Kona Blast Build Thread

[danielrlee]

I've been thinking about a second build for ages and after a lengthy search for a suitable bike, I finally bagged myself a used 2010 Kona Blast at a reasonable price on ebay. I'm looking forward to getting on with the build and getting everything ordered.

After a fantastic couple of years knocking around on the ghEttoBIKE, I am a lot more focused on my goals for a second build. My e-bike has become my main mode of transport to the point that I no longer own a car (although I do have access to my g/f's car when necessary), so reliability is extremely important for me. I'm also building for the specific task of a semi-regular return journey from Bath to London (120 miles each way) which I aim to do on this bike too. Actually having the bike with me now is forcing me to stop deliberating and finally make some decisions about the build.

Battery
I'm a lipo guy, have lots already and will probably be buying lots more. Triangle bag for the primary pack and secondary/tertiary packs in bags elsewhere. Not too sure about voltage yet, either 12s or 18s depending on motor wind.

Motor
For a motor I have been to-ing and fro-ing as far as geared vs DD, but I think I'm gonna go direct; either Crystalyte or 9C. I'd like to think a geared motor would do and I'd love their efficiency and torque, but it would never be 'bulletproof reliable'.

Controller
I can throw a decent number of watts into a DD motor to make up for the loss of internal gearing, so am thinking either 40A or 60A controller limit and I can dial back when needed from a CA.

I'm currently drawn to a kit from ebikes.ca, but cannot decide on a motor. How does the Nine Continent M300xRC compare to Crystalyte H3540? Does anyone have any comments based on your own personal experience?

Once I've got past this decision, I can pull the trigger on the necessary purchases.

For now, that's about it - my heavily pregnant girlfriend is calling Thanks for any input you may have.

 

[danielrlee]

Bump:

I'm aware that the 9C motors with a cassette hub are a fairly new development. Does anybody have any experience with them? It would be nice to be able to take advantage of the increased gearing flexibility over using a freewheel with a Crystalyte motor, but not at the expense of other areas of the proven H35xx.

 

[amberwolf]

I'm currently drawn to a kit from ebikes.ca, but cannot decide on a motor. How does the Nine Continent M300xRC compare to Crystalyte H3540? Does anyone have any comments based on your own personal experience?

No experience with the new 9C, but the HSR3548 I use in a 20" rear on a 12FET 40A does me well enough on CrazyBike2, using (I think 13g?) Sapim spokes from Grin Tech laced to an ex-Zero rim from Ypedal. (the original rim/spokes it came with didn't last long). I use it typical at under 20MPH, on a short 2.5-mile each-way commute, but it works fine for longer ones, too (more than 10x that).

On acclerations I also use a front 9C (2 generations back, bell covers) 2806 26" 12FET 40A, but I typically don't need that after I'm up to speed (and since it's noisier cuz it's in front of me instead of behind, I prefer to use the rear for cruising, and it also "seems" slightly more efficient in operation, though that could be an artifact as I've done no actual experimental setup).


As for info on the motors and how they compare, this is from the Grin site:

M3548R
Actual Weight (kg)  	7.4700
Motor Power Range (Watts) 	600-1200
Motor KV (RPM / V) 	10.4
Phase Resistance (Ohm) 	0.123
Magnetic Pole Pairs 	23
Hysteresis Losses (N-m) 	0.77
Eddie Losses (N-m / rad/sec) 	0.0185

M3004RC
Actual Weight (kg)  	6.28
Motor Power Range (Watts) 	500-1000
Motor KV (RPM / V) 	13.9
Phase Resistance (Ohm) 	0.082
Magnetic Pole Pairs 	23
Hysteresis Losses (N-m) 	0.7
Eddie Losses (N-m / rad/sec) 	0.013

So, theoretically, if you need the power the HS is slightly more capable.

But it also weighs more, by a little more than 1kg.

And it has slightly higher eddy losses.

It's also slower for the same voltage, which should mean it has more torque, but the torque constant's not specified on the page.

With a slightly higher phase resistance it ought to be slightly easier on the controller, I expect.



As far as the cassette freehub: It depends on how they designed it's supports: if it has bearing support on the axle at both ends, to support the chain pull regardless of which sprocket it's on, it should be ok. If it only has bearings at one end like a regular freewheel, it may not be any better than using one.

 

[danielrlee]

Thank you AW. I've always got the impression that your bikes are built with workhorse reliability in mind, so your input is appreciated.

Previously I have just been looking at the kit pages on ebikes.ca, but seeing the data you provided, I had a further hunt and found lots of additional info and stats that I hadn't realised existed within the specific motor pages. Thanks for bringing that to my attention.

My intent is to stick with a 26" wheel and probably a pack voltage of 44v nominal (12s lipo) since my entire charging setup is geared up towards that. Also, I have very little desire to top 30mph, so higher voltages shouldn't be strictly necessary anyway. For my requirements, I think either the H3540 or 9C 10x6 wind would be a good choice.

I'm gonna study the tech specs now and probably have one last look at the ebike simulator and hopefully make a decision before the end of the day.

 

[danielrlee]

Right, I've made a decision and I'm going with the H3540 kit from Grin Tech. I'm currently awaiting a reply from them about a couple of questions I have before ordering, but I'm wondering if anyone here can provide the answers:

1) Will I require an axle spacer if I use an 8-speed freewheel with the H3540 and if so, how wide?

2) Using the supplied half-twist throttle with the button, will I be able to fully utilise proportional regen without modifying/replacing my hydraulic brake levers?

Thanks.