I think this might be the shortest build thread I ever do! The scooter is effectively done - all that's left to do is get it licensed.
Today I soldered the balance wires onto each half of the battery. 8 cells each, so I just used these 14-way Molex knock-offs which do a pretty good job.
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LiFePO4 cells are funny. They can look like they're all over the place, but as long as they're over 3.35 V at rest, they're probably full. It makes battery management a PITA because voltage is such a poor indicator of state of charge. Still, I know it's full because I balanced the pack with the trusty BC168 charger.
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The battery is assembled into the bike as two half packs. Front half first, then the back half. I have to tape them up using some fairly strong tape as they aren't locked into place at this state. Kapton was overkill, but it's strong.
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I drop the front half in and push it all the way to the front. I then cut the cable ties on the wiring which goes down the side of the scooter as it tends to get in the way when lowering the second half in.
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The second half won't drop in unless you undo the screws holding controller compartment. All of the fairing screws have to come out so that it can shuffle up about 25 mm. This is just enough room to fit the rear half-pack through the gap and gently dropped into place. The screwdriver is my top tip for this stage
- Top Tip for installation.jpg (152.18 KiB) Viewed 2955 times
Then after pushing it forwards about 10 mm and joining the two half packs, I go about attaching the main positive and negative leads to the final terminals. They're bent up a bit so they fit properly without fouling the cell top covers.
Re-cable tie the wiring down the side and plug it in for a top-up. So easy now!
- On charge.jpg (124.13 KiB) Viewed 2955 times
I have to find the other battery cover to put across the top, and install a top box for Katherine to stow her helmet. But that's it - how to turn a lead sled into a viable scooter in 2 days! We get about 70 km range on a charge, and that's at full throttle everywhere you go. I will eventually get a BMS installed for low voltage limits, but for now we keep a pretty close eye on the state of charge. We never go further than 60 km in a day anyway.
Best of luck with your E-max lithium prescription!
Chris
