The S Man

I have a 12V +ve and -ve running to the horn. On a car the negative terminal, usually, of a battery is connected to the body work of the car. This then gives you the -ve voltage if required. Hence the term, negative earth. That's why if something "shorts" to the car body, it will blow up, or a fuse at least. On the bicycle there isn't that connection to make the circuit and cause a short. I hope that's all correct. I'm sure someone will correct me if I'm wrong.

I ordered a pair of snail, dual air horns for £6. Nothing poxy about them! 100+ dB. In the photo you'll also notice on/off switch at back of saddle, also horn and indicator control on handlebars. The bag on the cross bar contains the wiring and is a phone holder as well. Use Strava for speedometer and distance covered. Wiring still a work in progress.

Identical to the one I purchased I think. http://www.ebay.co.uk/itm/171943729717?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT I am running a tail light, head light that was 8.4v rechargeable, then I connected in a car cigarette lighter adaptor that has 2 usb plugs as well, which charges my phone constantly as I use a cycling app all the time for speed and distance. I also use a usb powered DVR camera. If i need a higher powered USB socket, the car cigarette lighter type will be an easy plug in. I have just ordered indicators and a horn all 12V which I hope will all be powered from this. I do have a 36V 25AH LiFePO4 battery, so drain shouldn't be a problem. 800W rear motor averages 35+ miles at average 24+mph, off road of course.

I suppose what I am trying to do is get my bike up to around 25mph for off road use, as cheaply as possible (£200ish), with the least hassle. Plus, being able to revert to road legal quite quickly and simply. My latest (and probably dumbest) thoughts are..... If I just connected a 48V 1000W motor into my existing 36V 250W setup without changing any wiring would the bike work at all. If reverse overvolting works (undervolting?), I would hope that a 1000W motor at 48V gives approx. 32mph then only supplying 36V would give 32 x 36/48 which would be 24mph. Mileage between charges is not that important, hopefully at least 10 or so! This would then leave me the option of further upgrade to battery, controller etc. when funds allow or building a complete off road bike altogether.

Thanks everyone for the replies

Apologies in advance...Complete Newb with 3 weeks experience! I have an eco expedition 36V 250W e-bike which I love. Like everyone else I would like more power when using it off road, and easily keeping it legal when on the road. Has anyone any experience of fitting a lower voltage motor to give more speed, rather than overvolting. I thought if I could pick up a 24V hub, I would try to connect it into my existing 36V system. No need to change anything else hopefully. Then when back on road a quick 5 minute swap will leave me road legal again.