liveforphysics
100 TW
I've been thinking about making a giant brushed controller for a performance EV conversion. However, controller cost in the $4000-5000 range seems like a lot of money I would rather put towards a custom motor and high C-rate LiPo.
This chip is $4.10 in a quanity of 100pcs.
http://ixdev.ixys.com/DataSheet/DS100127(IXFK-FX160N30T).pdf
They claim 160amps continuous each, but let's de-rate them to 100amps for our 2000amps build. This means we need 20 of them. That's $82 in FETs.
Photo-flash caps have pretty good properties for use in a 300v controller. 50pcs of the 330v 80mfd variety is $31 bucks. I would pick up a hundred of them. The overall quantity of capacitance makes no difference, just the ESR, and going with a group of little caps like this works out for best performance.
http://cgi.ebay.com/80uF-330V-Radial-Electrolytic-Capacitors-50-PCS_W0QQitemZ160370979733QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2556daf395#ht_3019wt_1026
Now you need a shunt of course, and there are tons of them available for cheap. A pair of these 1000amp shunts would work pretty nicely, because you would definitely want to be having at least two big 000awg leads in and out of the of the controller, so running a pair of shunts would make that more convenient. Make the end of the shunts also serve as the positive input power lug/terminal.
http://cgi.ebay.com/Weston-Current-Shunt-1000Amp-50Mv_W0QQitemZ320433788953QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item4a9b579819#ht_1618wt_950
Now it's a matter of some 000awg welding leads, some copper buss bars, scrap industrial heat sinks, solder, a pair of the $5 -7amp N-channel fet driver chips on flea-bay, and any old brushed E-bike controller to use as the brain (throttle input, switching signal, current limiting from the external shunt). I would guess another $100-150 for these parts.
Combine these parts with a lazy weekend of soldering with a 200w iron (big buss bars are tough to solder!), and you've got yourself a controller that will pump 800hp into motor and still have 38% current overhead left in the FET stage.
For those folks out there thinking about doing a performance EV, but budget limited, it seems very possible to DIY a controller for a lot of personal labor and a little bit of expense.
For something lower powered, pricing out the parts in an Alltrax controller, it looks like you could DIY the biggest Alltrax model for under $100 if you were willing to do some labor to save some cheddar.
Best Wishes,
-Luke
This chip is $4.10 in a quanity of 100pcs.
http://ixdev.ixys.com/DataSheet/DS100127(IXFK-FX160N30T).pdf
They claim 160amps continuous each, but let's de-rate them to 100amps for our 2000amps build. This means we need 20 of them. That's $82 in FETs.
Photo-flash caps have pretty good properties for use in a 300v controller. 50pcs of the 330v 80mfd variety is $31 bucks. I would pick up a hundred of them. The overall quantity of capacitance makes no difference, just the ESR, and going with a group of little caps like this works out for best performance.
http://cgi.ebay.com/80uF-330V-Radial-Electrolytic-Capacitors-50-PCS_W0QQitemZ160370979733QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2556daf395#ht_3019wt_1026
Now you need a shunt of course, and there are tons of them available for cheap. A pair of these 1000amp shunts would work pretty nicely, because you would definitely want to be having at least two big 000awg leads in and out of the of the controller, so running a pair of shunts would make that more convenient. Make the end of the shunts also serve as the positive input power lug/terminal.
http://cgi.ebay.com/Weston-Current-Shunt-1000Amp-50Mv_W0QQitemZ320433788953QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item4a9b579819#ht_1618wt_950
Now it's a matter of some 000awg welding leads, some copper buss bars, scrap industrial heat sinks, solder, a pair of the $5 -7amp N-channel fet driver chips on flea-bay, and any old brushed E-bike controller to use as the brain (throttle input, switching signal, current limiting from the external shunt). I would guess another $100-150 for these parts.
Combine these parts with a lazy weekend of soldering with a 200w iron (big buss bars are tough to solder!), and you've got yourself a controller that will pump 800hp into motor and still have 38% current overhead left in the FET stage.
For those folks out there thinking about doing a performance EV, but budget limited, it seems very possible to DIY a controller for a lot of personal labor and a little bit of expense.
For something lower powered, pricing out the parts in an Alltrax controller, it looks like you could DIY the biggest Alltrax model for under $100 if you were willing to do some labor to save some cheddar.
Best Wishes,
-Luke
