Search found 527 matches

by 4Springs
Sun, 19 May 2019, 07:56
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 385
Views: 47536

Re: Low cost BMS

I've been working on this project again, making a version for home storage batteries. (see the other topic here: http://forums.aeva.asn.au/viewtopic.php?f=64&t=5577 ) In working on a new version, I've replaced the diode on the module board with a MOSFET. This means that the shunt current can be prop...
by 4Springs
Sun, 12 May 2019, 16:40
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

Ok, I've placed the order for the modules. I ended up not putting in an explicit pull-down resistor, although as Peter said, one could be added using the through-hole pads. I eventually figured out how to properly search the components available through Seeed. The secret is to click on the link to '...
by 4Springs
Sun, 12 May 2019, 06:14
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

Some questions for the learned folk here: 1. I've put holes under the shunt resistors in an attempt to help them dissipate heat. The idea is that air will hopefully circulate, but I have no idea if that will be the case. Any comments on this? 2. I have no pull-down resistor on the MOSFET gates. My r...
by 4Springs
Sun, 12 May 2019, 05:40
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

So here are the current circuit diagrams and PCB layouts for the master: BMSMaster Storage - Schematic.pdf BMSMaster Storage-Top1.jpg BMSMaster Storage-bottom1.jpg Main differences between this one and the last version posted is that extra MOSFETs have been added so that we have the option of up to ...
by 4Springs
Sun, 12 May 2019, 05:08
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

Peter has raised a request and a concern on the cell-top moudule (in an email). The request is that holes be added to allow for through-hole or externally mounted shunt resisttor(s) and driver if desired. The concern is that the diode (DNBT8105) might not be passing the current that I think it is. W...
by 4Springs
Fri, 10 May 2019, 16:45
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

Had a request to modify the module board. Here is the latest Top layer: CellTopBMS-Top.jpg Bottom layer: CellTopBMS_Bottom.jpg I've added holes so that you can choose to add one or two through-hole balancing resistors. Also a hole so you can tap into the -ve with a wire if you like. Looking at these...
by 4Springs
Sun, 05 May 2019, 19:08
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

I've just got some cells from the latest AEVA battery sale - is it too late to order? No, not quite. I've been busy with a show for the last few days so I haven't ordered the parts yet. Will it keep a 48V 460A pack balanced? I'm betting on it, but I can't guarantee it. A version with a lower shunt ...
by 4Springs
Sat, 27 Apr 2019, 06:39
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

Would it work on NCMs? The BMS? Sure. It would suit many types of cell, the only difference between chemistries (from a BMS point of view) is the cell voltage range. According to a quick Google search, NCM has a higher voltage than LFP, apparently up to 4.2V. This BMS uses a PIC12F1822 microcontrol...
by 4Springs
Sat, 27 Apr 2019, 06:25
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

Is it possible to balance as the cells are charging? Yes, but fiddly and there isn't any need. As Coulomb said, you can't figure out which cell needs balancing while charging, only when the charge is almost complete. But you could remember which one needed balancing last time, and use that info to ...
by 4Springs
Thu, 25 Apr 2019, 07:43
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

Ok, so now I need to develop a program for the Master to suit home storage. This is a bit different to a car BMS, as it needs to be able to be set-and-forget. A car BMS is able to rely on the driver for some functions. Here is my logic table: Screenshot at 2019-04-25 09-18-55.png Charging: • Charger...
by 4Springs
Tue, 23 Apr 2019, 16:06
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

Something else that you'll need if you are going to build and program these yourself is a programming tool. I used the PICkit 3, which is available from Microchip (who make it), or I see that Element 14 also sell it for $69. The PICkit 4 is now available, but it looks like it doesn't have the very u...
by 4Springs
Tue, 23 Apr 2019, 15:33
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

Ok, for those buying their own components, here are some screenshots of my spreadsheet:
Screenshot at 2019-04-23 17-26-37.png
Screenshot at 2019-04-23 17-26-37.png (101.17 KiB) Viewed 265 times
Screenshot at 2019-04-23 17-30-16.png
Screenshot at 2019-04-23 17-30-16.png (55.82 KiB) Viewed 265 times
Send me a message if you'd like the original sheet.
by 4Springs
Mon, 22 Apr 2019, 07:10
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

The outcome from all this testing is that I'm now ready to place orders for the boards. So far I've received orders for an even 300 of the module boards, spread out over 13 customers. You can order complete boards (i.e. with components), or boards only, or a combination. Still time to order if you'd...
by 4Springs
Mon, 22 Apr 2019, 06:59
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

The Master board had a few bugs to iron out. I'm really glad I got some made to test. At first it just would not program. Many wrong paths later, I figured out that I'd ordered the wrong chip! I'd ordered the PIC16LF1847, instead of the PIC16F1847. This may have been deliberate on my part (I can't r...
by 4Springs
Mon, 22 Apr 2019, 06:41
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

Ok, in writing the above posts I realised that I really should get some boards to test. They are not too expensive to get just a few made, so I ordered the minimum quantity (I went through Seeed ( https://www.seeedstudio.com/fusion.html ), which I have used before). So here are the boards! IMG_20190...
by 4Springs
Wed, 03 Apr 2019, 13:51
Forum: Technical and conversion discussion
Topic: Hot rod EV - looking for advice.
Replies: 31
Views: 890

Re: Hot rod EV - looking for advice.

