Mark W Mark2 build/butcher thread

[Mark_A_W]

CRAP!!!

I broke my seatpost on the way to work - had to walk a ways...luckily I'm getting a lift home. Rack was leaning back onto the wheel.

So my RACK is indestructible....the next link in the chain is the seatpost. Lucky it wasn't the frame!!

I will get another seatpost and stick a fitted steel tube up it's bunghole.

And my battery is stuffed. 5300 kilometers, and one year later. I only get 2.5 Ah out of it now (I bought a CA from getadirtbike), instead of the rated 10Ah. Oh well, it's paid for itself, now I can get one that can do 35amps!!

 

[D-Man]

How much did the battery pack cost and where did you get it?

 

[Mark_A_W]

It cost A$550 with charger and I got it locally. About US$500 at the time I guess (almost equal now).

About 10 cents per kilometre.

Plus the removal of small beergut, general feeling of wellbeing (a little exercise does wonders), 8000k's my car didn't do (longer route to work with car, no shortcuts) and starting on the road to breaking my personal dependence on OIL.

Putting a 12v booster pack basically doubled the amount of current it was delivering on average, compared to just the 37v pack alone. Twice as bright...half as long...

Next pack will be LiFeP04, but of the cheaper variety. I hope to get two years out of that, but I will push it harder - 30-35 peak amps instead of 18-20 amps peak.

 

[voicecoils]

Hey Mark,

You might want to consider a Thomson seatpost. They're supposed to be extremely strong and well made. http://www.lhthomson.com/seatposts.htm

Shame about your pack, would a homebrew A123 pack be more economical in the long run? What's getadirtbike using for his packs? I really like the look of his new e-vader frame. Hopefully the Aus market for off road e-bikes is big enough to keep his operation afloat.

 

[Mark_A_W]

The problem I see with A123 cells, apart from the expense, is unless you use dewalt packs as is, then charging is a pain.

You either use an RC balancer or lots and lots of single chargers.

I need this simple - I charge it everyday (at the moment I charge at work too).

I'm not opposed to A123 cells, but I'd need about 80 of them....

I want about 60v, and 10-15 amp hours.


I picked up a $20 seat post. If it seems to clamp the seat well enough, I will jam a fitted bit of steel pipe up it's bunghole to reinforce it. Thomson stuff is $$$!!

Cheers

Mark

 

[AussieJester]

Nice setup mate great to see so many Australians on this forum to Im kicking myself a bit as far as the A123s go, i just recently got out of the model helicopter game and sold my 500 collar charger that would have been peeeeerfect for the batteries in question...ah wellz thems the breaks.

 

[voicecoils]

The problem I see with A123 cells, apart from the expense, is unless you use dewalt packs as is, then charging is a pain.
You either use an RC balancer or lots and lots of single chargers.
I need this simple - I charge it everyday (at the moment I charge at work too).
I'm not opposed to A123 cells, but I'd need about 80 of them....
I want about 60v, and 10-15 amp hours.

I picked up a $20 seat post. If it seems to clamp the seat well enough, I will jam a fitted bit of steel pipe up it's bunghole to reinforce it. Thomson stuff is $$$!!

Cheers

Mark

re: seatpost, I guess I'm a sucker for quality bike components. A broken seatpost is not something I'd want to impale myself on! Reinforcing it with a steel pipe should do the trick, perhaps not the lightest weight method though...

re: being on endless-sphere: I lurked for a while, signed up and lurked some more. I tend to research personal interests towards the end of Uni session when I should be hitting the books! Was on the old visforvoltage site, evdl mailing list, check evalbum.com regularly, etc...

Let us know how you go with the quote for LiFePO4 cells mentioned here: http://endless-sphere.com/forums/viewtopic.php?f=14&t=4265 If that seller can provide a decent charger, sounds like a good and almost local solution (from the auction I get the impression the cells don't get to Aus till after you order them). 60V of those cells is ~$1k plus charger, yeah?

 

[kbarrett]

I need this simple - I charge it everyday (at the moment I charge at work too).

I'm not opposed to A123 cells, but I'd need about 80 of them....

I want about 60v, and 10-15 amp hours.

The simple method is to do both.

Get a 60V charger from Thundersky. Use that for daily commuting charges.

Get a high amperage 3.8V lithium batt charger ... test your rows of A123s once a week, and use the one single charger to top off any rows that are low on the weekend.

