waste of time. don't bother.

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yeah i contacted xin
all she could tell me is made in usa-- she really didn't want to disclose where these are coming from or what they are- kept sayin grade a - which is a lie- i like honest re-sellers who have nothing to hide
i wanto see folks get thier rides on the road with these and get at least over 6 month of use with no defects before i say its worth it
these cba tests dont say much - in fact at 2.8 lvc u really only get 15-16ah out of these -i also noticed the performance between these cells vary way too much- some cells are strong others are weak giving out only 18ah lvc down to 2volts -ill try to get a 1c discharge graph from mavi cells to compare to the real deal
 
i don't know what they have to hide
pgt- use em for 6 months and than update us with a review-
 
Mine showed up today and look brand new.

I ordered 20 - 19 were 3.29V one was 3.25.

Well packaged each cell also bubble wrapped.

Will do some capacity tests when I can.
 
davec said:
i don't know what they have to hide
pgt- use em for 6 months and than update us with a review-

There are numerous possibilities of the source of these cells......all of which would not help either the seller or A123 if they disclosed this. The reason for their availability could be any one of the following, or something completely different:

- Chinese copies
- Reject cells that didn't make the A123 grade
- Chinese/Korean factories backdooring cells
- Cells from the suspect US production line of which 25% could have problems when compressed in a pack
- Cells surplus to requirements due to Fisker Karma (and others) not taking up projected quantities

All of the above options are possible and I reckon all of them are out there. It's my opinion that these cells that are from one of the last 3 scenarios.
 
davec,
it would have been terrific if you could get discharge graphs from Mavizen, real experience graphs from Mavizen.
It would finally provide same comparison point to A123RC/Victpower cells.

As far as I know A123 never published any discharge graphs, I saw pulse discharge, cycle graphs in their data sheets but NEVER real 1C, 5C or wahtever discharge graphs.

Mavizen must have such graphs , they do motorcycle conversion, have a shop, they build battery packs,must do discharge tests..
For sure Mavizen cells are NOT
from the same lot as A123RC and Victpower, I cannot imagine them to be A123RC/Victpower quality, Mavizen is an official A123 distributor.
And they charge $83 for 5-29 quanities not $19.
 
I am tired reading that they are new,
OFCOURSE they are new, imagine 9000 cells dissasembled from packs, imagine labour on this?
 
No way they are quality of ones destined for Karma car or for energy storage.
They are more probable QC rejects
especially now when A123 revieled problems on those 25% of cells from one of misaligned robot lines.
25% from robot production lines is a lot of cells - thousands possibly.
Even more mistery are those letters in the middle of cell: A, A1, A2 ,B etc. , etc.
We cannot even dicypher bar codes for year of production.
 
this thread is the mother of all 'throw the shit on' good stuff, hey mavizen, quit it. either offer cells at $19 per cell, or go cry in a corner! :lol:
 
i will get a chart from mavi - and post it here stay tuned- this should be interesting
im building a motor bike for commuting-im spending a good chunk of change on this- i need something that will last and won;t leave me stranded- putting reject cells into it makes me a bit nervous- i guess ill waite it out and see what you guys get out of these than make a decision- in the mean time i think ill settle with calbs....
 
Davec and and silverrich1 are both sangesf
They are debating each other to increase their post count
Others posters may also be sange but im not sure
Please lock this thread
 
flathill said:
Davec and and silverrich1 are both sangesf
They are debating each other to increase their post count
Others posters may also be sange but im not sure
Please lock this thread

Dear god people..... take off the foil hats ..

Davec is not sf........ thread locked.

Listen.. it's friday and i'm having controller problems with my new trike.. it's 9pm and almost black out there.. so i'm busy... regardless... no more of this accusing others of being puppets..
 
success! I just came back from the tyre shop, having tried on over 20 different assortments of tyres a pit bike tyre / knobbly combo, would give me the equivalent of a 20" bicycle rim on this. more pics on this later. it's a fat boy tyre. so might not need to install it into a rim after all, it's simplified it now, much safer this way, as all I need to do is customize the dropouts and install a 20" front rim.

dozentrio said:
drill holes around the perimeter of the "rim" and lace it. May need custom spoke lengths. Should work, in theory. Can't say how well. Good luck!
 
This is an ambitious build. Dare I say, square peg in a round hole?

What are your thoughts on weight?

At 22KG your hub is going to be so heavy, you won't want to lift your bike up. With another 20kg of batteries (minimum you'll need to go any range on a high powered hub) you are going to be stressing your frame. You'll need a new rear shock, new springs in your fork, and if you weigh alot yourself, I'd say goodbye to your bike... It looks like a cross country frame, not a heavy hitter DH frame. It might snap.

I've got frame fractures on bikes before, pay attention to your welds under the head tube. If you're bending the rear triangle hugely then this is tantamount to pre-fracturing it.

I strongly recommend a new frame, or a motor more suited to the application...sorry dude!

Sorry to sound negative, you might get it working... just know you can get 8KW out of much lighter motors. It sounds like a really cheap motor with an expensive shell for the tyres.


Qualification? I have a DH bike that has the lightest equipment on it - astro 3220, 15AH lipo, everything else is average weight. It's still about 35kg. Getting 8KW out of it is childs play :)
 
Couldn't have said it better man, that frame will be a spindly twig with a cannonball hanging off the back. Get yourself a decent bike to put that on, or go with something similar to Farfle's Genesis build:

file.php


Definately don't skimp on the frame if you have a 40 lb motor. I have a very similar motor off a scooter and have sidelined my project, but will get around to it soon.

