Search found 533 matches

by x88x
Jan 01, 2013 4:32 pm
Forum: Battery Technology
Topic: Battery module design for 11kWh lipo pack.
Replies: 23
Views: 3499

Re: Battery module design for 11kWh lipo pack.

It's still going...just keep getting side-tracked by other things...you know; life gets in the way... I ended up consolidating into two boxes, one with 20 packs, the other with 30, and consequently changing some of the series hookups. I'll try and get another update up this week.
by x88x
Oct 11, 2012 8:17 pm
Forum: E-Bike Photos & Video
Topic: A Very Very Low Cost Electric Bike from Pakistan
Replies: 453
Views: 55844

Re: A Very Very Low Cost Electric Bike from Pakistan

The benefit of more wires is that it is easier. But a circular cross section will only have a certain fill percentage no matter what, and changing the radius of the circle does not change this. More wires, however, increases copper fill loss because of the insulation on the wires. Just a quick note...
by x88x
Oct 07, 2012 2:10 pm
Forum: Battery Technology
Topic: Battery module design for 11kWh lipo pack.
Replies: 23
Views: 3499

Re: Battery module design for 11kWh lipo pack.

I gotta say that battery box looks really sexy! I'm taking notes honestly! I made a similar battery tray for my ebike using similar construction, but that battery box is really good looking. Thanks! My goal was simplicity and reduction of parts. Comparing what I ended up with to other large hobby l...
by x88x
Oct 06, 2012 5:17 pm
Forum: Battery Technology
Topic: Battery module design for 11kWh lipo pack.
Replies: 23
Views: 3499

Re: Battery module design for 11kWh lipo pack.

As long as they are crimped ok, with that many in paralell, you should have zero trouble. Might throw some clear varnish over the bolted connections though. Yeah, I've been trying to think of some way of insulating the whole bar assembly. Once the 2/0 cable is bolted to it though, it will be pretty...
by x88x
Oct 06, 2012 2:25 pm
Forum: Battery Technology
Topic: Battery module design for 11kWh lipo pack.
Replies: 23
Views: 3499

Re: Battery module design for 11kWh lipo pack.

30amp crimp terminal !! noooo Do you have reason to think that'll be a problem or is this just another 'crimp vs solder' thing? They're 3M 10AWG, 1/4" ID, 9/16" OD, 1mm thick, nickel plated copper, nylon insulated ring terminals, properly crimped. I can't find a current rating for them from 3M, but...
by x88x
Oct 06, 2012 1:09 pm
Forum: Battery Technology
Topic: Battery module design for 11kWh lipo pack.
Replies: 23
Views: 3499

Re: Battery module design for 11kWh lipo pack.

Well, it's been quite a while since I updated this. Life and work been getting in the way.. I do have some updates though. I ended up tweaking the module enclosure a bit in order to decrease complexity and increase strength. I'm using closed-end blind rivets on most of the connections instead of scr...
by x88x
Jun 22, 2012 6:48 pm
Forum: Battery Technology
Topic: Turnigy nano-tech round cells.
Replies: 23
Views: 2899

Re: Turnigy nano-tech round cells.

BTW, how are you getting the 138whr/KG figure? Did you know that this RC Lipo is actually 3.8v nominal? were you using 3.6 or 3.7v as the nominal voltage in your calculations? I used 3.7V. I've never really seen a good justification for any of the quoted 'nominal' voltages for lipo. LiFePO4 makes s...
by x88x
Jun 22, 2012 5:38 pm
Forum: Battery Technology
Topic: Turnigy nano-tech round cells.
Replies: 23
Views: 2899

Re: Turnigy nano-tech round cells.

Got the cells in today. Not quite thrilled with them, I have to say. Images (camera can't seem to focus well): http://i428.photobucket.com/albums/qq3/x13931x/1200lipoRoundLabel.jpg http://i428.photobucket.com/albums/qq3/x13931x/1200lipoRoundNoLabel.jpg Construction: Appears to be standard cylindrica...
by x88x
Jun 19, 2012 10:18 pm
Forum: Battery Technology
Topic: Turnigy nano-tech round cells.
Replies: 23
Views: 2899

Re: Turnigy nano-tech round cells.

