29 October, 2014

DIY: Turn your bike into e-bike for yourself - Step 3/5: Preparing the box to house batteries and controller

Table prepared to house the batteries that drive us
If you do not want complications, you can always put a rear rack on the bike, and then put the battery. But I have opted to place them on the table, which, though it takes more work,has a number of advantages: 
  1. The weight will be more evenly distributed, providing braking and acceleration. On the rear wheel and have about 6 kg. with the engine, if you also put the battery, it will be more difficult to transport and easier we can steal the most expensive part of the electric bike.
  2. In the picture we can put the battery in the format we want, taking advantage of an otherwise wasted space, and allows us to better cool the driver if you use one side of sheet aluminum. It will be better secured and more stylish bike.
  3. Good space and fixing. The table allows us to fix very well, so they do not "jump" with every bump. Furthermore, by using standard Li-ion batteries with 1C charge / discharge, we must use more units per cell to get enough power in case you want to overcome slopes of more than 10% without much help from us; 18650 battery using 9 x 10 cells obtain a 36V and 20Ah capacity, enough to make 50 kms without problems (helping us). A battery of this size would not be very aesthetic behind and go unnoticed.
  4. And aesthetically, "cool" a lot! We can put stickers, drawings, etc.
As Jack, whose tutorials I learned a lot, he used wood to prepare : 

I preferred the aluminum for enduring great weather, easy to assemble, lightweight, flexible and durable. 
My bike Jumper BH, as I mentioned in previous posts, has a peculiar box aluminum alloy, which makes it more resistant to the jumps with its diamond shape. After figuring out the various settings, I bought a 45x23mm angles and 2 meters long, riveted on what was to be the base of support of the battery cells, placed diagonally. 
IMPORTANT: The width of the frame must be in accordance with the width of the batteries that we stay; in my case 6 cm. approx.
As batteries go diagonally, must form an angle at the bottom, where the profile will not: 

Holding one side of the base with a sergeant, drill and drilled, and then riveted
Practica 4 holes for extra-long rivets 4 x 20 mm.de way it securely:

We put the matter the other side, and prepare a square metal (stainless steel if possible) that has to be well resistant, as will be the fulcrum of the greater weight of the batteries:

The bracket (hardware) shortened and made presentation
Subsequently, I placed a folded profile against the square to secure it. I took the bottles holder hole to put a screw or rivet:

On the other hand a smaller place and serve to close the back cover fastening profile. I used a recycled an old window profile:

The drawer is taking shape; put another angle 15x15 mm. on the top tube, but only on the side as a basis, which will cover with a sheet of aluminum, 3 or 4 mm.

To prevent entry of water and we do not get wet in the rain too batteries, I placed strips of rubber adhesive before tying the lid on top:

Prepare a template for the cardboard back cover:

And moved the drawing to the plate I had available:

It was recovered from scrap, so with the orbital sander, I gave it a new color, cleaning of rust and marks:

The lid ready. Then we will cover the holes that we can not take advantage of silicone:

Holding it with a pair of clamps, drilled with an HSS drill and we rivet it.

IMPORTANT: We must at all costs avoid any short circuit of the battery with the surrounding metal, so I've pasted the entire basis of duct tape strips.
In the support base rubber gasket I place of 5 mm. Thick to cushion possible knocks and on the side.

After replacing the batteries to see what space is left on the top, and we mark the holes for the rivets, plus remove the insulation where you place the controller to take advantage of the back sheet aluminum heatsink temperature as:

I applied conductive paste on the flat back of the controller; at first I tested one of the Kelly (the house KBS48101X, 40A, 24-48V ), a mini Chinese controller € 100 for motors without brushes and very flexible multi programmable options (progressive regenerative braking, etc), and will very well, but for now I will not use because it does not work if it fails any of the hall sensors, however the BAC-028X for GoldenMotor that came with the works with or without sensors kit, plus it has control cruising speed:

I riveted the controller, but can also be screwed with long-tapping:

And so would the driver, the only gap left me free. I had a problem with it; the colors of the wires from the hall sensors did not fit and I had to keep trying until engine configurations worked quietly and with power (in the hall are PROKIT 901 to 120).

The cables are very long, to connect to the part of the bike you want, but I hindered me so I cut all to the extent required, only leaving a few inches to spare (if necessary re-connect with the welder).

Since I was only making the top, and I decided to use a sheet of 1 mm. a shelf, cutting it in the mold and placing hinges at the top, as did Jacopo To adjust better you sinned a small fold at the bottom with a rubber mallet, adapting it to the profile.:

After we marked and drilled the frame where the hinges match:


To paint it gray, it's best to sand the paint with a little first so that grip well: 

I have applied a more corrosion resistant than normal forging style gray paint, but it takes 5 times longer to dry completely:

And it only remains to place short self-tapping screws to access when you need:

Placing switches

To connect the battery to the controller and start the bike you need one that can support enough amps switch; I used one recycled rather large (15A 220V).
At the time of the connection there is a peak of large voltage (capacitors driver loaded), so you can jump a small spark that eventually deteriorates the switch contacts, so the more amperage stamina, better contacts will. To avoid this it is also possible to use a large resistor, which will "preloading" the capacitors to prevent the spark.

To avoid flicker can put a resistor, 10W and 1Kohm (or 2Kohm) discharges the battery a bit to keep the preloaded capacitors (essential in high power drivers as Kelly), extending the life of the switch and controller. Consumption is so small it takes to discharge the battery months, highly recommended:

To place the switch so a little tight, I first drilled with a big drill several holes where you will spend the mechanism, then finish with the dremel and a burr to round off the corners:

This is the aspect that has been:

And with the switch placed:

I have placed an additional half hidden switch to activate / deactivate the controller or throttle, so that in case of theft does not go "flying":

I have placed opening a hole in the rear profile:

And so we have:

And that's all for now! In the next posts of this tutorial we will see how it looks with the battery, configure the controller (both the Kelly as the BAC-028X), in addition to placing an LED powered by the battery, and the battery adapted for load balancing, ultimately make legal in Europe as far as possible (PAS weight limit and maximum speed).


  1. That is a pretty cool DIY, since bikes are quite popular right now. Using aluminum is definitely a great thing, as it is durable and very light. The procedures are not that easy, especially if one isn't used to those tools. But with this tutorial, it could be done by almost anyone. Anyway, thanks for sharing this post with us. All the best!

    Bernice Parsons @ Badgeranodising

  2. Wow, you did a pretty awesome job at it! It looks quite sturdy and reliable, which is a good thing when passing through rough roads. And the aluminum certainly adds to the much-needed protection for the cables and power supply. Anyway, thanks for sharing! Have a great day!

    Rosemary Bailey @ Wabi Iron & Steel Corp.