What I mean is I’m still waiting for the master controller unit! The waiting-for-parts thing has been a big thorn in our sides. I sometimes wonder if this may be because our interstate supplier might like to corner the local market and serve his customers there first with their EV conversions. Ah, but perhaps I’m just being paranoid :-O .
BMS close-up.
The Battery Management System Modules (BMS) are pretty good though, custom-made in Australia for use on Thundersky batteries. One of the annoyances when I received these was that they were not wrapped in anti-static bubble wrap. Call me fussy but I if I was to deliver electronics, no matter how robust, I’d always supply with anti-static packaging (such as that nice pink special purpose anti-static bubble wrap one can buy).
The other thing that was somewhat annoying was the copper connectors bridging the batteries which have been layered several times to hold the current – I would have preferred a solid thick piece of copper, but then nothing’s perfect in this world, is it?!
You can see the BMS modules below. I was also expecting LEDs to be supplied soldered to each so I can know which has tripped under charge but the PCB components aren’t even labeled (talk about protecting one’s own interests!). Which is fine, really, I guess, but a simple piece of electronics in my altruistic opinion should be available for everyone, rather like open source (but then no one would make any real money, would they? ;-P ). We’ll check with the supplier on addition of LEDs which we can solder here as there appear to be a couple of holes provided (the other for PC connection to firmware for programming), but need to confirm correct terminals and polarity.
BMS in packaging.
Thundersky battery with BMS attached.
Also, Nathan’s been welding up the framework for the traction battery pack. A slide-rail concept is the simplest to do which insures the integrity of the frame is strong. I mentioned to him, as talked about on the Thundersky site somewhere, that the batteries should be packed tight as they can tend to expand when hot. He wasn’t sure of this, but had made it up tight the way I wanted as originally I didn’t want movement or play in rough driving conditions. The following image shows the prototype rack for a row of eight Thunderskies.
Thundersky batteries in rack.
{ 7 comments… read them below or add one }
The connecting copper devices connecting the batteries are best designed as multiple layer slightly bent as they are. This is to allow for some flexing when temperature changes and reduce stress on the terminals.
Concerning the lack of antistatic packing I agree with you..
Yes my husband was looking at these layered busbar connectors too and decided that, putting resistance issues aside, the connectors were not that flexible anyway. He’s now gone for modified braided earth straps crimped to solid connectors each end.
I am building a solar car for a school competition and we are using ThunderSky batteries. I am very interested in your battery management system! Who manufactures it and where can I learn more about it?
Hi Alyse, the battery management comes from Blade Electric Vehicles, http://www.bev.com.au/ -it is not too difficult to design a battery management system, the BMS modules employ an Atmel TINY13 8 pin controller chip that handles the top/bottom voltages, programmed in C, switchable via a comms master controller. There’s plenty of resources on various BMS on the net but I feel the EV Power bms is the best; Rod Dilkes from evpower has developed his own, the TS-90 for Thundersky 90Ah batteries (http://www.evpower.com.au/-PROJECTS-.html) and I believe now he has TS-160Ah BMS – these modules are sealed in resin and robust in design (saving you the time applying mil spec conformal coating like I had to, to the Blade BMS). Anyway, hope this helps. Carmel
A solar car project is fascinating, I know a couple of people who worked on the IVy Project. If you want a solar-only car, I suggest you get the Thundersky polymer batteries as these are a lot lighter than the batteries I use (and have been successfully used in an electric helicopter project).
dear sir,
I am interested in purchasing the BMS for the thundersky batteries that i have already purchased(90 ah). You had mentioned that this is available in australia. could you please send me the contact information of the person who sells these components?
Thanking you,
ABHISHEK FERNANDES
Hi Abhishek, the bms has been available from EVworks http://www.evworks.com.au. On quick checking, I did not see their 90Ah version so it’s worth contacting them to see if they are in stock. BMS master control is also recommended, http://evworks.com.au/index.php?category=6. Cheers, Carmel (Ms)