to ask Gates if they had aluminum in the pg2 line. My sprockets are cast on the perimeter, (just a guess). Usually cast iron pulleys are the smoothest running and the easist on belts but have seen drastic improvements in aluminum pulleys in the last few years. Very interested on this new development. Probably 90% of my belt noise, which is minimal, is from my over bored sprocket. My chain noise comes from the 14 tooth sprocket. Unbelievable the difference one tooth made. The chain was silent with a 15 tooth.

Chuck

[b]AGM BATTERIES[/b]

MB-1-E's picture

Thanks,

I'll let you know when I go to do this, might have a question or two. I'm sure a machine shop will want $50 to do it too, I could mess one or two up and still be ahead ... SDP has pretty good prices, Gates is spendy ... I'm not sure of the quality difference.

You asked what software I used to make that sketch of Reikiman's scooter belt.
That AutoCAD ... I'm a draftsman by trade.

Dave

MB-1-E
Electric - Bridgestone MB-1 Mountain Bike
Icon Photo of lighning striking Eiffel Tower Jun 3, 1902, taken by MG Loppe'

Dave B

MB-1-E
<a href="http://visforvoltage.org/book-page/996-mountain-bike-conversion-24v-3-4h... - Bridgestone MB-1 Mountain Bike</a>

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