Electric Moped Update #1: New Battery Install

The first few modifications of the moped were aimed at getting it running again with as little work as possible. When I bought it both tires were flat, it wasn’t running, and I was missing the charger. It should just take a little air to get the tires fixed, they probably haven’t been inflated since it was assembled by Walmart. The Lead-acid battery in it is most likely dead and that’s probably why it’s not running but I’ll have to see if it just needs to be charged or if it’s completely dead and needs to be replaced.


I was pretty sure the battery that came with the moped had been ruined when I bought it so I was sure I was going to have to replace it somehow. I got the seat off when I got back to the dorm and checked the two batteries voltage. each 12v battery came out to 5v  (normally anything below 10.5v means the battery has been damaged) so the batteries definitely needed to be replaced. The moped is a 24v system. My electric bike runs off of a battery pack that puts two 24v batteries in series for a 48v supply voltage. If pop this on the moped and only run one of the 24v cells it should work perfectly and give me some extended range. The bike battery is pretty big so I ended up cutting a hole in the storage compartment of the moped to fit the battery in I then soldered on two xt90 connectors so I can connect the battery to the mopeds power system. the original plan was to try running 50v but when I tried it the smell of smoke filled the air and the motor started acting pretty crazy. But when I tried running 25v again it works fine without any sign of damage (odd….) so for now, I’ll just leave it at the slow 24v and I just put a loop key in the extra xt90 plug to act as a key for the moped. The battery also doesn’t fit perfectly so I use a rolled up t-shirt jammed between the battery and the frame to stop it from rattling around.


For now, both tires are flat so I need to see if I can inflate them or patch the tubes. looking closer at the wheels the valve stems are at a really steep angle almost like the tubes shifted after being ridden flat. I tried to shift the tube back in place but couldn’t get it to move without taking the tire off. Didn’t have a tire wrench so I ended up using a flat head to get the tire off (yeah I know a bad idea). The front tire was an easy takeoff but I’d punctured the tube trying to get it off. I didn’t have a patch at the time and really just wanted to get it going so I ended up cutting up a rubber glove and super gluing it over the hole (I’m writing this 5 weeks later and it’s still holding). The back tire was a lot more difficult. I had to dismantle the chain guard and chain tensioner and loosen the bolts holding it on to get it off. I didn’t have the right tools in my dorm room so I used a crescent wrench and it was an absolute pain to get the little bolts and nuts off with it. Once I had the wheel was off I tried to get the tire off but it was next to impossible. I ended up taking it home with me for spring break to get some help from my dad. finally, both of us managed to get the tire off. The tube was destroyed so I picked up a new one from Fred Meyer and popped it on. bolted the wheel back on when I got back from spring break and after reattaching the chain guard and tensioner she was all good to go.


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