Search found 28 matches

by Teslafly
May 10 2017 3:50pm
Forum: E-Bike General Discussion
Topic: Folding 27.5+ wheel frame for 12s 1kw ebike
Replies: 9
Views: 1352

Re: Folding 27.5+ wheel frame for 12s 1kw ebike

While I have investigated mid drives, and they definitely have a better torque option, there are a couple of things I don't like: - loss of regen - integrated controller (I eventually want to design / experiment with my own brushless controller) - higher cost - more complex and higher wear. I can us...
by Teslafly
May 10 2017 1:43am
Forum: E-Bike General Discussion
Topic: Folding 27.5+ wheel frame for 12s 1kw ebike
Replies: 9
Views: 1352

Folding 27.5+ wheel frame for 12s 1kw ebike

The time has come to build myself an Ebike. With a monster hill on campus when I'm at school, a 4 mile commute to work during the summer (reasonably flat & bikeable, but leaves you fairly winded), and a slight amount of inspiration coming from the Moar kickstarter, the time has finally come to build...
by Teslafly
Jan 31 2015 5:04pm
Forum: Battery Technology
Topic: OSBMS - A scalable, low cost, and full featured BMS
Replies: 56
Views: 19274

Re: OSBMS - A scalable, low cost, and full featured BMS

All prototypes are currently spoken for. Rev2 may come into existence in 1-2 months. I am currently writing the post detailing this.
by Teslafly
Jan 29 2015 11:29am
Forum: Battery Technology
Topic: OSBMS - A scalable, low cost, and full featured BMS
Replies: 56
Views: 19274

Re: OSBMS - A scalable, low cost, and full featured BMS

Nope. They turned out perfectly. I think I used a -.05% swell and got my stencils from oshstencils. $6 per stencil for a project like this isn't bad.
by Teslafly
Jan 29 2015 3:19am
Forum: Battery Technology
Topic: OSBMS - A scalable, low cost, and full featured BMS
Replies: 56
Views: 19274

Re: OSBMS - A scalable, low cost, and full featured BMS

Progress update Lots of stuff has happened since the last big update, and if that one was a "design" iteration, then this one is definitely a "test" iteration. This post is probably also longer than strictly needed, but I partially want to document this thing so I can go back and look back at it an...
by Teslafly
Jan 28 2015 3:04am
Forum: Battery Technology
Topic: OSBMS - A scalable, low cost, and full featured BMS
Replies: 56
Views: 19274

Re: OSBMS - A scalable, low cost, and full featured BMS

There are no provisions at the moment for full current battery passthrough. There are two npn power mosfet outputs that could be used to drive a contactor or your own high current mosfet bank though. I made this decision because I figured it was much easier, cheaper, and scalable to use simple low c...
by Teslafly
Jan 26 2015 1:39am
Forum: Battery Technology
Topic: OSBMS - A scalable, low cost, and full featured BMS
Replies: 56
Views: 19274

Re: OSBMS - A scalable, low cost, and full featured BMS

Well, A lot has happened since my last update. I've been working on the BMS almost the entire weekend and have made lots of progress. (aka, boards assembled, code tested with balance resistors and voltage measurements -intermittently?- working) I'll post the actual update tomorrow or tuesday (hint, ...
by Teslafly
Nov 23 2014 3:21am
Forum: Battery Technology
Topic: OSBMS - A scalable, low cost, and full featured BMS
Replies: 56
Views: 19274

Re: OSBMS - A scalable, low cost, and full featured BMS

Huh, well I guess that this system wouldn't be the best for them unless they wanted to spend the extra $ for a 6s board that effectively manages 1 cell. You may be better off knocking off a cell or using a cheap Chinese "BMS" for those lower power setups. Blocks of 6s are the best, but if you can ge...
by Teslafly
Nov 22 2014 8:40pm
Forum: Battery Technology
Topic: OSBMS - A scalable, low cost, and full featured BMS
Replies: 56
Views: 19274

