Kona Kahuna build - 1000 mile review

patrickza

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Jul 6, 2008
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I've been a lurker here a long time. A really long time. In fact I can remember reading a post by some newbie named Doctorbass asking whether he should go for a 5304 or a 5305!

Anyway my name is Patrick and I'm from sunny South Africa. Except when it's raining. Or night. Apparently I'm a geek, but a cool one or at least so I've heard... In my spare time I fly my paraglider, sometimes with a motor sometimes without.
myglider.jpg


While I really like my glider, it doesn't really work so well for the my 10 mile each way commute. If you want to know why you can ask Jérôme Daoust on this forum and he just happens to be quite possibly the most knowledgeable guy on the planet when it comes to paragliding. Anyway to fulfill that purpose I bought myself a small bike.
IMAGE_036.jpg


It's a yamaha tw200, does 80mpg and will climb a tree if you can hang on to it. It has two problems though, it uses 80mpg too much fuel, and I can't carry it up the stairs to my apartment, or put it on my cars bicycle rack when I'm travelling. I get to do that quite a lot for work, Most of Africa, usually in really dodgy places. Basically if there's been a war, famine or disaster I'll get sent there.

I spend quite a lot of time travelling in Africa. In Zimbabwe last year I became a billionaire.
zimdollars.jpg


Fortunately Zimbabwe is right on top of the list in terms of education in Africa, you needed a PHD to figure out how to pay for lunch. About a month after I left all those notes were worth less than toilet paper. Eventually they released a 100 trillion dollar note just before the printing presses gave up completely.

Also regular citizens had no petrol and seldom electricity for quite some time. The guy I stayed with had solar panels, and the office had a generator, I could have really used an ebike then.

Anyway, so that brings this intro onto topic. I want an ebike. I don't need one, it possible doesn't even make financial sense, but I want one.

This is my trusty steed I've picked for the job:
DSC05280.jpg


It's a kona kahuna full suspension with disk brakes but v brake compatible, if I need them on the rear. I've managed to save some konion cells from being recycled prematurely. Unfortunately it only works out to 3 packs a month, so I think I'll either have to wait another 8 months, or try buy some packs from the doc.

My kahuna has quite a decent sized triangle, and using my mildly primitive cad software I've worked out I can get a 20s pack on and below the triangle without too much difficulty. The width will depend on the number I go in parallel. I'd love a 20s10p, but might need to settle for a 20s8p.
DSC05282.jpg


For the motor I'm going for a 5305. Again I probably don't need one, but I want one! I tried to see if crystalyte would give me a 5306/3 dual speed that doc has mentioned, but they say they're not ready yet. They did offer me a 5404 or 5405 which has the 40mm magnets. Should be a real torque beast if you have the width for it.

I'm looking for some advice on controllers. So far I've been thinking of going for the the crystalyte 72v controller too, but it doesn't have regen, and I like regen even if it's just the idea of it. Any advice there? Also what about a charger. I'll eventually try to build a dc to dc homemade charger, but initially I'd like something ready made so I can charge up my cells and test them for my pack design. Don't mind spending a little money here if it's something good.

Finally just a thanks to the forumites for answering my pm's and keeping me entertained while making me flex some gray matter almost daily. Everytime I think I'm finally getting it someone will go and say something that flies right over my head!
 
I have used the 48a digital crystalyte controller on 5303 and 5304 motors and it worked very well. They have a new model with 18 fets this year ebrake output, cruise control output among other nice features. I will be buying one soon. I tried the 35amp analog and it is a dog in comparison it uses different mosfets and they are not too great. The 4110 mosfets are the way to go with the x5 motors. I would make sure the controller has those mosfets in the future. Are your dropouts made of steel? Just make sure you install good torque plates or torque arms before you test it out it will save you some grief. If your dropouts are aluminum you might want to use another bike. From my experience you will need about 3/8" wide steel to secure it properly. The bike I run now has steel dropouts but I also added a 3/8" steel plate with a slot milled in it the width of the axle for extra protection.
 
Welcome to the forum, sounds like your on the right track, just search the forums for controllers, there have been a few group buys that you can get in on for custom controllers to suit your needs, I think theres one going on now.


On another note, PM me about the powered glider...I've been looking into them.
 
Allways glad to meet another pilot, especially one that flies something odd. My hot air balloon is a crappy commuter too, especially since after a flight, you have no desire to work at all, ever. Just want to keep flying.

Your plan sounds very good. Given where you will be using it, backups for stuff, like controllers, would be a good thing to have on hand. Your build plan looks really sound to me.
 
