Search found 160 matches

by webfootguy
Jun 20 2014 4:40pm
Forum: Battery Technology
Topic: A123 20AH cells source?
Replies: 520
Views: 57894

Re: A123 20AH cells source?

I would add http://a123rc.com/ as selling A123 20Ah cells as well (but I don't know their source). The pictures show "made in Korea".

Phil H.
by webfootguy
Nov 21 2012 12:54am
Forum: Battery Technology
Topic: am i correct in calculating this amount of surface ?
Replies: 18
Views: 795

Re: am i correct in calculating this amount of surface ?

The M1 cells are "hard" to solder to directly. You need high heat and high thermal mass to heat the end quickly and solder the tab to it. If you heat it more than a few seconds, the insides of the cell get too hot (some of the internals are plastic) and they melt damaging the cell. The damage might ...
by webfootguy
Aug 01 2012 11:50am
Forum: E-Bike Technical
Topic: Most cost effective, timely method of matching 350 M1 cells.
Replies: 8
Views: 1287

Re: Most cost effective, timely method of matching 350 M1 ce

Here is what I would do: 1) charge all cells to 3.65 until current drops to C/20. You can do this cell by cell or in a big parallel group if you have good temporary connetions. Let cells rest for 24 hours. Measure voltage again. Good cells will still be 3.45 to 3.5 while marginal cells will have dro...
by webfootguy
Jul 18 2012 12:46pm
Forum: Battery Technology
Topic: Purchasing from ShenZhen Victpower Technology
Replies: 170
Views: 19650

Re: Purchasing from ShenZhen Victpower Technology

The reality is that A123Systems has about 5 months of cash on hand (go read their shareholder reports). If they do not find more financing or reduce costs (layoffs, drop products,etc.) or suddenly sign a big contract with up front $$, they will probably go Chapter 11 in 6 to 12 months. This does not...
by webfootguy
Dec 13 2011 12:34pm
Forum: E-Vehicles General Discussion
Topic: DIY Aptera knockoff?
Replies: 292
Views: 53294

Re: DIY Aptera knockoff?

I have a Twike designed in the mid 90's. It weights 520lbs with 112lbs of battery (and no driver or passengers). It is made from aircraft aluminum and plastic. Not as fancy as the Aptera but highly efficient for a commuter vehicle. I have some pictures that were taken at the factory in Switzerland i...
by webfootguy
Dec 02 2011 4:34pm
Forum: Battery Technology
Topic: BVM-8s - new 1-8 cells battery monitor device?
Replies: 41
Views: 7107

BVM-8s - new 1-8 cells battery monitor device?

Has anyone seen or used this new battery monitor device called the BVM-8s? It showed up on ebay this week.

http://www.ebay.com/itm/200682907061
by webfootguy
Nov 10 2011 12:47am
Forum: Battery Technology
Topic: A123 20Ah Prismatic cells AMP20M1HD-A on Ebay
Replies: 0
Views: 443

A123 20Ah Prismatic cells AMP20M1HD-A on Ebay

I just noticed that someone is selling 50 of the A123 20Ah pouch cells on ebay (with full tabs). Price is a very reasonable $34.75 plus shipping (expensive shipping unless you buy lots). They are listing them as NEW but in the picture I would have my doubts as the cell looks like it has had at least...
by webfootguy
Nov 06 2011 1:13am
Forum: General Discussion
Topic: Revenge of the electric car
Replies: 18
Views: 1886

Re: Revenge of the Electric Car is coming to Portland, Orego

Thanks to those that attended and took the opportunity to support EV's and meet Chris Paine. It was cold and wet outside but warm and friendly inside. http://lh3.googleusercontent.com/-csXEmhnD5LM/TrSlze5pv0I/AAAAAAAABKk/mUHykf9p54w/s512/IMAG0302.jpg http://lh6.googleusercontent.com/-sRJvaOCV4Fg/TrS...
by webfootguy
Nov 03 2011 2:06pm
Forum: Battery Technology
Topic: Accurate affordable RI meter for low impedance cells?
Replies: 28
Views: 2884

Re: Accurate affordable RI meter for low impedance cells?

texaspyro wrote:I have one on they way... I know how to torture it...
Looking forward to your analysis of how it did ;-)
by webfootguy
Nov 02 2011 2:21pm
Forum: General Discussion
Topic: Revenge of the electric car
Replies: 18
Views: 1886

Revenge of the Electric Car is coming to Portland, Oregon

Just a quick note to folks local to Portland, Oregon area. The movie "Revenge of the Electric Car" that is a follow on to "Who killed the Electric Car" will be shown starting Friday, 11/4/2011 at 7pm and 7:30pm at the Hollywood Theater. There is a EV Road rally scheduled just prior to the showing (I...
by webfootguy
Nov 01 2011 5:39pm
Forum: Battery Technology
Topic: Accurate affordable RI meter for low impedance cells?
Replies: 28
Views: 2884

Re: Accurate affordable RI meter for low impedance cells?

this seems to work ok http://www.ebay.ca/itm/20R-Internal-Battery-Resistance-Impedance-Meter-Tester-/320514894112?pt=FR_YO_Jeux_RadioComRobots_VehiculesRadiocommandes&hash=item4aa02d2920 The lowest scale on that thing is 0.2ohms, that's 200 mOhm. It also only has 2 digits after the decimal so unles...
by webfootguy
Aug 16 2011 11:32am
Forum: Battery Technology
Topic: Rectified mains charge lead
Replies: 24
Views: 2341