Re: OSBMS - A scalable, low cost, and full featured BMS

Just so I understand correctly, the standard "48v" 13S system would require 1x master and 2x slaves, with the last slave being used for the final 1S unit ? Do you mean 12S system? I am unaware of 13S being a standard, but am aware of 12S, 16S, 20S and 24S being pretty common. Each balance board can...
by Teslafly
Nov 19 2014 10:09pm
Forum: Battery Technology
Topic: OSBMS - A scalable, low cost, and full featured BMS
Replies: 56
Views: 19274

Re: OSBMS - A scalable, low cost, and full featured BMS

By the way, very similar design: http://ev-power.com.au/webstore/index.p ... cells.html ... Not really. not really at all. All BMS systems are going to have a bit of the same design concepts because they accomplish the same function, but the board you linked to really doesn't have anything to do or...
by Teslafly
Nov 18 2014 3:08am
Forum: Battery Technology
Topic: OSBMS - A scalable, low cost, and full featured BMS
Replies: 56
Views: 19274

Re: OSBMS - A scalable, low cost, and full featured BMS

UPDATES! REV 1 is ready for prototype manufacture. The Rev 1 Balancer board has had it's silkscreen cleaned up, mounting "holes" added, and BOM completed. All parts are selected and ready to be ordered. The final estimate for parts cost is ~$18, not including solder paste and other manufacturing stu...
by Teslafly
Nov 08 2014 6:56pm
Forum: Battery Technology
Topic: OSBMS - A scalable, low cost, and full featured BMS
Replies: 56
Views: 19274

Re: OSBMS - A scalable, low cost, and full featured BMS

Development wise this project has slowed but not stopped as of late. School has been a bit more work intensive and I haven't had that much time to work on this until this weekend rolled around. I have started writing code and believe I have most of the rudimentary communication pinned down. This ver...
by Teslafly
Oct 07 2014 4:14pm
Forum: Battery Technology
Topic: OSBMS - A scalable, low cost, and full featured BMS
Replies: 56
Views: 19274

Re: OSBMS - yet another "open source battery management syst

Why the 100ohm resistors between Vdd and ground? If you look at the ATA6870N reference schematic It has them as well and specifies their value in the datasheet. I believe that the ATA6870N chip has tvs/zener diode protection built in - Hence the 1k resistors on the voltage sense inputs and 10 ohm r...
by Teslafly
Oct 07 2014 12:22am
Forum: E-Vehicles General Discussion
Topic: Open source integrated EV Electronics system
Replies: 31
Views: 3986

Re: Open source integrated EV Electronics system

Ok, I created a new thread just for the BMS. Discussion for that branch of this project should head over there: http://endless-sphere.com/forums/viewto ... 14&t=63863
by Teslafly
Oct 07 2014 12:20am
Forum: Battery Technology
Topic: OSBMS - A scalable, low cost, and full featured BMS
Replies: 56
Views: 19274

OSBMS - A scalable, low cost, and full featured BMS

For the last month or so (and just thinking about it long before that) I have been developing a battery management system based off the ATA6870N-PLPW ( http://www.mouser.com/Search/ProductDetail.aspx?R=ATA6870N-PLPWvirtualkey55660000virtualkey556-ATA6870N-PLPW ) and an embedded teensy 3.1 microcontr...
by Teslafly
Oct 06 2014 5:11pm
Forum: E-Vehicles General Discussion
Topic: Open source integrated EV Electronics system
Replies: 31
Views: 3986

Re: Open source integrated EV Electronics system

Nah its not for 1 battery its for 3 battery's. Oh, so you're gonna need three master boards as well. ok. I'm less concerned now, although I would push you to only use it on one ev as it is in no way guaranteed reliability. also, so I know what some others would like, could you provide me with the s...
by Teslafly
Oct 06 2014 12:37pm
Forum: E-Vehicles General Discussion
Topic: Open source integrated EV Electronics system
Replies: 31
Views: 3986