Well, today I finally got the "you weren't home so we'll try again later" note. So that's 14 days from arrival at "sorting" at my zip code to delivery. I can only assume that the majority of that time was spent in customs. Unfortunately, I won't be able to pick it up from the post office until Thurs...
by x88x
Jun 19, 2012 7:10 pm
Forum: E-Scooter and Motorcycle Photos & Videos
Topic: Vintage Cafe/Roadacer- R5e
Replies: 179
Views: 37698

Re: Vintage Cafe/Roadacer- R5e

teddillard wrote:(In the middle of it all, I had to rebuild my wife's MGB. It seems that the hole in the piston isn't really great for optimum performance, and she wouldn't let me slap an AC50 into it... yet... :twisted: )
Nah, wait for that water-cooled 9" they keep hinting at. ;)
by x88x
Jun 13, 2012 3:43 pm
Forum: Battery Technology
Topic: Turnigy nano-tech round cells.
Replies: 23
Views: 2899

Re: Turnigy nano-tech round cells.

So...yeah...if you're ever ordering stuff from HobbyKing's Hong Kong warehouse, I cannot recommend Swiss Post. I bought 5 5S 20C Turnigy packs the day after I placed this order, shipped them with Singapore 'Speedpost', and figured I'd see which was faster (this order was with Swiss Post btw). Both s...
by x88x
Jun 12, 2012 11:14 am
Forum: E-Bike General Discussion
Topic: Hobbyking LiFeP04 ?
Replies: 82
Views: 2908

Re: Share your experience on HobbyKing LiFePo4 battery.

Even if it weren't for the reported crap QC, the price (IMO) makes them ultimately pointless unless they could actually deliver on that claimed C-rate. I plugged them into my battery stat spreadsheet (sig), and they come out to $0.86/Wh, 96.34Wh/kg, and 185.51Wh/L raw (ie, ignoring packaging). That'...
by x88x
May 28, 2012 12:56 am
Forum: Battery Technology
Topic: Turnigy nano-tech round cells.
Replies: 23
Views: 2899

Re: Turnigy nano-tech round cells.

And all this ^^^ is why I just gave in to my curiosity and ordered a few. So we can skip the speculation stage where we all sit around and talk about how we think something would work based on one picture that doesn't exactly show anything about it very well. Besides, they're pretty cheap. Worst cas...
by x88x
May 26, 2012 9:13 pm
Forum: Battery Technology
Topic: Turnigy nano-tech round cells.
Replies: 23
Views: 2899

Re: Turnigy nano-tech round cells.

Have you compared volume/density when you have multiple of them made up to a same Ah pack as the flat pack types? They maybe better per cell, but I am wondering once you pack them and the gaps between the cylinders how they compare So the smallest pack you could make for easy comparison would be 30...
by x88x
May 25, 2012 1:13 pm
Forum: Battery Technology
Topic: Turnigy nano-tech round cells.
Replies: 23
Views: 2899

Re: Turnigy nano-tech round cells.

Apentier wrote:
x88x wrote: Will report back when they come in.
When it going to be?
Don't know. According to the shipping tracker, they're somewhere between Singapore and the US right now. Last update was them leaving the country.
by x88x
May 24, 2012 3:16 pm
Forum: Battery Technology
Topic: Need to make a Battery Cycle test setup~ PL6, CBA, icharger?
Replies: 2
Views: 281

Re: Need to make a Battery Cycle test setup~ PL6, CBA, ichar

The Cellpro Powerlab 8 does full cycling and communicates with their software on a connected computer quite well. You can even set it to run any arbitrary number of cycles and just let it run. If you are powering it using a battery it can do up to 40A discharge, and supposedly can do up to 40A charg...
by x88x
May 22, 2012 1:17 am
Forum: Battery Technology
Topic: Battery module design for 11kWh lipo pack.
Replies: 23
Views: 3499

Re: Battery module design for 11kWh lipo pack.