Seen here:

http://endless-sphere.com/forums/viewtopic.php?f=3&t=29942&hilit=scooter+hub+motor
 
Id love to see some pics of the motor! I am planning on getting the exact one.

------------------------------------------------------------------
Thanks for your email for the 2kw 13inch hub motor.

As price indicated,it cost USD245.00

And shipping cost to Orlando FL 189.00 by FEDEX.

So total will be USD433.00
------------------------------------------------------------------
 
I bought a blackberry playbook with the intention of repairing it's battery. Although not the best device out there, it serves my purposes as a battery monitor using 'battery guru' to detect cells in series/parallel and to create a pleasant touch screen interface as well as a portable media source on my e-bike. This is generally aimed as a fun project for those who have not got into the tablet way of things yet to see some point in getting one to fix.

The housing of the PB contain two 3780mah batteries at 4.15v each.
Internal resistance of the li-polymer cells was between 15 and 17 m Ohms suggesting that the high IR of the cells showed that they were either poor quality or on their way out.

however my ultimate aim is to replace these two cells inside the PB and get the original battery life, but until parts become readily available (like the cc/cv charging circuit) I will have to make do with building an external battery, and as a plus, obtaining a much higher ah rating for the PB. This should make it very useful using it on long car journeys / as a reader / media player etc.
I should add that the speaker quality of the playbook and webcam ability far surpasses that of the ipad.

my curiosity got the better of me, and I opened the playbook to find out the innards more accurately.
I decided it would be Ideal to share photos and info (for those of us with dead ipad or playbook lipo cells on replacement sources or hardware (external) upgrades.

In this instance, I have managed to upgrade the battery by adding hinges to an external 15000mah power source that I picked up off dealextreme.com and added two laptop screen hinges I had lying around.
The benefits of this project adds self standing ability to the playbook, space for a keyboard (to hinge out from under the external battery), and nearly triples the battery life of the device from 5400mah to 15000mah, thereby the playbook now lasts up to 40 hours of continuous usage / ebook reading / need for speed gaming, wifi browsing and other things. I must also add that, after removing the two lithium polymer batteries, the playbook has added negligible weight, making it slightly thicker, albeit the battery time more than makes up for this in my opinion.

I will be adding photographs of the hacking attempt, and would welcome any positive feedback on component parts / charging cc/cv modules for other people in and out of the forum to comment.
The reason I did not post this on crackberry.com is because I like this site and want to contribute positively.

Kind regards

silverrich1
please note, this is for educational purposes only, i don't take responsibility for anything you do with lipo, lipo cells are dangerous, this is strictly a hack, and voids your warranty, you do all this at your own risk, I did it at my own risk.



below I have attached some photographs of the hacking attempt, what the blackberry playbook looks like inside,




 
Internal fix, from hobbyking.com
It has the dimensions to fit partly in, and fits with modification to the PB, having a much higher lithium polymer capacity, it should last 30% longer than the original battery. There is also space for a third cell by modifying the motherboard.
reserved for battery guru software and replacement cells 1s 5000mah x 2

18560.jpg

http://www.hobbyking.com/hobbyking/store/__18560__Turnigy_5000mAh_1S_20C_Lipoly_Single_Cell_.html
 
Hi Silverrich1:

I happen to be also into tablets. I recently dramatically upgraded the coby7015 battery from 2400 mah to 4200mh (a sizable difference in battery time). I understand that in most cases where there are 2 batteries wired in parrallel you now can find a single substitute battery of considerably higher capacity.Replacing the battery often is a lot simpler where there are only simple wires vs ribbons connecting the batteries to the pcb. This is because most replacement batteries have no ribbon I found. I use Batteryspace for replacement batts.
 
The trouble is, that the PB comes with ribbon cabling, thereby making my task a little harder to figure out (cant see them)
these batteries are in parallel.
the playbook leaves 30% capacity of the battery for emergency usage. therefore the useable charge in the playbook is only 5400mah and not 7560mah.
you can replace the playbook's 2series with a 1series of higher capacity, like a single large capacity 3.7v 15000mah cell with the right dimensions.
pictures to follow soon.



chessir said:
Hi Silverrich1:

I happen to be also into tablets. I recently dramatically upgraded the coby7015 battery from 2400 mah to 4200mh (a sizable difference in battery time). I understand that in most cases where there are 2 batteries wired in parrallel you now can find a single substitute battery of considerably higher capacity.Replacing the battery often is a lot simpler where there are only simple wires vs ribbons connecting the batteries to the pcb. This is because most replacement batteries have no ribbon I found. I use Batteryspace for replacement batts.
 
Hey just discovered this thread.

The Bofeili powerplant is extremely similar in purpose to our ageing bottom bracket Aprilia which we are starting to wear gearboxes out at 1200 watts. This unit could be a good replacement. And it is brushless, not like our old brushed ones.
There is nothing like shifting your powerplant back through the bike's gearset.
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=18505&p=603096#p603096

Great builds Nader, and love the waterbottle batteries! :p

I would really like to know how that Bofeili powerplant holds up on a 30 amp controller rather than the stock 15 amp one. Any ideas?
 
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