Electric Bikes - Help! Need guidance on what kit I need
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12-18-08, 04:45 PM
I want to add an electric motor to my recumbent bike, but I am confused as to all the options (motor type, battery type, controllers, voltage, etc). I ride 25 miles to work, it takes me up to 2 hours. I need to increase my average speed to 25 mph to make a daily commute reasonable, hence my desire to add an electric motor. I intend to pedal as well.
Bike: Thunderbolt recumbent (Lightning Cycle Dynamics)
Wheels: 20x1.5 in the front, 26x1.5 in the rear
Commute: 25 miles, mostly flat terrain
Target Kit Cost: around $500
Technical/Mechanical skills: medium
My initial thought was a front hub motor (for ease of installation) with SLA batteries (to keep the cost down.) After a year with the SLA, upgrade to lithium batteries if I'm still using the bike. But other than those general choices, I don't know about motor manufacturers, motor power, battery requirements, controller types, throttle types, etc. There seem to be many choices and I can't tell what's best for my case. I appreciate any advice you may want to share. Thanks!
12-18-08, 04:53 PM
I have some feedback, and then some questions, to help narrow down choices.
Feedback first. I've checked the Thunderbolt online, and it seems a good spec to take a rear motor as well. The drive train and design is already suitable for direct conversion without hassle, unless you have modified the bike - so don't discount rear motor kits, they could be easy in this case as well = )
If you are set to the idea of having a front motor kit, a 20" wheel is considerably smaller than a 26" wheel of course, and will change the way the kit outputs - more torque, less speed. If you go front wheel, most kits are not designed for 20" use and you will *need* one which is wound/geared/designed to operate optimally on that wheelsize, or else it will end up being high torque, but low speed.
Crystalyte and eZee offer this, off the top of my head. Others do as well. But you will want it.
Question: How much weight in lead are you willing to carry? 25 miles of lead is a lot of weight.
Additionally, how hilly is your ride?
Hope we can help you out.
12-19-08, 10:05 AM
Thanks for the advice. I was opting for the front wheel motor to balance out the weight, because otherwise the back would have to carry me, the motor and the batteries.
The bike is unmodified.
For the purpose of the conversion, I would consider the terrain flat, even though I have a big hill at the end.
I would prefer not to have the heavy lead batteries, but it seemed like a good low-cost option to test out the conversion and see if I use it for more than a year.
Thanks again for any advice
12-19-08, 06:50 PM
Check out, http://www.ebikes.ca/index.shtml, they have a simulator for various motors, wheels and batteries. They also have drawings of Crystalyte motors, you may have a problem with axle diameter compared to the one used on your bike.
Golden Motor, http://www.goldenmotor.com/ has pretty reasonable prices.
Twenty five miles might be a bit far for SLA's, starting eats up lots of power.
If you're not looking to go more than 25 or so, and if you're looking at upgrading to better batteries as they become cheaper I'd go with a higher quality Crystalyte Roadrunner kit. Remember that with electric bikes, you get what you pay for (unless you're paying 2 or 3K for a bike that does 20 mph branded by large companies - ugh)
An electric bike system is so much more than just the motor and the batteries. It's having cruise control, quality speed controllers, a choice between thumb and twist throttle, and most importantly - the quality of the hub. If you get a quality hub, you'll have that thing forever. That's why I always recommend Crystalyte brushless hub motors. Nice, noiseless ride.
You can check our website if you want - we've got some good stuff and maybe some stuff you probably haven't thought of as well - we're always adding more products too. www.wattcycle.com/shop/home.php
12-24-08, 12:15 AM
Here are some of the choices I've narrowed down:
batteries: lithium , as the cost is comparable to SLA considereing the lifecycle and weight issues. IF I calculated it correctly, I need at least 10ah at 48v
voltage: not sure if 48 is enough for my speed requirement (need to average 25 mph for 1 hour)
motor: front hub. Crystalyte, perhaps 5303 or 5304 48V
throttle: thumb - for variable speed, and because I have twist shifters. Not sure if cruise control might be more comfortable over a long ride.
controller: not sure how much amperage I need
Again, I appreciate all the help and advice.
25mph for one hour, go with a 20ah 48volt.
My bike can go about 25mph/40kmh. I use the crystalyte roadrunner kit with a 48v 10.5 ah lithium polymer battery. I used to take it to work and back. so I would be traveling about an average of 25mph for about 45 min both ways, then once i was home, i would then charge my battery. And I have a rather large cruiser bike. However, I am also a lightweight, so that may be one reason I was able to go that fast.
Something else that you might be able to do, if you really want to be able to go at a higher speed, is use two 37v batteries together, with either a parallel or series wire connection. depending on which set up you go with, will either give you distance or speed. and I know that they work well, because I make those wire connections myself!
Here is a web site that may interest you.
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