Re: Rectified mains charge lead

Hey, I charge at 425 Volts every day off a 120 volt mains on my TWIKE. It was designed for 240v mains from Europe and was converted to 120v by using a 1-2 step up transformer (internally mounted) but with a bit of work, I can put in a J1772 and charge faster off the free chargers going up all around...
by webfootguy
Jul 26 2011 1:07pm
Forum: E-Bike General Discussion
Topic: Twike Velomobile
Replies: 8
Views: 1166

Re: Twike Velomobile

The one i heard about is a twike ez (no pedals) with a burned out bms and battery pack. Problem is i hear that it is very hard to replace the batery packs because of the proprietary controller, bms and charge system. Also i heard parts from switzerland are very expensive. Webfootguy...how did your ...
by webfootguy
Jul 25 2011 1:52am
Forum: E-Bike General Discussion
Topic: Twike Velomobile
Replies: 8
Views: 1166

Re: Twike Velomobile

I have one and I rebuilt my battery packs. Because the charger and controller are integrated and proprietory, homemade lithium solutions are a challenge. Factory lithium solution is available but about 10k.
by webfootguy
Jul 21 2011 11:07pm
Forum: Battery Technology
Topic: A123rc.com... safe to buy from?
Replies: 7
Views: 1988

Re: A123rc.com... safe to buy from?

I bought a couple of 20 Ah A123 pouch cells, some M1 cells, and some 18650 cells to test. All arrived as described and since they take paypal, I felt protected from fraud. Ok in my book.
by webfootguy
Jun 17 2011 5:52pm
Forum: Battery Technology
Topic: "Zephyr" - Finally, the "v4" Fechter/Goodrum/Hecker BMS...
Replies: 951
Views: 122056

Re: "Zephyr" - Finally, the "v4" Fechter/Goodrum/Hecker BMS.

Gary, if you end up not being able to recover your web site, you might be able to get some things back using archive.org or the google cache. Good luck.
by webfootguy
Jun 07 2011 10:18am
Forum: Battery Technology
Topic: A123 20AH cells source?
Replies: 520
Views: 57894

Re: A123 20AH cells source?

The only place I have seen anything official looking is here: http://mavizen.com/A123.html Specifications: 20 Ah Cell Specification: -------------------------------------- Normal Voltage: 3.3V Capacity (1C to Vmin=2.0V): minimum 18.5AH, typical 20Ah Whr/Cell: 64.6 Dimensions(mm):7.2 x 161 x 227 Weig...
by webfootguy
Jun 03 2011 2:29pm
Forum: Battery Technology
Topic: A123 20AH cells source?
Replies: 520
Views: 57894

Re: A123 20AH cells source?

The 0.5 milliohm implied in the picture is probably wrong at worse and misleading at best. A123Systems themselves spec these cells as <2.0 milliohm and the testing I have done puts the cells I got between 1.5 and 2.0 which on spec as far as I can tell (i.e. you will get some loss to heat at very hig...
by webfootguy
Jun 02 2011 12:16am
Forum: Battery Technology
Topic: A123 20AH cells source?
Replies: 520
Views: 57894

Re: A123 20AH cells source?

More and more of these cells are starting to show up online. For example:

http://cgi.ebay.com/ebaymotors/Original ... 676wt_1165
by webfootguy
Jun 01 2011 8:38pm
Forum: Battery Technology
Topic: Substituting Nimh for NiCD
Replies: 5
Views: 410

Re: Substituting Nimh for NiCD

I agree you can sub in NiMh for NiCD in this application. I wanted to add that I have had great luck with the new low self discharge cells from HobbyKing. Great price and great capacity.

http://www.hobbyking.com/hobbyking/stor ... duct=10456
by webfootguy
May 17 2011 4:54pm
Forum: Battery Technology
Topic: A123 20AH cells source?
Replies: 520
Views: 57894

Re: A123 20AH cells source?

I'll have to agree with the rant. If nothing else, we need to fix access to quality cells at a reasonable price.
by webfootguy
May 16 2011 2:17pm
Forum: E-vents
Topic: Portland, OR: Meet and Greet...
Replies: 71
Views: 9804

Re: Portland, OR: Meet and Greet...

I can bring it by (and this time I can drive it there rather than trailer it :-) ). Do you have a schedule for the weekend? What day should I pick (Sat or Sun?)

Phil
by webfootguy
May 16 2011 12:39pm
Forum: E-vents
Topic: Portland, OR: Meet and Greet...
Replies: 71
Views: 9804

Re: Portland, OR: Meet and Greet...

As of last week, my Twike is back on the road with new battery cells and more range than it has ever had (boosted cell capacity by >30%). I'm waiting for a firmware update to get the on-board computer to register the full range but I should be able to get 35 or 40 miles of range with a single charge...
by webfootguy
May 11 2011 4:10pm
Forum: Battery Technology
Topic: A123 20AH cells source?
Replies: 520
Views: 57894

Re: A123 20AH cells source?

An auction for 8 20 Ah cells just showed up on ebay. Seller has zero feedback and is based in China. The cells have the tabs cut off but so far the price is right if someone wants to try to get some cells cheap.

http://cgi.ebay.com/8-Nanophosphate-AMP ... 0817838393
by webfootguy
May 08 2011 5:51pm
Forum: Battery Technology
Topic: A123 20AH cells source?
Replies: 520
Views: 57894

Re: A123 20AH cells source?

Please give the prices of the cells in the threads. I bought 2 cells for $40.99 each (with free shipping) at a123rc.com. Price has since gone up to $59.99 each. My cells appear to have come from the new plant in Michigan as they have "Made in the USA" printed on them and appear new (no marks on the...