If you go 20s8p, based on 18650 cell dimension, you may be able to fit it into the triangle, but it depends on your frame size. I am doing a similar project, but it is not clear how our bikes compare in size. My "CAD work" is based on simple scaled photos and Visio drawings, but it works OK. I can fit 20s8p into my triangle with no sweat, or 24s8p with no margin. My frame is a Raleigh Ram XT 2500, which is similar in configuration to the Kona (here is the catalog shot):

ram2500.JPG

BTW, doctorbass has an excellent thread on building LiMn packs which is germane to this discussion.
 
wanders said:
If you go 20s8p, based on 18650 cell dimension, you may be able to fit it into the triangle, but it depends on your frame size. I am doing a similar project, but it is not clear how our bikes compare in size. My "CAD work" is based on simple scaled photos and Visio drawings, but it works OK. I can fit 20s8p into my triangle with no sweat, or 24s8p with no margin. My frame is a Raleigh Ram XT 2500, which is similar in configuration to the Kona (here is the catalog shot):

BTW, doctorbass has an excellent thread on building LiMn packs which is germane to this discussion.

Nice looking bike Wanders, it does seem similar. I measured my triangle, it's roughly 48cm x 31.5cm x 57cm. It's a medium. I'm sure I could get 20s into it with clever packing. How are you planning on mounting the batteries. I'm looking at building a plastic box and using some stainless steel zip ties to keep it on the frame.

I think I'm going to go a different route to what doctorbass went with his pack. I'll most likely be using the white inserts from the makita packs, and then keep the twenty 10 cell packs individually packed into their own pigeon holes. If this is a bad idea would someone let me know.
 
patrickza said:
How are you planning on mounting the batteries?

I'm going to build a custom fiberglass box that will fit in the triangle to hold batteries, BMX/LVC and hopefully controller as well, although I will probably mount the controller on the outside in the breeze to cool it. I'll use a foam mold covered in waxed packing tape. This fiberglass technique is well documented elsewhere on the web, though I will also do a photo document for ES.
 
Mhm... can't believe I missed this thread! Hi Patrick.. I fly paragliders also (most recently I flew a Skywalk Tequila)! I've always wanted to go fly Table Mtn in your neck of the woods there. :mrgreen: I'm also trying to build a custom triangle mount with 18650s, but I'm doing a 14s7p 98 cell arrangement as I'm allowing for each cell to be very easily replaceable so the cell holders add considerable "bulk". I'll still have ~500wh, which is plenty for my 8mi mountain climb commute. I've just got a new older model Clyte 504 that's symmetric with single gear and has the wider magnets you mention... I'll let you know how it runs. I was told it will indeed have a bit more torque than the newer 5304 and that there is a little less cogging because the magnets are mounted at more of an angle or something. Anyway.. it was a good price so... :D I was going to use the Makita white spacers also, but decided it wouldn't work for me. If you need any extras I've got like 30 of them... though shipping them to you would probably cost more than they are worth.. haha.

Anyway.. below link is the triangle pack I'm working on.. I'm actually quite a bit further along now and will update more photos tonight. The individual cell holders are Schedule 80 PVC pipe cut into 2.75" lengths that you drop the 18650s into snug as a bug... got the idea from safe and VRDublove. My max sustained output will be around 4-5C for 12-15min so heat shouldn't be a issue. It will add quite a bit of weight to the pack, but allow me to replace cells on the trail in moments... and it seems I'm always breaking down deep in the Montana woods so I need to be able to fix anything in the field including dead konions! :mrgreen:

http://endless-sphere.com/forums/viewtopic.php?f=6&t=9691&p=157096&hilit=escalador#p157096
 
Welcome to the site.

Thats a good looking doner bike. I'm running a Kona Stinky Myself, which is the same design with beefier componants. the frame isgreat for batteries.

have you considered Lipo over limn? hobbycity.com has some great (read that cheap) deals on RC grade Lipo packs. 4 packs of 18.5v 5ah cells fit easily in a frame bag sold by Ebikes.ca
I'm working on a custom bag like the one you drew out ...wait, almost exactly like ... have you been spying? :twisted:
Seriously though, I'm putting together a hard framed bag, it will be bolted and strapped on, and hold the cells ridged, but have cloth sides for stealth. I should be able to get 720 watts of battery in there with room for spares, tools, and the occasinal sandwich.
 
pwbset said:
Mhm... can't believe I missed this thread! Hi Patrick.. I fly paragliders also (most recently I flew a Skywalk Tequila)! I've always wanted to go fly Table Mtn in your neck of the woods there.

