Marin ebike project

[wurly]

Here is my new bike. A Marin Muirwoods 2009 model. I got this at a bargain price and luckily for me it was the last one they had.

I like the look and design of these bikes and have been looking at these Urban bikes for a while. It has a lightweight mountain bike frame, skinny kevlar tyres TruvativDeore gears with an outer ring of 48 fairly for high speed.
I've been getting used to it for a few months now while i decided how and what i 'm going to do it. I was going to build the bike as a crank driven hill climber with frame mounted motor driving the 28 tooth ring and the outer two ring sets 38/48 for pedalling speed, hence careful choice of bike that had the chainset gears i needed. However i have decided against it completely. Not that i can't engineer it that way, i figured my fitness level has increased so much the combined effort of front mounted tongxin motor and me can get up most hills.

First stage is fit the hub motor. The Marin wheels are Alex rim double walled with 32 holes so rather than get a new 36 hole rim and lace it up, i simply took the wheel off my old creaky worn out Claud Butler bike.
This wheel has a Tongxin 260 rpm motor into a 26" wheel to give's a 'nice' speed.

I couldn't have a shiney aluminuim wheel when the rest of the bike is matt black, so i waited until i had a few things to paint, etched primed the wheel and shot some matt black over it. Looks rather stealthy at the moment, can you see the fibreglass mudguards? i couldn't buy any i liked for narrow tyres, so i made some.

mmmm...could be the theme of the bike? not sure yet.
This weekend i tried out it's freewheeling ablitilies. How about 35mph down hill, no pedalling. These Tongxins have hardly any noticable drag, you hardly know they are there.

I have a 36Volt 5ah Ping battery on it's way, and i will add another 5ah from my wifes bike whenever i need to ride some distances. I have a few tricks i want to try out, but need to house all the electrics.
I came up with this photoshopped permanant box arrangement in the middle of the frame. Although i can keep it very narrow(width of batteries) i am beginning to think it looks a bit ugly on a nice looking bike.

I thought it would be good to have a housing that would have the capabilties of carrying serveral batteries, controller, switches, current limiter, power analsyer and charger, all safely locked away.
I will tig weld the housing together and paint it matt black to match the rest of the bike.

I rigged up the electrics a few days ago (battery and controller in my rucksack). Immediate problems i encountered was having the throttle and brake levers all fighting for their respective position on the handlebars. I could put up with that on my last bike, but want a proper solution to this one. First thoughts are thumb lever or different gear shifter or even a simple on/off trigger on a micro switch
I'll post some more photos as the project develops.
Mel

 

[flecc]

Immediate problems i encountered was having the throttle and brake levers all fighting for their respective position on the handlebars. I could put up with that on my last bike, but want a proper solution to this one.

Nice job Mel. My solution to the controls on my bikes is a r/h twistgrip changer and l/h twistgrip throttle, this leaving the levers unaffected and plenty of space for meter etc. I use the Shimano compatible SRAM twist shifters. You'd still need a front changer of course, I use a single chainring.

I think the BionX style in-frame box could grow on one after a while, and maybe a logo or surround edge lines on it could break up the visual size impression.
.

 

[Straylight]

Very nice, and a great bike to base it on. I've had a Marin ALP for well over a decade, and I can't speak highly enough of it's build quality and attention to detail - nice one, I look forward to seeing how the in-frame box turns out.

 

[Lloyd]

Marin are one of the great original MTB manufacturers, I remember spending my school years lusting over a purple and white Marin Nail Trail after seeing one in the flesh at Phil Corleys in Milton Keynes.

They are one of the only companies that offered a lifetime warranty on their bearings used for the full suspension bikes. Lifetime warranty on a moving part? Now that's cool.

I'm liking the stealth look, and do those mudguards not have any stays? They look quite cool.

 

[wurly]

Thank for the comments.
Of all the makes i could have opted for, i am pleased with the Marin. It has some nice parts with it. It cost me £380 which is a nice price for a quality bike as the basis of the project. I already have the tongxin parts.
With the nice weather here again, i'm getting back into the ebike interest.
I have tested most of the parts, when the battery arrives i will quickly have the housing made and fitted.
I really need to address the throttle options fairly quickly. It is the bulky part of the throttle where the LED's are situatated that cause the problem. I cannot reach around it to change gear.
I will look at different gear changers first.
As for using it off road? no way....i'm aiming to build it to average 20mph with minimal drain from the battery. Lightness is the key i think. Maybe do the Ching Challenge this year with it.
The rear guard is ok with no stays, but i think the front will have to have the bracket extended further to the front, there is quite a bit of up and down movement, i will tackle that soon. They look almost invisable from the side. They keep most of the water off me.