 

[Mark_A_W]

They are ok to balance as a parallel row, rather than individual cells?


At the moment, I'm toying with the idea of the white version of the LifeBatt cells. Not cheap though, but here, probably cheaper than A123s.

All this battery stuff has put my frame modding plans on hold

 

[kbarrett]

They are ok to balance as a parallel row, rather than individual cells?

That's how you have to do it.

Breaking up a parallel set to do individual cells in kinda insane.

Until you get a good BMS/CMS solution, you can fake it with a 3.6-3.8 volt charger, and a set of alligator clips.



I simply decided to bite the cookie, and bought 12 voltfreaks chargers, two power strips, a wiring harness with goodrum's LVC, and stuck a fork in it and called it done. I'll probably buy a high amp Soneil to mass charge during the week.

 

[recumbent]

All this battery stuff has put my frame modding plans on hold

I ended up buying the 48 volt pack from Justin at ebike.ca, works great so far, very convenient, all in one, just plug it in and the BMS never tripped or anything. Been using them for over a week and they still hold the same charge for a good 1-1/2 hours before it starts to drop a volt and then you gotta think about charging soon because you only have 1/2 hr left of riding. No peddaling.

 

[Mark_A_W]

Crap...now I've broken the frame in half.

60v and 45km/h over speed bumps was too much for it

I'm rebuilding it onto an old Mongoose Pro downfill frame.

 

[lawsonuw]

Yikes, that looks like it was exciting! Still, the broken weld on that arm is in about the worst spot possible. What genius thought it'd be smart to jack the pivot for the top link up so high and NOT add a gusset?

Well I guess you survived :wink:

Marty

 

[Mark_A_W]

It was actually quite uneventful.

I hit a speed bump at 40 km/h, the back end sagged and the rear locked up. I skidded gracefully to a stop. I remembered to unclip just in time, so I didn't fall over when I stopped.

Flat spotted the $70 tyre though....grrr.


My brother had to come and pick me up with his car

 

[docnjoj]

Good thing the motor wasnt in the front! Or was it?
otherDoc

 

[Mark_A_W]

Motor is on the front.

There's no motor in the broken bike pics, and that is the REAR.

 

[docnjoj]

That's why its a good thing! I'd rather have a rear triangle fail any day of the week!
otherDoc

 

[Hyena]

Hi Mark,
Have you thought about using one of these battery monitors with a buzzer for keeping track of your lipos ?

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7227

I've just ordered a few lipos and one of these as a safeguard in the absence of a BMS. I have a watts up meter but for an extra $10 odd delivered I figure it's worthwhile having the audible buzzer if they're dropping under load and you dont happen to notice it.

Also any updates on your soopower LiMn pack ?
I bought one about 2 months back but it must have had a dud cell from new as I haven't been able to get more than 10km range out of it.

 

[Mark_A_W]

I really need to update this thread...

My lipos are now well over a year old, and sag a lot more now, but are still holding up. A multimeter has been enough of a BMS.


I replaced the soopower pack with a 48v Headway LiFePO4 pack from Getadirtbike, and added the 12v lipos as a booster.

60v = 45 to 50kmh on the flat The lycras don't know what hits them!


Unfortunately, it also meant ~40kmh on pot holed dirt roads and off gutters....which was fun, until I cracked another frame. I had the batteries on a cantilevered rear rack and the seatpost tube couldn't take it.


Anyway, I've won a Kona Dawg frame on Ebay, which should let me get the batteries in the frame triangle (fingers crossed). This should mean the weight distribution is better and if I go a bit easier it may last more than a month or two.

And I'm picking up a Da Vinci Hucker hardtail freeride frame from Voicecoils (who's a mate through another hobby). The Hucker will not break.

These dual suspension aluminium frames just aren't up to what I put them through, I'd really like a Cro Mo frame from Getadirtbike, but my funds don't stretch that far.

The Hucker is my fall back, although I would like to get an ally dually gussetted up BEFORE I break it.

 

[voicecoils]

The Kona Dawg sounds nice. Well done. gusseting it up beforehand sounds like a good plan

I'll be sending your bafang 'heavy metal' gears down soon. Hopefully tomorrow at lunch.

The Hucker frame I'm hoping I'll be able to drop off around New Years.