A couple of years back, I spent four months as a paragliding bum in Cape Town. Table mountain is a tough site to take off from, sheer cliff drop with the associated rotor, no run up and fynbos (really clingy shrubs) on take off. A better bet is to wait for a WSW on lions head, soar up the side of that and then hop over to table mountain. With the right wind you can climb at 5m/s up the side of TM, blow past the top and work your way down the 12 apostles (mountain range). Then of course you have to go land at La Med, the trendiest beach spot in the cape, that is if you don't get too distracted by the topless women on clifton. :mrgreen:

That's a really interesting arrangement, I'm keen to see how it'll work. Any idea on the amount of weight it will add? Post some new pictures for us!
 
Drunkskunk said:
Welcome to the site.

Thats a good looking doner bike. I'm running a Kona Stinky Myself, which is the same design with beefier componants. the frame isgreat for batteries.

have you considered Lipo over limn? hobbycity.com has some great (read that cheap) deals on RC grade Lipo packs. 4 packs of 18.5v 5ah cells fit easily in a frame bag sold by Ebikes.ca
I'm working on a custom bag like the one you drew out ...wait, almost exactly like ... have you been spying? :twisted:
Seriously though, I'm putting together a hard framed bag, it will be bolted and strapped on, and hold the cells ridged, but have cloth sides for stealth. I should be able to get 720 watts of battery in there with room for spares, tools, and the occasinal sandwich.

Thanks Drunkskunk

Never actually saw your bag before, there are only so many ways of fitting them in, but now that I see your rear rack design :twisted:. Tell you what, if I copy your rack I'll put a label on, inspired by drunkskunk!

I've looked at the lipo but as this is my first experience with lithium, and that I want to charge the batteries on the bike unattended I'll be sticking to more stable chemistries.
 
Nice Kona! You chose a great project bike especially with the rim brake bosses on the back making a rear hub install easy.
I have a kikapu and a stinky that I am converting right now. One is 72 volt 15amp/hr and the other is 60 volt 20 amp/hr. I would highly recommend using a Lithium iron phosphate battery. Honestly, I think that I have done some electronically horrific things to my batteries and they never stop.

good luck
 
mikebikerad said:
Nice Kona! You chose a great project bike especially with the rim brake bosses on the back making a rear hub install easy.
I have a kikapu and a stinky that I am converting right now. One is 72 volt 15amp/hr and the other is 60 volt 20 amp/hr. I would highly recommend using a Lithium iron phosphate battery. Honestly, I think that I have done some electronically horrific things to my batteries and they never stop.

good luck

Thanks Mike, I must admit I've been enjoying the bike so much without power that I'm almost a little sad to be converting it. I'm sure that won't last once the EV grin kicks in though.

I have decided to go for 24s1p headway cells for now. The konions are taking forever to come in and I'm keen to get moving so I've ordered the headways for now. 72v10ah should hopefully get me the 20 miles I need for my commute.

I've also received my 5305 with disc brake, 72v48a 18 mosfet digital controller (apparently with fake 4110s) and a split grip throttle. My cycle analyst is on order.

It's getting closer and I'm getting more excited, but I'll have to keep things under control until I have everything I need. I'm hoping to do a triangle mount for the headways. If I use 3mm abs for my case it'll be very close, so I just hope I can make it work. This is how I hope it will fit:
headway24s.jpg


As you can see it'llbe very close. The triangle will have a frame, and each 3 cell group will be in individual pigeon holes with either silicon or hot glue (any opinions on those?) to keep things steady. Case width should be 12cm, and I've tested pedaling with a cardboard cutout and I just seem to clear it.

I've tried to find the build threads for your bike but had no luck.
 
That will be very nice! with 10 amp/hr you will be pushing the limits going 20 miles. If you pedal a lot then it will make it much more possible. My build threads are to come because my girlfreind has my digital camera and she is gone for a few days. Ill have it up early next week.

the frame bag that "skunk drinker" is a very nice way to manage all those loose cells. Try to keep all the resistance in the pack down by keeping the wire runs as short as possible. I use a metal riveted box to house the batteries and mount them on an aluminum bracket connected to the water bottle holes. pics to come early next week

good luck getting the batteries, it can be a pain to wait i bet
 
mikebikerad said:
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.
 
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:
 
And mounted onto the bike:
 

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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...
 
Sacman said:
Wow! I'm really liking that battery box patrickza. That's SCHWEEEET! :mrgreen:
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?
 
Mark_A_W said:
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.
 
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..)
 
Mark_A_W said:
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: http://endless-sphere.com/forums/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.
 
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 :twisted:

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!
 
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