 

[Barnowl]

Damned computer - can't see the piccies for some reason...

Interesting you mention the BionX in-frame box/battery Flecc. Not my cup of tea either but it might grow on me. Not seen this conversion yet so can't comment. Reads interesting though.

 

[wurly]

Hi Everyone
Time for an update.
Our second Ping battery arrived the other day. One for my bike and one for my wife's bike. Both bikes get used for commuting (albeit not very far) so getting to finish mine off has taken more time than i wanted.

This is another nice and light 36Volt 5ah.

And two makes 10ah's available whenever i want to ride plenty of miles.
You can see both batteries have shunt resistors added on the negative side and my current limiter is plugged into it via jack plugs. The limiter uses the volt drop across the resistor and clamps the throttle voltage by a adjusting the threshold.
I tried to figure out how to mount then between the frame with the controller....

but alas, not enough room, plus i might need to carry all this gear on occasions. Tools, phone, chargers, spares, drinks, jacket etc etc mean't i need to have a rack and panniers....there is no way around it.

 

[wurly]

So, to the garage and knock up a housing for the batteries. It needs to be strong and more importantly secure, should i leave the bike locked up for any amount of time. I had some galvanised steel to construct a nice box exactly the size need to fit both batteries.

Using basic tools and within an hour later i had this.

Another evening i managed to finish the box with a hinged lid. And also made a bracket for the connections housing and controller, I decided to make this available for easy access. The paniers will cover it anyhow.
Add a welded on bracket with a small padlock makes the whole secure and a small hidden 20A on/off switch and we are nearly there!

 

[wurly]

I was running out of space on the handlebars. A minura space saver was an ebay bargain. This has my current limiter and speedo attached. The turnigy meter is temporarly fitted to the stem so i can monitor Wh's used.
The small light is my summer one...it has a fast bright strobe. I found to many people pull out in front of you not realising how fast i can be travelling towards them, i recommend them.

Here we go. Charging up both Pings. Turnigy meter lets me know how much has gone in, and reconfiguring the wiring lets me know how much i am using.

The final results with panniers. Not the stealth bike i was hoping for, but i am pleased with it. High pressure slick tyres, chainset of 48/38/28 makes for fast riding.

I did a ride of 25.4 miles today. I used a total of 184Wh's, giving me 7.2 Wh's per mile. Peak power was only 8.2 amps. The trip took 1hr 30 mins giving me an average speed of 16.9 mph (oh yes, i should say that was with a helluva headwind). I was surprise to find i only used about 3/4 of the power available from each battery. Still no problem....my motto is 'never thrash your batteries'.
Next job is to finish off painting the housing and brackets in matt black (when i get 5 minutes).

 

[NRG]

Flippin' eck! 7.2wh is good going, I take it you are a) fit and 2) somewhat younger than the average pedelec member! Great conversion BTW

 

[wurly]

I'm fairly fit at the age of 52 (not exactly young though). I've had trouble with one of knees for a while and i guess it's not going to get any better, 10-15 miles and it starts to hurt quite bad. Yesterdays ride of 25miles and it was fine. Having a small amount electric assist is taking the strain out of pedalling. Benefits are obvious, but we all know that.
I plan a ride to my friends house soon. It's a 50miler there and back and i reckon it's do-able. Charge the packs while i'm there and return later in the day. I reckon i'll give it more amps though 7.2Wh per mile is being too thrifty with power.

 

[Committed]

Great! That's my ideal prototype...

I have a Marin Juniper Trail I would like to eKit with **all** quick-release componentry. I need to develop that on my old black CroMO Specialized Stumpjumper frame.
Can we get some practical details from you on this project? The exact controller, for one thing (is it bio-sensing), and is that an old Ping model? Their www only quotes 10Ah and up for 36V packs. Is the Ping BMS (CHR045025001) really only 33USD? Heck, a whole BOM would have me firing away internet orders. It's getting late in the season to start & I gotta have it!
Please help - I am an engineer with scant electrical knowledge. I need a drive combo that will max out above 25MPH because I have test-driven the bio-responsive store models and the auto-cut-out when I am really cranking is exasperating. I think if I am spinning much more that 90RPM, the computer should know I mean business. Maybe if controllers, motors and wheel aren't all matched, I can crack this problem myself or with help from the automation apps engineer in my group. Sorry if I mussed up your showcase. VERY swank project!

 

[z0mb13e]

Nice conversion! Lovin' the matt black approach.

I had given serious thought to converting a matt black Canondale Bad Boy with mono fork but wasn't sure if the spindle/axle in a hub motor would be strong enough to support itself on one side only.