Eric's Project #002

[dirty_d]

you have the same sprocket and freewheel that i used on my bike thats 65t right the #25 one? my freewheel broke after a couple of minutes i think from the motor accelerating the sprocket so fast that the ratchet teeth on the inside bent or something and wouldn't spring back out. after that i just welded it all together into a fixed sprocket, worked fine. one thing though, im guessing you have the same sprocket on the motor as me the 11t #25 and the 65t rear sprocket, that gives you a 5.9:1 ratio, thats going to overload your motor at full speed but it will be good for low speed 15-20mph as the motor will be close to peak efficiency. im basing this on 22" wheels that is what you're using right?

 

[Beagle123]

im guessing you have the same sprocket on the motor as me the 11t #25 and the 65t rear sprocket

I'm using the same front sprocket with 80 tooth rear sprocket. I agree with you it all looks a bit cheap. I've ordered a 10 tooth sprocket for #35 and a 80 tooth for the back. I'm sure I'll decide to use that instead. Its been a comedy of indecision.

 

[Beagle123]

I'm about to take the Plunge on Batteries

Xter has given me some great advise on batteries on this thread:

http://endless-sphere.com/forums/viewtopic.php?t=2152

He suggested using the <a href="http://www.amazon.com/gp/offer-listing/B0009F5E5M/ref=dp_olp_2/103-8255952-7926214?ie=UTF8&qid=1189484543&sr=8-2">Milwaukee v28 battery packs</a>, and these chargers:

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1231

Here are the details of my plans for batteries. Please let me know what you think.

I'd like to create a battery pack that's 48-56 volts, and is 15-21 ah.

First of all, I'm planning on enclosing all the batteries in the frame of the bike. This means that I do not have the option of keeping the battery pack intact because I'd have no way to conveniently charge the batteries. TO charge them I"d have to open my battery box, taking out all 14 batteries and plugging them into an individual charger. I can't just wire-up the packs either because thay have a built in BMS which is hard to bypass. Also, I'd have to buy 14 Milwaukee chargers etc. Finally, only 6-8 batteries will fit into my box.

So my best option is to dismantle each pack, taking out the individual cells, and building my own battery packs. I'd also have to create a charging set-up. Luckily xter has devised a great charging set-up ising the above chargers.

Using his idea, I'd need to make smaller sub-packs of 7 batteries in parallel. Each Milwaukee cell is 3.7v, 3ah each so 7 of them together would be 3.7v, 21ah. Then I'd string 14 of these sub-packs together to make a 52v, 21ah pack. To charge this battery pack. I'd need to use 14 3.7v chargers to charge each sub-pack. I'd use a set-up like this:

 

[Miles]

AN interesting fact I learned is that the ENO hubs are rebuildable. That means you could take them apart and weld a sprocket onto them, then reassemble them.

Yes, you can also buy spares for any of the individual parts 8)

So, if the welding doesn't work........

 

[Beagle123]

Battery plan Cont...

To make the sub packs, I'd create a plastic box that exactly fits 7 batteries. I'd have to make 14 of these boxes. I'd make these boxes out of abs plastic about 1/8in thick. I'd put a strip of aluminum across the top and bottom for contacts, and attach terminals to the aluminum. These boxes should be about 7.5 X 3.5 X 1.25 inches. They should fill my battery box perfectly standing on end because my box is 7.75 inches tall.

I'll make the sub-pack boxes using this:

<a href="http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=41592">plastic welder</a>

Then I plan to buy a couple of power strips like this:

<a href="http://www.amazon.com/Surge-7-Outlet-25FT-Cord/dp/B000UD679U/ref=sr_1_6/103-8255952-7926214?ie=UTF8&s=electronics&qid=1189481436&sr=1-6">power strip</a>

or an octopus of extension cords to plug-in all 14 chargers to make a big blob of chargers, then stuff them into the neck portion of my frame. Keep in mind that these chargers' dimensions are 1 X 1.5 X 3 inches each. I think They'll fit.

Then I'll run a power wire to the back of the bike so I can plug the bike into 110v ac outlet.

I'll install one of these:

<a href="http://www.allelectronics.com/cgi-bin/item/ACS-42/915/IEC_POWER_INPUT_RECEPTACLE,_RT-ANGLE_.html">PC Power Jack</a>

Then I can use one of the dozens of old PC cords I have laying around here.

Are y'all with me?

 

[Beagle123]

Speedometer installed

You guys might already know about this but, I saw this wireless speedometer in Wal-Mart today. Its pretty cool. You don't have to run a wire to the sensor on the wheel. It was $20.

It makes you realize that a good company set out to make a good electric scooter, they could make a awesome one cheaply. This part could be an onboard computer. All it needs is a current sensor (it already has a RPM sensor) and it could manage the motor's current at different speeds and protect the batteries. Imagine if they set out to make a 98% efficient drive train etc.

I digress.

