Search found 53 matches

by Astroboy
Wed, 02 Jul 2014, 02:50
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

Ah well, you must've read this: http://forums.aeva.asn.au/viewtopic.php?title=wanted-an-amp-hour-meter&t=3368 Send me a PM and I'll send you all the details so you can make your own. And develop it into something new. Wow, i actually hadn't seen that thread. Now i feel like half the work is already...
by Astroboy
Wed, 02 Jul 2014, 00:14
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

That's why i was thinking of using a modified cell top module to interface to the hall effect sensor. Even with the less efficient free xc8 compiler the celltop module is only using 37% of its program capacity whereas the master module is pretty much maxed out. Also it would solve all issues of volt...
by Astroboy
Tue, 01 Jul 2014, 06:50
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

You can, you know, get too carried away with this stuff. In nearly 2 years and some 6000 kms of running my car with my bms I never had a comms failure once. Also, the error rate was insignificant and when it did get the odd bad value, the poll rate was so high that a new, good value appeared almost...
by Astroboy
Tue, 01 Jul 2014, 04:46
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

While I was testing to make sure that everything still worked I decided that I needed a way to tell what the Master was telling the charger. So I modified the Balancing screen to show a Charger output: <img src="uploads/1844/ChargeScreen.JPG" /> The number next to "Chgr" is one of: 0 = Charger is n...
by Astroboy
Tue, 01 Jul 2014, 03:40
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

I looked into the other bug that Astro found - the one where the Master doesn't add up the total pack voltage accurately. This was from my (recently added) rolling average code. I have now promoted the variables concerned to 24 bit to make it more accurate. There is a similar problem with the volta...
by Astroboy
Mon, 30 Jun 2014, 09:33
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

Coulda sworn my original module code turned the shunt off if no comms received within a certain time, so it WAS fail-safe! Independent of the master. Pity the LM385 makers produce all those variants! Keeps you on your toes though. I think that is happening. It is only the cells that are still recei...
by Astroboy
Mon, 30 Jun 2014, 09:26
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

I haven't checked the code yet but i'll have a guess. When in comms fail mode the master displays 3.99v for the cells. Could this be triggering the master to send out a shunt "on" command to all the cells. Well at least the ones it has no data for because it beleives they are at 3.99v? So before it ...
by Astroboy
Sun, 29 Jun 2014, 09:11
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

So now that i have the modules and master working i went ahead and built another module, so three now. (whoohoo i know, lots more to go) But whilst testing and reprogramming i noticed something i thought i would share. I currently have 4springs code running. (Love the module identifier on comms fail...
by Astroboy
Sun, 29 Jun 2014, 04:14
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

And here is a copy of my PCB if you'd like to compare that. <img src="uploads/1844/CellTopBMS-SE130AHA2.jpg" /> We have a winner. http://forums.aeva.asn.au/smileys/smiley4.gif 4Springs, your PCB image is what did it. The LM385 has 3 pins but on the schematics it is always pictured with 2. So every ...
by Astroboy
Sun, 29 Jun 2014, 00:21
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

I dont think it is the celtop modules. Have you tried checking the masterPCB drawing i gave you? Actually i remember i had similar problem using first iteration master untill Neville sent me the next. Try tracing your master board with this... <a href="uploads/2925/CellTopBMSMaster_-_PCB.pdf" rel="...
by Astroboy
Sat, 28 Jun 2014, 08:04
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

... Also i see you use the new code... First try your modules with my code to see if the problem is there. There is no need to change all modules. Just program one master and couple slaves... ... I loaded your code and unfortunately i got the same result. High and low voltages of 2.21 The temperatu...
by Astroboy
Fri, 27 Jun 2014, 09:03
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

But hang on the voltage levels reduce with each subsequent measurement so that within a few seconds the voltage measured drops to 2.22 and the master eventually shows E3 (voltage too low). I just had another thought. The voltage reading depends on the voltage of the reference zener connected to pin...
by Astroboy
Thu, 26 Jun 2014, 20:00
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

2.2V is the minimum voltage that the cell module can report. This corresponds with a value of 0xFE sent by the cell module. The master is not reporting any comms faults, so it looks the cell modules are actually sending that value. I presume that your highest and lowest values are both 2.2V, so bot...
by Astroboy
Thu, 26 Jun 2014, 07:54
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

Two steps forward one step back. I double checked and the connections to the opto on my master board do seem to be reversed. So i lifted one end of the opto and put in a couple of short pieces of wire to crossover the pins. Hook it back up and yay comms error gone. I am getting voltage levels other ...
by Astroboy
Wed, 25 Jun 2014, 09:02
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

