Is there a cheaper alternative? Turning a Tern folding into an electric bike.
 

Folding bike motor kit for 20 inch wheels – NYCeWheels.com I saw this and wanted to know if there's a cheaper/faster option? Btw I don't know anything about putting on a kit on a bike but would consider buying cheaper parts and paying for the labor only if it's just as good or better than the above kit that's in the link. Btw how fast/far can 15 v take me? From some reading I see larger batteries mentioned so I know they exist and larger batteries usually mean more speed.
My current bike is a Tern, 20 inches. Thanks in advance.

If your Tern has an aluminum fork, I'd pass on the kit you have listed.. if you're near nycewheels, go look at their Purpose Built Electric Folder for a couple of hundred dollars more .. and ride it.. see if it's something you'd like.. you could trade in your Tern and be money and time ahead .. but in answer to your question, there are many cheaper 20" wheel kits available for lots less money.. ebay would be one place to browse..

Agree totally with Bruce that this kit is priced too high for nothing special. If you're going to spend that much for a kit, get a BionX which (I THINK) has a three year warranty or, if they don't have a system for 20" wheels, something similar. The kit you referenced comes with a 36V, 10 a/h battery or
360 watt hours. At 18 mph, flat road, no wind, 180 pound rider, 50-60 pound bike, you would use 20-25 wh per mile with a little pedaling, so good for 15-20 miles.
BTW, installation of a kit is very intuitive even if the directions suck. Do it yourself and learn.

I have a 20" kit from gocarlite.com: 36V Complete 900+ Watt (peak) Geared Motor Kit - 2 Year Motor Warranty - Electric Bike Solutions, LLC Without the pedal assist, it's $900 including shipping.

I also say to skip the front wheel conversion kit. A rear wheel kit would be much safer with an aluminum front fork (BionX). Or, as also suggested, get a purpose built folding ebike. No worries about installation,...

Thanks all. I'll check out the kit and Bionx since two bikes are not an option but a good idea.