 

[Beagle123]

Back End Welded, Panels cut, #35 Sprocket Bored to 12mm!!!!

I finally tackled my sprocket problems (I think). After all that agony, it took the guy at my machine shop about 10 minutes to bore out a 10 tooth #25 sprocket w/ 3/8 inch bore, to a 12mm bore. The sprocket is perfectly centered, and spins perfectly when I touch a 9v battery to the termainals.

I had the back pieces welded on. It went pretty smoothly. I really cleaned the parts properly using a stainless steel brush wheel attached to a cordless drill. Then I wiped the surface with acetone. The welds were clean. I want to know how to get good looking welds so the outside of the bike looks nice when we weld the panels on.

Side panels cut etc.

I assuming that everyone's silence on the battery plan means that you all approve. Any thoughts before I spend $1300 on batteries?

 

[Toorbough ULL-Zeveigh]

The Emoli/Milwaukee batteries are a safe bet, probably the best choice available at the moment, but then I'm biased towards a fine Canadian product.
I'd go that way but for the whack of chargers it takes, I'd rather be spending my money on batteries. There's got to be a better way to run a railroad so I'm holding off until something can get figured out that it only takes a single charger that you can carry along with you.

I think everyone's silence re: batteries is for much the same reason as my own.
If anything should go wrong with a thirteen hundred dollar investment, like if it should blow up or something I don't want to feel like I steered you wrong or gave you bad advice somehow.
Basically if you're gonna take the plunge, we can cheer you on & support your decision, but you walk the plank alone.

 

[newbie electric rider]

Hey Beagle,

Your plastic battery packs sound great. I am just wondering why you are going to use aluminum. Wouldn't copper strips be a better choice. I am wondering over time, that the aluminum might oxidize, and not make a good contact, which may get those batteries out of balance.

 

[dirty_d]

hey beagle nice job with the sprocket, you got that off mcmaster.com right? theres just something i need to know, what is the distance from the center of the set screw holes to the end of the hub?

 

[TylerDurden]

I also think copper is the better choice.

If you have all the flat-panels cut, throw the frame and panels on a bathroom scale. It would be interesting to check the weight before you close it up.

 

[safe]

This is a good picture to present again. This was what I was talking about a long time ago, buy a generic front sprocket and just bolt it on. No need to weld other parts together. I've already got all the parts to weld one up, but the idea of just buying the part you need is a heck of a lot easier and will work better. (though costing another $20 or so) If my welded one fails this is what I'll do. For my case I've got the MY1020Z3 motor so my shaft is closer to 5/8" of an inch and my intended front sprocket is an 18 tooth bicycle chain size. (about 2.5" across)

Note: You might be able to reverse the sprocket and get the teeth closer to the inside. As long as there is enough clearance for the chain you could effectively improve your motor alignment. (you can bring the wide motor in by half an inch or so)

 

[fechter]

I hope this isn't a dumb question, but how are you going to place the batteries inside the box? The opening looks quite a bit smaller than the space inside. I suppose if the battery is on the small side with lots of space on the sides, no problem.

On my scoot, I had to bend and grind the frame to make the opening larger to accomodate the largest possible batteries.

 

[xyster]

The Emoli/Milwaukee batteries are a safe bet, probably the best choice available at the moment, but then I'm biased towards a fine Canadian product.
I'd go that way but for the whack of chargers it takes, I'd rather be spending my money on batteries.

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1231
At ~15$ per charger, total price is on par, or less than, the popular all-in-one charging/balancing solutions. An array of single-cell chargers can effectively be made into a highly modular, all-in-one solution with blocks of Powerpole connectors. Should a charger fail, the whole kit-and-caboodle need not be replaced. I was fortunate to buy 21 of these when the price was $9 per. They've worked great for me for over a year now. Except for one that I opened-up to experiment on -- that one died. So now I've got 20, one for each of my 20, 15-cell parallel subpacks.

 

[dirty_d]

theres no way you could reverse that sprocket the holes for the set screws would be over the flated part or the threads.

 

[Beagle123]

I hope this isn't a dumb question, but how are you going to place the batteries inside the box?

Actually it would be dumb of me if I didn't have the answer. I thought about that, and I hope that my plan will work:

I hope to make 14 sub-paks with 7 cells each. I plan to make each sub-pack a 1.125 X 7.5 X 3.25 inch box as described above. To get them in there I plan to stand them on their ends (put-in from the top). The top lid won't be welded on. I'm going to screw it down. I'm emotionally prepared to cut-into my frame if I must. This is what it should look like from the top:

(now that I look at it I'm realizing that I could add a pack, and make it 60v easily.

 

[Beagle123]

theres no way you could reverse that sprocket the holes for the set screws would be over the flated part or the threads.

I think that puts the sprocket too close to the body of the motor, but I'll check again.

