Kona Kahuna build - 1000 mile review

[patrickza]

That will be very nice! with 10 amp/hr you will be pushing the limits going 20 miles.

I've been wondering myself how far I'd get. The 24 headway cells will give me a nominal 76.8v and at 10AH means 768whrs. I'm hoping to keep energy consumption under 30wh/mile which means that 20 miles (10 miles each way) would be a discharge of 78%. Now that's just the theory, in practice I have no idea how much I'll do. I could take a charger along, and charge a little there, but I'll only have an hour and a bit before I head home again, so I don't know how much that will help. That said I plan on pedaling home again for exercise. Not all the way, but definitely more than on the way there.

[patrickza]

Ok time for an update.

All my parts have arrived. I'm still ordering an ES-BMS from Andy as I think it will be a better solution than the headway BMS, and I can get on forum support if needed.

Nearly screwed up my motor. was tightening up a bolt and something stripped. I checked and unfortunately it's partially the motor thread. Soft steel. I had to remove the locking washer and use another bolt to get things working. I do have a serious torque arm on both sides which I'll tighten with a couple of pipe clamps, so that should hold. I won't tighten the bolts as much in future. What are my options be if I strip more of the hub?

Anyway, my battery box was completed a while ago, built the pack this evening and have that in the box. Must thank dnmun and Sacman for help with the headway BMS. From now on it should just be connections. I'll try a little tonight and hope to have the bike on the road by the weekend. Here's a pic of my battery pack:

[patrickza]

And mounted onto the bike:

[Sacman]

Wow! I'm really liking that battery box patrickza. That's SCHWEEEET!
You gotta spill the beans on where you got that made. Is there a cover to it?
So did the BMS wiring connections work out for you?

[Mark_A_W]

I'm very interested to see how this Kona frame holds up.

I have a very similar frame - a Kona Dawg, and I am quite frankly too scared to fit an X5 motor to the rear swingarm. There is not a lot of meat around the main pivot (near the cranks), at least on my bike.


I already broke the rear swingarm on a Jamis Dakar...and the motor was on the front wheel!

These swingarms are not meant to carry an extra 10kgs...

[patrickza]

Wow! I'm really liking that battery box patrickza. That's SCHWEEEET!
You gotta spill the beans on where you got that made. Is there a cover to it?
So did the BMS wiring connections work out for you?

Thanks Sacman, it's a homebuilt box. I'm not the handiest guy but I do like to try things myself. I bought a very large sheet of 3mm ABS plastic and a small bottle of glue the plastic manufacturer uses. Tried a number of methods for cutting straight lines but the easiest was simply scouring (correct word?) the plastic a few times and then snapping it off along the edge of my kitchen counter. Their glue was really fast drying but not so strong so I got a large plastic eye dropper type bottle, filled it with acetone and dropped quite a few off cuts into it. The ABS dissolves in acetone, then you drip it along the join lines, the acetone evaporates and you're left with a weld like finish.

I haven't tested the BMS wiring yet, the harness is connected though. I'm going to mount the BMS on top of the triangle this evening and then do some more connections. I usually rush projects and damage stuff in the meantime, but I'm taking this one slow and trying to get things right.

I'm still deciding of a cover, 10 points to the best suggestion. I'm thinking maybe lycra?

[patrickza]

I'm very interested to see how this Kona frame holds up.

I have a very similar frame - a Kona Dawg, and I am quite frankly too scared to fit an X5 motor to the rear swingarm. There is not a lot of meat around the main pivot (near the cranks), at least on my bike.


I already broke the rear swingarm on a Jamis Dakar...and the motor was on the front wheel!

These swingarms are not meant to carry an extra 10kgs...

We'll have to wait and see. I hope I don't break anything. Remember the motor weight is not on the swingarm, but the rest of the equipment is. The guy I bought the bike from was about 15kg heavier than me, so it should handle the weight fine. I was more worried the axle twisting so I have two 6mm torque arms on the bike.

[Mark_A_W]

Adding extra unsprung weight increases the load on the pivots. There's no way around that - when the wheel moves up (or down) and is stopped by the shock, the forces are reacted through the main pivot.

If your bike holds up I may try a heavy rear motor on mine, but I don't want another swingarm failure at 45km/h (although the last one was surprisingly uneventful, I don't want to push my luck..)

[patrickza]

Adding extra unsprung weight increases the load on the pivots. There's no way around that - when the wheel moves up (or down) and is stopped by the shock, the forces are reacted through the main pivot.

