LiFePO4 to fit in Triangle Frame

[Dave Sloan]

Why do they not make 36v and 48v configurations to fit in the frame of the bike. On Ebay you see battery carriers for sale for SLA batteries but nothing advertised by the battery assembly places (mostly China) that advertise triangle configurations. Some have been doing it on the side for quite a while - see the cross Canada guy - Jason - he made himself one. I hear on quite a few forums about what an advantage this is for rear wheel drive - but nobody is pushing the assembly factories in China. I am sure that if they would put up for auction a triagle configuration that they would get a few bids. The BMS would be attached to the non frame side and they could team up with a nylon bag manufacturer and have a great product. Put Environmentally Friendly on the bag like they do with the Canadian Tire reusable bags and away we go.

 

[John in CR]

Because bike triangles are all different shapes and sizes.

 

[GreenKnight]

John's right.

A solution: Get a sheet of polystyrene larger than the triangle frame area.
Cut so it fits within the frame and is a smidgen thicker than the cells your going to use, (this might be one or two cell diameters depending on your total number of cells)
Use an epoxy resin (not polyester resin this dissolve foam) and fiberglass to get the stiffness you desire on the one flat side and edges.
Repeat process to make other side making area a fraction smaller so as to fit with in the first side.
Once cured, use stiff cardboard or ply to make selves in the small side and fiberglass/epoxy in too place.
Once shelves/battery supports in place and cured,
drill holes for wires and zip ties,
add batteries,
put both sides together,
use self tapping screws to secure sides together, making sure screws don't penetrate batteries(use a dollop of silicon rubber adhesive over screw to prevent it rattling loose),
paint as desired,
zip tie to bike frame.

 

[GreenKnight]

Missed a step out.
Prior to making the shelves/battery supports
1) dissolve the foam using a solvent acetone or petrol (use care and be thoughtful of where you dispose of the used solvent) or
2) Use a a hot wire foam cutter to cut your battery supports out of the foam. Note you'll need to be sure your batteries never get above 105-110 degrees Celcius (melting point for polystyrene)

 

[patrickza]

I used ABS plastic, really cool stuff to work with: http://endless-sphere.com/forums/viewtopic.php?f=3&t=10256