DIY Electric Bike Costs Breakdown

$236    ebay.com/yescomusa  36V 800W 26" Rear Wheel Electric Bicycle Hub Motor Kit
$  28    ebay.com/mj_warehouse  (4) Craftsman Cordless 19.2 Volt Worklights
$    6    ebay.com/sim_eagle 10 Pcs 50 Volt 10 Amp Schottky Diodes,
$170    Current Batteries  4 Each, 19.2 Volt 3.7 Ah Lithium Rechargeable Tool Batteries
$    6    ebay.com/floorscrubberparts   2 Each,  Anderson Connector SB50, #8AWG, 50A
$    4    D and B Supply  ATC Automotive, Inline Fuse holder, with 30A Fuse
$  10    Harborfreight.com  Heavy Duty Battery Cutoff Switch (Discontinued)
$  10    Misc. 3' 16GA Wire, 5/16" Ring Crimp-on Connectors, Heat Shrink Tubing, Hot Glue sticks and Electrical tape

$470     Total DIY Electric Bike Conversion Parts
$  30     Purchase of Specialized Hardrock 26" 18 Speed, mountain bike from Deseret Indusrties.
$500    GRAND TOTAL
Note: *All prices rounded to nearest $

2011 Drivers Pay Highest Ever In Christmas Gas Prices

Hi, Well here we go again, The price of fuel did NOT go up! it actually went down to the lowest price of 3 years.
Why does the media say crap like this? To keep us emotional about things that we cannot control.
We all need to break free from the scare tactics and lies of the media.  This is one of the reasons why I drive and ride electric!!

Battery Groups Glued and 50 Amp Connector

The 50 Amp Anderson connector came a few days ago and I have purchased a 30 Amp fuse holder and 30A fuse. I think I have all of the stuff to finish securing the battery holders to each other.  I did not like the exposed wiring connections. It looked to me that when I was connecting the batteries into the holders it was possible that the exposed wire terminal ends could get in contact with another battery holder terminal.
I used High Temperature hot glue to glue the battery holders together.

I connected the keyed battery cutoff switch inline with the negative battery wire.

Completed DIY Electric bike

First test Ride!! WooHoo!!

I have a 50 Amp Anderson connector on order. I also want to add a keyed battery disconnect switch on the Lithium battery pack. I mounted the disconnect switch but, I will wait to do the final wiring when the Anderson connector is here.

But, I want to get a ride or two in before it gets any colder out side.  We are in the hi 30s today buy the wind is blowing making the wind chill in the 20s.  I used wire nuts to temporary connect the battery pack to the motor controller.  Cool! the fuse did NOT burn out when I connected the final battery connection and even COOLER when I pressed the thumb throttle and the hub motor spin to life!!

 Here is the location of the controller in the outer side pocket with it's associated wiring.

 Okay, every thing looks good, I did a final check of the brake adjustment.

Let's take it for a spin.............Our pet dog was sure she was getting left out of the fun!

I am impressed with the torque of the motor. The power comes on smoothly with the thumb throttle.
The bike was allot of fun to ride, I almost forgot how cold it was going into the wind, the addition of motor power made the ride into the wind enjoyable, but still cold.


After riding several miles I returned home and parked the bike in the garage, removed the individual 19.2 Volt batteries and put them in the 4-Way Craftsman recharger.

I went in the house to warm up!

Secure Control Wires and Cables

I used several wire zip ties to tie the control wiring and cables to the bike frame.  I made sure that I had full turning movement of the front wheel and handle bars.
The wires fit nicely against the tube frame of the bike.

The batteries fit into the battery compartment. and the output leads are ready for a connection to the controller.

Battery Connections

The 4, 19.2 Volt Craftsman batteries are arraigned into a  2 batteries in Series and 2 batteries in Parallel arraignment. This will give me a total battery pack Voltage of 38.4 Volts and sustained current of up to 20 Amps.

There are 4 Shockley Diodes, one across each battery output, to protect each battery's BMS.

The battery connections are made using heavy 16 Ga. speaker wire. I used a grinding bit to remove enough plastic from the stem of the battery socket to get the wire to fit flush with the top of the plastic.
Then soldered the battery connector wires and the Diodes in place.

Battery Sockets (continued)

To get the battery sockets to fit together better I used a small round carbide bit to gouge a couple of holes in the plastic sockets.  This will allow the solder terminals to fit into the gouged holes to get the battery packs to fit into the battery compartment of the bag.

A "Kick Back" Diode needs to be placed across each batteries terminals on the battery socket to prevent the burning out of the BMS incorporated into each of the Lithium batteries.
In the event that any of the individual battery management systems is to shut down a battery while under a load there will be a very brief back voltage and current trying to back flow into the remaining batteries that are still connected in the 3 remaining battery arraignment.  A 50 volt, 10 Amp, Schottky Diode across each battery will prevent the back flow of current into any remaining battery BMS still under load at the time of battery circuit interruption.

I used a small carbide grinding tool to make a pocket for the diode to set inside of the solder terminal area of each battery socket.

 The Red paint demotes the Positive terminal of the solder terminal, the banded end of the diode will connect to this Red terminal.  This will only allow current flow in the reverse direction, like when "kick back" would occur.

Battery Sockets made from Nonworking 19.2 Volt Work Lights

I purchased 6 nonworking 19.2 Volt work lights on ebay.  I will cut the unneeded portions off leaving just the battery socket. It is going to be a snug fit to get all 4 batteries into the center compartment of the bag.

Attach Battery & Control Bag

The 600D Oxford cloth carrying bag has a zippered main compartment for battery and 2 side compartments for Motor Controller, on one side, and on the other side, a compartment for the Lead Acid Battery Charger.
I am going to use 36 volts of Lithium batteries so that way, I will use the battery charger side for spare parts or a tool kit. I will remove the Lithium batteries from the bag to recharge them.

The bag attaches with Velcro strips that wrap around the metal shelf's frame.

Adjust Thumb Throttle Position

I have concerns that the right hand gear selector will interfere with the Battery Power Level Indicator & Thumb Throttle. I removed the handle bar grip and cut off 1 inch of the grip to get more room for the gear selector.  This gear selector may need to be moved in the future if it is uncomfortable to select the rear gears.

Making Battery Sockets from 19.2 Volt Work Lights

I will cut the Craftsman 19.2 Volt work lights off at the work light battery slide connector.  I tried to match the contour of the work light base that mates to each other.  Notice that the solder wire terminals are protruding above the cut.  I need to get these socket and battery assemblies as short as possible to get them in the battery compartment.  The total battery length needs to be under 16 inches.

In the last photo the protruding solder tabs are plainly visible and I will need to grind some relief holes in the mating battery holder.

Attach Rear Shelf

I attached the rear shelf with #10, 32 TPI Socket Head Cap Screws and 1/8" Fender Washers as needed.
I put a slight bend in the metal shelf support rods, behind the seat, to get the shelf to be level over the rear wheel.