If your bike holds up I may try a heavy rear motor on mine, but I don't want another swingarm failure at 45km/h (although the last one was surprisingly uneventful, I don't want to push my luck..)

Wow 45km/h is quite some speed to have a swingarm failure, glad you survived it unscathed. Have a look at mikebarads thread about his kona kikapu. Same frame again, and also 72v: viewtopic.php?f=6&t=11395&p=174176#p174176

He's using a 9 continents which is about 8kg compared to the 12 for the 5305, but there is a video clip of him doing a long long wheelie. I imagine he's putting quite a lot of stress onto the frame, maybe he can let us know how it's been holding up, and what he's using for torques arms.

[mikebikerad]

Ive been using the stock ampedbikes kit torque arms. They are not long but they work and usually line up with the holes already built into the frame for paniers/racks.

As far as the frames go, The Kona Kikapu, which is almost the same bike as the kahuna has held up really well. I was also skeptical. I check my axle tightness before each ride. I figure that if the bike is meant to accommodate heavier individuals >200lbs, then I should be relatively safe strapping on 20-30 pounds of components being 170lbs myself. Im sure the wheeling doesn't help but

I also tried using plastic for my case. patrickza: disolving some of the plastic into the "glue" is a great idea. Wish I tried it myself! would have had better results.
great build!

[patrickza]

Ive been using the stock ampedbikes kit torque arms. They are not long but they work and usually line up with the holes already built into the frame for paniers/racks.

As far as the frames go, The Kona Kikapu, which is almost the same bike as the kahuna has held up really well. I was also skeptical. I check my axle tightness before each ride. I figure that if the bike is meant to accommodate heavier individuals >200lbs, then I should be relatively safe strapping on 20-30 pounds of components being 170lbs myself. Im sure the wheeling doesn't help but

I also tried using plastic for my case. patrickza: disolving some of the plastic into the "glue" is a great idea. Wish I tried it myself! would have had better results.
great build!

Thanks for the info, hopefully I have the same result. As for building out of plastic, I read about a guy who built a boat for his kids entirely our of ABS, so that was where I heard of the technique. Worth a read if you plan ondoing minor plastic building: http://www.duckworksmagazine.com/07/des ... /index.htm

[michaelplogue]

it's a homebuilt box. I'm not the handiest guy but I do like to try things myself. I bought a very large sheet of 3mm ABS plastic...

Wow! that's really nicely made, and a fantastic method of 'welding.' Initially, I thought it was welded steel that had been painted grey - and then I saw the battery studs looking like they were ready to come into contact with the 'metal.' My initial post was going to warn you about potential shorts......until I read your follow-up post...

Very nicely done - Kudos!

.

[docnjoj]

That is one classy battery box, patrickza! Any chance of more photos from different angles. I need to replace my Frankenbox with something a bit better looking. What thickness ABS did you use? Thanks in advance.
otherDoc
edit: Whoops, just saw the 3mm thickness!

[patrickza]

That is one classy battery box, patrickza! Any chance of more photos from different angles. I need to replace my Frankenbox with something a bit better looking. What thickness ABS did you use? Thanks in advance.
otherDoc
edit: Whoops, just saw the 3mm thickness!

Thanks, yeah they sell it as 3mm, but it looks more like 3.5 to me. Here's some pics I took when I was building it. My box had a few weird angles, I think a rectangular box would have been a piece of cake. The plastic is strong. I could stand on my box on it's side no problem. I also modified a plastic vacuum sealer to turn it into a plastic bender. It worked quite well, but I had better results cutting and glueing so I didn't use it at all.

[dnmun]

looks great, duane told me about ABS and i am gonna build something similar, like deecanio did too, and bob mccree on his original nicad pack build. and they all fit.

be gentle torquing the axle nut, they don't have as much thread as a regular bolt and can strip pretty easy, use the torque arm to hold it in place, you can't tighten enuff to overcome the torque anyway, especially with that much power.

add a second nut/locknut to the first if you can find space on the end of the axle to compensate for losing some of the threads inside.

[docnjoj]

Thanks, partickza for the extra photos! I am inspired to fully enclose my Fatpacks in my triangle under the seat. I think the huge Ping will just simply be too big for my purposes.
otherDoc

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[patrickza]

IT RIDES!

So finished all the connections, plugged everything into place lifted the (very heavy) rear wheel and gave the throttle a quick turn. I was so shocked, it worked! None of my projects ever work first time round, woohoooo. I must say, I feel like I've learnt more in the past couple of weeks here than I have in the 7 since I got my degree...

