I'm new to the forum (been reading for some time, but never posted), and to ebikes as well (converted my trek last year). This year I'll be modifying my setup to fix a couple of issues I found.
A little background on my setup:
26" Trek Mountain Bike
Crystalyte 406 Rear hub motor
36V 8Ah NiCd battery pack
The two main modifications I'll be making is:
Add a second battery pack (36V 8Ah NiCd again) and replace the throttle with my PDA (Palm OS).
The PDA will be interfaced to a microcontroller that will be controlling the throttle, monitoring the battery packs and (the reason for the post) selecting the active battery pack.
I need some advice on selecting a relay to switch between the packs. There are lots of different ones available, and I just can't settle on one (either because of cost, availability or odd specs from the supplier), perhaps somebody here has already gone through the pros/cons/cost of different ones and has something to share.
I would like to have (but can compromise):
2) 5 volt coil (same voltage as the microcontroller)
3) Capable of switching 36V 30A
4) Easily available (through Digikey, Jameco, Mouser, Canadian Tire, Radioshack ...)
5) Not terribly expensive (less than $10 would be great)
6) Later I'll likely be modifying it so that the I have a couple of relays that will switch between the battery packs OR tie them in series to give me 72 volts on the fly - has anyone looked at 72 volt high current relays?
Any pointers would be fantastic!