One thing I'm struggling to find is a diagram or description of how the EV setup works, power in -> various boxes, cables and batteries -> electric motor -> differential -> wheels. What happens in the middle? There isn't very much to it when looking at it from a high level. Cells have positive and ...
by 4Springs
Tue, 02 Apr 2019, 18:30
Forum: General EV Discussion
Topic: EVs available in Australia (list)
Replies: 15
Views: 1660

Re: EVs available in Australia (list)

Email from Motors in Hobart re Kona: We’ve been notified that Kona EV’s have now hit the shore and we should have a vehicle to test drive from Monday – ish onwards! Pricing has also been launched, drive away price including 12 months registration as below: Elite $65256 Highlander $69936 Highlander T...
by 4Springs
Tue, 02 Apr 2019, 18:20
Forum: Technical and conversion discussion
Topic: Hot rod EV - looking for advice.
Replies: 31
Views: 890

Re: Hot rod EV - looking for advice.

Hi blwnhr, and welcome! That is some machine. It certainly has potential, and your 5-7 years sounds realistic! The battery and motor/controller are definitely the most pricey parts of a conversion, and they do change with the times. Unfortunately they are also the hardest to leave until last, since ...
by 4Springs
Tue, 05 Mar 2019, 16:55
Forum: Batteries, charging, management and monitoring
Topic: E63 LG 63Ah NCM battery group buy
Replies: 12
Views: 769

Re: E63 LG 63Ah NCM battery group buy

rutuja wrote:
Tue, 05 Mar 2019, 14:37
An excessive number of different activities in a hurry...
We appear to have some kind of re-posting bot here? Interesting...
by 4Springs
Fri, 22 Feb 2019, 13:45
Forum: Batteries, charging, management and monitoring
Topic: E63 LG 63Ah NCM battery group buy
Replies: 12
Views: 769

Re: E63 LG 63Ah NCM battery group buy

Mmmmm.... If I've done my sums right, a 150V 37kWh pack would cost about $10k (AUD). It would weigh about 160kg without the mounting hardware. That's 166 cells. I'd decrease the weight of my vehicle and increase the range to about 150km. I might be in the market for a new battery soon, and this is v...
by 4Springs
Mon, 11 Feb 2019, 14:08
Forum: Hyundai
Topic: Hyundai Australia Kona EV info
Replies: 103
Views: 14595

Re: Hyundai Australia Kona EV info

reecho wrote:
Sun, 27 Jan 2019, 21:31
According to a dealer in Melbourne pre orders have started.
Are they ordering the tow kit?
by 4Springs
Mon, 11 Feb 2019, 14:06
Forum: General EV Discussion
Topic: Highway travelling at slower speeds
Replies: 5
Views: 438

Re: Highway travelling at slower speeds

I'd echo everyone else here. We travelled on that road up to Canberra last year. As I was driving I was thinking about the trip that you are thinking of undertaking. There are just so many vehicles! Even something going 90kph slows the whole four lanes down, as the cars from the left lane move over ...
by 4Springs
Sat, 02 Feb 2019, 17:48
Forum: For Sale/Wanted
Topic: BMW i3 Rex wreck
Replies: 9
Views: 828

Re: BMW i3 Rex wreck

Location?
by 4Springs
Tue, 29 Jan 2019, 13:55
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

I guess the circuitry difference between top-balancing and bottom-balancing is too great to be able to include both and switch between the two? No difference in hardware, the difference between top and bottom balancing is all in the software. Nevilleh's original BMS was setup for bottom balancing, ...
by 4Springs
Sun, 27 Jan 2019, 15:03
Forum: Renewable Energy and Storage (Non-EV)
Topic: Low Cost BMS for Home Storage Batteries
Replies: 51
Views: 3828

Re: Low Cost BMS for Home Storage Batteries

Good news! 10 people have decided to jump in on the order for these boards, meaning over 200 of the celltop module boards to manufacture. This has dropped the unit price dramatically. So dramatically that it has now become economical to get some of the components pre-assembled. The new prices are: M...