Anyway I got a million zip ties, tied all the cables out of the way and carried the heavy beast down the three floors to the ground. Took about a 5km ride around the neighborhood grinning like a fool and feeling like a kid.

Carried her up the three flights of stairs again, I have a feeling I'll be building a few more muscles soon. Anyway, plugged in the charger, and just saw the green light appear. I do have one problem though, so it's not perfect. After the charge (which stopped at 80.4v according to the cycle analyst) I switched on the cycle analyst to see the voltage. Lifted the rear and gave it a spin then turned off again. Went back a little later and turned on the cycle analyst and the light comes on, but nothing displays on the screen. Also when I spin the rear wheel with the cycle analyst plugged in it goes much slower then when I do the same with it unplugged. Any ideas?

Here's a few more pictures:

[snowranger]

Very nice build. I was wondering how you lock the bike up though.

[patrickza]

Ok I got some advice from voicecoils about the cycle analyst and the screen has come back to life after soldering in a new resistor. The backlight is still flickering but I can live with that for now.

Next up I'll need to start thinking of a cover...

Very nice build. I was wondering how you lock the bike up though.

Thanks, yeah i thought about locking up methods for a while. The crime rate in South Africa is pretty bad. I'll mostly be taking the bike in with me when I go to the office etc, but there is also a gap between the shock and the seatpost for locking things up.

[snowranger]

You could also run a cable to your front wheel too.

[GreenKnight]

Yep looks like a nice bike. If you do run out of space you can consider putting a few of you triple cell units either behind and under the saddle or in front of the of the handle bars. Where or what are the triple containers from?

As for for the adhesive I would go with the silicon rubber. Its strong enough to hold things together, doesn't conduct and can be cut with a sharp knife if you need to disassemble.

[patrickza]

Thanks, partickza for the extra photos! I am inspired to fully enclose my Fatpacks in my triangle under the seat. I think the huge Ping will just simply be too big for my purposes.
otherDoc

I agree, you should get going docnoj! Looks like a good candidate for some ABS building. It's a fun material for working with too. You should be able to knock together something in two evenings. Where the thought will come in is how you open and close it. I made the inner triangle just fit the frame, then put a double layer around the left edge, and built the right triangle cover 3.5mm wider so it slides on. You'd probably make a top cover which lifts off to gain access to the cells.

Where or what are the triple containers from?

They're not really containers. it's 0.8mm double sided tape in between cells with duct tape around it. Then I connected the cells using copper braid I salvaged from some cable. The edges of the copper braid would fray a little so I dipped the end few mm into my ABS acetone mixture and let dry, then repeated again. They came out so strong that the copper would break before the cables frayed.

[patrickza]

So just got back from my second ride I'm still grinning from ear to ear. Took it to show my grandparents, they're both in their 80s but like seeing new ideas. My grandfather used to be quite a tinkerer when he was younger so he was really into it.

Ok so stats for the ride were as follows, I haven't calibrated the cycle analyst apart from setting the wheel circumference:
Distance 30.8km
Starting voltage: 80.4v
Ending voltage: 78.8v
Lowest I saw under heavy load towards the end of the ride: 69v
Cycle analyst reported 4.6ah used.
Top speed: +-55km/h on the flat.

I'll hook up the multimeter to try get it calibrated this week sometime, Justin said the rshunt could be anywhere between 1 and 2 mOhms.

[patrickza]

Well the white stood out quite a lot. The street vendors here love the bike, I get tons of thumbs up wherever I ride. Anyway I was feeling decidedly under duct taped, so in following with the inspirational doctorbass, my case has been duct taped up. I think it looks better, but also it will protect the plastic from the sun in the upcoming summer months.

A quick update on my stats, I've done 170km since finishing the bike. I'm taking it easy on the batteries for the first while so I tend to only go uphill at 20mph while pedaling along lightly. So far my cycle analyst says I've used up 26ah however it needs to be calibrated. Using Justin's technique of seeing what the highest average amperage is and comparing that with the controller peak it looks like I'm over reading by about 30%. This means the 170km's have been at a cost of +-18ah, not bad going. My average wh/mile is about 20 so I should make my 30km round trip commute on one charge. Only done it once so far and I charged at the destination.

I'm still waiting for a second charger to arrive from ecitypower, I might mount this one to a seatpost rack for on-board charging.

Here's my duct-plastered bike:

[michaelplogue]

Here's my duct-plastered bike:

NOOOOOOOOOOO!!!!!!!!!!

That's just frigin' criminal! How could you do that to such a beautiful build?


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