What's he building in there?

[mauswerkz]

awww man this is so awesome, wish I had the attention span to do an engineering degree. Which degree are you doing?

P.S saw you on Robsons Rd this morning on my way to TAFE, was going to flash my lights but wasn't sure it was you, I later thought who else would be driving a white beemer with a black bonnet.

Yeah, was probably me on my way to Jaycar around 8:45. I'm doing a mechatronics engineering degree. Sorry about leaving the meet suddenly and not convoying back to the 'gong with you on Sat. Got invited to meet up with a mate while I was up in Sydney.

[Nick]

It's all cool, next time.

[mauswerkz]

Made up a string of my battery management boards and installed them one of 11 "bricks" of lithium batteries I've made. This is the first time I've tested a string of more than 3 of these and I'm very happy that they're working exactly as expected! Just out of view on the breadboard is a microcontroller "brain" that communicates with each of board (there's one for each parallel segment of the pack). The brain retrieves the voltage from each cell, then calculates the maximum cell voltage, the lowest cell voltage, the average cell voltage, and the total battery pack voltage. This information is very useful in an electric car as it allows the controller to dynamically vary its parameters to protect the pack if a cell gets too low. It can also tell the charger when the last battery reaches full charge so it can shut off.

The white blocks on the boards are resistors which are used to bypass current around cells as they reach full charge. This allows the charger to continue to charge the lower cells without overcharging the ones that reach full first (this is called balancing). When there are 120 cells in series, this is extremely important.

2011-08-27 11.38.10.jpg

[mauswerkz]

2011-09-05 16.46.19.jpg
Got my first production-ready batch of main circuit boards for my motor controller today. Very excited. Spent most of the evening getting started populating it with parts. I'm about 1/3 of the way done. Testing each part of it as I go and so far everything is working as designed. I'm very pleased.

[Rosey]

Amazing, confusing, expensive. Best of luck, looks like everything is going according to plan.

[mauswerkz]

Finished populating the board and did the first spin-up of my test motor on the new controller today. Works exactly as planned! This is also the first test of the higher frequency mode of the controller, running it up to 165Hz. That's more than three time the frequency you get from the mains. This allows me to spin a 4-pole 3-phase motor up to near 4500rpm. A little 370w 3 phase motor spinning away at that speed on my desk worries my roommates, but it makes me giddy. I think it's time to go ahead and order the full-size motor that will end up in my BMW.


Here's a zoomed out shot of the controller in its enclosure. Best not to touch anything in there. High voltage.

[Rosey]

If I was your roommate i'd be worried too! Can't wait to see full scale tests in the BMW, it'll be quite an achievement when you finally get it on the road.

[Jenga]

Mmmm, looking good. Glad to see the new board is working as planned, it's always a nice feeling when that happens

Out of curiosity, who did you get to make the PCB?

[mauswerkz]

Out of curiosity, who did you get to make the PCB?

Got it done at PCBCart in China. I'll be getting my battery management and capacitor boards made by them as well. Good quality and the price it right too. If I'm only getting a couple boards made and don't need solder mask or silk screen, I get it cheaper from Futurlec. They do solder mask and silk screen, but the cost make it worth going for PCBCart. PCBCart's specs are better too (finer clearances, testing, free solder mask on bottom of board, etc).

[luke641]

Holy Crap the nerd level just reached an all time high

Its like a computer convention in here, Martin being a nerd, MausWerkz being nerdy but cool.

Its just so confusing. Haha


Nice work but dude. Looks mint

[luke641]

Also if you need batteries, ill seee what i can do for you, working at a battery shop..

[mauswerkz]

Also if you need batteries, ill seee what i can do for you, working at a battery shop..

Thanks, I think I remember seeing you post in the MCM Hookups thread. I need Lithium batteries for this project, but I'm playing with the idea of converting a smaller car just for driving around town that could use lead acids. I'll keep you in mind if I go for that.

Also, most of my hook-ups tend to fall through once I tell them that I need 32 12v batteries, not just a few ;-)

Martin being a nerd, MausWerkz being nerdy but cool.

Hey, Marty is cool too. I was inspired by him when I did my hacked cassette player aux input mod in my Astina!

[luke641]

Thanks, I think I remember seeing you post in the MCM Hookups thread. I need Lithium batteries for this project, but I'm playing with the idea of converting a smaller car just for driving around town that could use lead acids. I'll keep you in mind if I go for that.

Also, most of my hook-ups tend to fall through once I tell them that I need 32 12v batteries, not just a few ;-)

32 12V Lead Acids?? To what specs?

I could also try and get lithiums, but to what extent/cost/specs im not sure.. Send me a PM and we can go from there dude

[Marty]

Martin being a nerd

reaching for the ban stick...

[jmacman12]

reaching for the ban stick...

Let me assist you



Love ya Lukey <3