Well, it's been a while, but I finally have some exciting updates! :D I finally finished testing all the battery packs for phase 1 (ie, smaller pack while I wait for them to re-stock the US warehouse)! And a beautiful sight it is too. :D http://i428.photobucket.com/albums/qq3/x13931x/e15_28.jpg I en...
by x88x
May 21, 2012 1:12 pm
Forum: Battery Technology
Topic: Best watt hours per dollar in lithium - CALB, headway, tSky?
Replies: 29
Views: 1919

Re: Best watt hours per dollar in lithium - CALB, headway, t

Not exactly cheap but what about FFR Trikes Dow Kokam's? They had/have large formats available and most the money appears to stay here in USA. That's how I would probably go for building packs larger than 1kWh. Can you actually buy those separately? I'm not seeing anything about getting just the ba...
by x88x
May 21, 2012 3:18 am
Forum: Battery Technology
Topic: Best watt hours per dollar in lithium - CALB, headway, tSky?
Replies: 29
Views: 1919

Re: Best watt hours per dollar in lithium - CALB, headway, t

Look at the thread I linked, you can see problem for a lot of buyer and how Victpower "help" them To be fair, I stopped paying attention to that thread a long time ago out of sheer exasperation, but most of the "problems" I saw people have sounded like standard Chinese trading house business practi...
by x88x
May 21, 2012 3:10 am
Forum: Battery Technology
Topic: Best watt hours per dollar in lithium - CALB, headway, tSky?
Replies: 29
Views: 1919

Re: Best watt hours per dollar in lithium - CALB, headway, t

thankx x88x, that spreadsheet was helpful. You're very right about the sinopoly cells, and there are new 60AH cells that are a bit lighter and smaller out now. I knew the headways were a little expensive but it didn't occur to me how much more expensive they were 'till i saw the spreadsheet.. damn!...
by x88x
May 21, 2012 1:30 am
Forum: Battery Technology
Topic: Best watt hours per dollar in lithium - CALB, headway, tSky?
Replies: 29
Views: 1919

Re: Best watt hours per dollar in lithium - CALB, headway, t

This might help. ;) https://docs.google.com/spreadsheet/ccc?key=0Al-9VZS5gw_udFQwTTlCdXBFRUo0VVloa3dreVlJeEE Aside from the 4S Turnigy hardcase packs, which have been quite elusive, the lowest $/Wh I've seen is the Sinopoly's at ~$0.36/Wh or A123 M20's if you can get them for $23.30 or less. Persona...
by x88x
May 20, 2012 5:46 pm
Forum: Battery Technology
Topic: Turnigy nano-tech round cells.
Replies: 23
Views: 2899

Re: Turnigy nano-tech round cells.

Well, I went ahead and picked up 10 of them to see what I can see. Will report back when they come in.
by x88x
May 20, 2012 4:45 pm
Forum: Battery Technology
Topic: Turnigy nano-tech round cells.
Replies: 23
Views: 2899

Re: Turnigy nano-tech round cells.

Fair point. What caught my interest was the 50% greater volumetric density when compared to the 5Ah 20C's. Even compared to the big 12.8Ah 40C pouches (best volumetric density I've seen in a non-cylindrical cell of any type) they edge them out by a good 33%. How much of that would get swallowed up i...
by x88x
May 20, 2012 4:25 pm
Forum: Battery Technology
Topic: Turnigy nano-tech round cells.
Replies: 23
Views: 2899

Turnigy nano-tech round cells.

So I was on HobbyKing's site today, checking to see if they had restocked their US warehouse yet, and I ran across these interesting things. Apparently now they are making the nano-tech's in small cylindrical format. I took the largest capacity one they have listed (1.2Ah), and ran the numbers on it...
by x88x
Apr 23, 2012 11:18 am
Forum: Battery Technology
Topic: Battery module design for 11kWh lipo pack.
Replies: 23
Views: 3499

Re: Battery module design for 11kWh lipo pack.

Been a while since I've been able to update on this; got stuck working 5 days straight of 12 hour shifts....not fun... So, updates.. Got my Powerlab in; that thing is serious nice...even if it wasn't obvious that it needed to be running off a battery to discharge more than 100W. -_^ I also got the r...