the resin rocket

[oldskoolhead]

well i started out and added a 36v 1260w cyclone kit to my bike with a 24ah headway battery in an old flight case on my back rack.




as you will see in future pics despite being rated to carry 25kg the rack didnt fair up too well and i ended up replacing most of it with angle iron so it was time for a rethink and this is what i did





i created 2 polystyrene plugs these are the bases which measure 600mm long 200mm high and 50mm deep





i got some glass fiber cloth 300gsm and some epoxy laminating resin and a decorative black carbon and blue polyester cloth and wrapped my polystyrene plugs with i think it was 5 layers of 300gsm glass then wrapped them in the carbon/polyester cloth






i then added more resin layers and sanded/polished them up and then made my lids in a similar way with a 50x50x600mm with a 25mm piece on the bottom which i drew round my bases to create a lip to fit the bases i added 4 layers of glass to the top part excluding the 25mm lip then used some easy sand car body filler to level up to the 25mm lip then added another 4 layers of glass and then finally wrapped the lids in the carbon/polyester cloth then added more layers of resin, i had to do a bit of grinding to get them to fit properly but managed to get them to fit, i then drilled through each end and added an m5 rivnut so they could be bolted on.





i then got some u bolts which i had to modify and cut the threads longer added some shrink wrap and some 12mm aluminum tube to cover the threads and got some 30mm x 40mm car engine valve springs some locking nuts and some 30mm repair washers and made a bracket from 20mm box tube steel.





i then built a frame with 12mm box steel and some l brackets and some flat 2x20mm bar to mount my controller with some m4 rivnuts





then i drilled and fitted the bases to the frames using some m6 rivnuts





i drilled various 10mm holes and added grommets to link the 2 halves of the battery up and added a hole to put my charge lead through so i didnt have to keep opening and closing the lid and have rested the charge lead down the middle, i used some 8 core network cable for the bms link and shrink wrapped the bms and the connecting blocks i used for the bms links.





i put the lids on and have been for a test ride and its miles better without the heavy lump on the back lol





i was thinking maybe i could make a mold but they would be in 4 pieces then instead of 2 and make 2 u shaped box tube frames to join them and add some rubber trim to the edges of the lids to get a professional finish and maybe redesign the shocks to a mono shock design and use flat bar for the hangars to recoup some of the extra width this design would add to the battery cases making them 62mm deep, this would then enable packs of 8 a123 20ah prismatic cells to be fitted inside i think.

all i need now is a new bike rack lol and maybe a nuvinci hub lol

 

[Dauntless]

Looks great. Doesn't the width affect your pedaling?

You look like you have some solid composite knowledge. Or maybe you just follow instructions.

 

[oldskoolhead]

hi thanks, the extra width doesnt affect pedaling too much its a bit awkward when you are standing with both feet on the floor but not too bad, and yes my composites knowledge was learned off youtube and a bit of trial and error and guessing, the way to go is definitely making a mold and using resin infusion but this would add to the cost significantly and i didnt think it worth while to make a single item.
i was thinking of maybe re-designing the hangars using flat bar instead of box tube and using box tube to join the 2 halves of one produced from a mold which would put more of the overall width into battery space which could fit up to 48 a123 20ah cells and maybe selling them as a custom kit as they can be made in a whole host of different finishes and cloths from plain carbon to kevlar and you could even use denim lol
this would require some further investment in tools and materials but i think the results would be excellent and would also reduce the time to produce one as hand lamination takes ages as each layer requires a couple of hours cure time and getting the corners to stay down is a task in itself lol
it would also enable me to use the cheaper polyester resin if desired as i was using polystyrene plugs my only option was epoxy as polyester would melt the polystyrene but this is not the case if using a mold though epoxy is stronger and the better option anyway.
the great thing about this set up though is the incorporation of a spring system to carry the weight of the battery as it makes the bumps much less cringe worthy and the bike feels much better balanced with the weight distributed across the frame and centralized but again i could reduce the width using 2 single springs in the center instead of 2 on each side though im not sure how much width could be saved here due to the oversized bottom tube still needs to be cleared though it could be angled slightly

 

[Dauntless]

Good cheap aviation approved epoxy. Still more than polyester, but the tradeoffs might make it worth it.

http://www.aircraftspruce.com/catalog/cmpages/ezpoxy.php