 

[Beagle123]

I'm planning on using this controller:

48v Controller
http://tncscooters.com/product.php?sku=101215

Would there be a problem if I ran this at 56-60 volts?

 

[fechter]

A 48v lead acid battery is close to 60v at peak charge, so I'm sure the controller can handle 60v. I might have pics of the insides of one somewhere?..

Seems to me that model does NOT have a current limiter. The 100 amp limit is probably imposed by the resistance of the wires

This means you can get really good acceleration

You might break or fry something too. The add-on limiter circuit works to tame it down.

I could be wrong about the particular model, so maybe it does have a limiter and it will be fine. You should be able to tell fairly quickly once you ride it.

OK on the batteries. I have one scooter where I have to pack the cells in a particular order so they clear the frame. The one in the middle goes in last. Just wanted to make sure you had thought about it. If you had one big battery, it could be a problem.

 

[Beagle123]

Got Sprocket Today

I got this 80T sprocket for #35 chain in the mail today. It's clearly made to be put on a tank. It weighs almost 3lbs! (2lbs 14oz.) I'll be damned if I going to go to all this trouble to make a light bike, then have to put a 3lb sprocket on it. I'm going to drill a million holes in this thing.

 

[Beagle123]

Top Brackets for Shocks Made

I cut these brackets for the shocks. It took me all afternoon. It turns out the the right side of the back portion of the frame is about 5mm higher than the left side. I had the pieces cut, then I decided to re-cut another bracket for the right side. I want there to be equal weight on the shocks, so I didn't want to compress the left shock to make it fit. In the end, it all worked out well because there isn't a problem having one side 5mm higher than the other as long as the place where it meets the shocks is correct--which it is now.

 

[TylerDurden]

I'll be damned if I going to go to all this trouble to make a light bike, then have to put a 3lb sprocket on it. I'm going to drill a million holes in this thing.

You could also go drill-happy on all the frame members that get plates attached, without compromising strength.

 

[newbie electric rider]

Got Sprocket Today

I got this 80T sprocket for #35 chain in the mail today. It's clearly made to be put on a tank. It weighs almost 3lbs! (2lbs 14oz.) I'll be damned if I going to go to all this trouble to make a light bike, then have to put a 3lb sprocket on it. I'm going to drill a million holes in this thing.




You wanted more teeth, you got more teeth

Starting to look real nice there Beagle! :lol:

 

[Beagle123]

Contemplating Battery Configuration

I got one Milwaukee v28 battery pack and dismantled it. Pics below.

I posted a picture above of how I planned on making my battery sub-packs. The pic is a view from the top. Basicly I planned on making a simple row of 7 batteries together in parallel. Unfortunately, the subpacks will turn out to be EXACTLY as tall as my box, so I doubt they'll fit (there won't even be room for the wiress and connectors. This leaves me in a dilemma.

Here are my calculations:

width of 7 batteries = 7.35 inches (exact)
Height of battery box = 7.71 inches.

Difference = 0.36 inches

But I plan to make plastic boxes, and the thickness of the plastic must be at least 3/32 inch (.094) So 2 X .094 = 0.19)

0.36-0.19= 0.17 inches clearance from top of sub-packs to top of battery box.

So they will fit, with only 0.17 inches left over. This could make it very difficult to wire the boxes.

Options:

1) make a block of 7 batteries with a row of 3 on top of a row of 4. This will compress the batteries more to make more space, but will make the plastic box idea hard to execute. I maight have to resort to shriink wrap.

Even then it would be a struggle to fit 14 of them into the battery box.

2) Use 6 batteries in the each sub-pack. This would drop my Amp-hours to 18. I was hoping to get 21ah. Then they would fit with 1.25 inchess to spare.

What do you guys think of dropping to 18 ah? I have experience with SLAs. My current scooter has about 17ah @ 48v. Would the new lithiums perform better (give more actual amp-hours) or less? My range right now is about 15 miles. I could also save $200 because I could buy 2 fewer Milwaukee packs.

DO you guys have any ideas?

Here are my exact battery box dimensions:

5.80 inches wide
11.6 inches long
7.71 inches tall

batteries:
1.04 inches in diameter
2.75 inches wide.

Keep in mind that space has to be made for connections to the battery ends.

 

[xyster]

What do you guys think of dropping to 18 ah? I have experience with SLAs. My current scooter has about 17ah @ 48v. Would the new lithiums perform better (give more actual amp-hours) or less? My range right now is about 15 miles. I could also save $200 because I could buy 2 fewer Milwaukee packs.

I haven't contemplated your layout conundrum, but would note that under average ebike riding conditions, SLAs provide about 60% of their rated capacity. You'd be doing well to be getting 10ah out of your present SLA pack. Each "3 ah" emoli cell provides about 2.6 real-world amp-hours, including at high drain rates. A 6p emoli pack will provide about 15.5ah -- a 50% increase which should increase your range from 15 miles to at least 23 miles.