Well i hooked up the scope and it allowed me to find one fault which was a lifted leg on one of the cell module's optos. But that only affected that one module the other was fine. so fixed the lifted leg and now have two good cell modules that produce the expected data out individually and when hook...
by Astroboy
Tue, 24 Jun 2014, 07:11
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

I can complile/build both the master and celltop hex files but when looking at the code in the IDE i get several red underlined identifiers. The __delay_ms_ and the __delay_us_ are all underlined. It still complies without error so i am assuming the compiler knows what they mean but the IDE doesn't...
by Astroboy
Mon, 23 Jun 2014, 17:31
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

Hello Everyone, I've created a SourceForge page for the Low Cost BMS. Link is here: <a href="http://sourceforge.net/projects/low-cost-bms/" rel="nofollow">Low Cost BMS</a> I have uploaded all of my files so that anyone can download them. ... I have downloaded the files and added the two mplab proje...
by Astroboy
Sat, 24 May 2014, 07:20
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 443
Views: 73179

Low cost BMS

I have finally got my hands on the PCB's for the BMS. They look great. Many thanks to Arber333 for all the assistance in adapting the circuit to fit 40Ah and 60Ah Winston cells (same terminal separation on both). Getting a PCB manufacturer to produce the PCB's is all new territory for me. The last t...
by Astroboy
Sun, 04 May 2014, 05:47
Forum: General EV Discussion
Topic: Crowdfunding the ideal electric vehicle
Replies: 19
Views: 2597

Crowdfunding the ideal electric vehicle

Back to ADR 69. Spoke to a local engineer today who referred to VSCCS bulletin #2 19/11/2012. Page 10 69/00 reads: " The vehicle is exempted from crash-test requirements of ADR 69/00. A label warning passengers that the vehicle has not been crash tested must be affixed on the dashboard in front of ...
by Astroboy
Fri, 14 Mar 2014, 22:58
Forum: General EV Discussion
Topic: Crowdfunding the ideal electric vehicle
Replies: 19
Views: 2597

Crowdfunding the ideal electric vehicle

It seems like most DIY EV conversions are done to pre 1996 vehicles which i imagine is due to the ADR69 requirement and the necessity to crash test a modified vehicle to pass the test. You assumed wrong. The crash test is for production vehicles. You do not need to crash test a conversion. I recent...
by Astroboy
Fri, 14 Mar 2014, 22:08
Forum: General EV Discussion
Topic: Crowdfunding the ideal electric vehicle
Replies: 19
Views: 2597

Crowdfunding the ideal electric vehicle

Some people will go the OEM EV route. Personally i like the idea of building my own. I like a car that looks nice, not like a prop from a sci-fi movie http://forums.aeva.asn.au/smileys/smiley1.gif I don't want to enter a leasing agreement for my batteries that ends up costing me more than the petrol...
by Astroboy
Fri, 14 Mar 2014, 16:34
Forum: General EV Discussion
Topic: Crowdfunding the ideal electric vehicle
Replies: 19
Views: 2597

Crowdfunding the ideal electric vehicle

Also as this would all be community designed and developed there would be scope for all skill levels to get involved. Those with the technical background and/or experience in building an EV may want to help out with the design. Maybe somebody lacks the technical skill but is a wiz at organisation an...
by Astroboy
Fri, 14 Mar 2014, 14:45
Forum: General EV Discussion
Topic: Crowdfunding the ideal electric vehicle
Replies: 19
Views: 2597

Crowdfunding the ideal electric vehicle

Just thought i would throw the idea out there. It seems like most DIY EV conversions are done to pre 1996 vehicles which i imagine is due to the ADR69 requirement and the necessity to crash test a modified vehicle to pass the test. So everyone is "forced" to pick the vehicle that best suits their ne...
by Astroboy
Sat, 01 Feb 2014, 00:57
Forum: Technical and conversion discussion
Topic: List of cars with electric power steering pumps
Replies: 22
Views: 148660

List of cars with electric power steering pumps

I think you are correct, it looks like the unit is bolted directly to the panel.

When i heard the youtube video for the first time i was thinking it was loud to start with then it just got louder and louder. Louder than any EV drive motor i have heard and it was just the power steering.


by Astroboy
Thu, 30 Jan 2014, 19:27
Forum: Technical and conversion discussion
Topic: List of cars with electric power steering pumps
Replies: 22
Views: 148660

List of cars with electric power steering pumps

@BigMouse Found a youtube video of what looks to be the same unit you are using. Is your's as noisy as this one? http://www.youtube.com/watch?v=XrHW7RXHHZY I suppose noisy is a relative term and hard to tell with no other sounds in the video to relate it to but i would have called it noisy. Just wan...