Fisher Price: My First Delta-Wye Conversion

So I've been saying I'll do it for years but now I've started getting the parts together and I'm actually diving in to my first delta wye conversion. I've read many threads on ES covering other peoples conversions, including the DocWatson's now massive thread http://endless-sphere.com/forums/viewtopic.php?f=2&t=9215&start=255

I plan to document my build here in a new thread because a) the other threads have become so bloated that it is hard for newcomers to glean useful how-to information from between the conflicting/partial build reports and the chit-chat and b) because I have a few questions that I haven't seen clear answers to yet in other threads.

My plan is to use a 9C 6x10 motor (love that slow wind!) with a 13s 20AH LiCoMn pack. I'll be running the 3 extra wires out the axle, which doesn't appear too hard, just frustrating sometimes. I'll also be using a KU 153 controller, 15 mosfets 30A.

I have ordered 4 of these 12V70A SPDT relays (one is a spare since minimum order quantity is 4): http://www.fourthgen.net/relayscart70A5P.shtml


I plan to use this switch to fire the relay (with the safety cover mostly for cool looks as well as reminding me to close the switch to return to wye mode once I've slowed down) https://www.sparkfun.com/products/11310


I'm also going to wire this keyswitch inline with the toggle switch. I will use it as a safety interrupt for times that I want to let someone ride my bike but I don't want them screwing with the delta/wye and blowing my controller or hurting themselves, not necessarily in that order. https://www.sparkfun.com/products/10445


Both the toggle switch and keyswitch will be mounted on a panel on the handlebars, along with a few other smaller switches for accessories, lights, charging etc.

One question I have that I haven't seen an answer to is will the order of phase and hall wires change when I switch from wye to delta? From DocWatson's picture of his build and relay wiring, it seems like the order is different, unless I'm just looking at his relay wrong. his pic is at the top of page 19 in this thread: http://endless-sphere.com/forums/viewtopic.php?f=2&t=9215&start=270


My second question is that the switch has an LED in it that would be cool if I could use, but it needs 12V and I'm running 48V. If I blow the LED, no big deal, but if I could drop the voltage and have the LED work too, that would be nice. Can this be accomplished with a simple voltage divider circuit?

Thanks for anyone's help that can review my build plan and let me know what you think.

Those Sparkfun key switches are crap... avoid them!

mlt34 said:

My second question is that the switch has an LED in it that would be cool if I could use, but it needs 12V and I'm running 48V. If I blow the LED, no big deal, but if I could drop the voltage and have the LED work too, that would be nice. Can this be accomplished with a simple voltage divider circuit?

Click to expand...

LEDs are current-based, so if it's just an LED with dropping resistor, you just need to calculate the right resistor to give sufficient current to drive it at the voltage you want. Measure what it uses at the 12V with existing resistor. Use that and ohm's law to determine what resistor you need for your voltage to get the same current.

one other item I thought of, regen braking. If I pull the brakes at 38-ish miles an hour while in delta mode, is that going to be a damaging amount of current to charge the battery with? I'm planning on using a 13s LiCoMn shrink wrap battery from BMSbattery.