Re: Open source integrated EV Electronics system

10 boards? = 60 cells = 222v nominal? What sort of battery pack are you running? And are you sure the mere 420ma balancing current will be enough for what sounds like a huge pack? I only have the capability to test up to 40 cells 5ah. Once balancing and fault control is working are you sure you want...
by Teslafly
Oct 05 2014 10:58pm
Forum: E-Vehicles General Discussion
Topic: Open source integrated EV Electronics system
Replies: 31
Views: 3986

Re: Open source integrated EV Electronics system

You didn't loose me with the sarcasm, I am just horrible at responding to it. I'm told I have a very dry, "english" sense of humor. As for the 4gb winbuilder, yeah, it's big. It's either download a huge file, or download a ~700 meg file and all it's dependencies and wait a couple of hours for it to ...
by Teslafly
Oct 05 2014 11:25am
Forum: E-Vehicles General Discussion
Topic: Open source integrated EV Electronics system
Replies: 31
Views: 3986

Re: Open source integrated EV Electronics system

Are you running a branched or beta product? I can't see a stable release newer than Oh, yes. I am running the latest version compiled from source. If you want to compile it yourself, you can either run kicad winbuilder: https://launchpad.net/kicad-winbuilder or build it another way: http://www.kica...
by Teslafly
Oct 05 2014 2:14am
Forum: E-Vehicles General Discussion
Topic: Open source integrated EV Electronics system
Replies: 31
Views: 3986

Re: Open source integrated EV Electronics system

Could you post a PDF or image of the schematic? I didn't see one in the Github folder. There isn't a pic of the schematic in the github folder as of now. However, there is the raw kicad project files, so if you want to see the schematics you will have to open them with that. I will be adding more p...
by Teslafly
Oct 02 2014 12:10am
Forum: E-Vehicles General Discussion
Topic: Open source integrated EV Electronics system
Replies: 31
Views: 3986

Re: Open source integrated EV Electronics system

Ok, the first board is complete. Between classes, lots of studying, and a hard drive crash I finally got it completed. You can view the results here: https://github.com/Teslafly/OpenBMS I will create it's own es thread once I finish the main board as well. (est 5-10 days) http://endless-sphere.com/f...
by Teslafly
Sep 11 2014 2:33pm
Forum: E-Vehicles General Discussion
Topic: Open source integrated EV Electronics system
Replies: 31
Views: 3986

Re: Open source integrated EV Electronics system

The problem with the Arduino boards themselves in regard to power consumption is not the mcu itself, which is just a standard ATmega, it's the voltage regulators that are not that efficient. In my designs I just use a straight ATmega328P (or other MCU), and more efficient power supplies. It's "Ardu...
by Teslafly
Sep 11 2014 12:10am
Forum: E-Vehicles General Discussion
Topic: Open source integrated EV Electronics system
Replies: 31
Views: 3986

Re: Open source integrated EV Electronics system

Actually, scratch what I said about the teensy 3.1 being a current hogging beast. I took a closer look at the datasheet ( https://www.pjrc.com/teensy/K20P64M72SF1.pdf ) and found a couple tables on pages 14 to 17 that give the current consumption throughout many modes of operation. specifically 30 u...
by Teslafly
Sep 10 2014 3:01pm
Forum: E-Vehicles General Discussion
Topic: Open source integrated EV Electronics system
Replies: 31
Views: 3986

Re: Open source integrated EV Electronics system

I also looked at the ATA6870, but availability was 0 at that time. Looks like it has improved a little since then. That said, if you stick to the BQ76 chip I can supply you with code to start with that already has the communication basics worked out, which IMHO is well worth the cost difference. If...
by Teslafly
Sep 10 2014 9:16am
Forum: E-Vehicles General Discussion
Topic: Open source integrated EV Electronics system
Replies: 31
Views: 3986

Re: Open source integrated EV Electronics system

Thanks for the links guys. I am actually very aware of the things Charles has done. I've been following his blog for years now. (and have learned lots from it, especially about motors and gate drives) As for dmwahl, I know that if this system isn't cheap / full of enough features that no one will wa...