Author Topic: Smoking a Fatty  (Read 3105 times)

PonoBill

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Smoking a Fatty
« on: May 31, 2016, 09:11:11 PM »
Built this bad boy today. It's a trek semi-fatty I bought last year, added a Bafeng 1000 watt crank drive electric motor and an ultralight battry pack (three pounds). The assembly took about four hours because I had to machine some special adapters, the trek bottom bracket is non-standard. Other than that it went super smooth. I plan to make a slicker battery box, but this one works for now. the next one will fit right down into the V of the frame and I'll do some fancy-schmancy aluminum work.

I hacked the bafeng to give me 1400 watts when I want it, and to elminate the cutout at 25mph. But after playing a while I backed it off to 1200 watts. !400 is a ilttle abrupt, the power curve is a bit too sudden. 1200 is still a little wanky but it's not trying to toss me off when I start pedalling now. In contrast to the el-cheapo fatbike I built in Maui, I find I'm using the assist more than the throttle. Not sure why, but it feels good on this bike. When I get to a big hill I just jack up the assist and drop a few gears. Cranks up smooth as glass.

The three pound battery is pure nutball LiPo. 5amp-hours at 44V nominal (53 actual) in that tiny, light case. I can stuff two extra sets (three batteries each) in my backback and barely feel them. Disconnects the weight from being statically connected to the frame, and I'm carrying 15 amps with just nine pounds. By contrast the 20A 48V LiFe batteries on my trike are 35 pounds each. I have some 10 AH graphene packs on the way that are the same size and just a little heavier (half a pound). Batteries are getting crazy good as long as you have the electronics chops to keep them from blowing up. Someday soon the BMS will be a little more automatic and these things will be much safer. As it is right now I have two really good BMS' sitting on my desk, but I wanted to monitor the battery health directly. I'll trust a plug-in charge later, for right now I'd rather monitor the buggers.

High performance, off road is the plan here. Other than the battery pack it's pretty stealthy. Next iteration of the pack will be cleaner, smaller, less obtrusive and let me switch out batteries faster. Plug and play.





« Last Edit: May 31, 2016, 09:18:10 PM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

TallDude

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Re: Smoking a Fatty
« Reply #1 on: May 31, 2016, 09:33:57 PM »
I'm eyeing one of those tweeners. Aren't they 27.5" rims and 3" tires? I'd watch that motor on curbs and boulders.
It's not overhead to me!
8'8" L-41 ST and a whole pile of boards I rarely use.

TeachSB

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Re: Smoking a Fatty
« Reply #2 on: May 31, 2016, 09:55:32 PM »
 ::) barends
Focus Smoothie 9' x 32"
PSH Wide All Rounder 11' x 30"

PonoBill

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Re: Smoking a Fatty
« Reply #3 on: May 31, 2016, 09:58:24 PM »
I'm eyeing one of those tweeners. Aren't they 27.5" rims and 3" tires? I'd watch that motor on curbs and boulders.

Yup. The motor case is hell for stout. I'm thinking about a bash plate, but I don't want to junk it up. I'll beat it up a little and see how it goes. I've got about seven more of these motor kits, so if I trash one, life will go on. Learning experience.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

all~wet

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Re: Smoking a Fatty
« Reply #4 on: May 31, 2016, 10:46:19 PM »
One of those toys I've been pining for but wondering how much I'd actually use it in the day to day. Then again... I can't help but think how perfect that would be for self shuttling downwinders.....................

PonoBill

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Re: Smoking a Fatty
« Reply #5 on: May 31, 2016, 11:04:15 PM »
I just realized I can swing the motor up higher. Picked up about six inches of ground clearance. I don't think the higher CG will matter.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

PonoBill

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Re: Smoking a Fatty
« Reply #6 on: May 31, 2016, 11:06:22 PM »
::) barends

Yeah, I know, covesurfer gave me shit about them, but I like them for sitting up straight and resting my back. Geezer bars. Could be worse, I could have gone for apehangers.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

yugi

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Re: Smoking a Fatty
« Reply #7 on: June 01, 2016, 02:11:53 AM »
the higher you put your hands the more yo' ass hurts.

It's a choice!

TeachSB

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Re: Smoking a Fatty
« Reply #8 on: June 01, 2016, 06:34:01 AM »
I get it it had to make the comment anyway. If you want to be a real nerd you might try "bar-ins" where you mount them inside the grips. It looks horrible but it makes my shoulders happy, so I've considered it.
Focus Smoothie 9' x 32"
PSH Wide All Rounder 11' x 30"

1tuberider

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Re: Smoking a Fatty
« Reply #9 on: June 01, 2016, 07:15:28 AM »
How fast can you go before you have tire bounce?

I use mine (origin8 crawler)on the beach exclusively. I picked up about 5 pounds of
agates on Monday. I have the nuvinci hub on mine. Its a great match
for a beach bike. I have around 20 miles of beach to ride here and more short trips away.
Its amazing the things you find on remote beaches.

I am using the samsung bottle battery at 52v 13.5 ah. So far I have only run out of
power on one trip. Cruising the beach a 15 mph covers distance fast. Pumping without
the power not so fast.

I thought you were smoking something else.

stoneaxe

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Re: Smoking a Fatty
« Reply #10 on: June 01, 2016, 09:11:17 AM »
I need to add this to the list of projects I won't get done.
Bob

8-4 Vec, 9-0 SouthCounty, 9-8 Starboard, 10-4 Foote Triton, 10-6 C4, 12-6 Starboard, 14-0 Vec (babysitting the 18-0 Speedboard) Ke Nalu Molokai, Ke Nalu Maliko, Ke Nalu Wiki Ke Nalu Konihi

PonoBill

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Re: Smoking a Fatty
« Reply #11 on: June 01, 2016, 09:13:23 AM »
I've got a spare NuVinci hub up at the shop, but it's laced to a wheel sized for the back of my trike. Hate to redo it. The trike has an Alfine 8-speed rear hub. I'm thinking I'll get around to puting the NuVinci on the trike, make sure I don't toast it (vastly over the spec power rating) and if it holds up I'll stick the Alfine on the fatty.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

SlatchJim

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Re: Smoking a Fatty
« Reply #12 on: June 01, 2016, 10:35:19 AM »
the higher you put your hands the more yo' ass hurts.

It's a choice!
T-shirt worthy.

headmount

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Re: Smoking a Fatty
« Reply #13 on: June 02, 2016, 08:02:22 PM »
Cool looking bike but I thought it was going to be flash back thursday with a younger PBill puffing away on a stogie.

 


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