What is wrong with my battery?


New member
Local time
5:14 AM
Jun 30, 2024
It is lead acid for Emmo urban, 48v 14ah. Power cut out totally for a second and then came back on - it did this a few times over the months. Then power suddenly diminished to almost zero and stayed that way so I could drive like 5 mph. So I bought new cells. New cells didn’t change anything. So I washed the rust off the wires connecting the batteries and put them back on, and the battery worked like new. Then power cut in and out again for a second here and there, cut out like zero power and bike turned off. And finally it didn’t come back on. And now battery won’t charge. I have tried replacing some of the wires but can’t replace all of them - because some of them I don’t know how to replace - for example the wire that goes from the fuse to the battery. Or the wire that goes from the inlet to the battery. I’m not even sure I’ve gotten the correct replacement wires. Awg seems correct but voltage is like 800 and I have no idea if that’s good or what the previous wires were. Also the circular metal connectors don’t fit correctly so I have used the old ones in combination with them. And the fuse might be blown? But the bike has been suddenly losing power for a split second for so long so why would the fuse be the problem? I don’t know, I am total noob. Is replacing all these wiring parts expensive? Are they the problem? Do you know what parts need to be replaced? Maybe I should contact Emmo. I don’t want to go to a shop. I’ve went there to one and they seemed too greedy. Too change the pricey. Maybe I should mention they changed the inlet plug because I touched it with pliers and arched it. That was before I got new cells.


  • IMG_6957.jpeg
    172.3 KB · Views: 8
  • IMG_6952.jpeg
    163.5 KB · Views: 6
  • IMG_6948.jpeg
    185.6 KB · Views: 7
  • IMG_6947.jpeg
    203.1 KB · Views: 7
  • IMG_6946.jpeg
    206.7 KB · Views: 7
  • IMG_6945.jpeg
    220.9 KB · Views: 9
The 800v rating on the wires is no problem. That just means the insulation is rated for up to 800v.
There are two more important things, AWG being the most important because that lets you know how much current the wire can handle without getting hot.
Secondly you want to consider how many strands there are in the wire. More smaller strands mean the wire is more flexible and you can bend it more often before it breaks.
You can get a replacement inline fuse holder at most hardware or auto parts stores.
If the battery drops off momentarily then comes back that means a connection is not solid. It could be the fuse holder or one of those cheap crimp on connectors you are using. They are famous for that.
If you are crimping them on with a cheap plier type squishing crimper throw that in the trash and go get a good ratcheting crimper.
I would also suggest taking it a step further and soldering those connectors as well as crimping them to eliminate any momentary disconnects.
You absolutely want to replace all wires where the insulation is worn or broken with copper wire showing.
If you can read battery voltage at the charger plug it should charge unless the charger is dead.
Ok great thanks. Here are the old and new wires. Both are 12 awg. Seemingly the replacement inlet fuse doesn’t need to be housed in the same way as the one in my current battery. Like I can just get a new one that sits inside the housing loosely. And the new inlet socket should be easy. My current inlet socket seems ok but the wires attached to it are messed, and I don’t know how to attach the wires to the socket so that’s why I’m thinking I’ll need a new inlet socket with the wires already attached. I’ll get new circle metal connector things. Is this new wire ok? If so I’ll go to Home Depot , ask for new inlet socket, ask for new fuse and fuse holder, new circle metal things, and that ought to fix it. The charger doesn’t charge it at all but I think the charger works and the problem is with the wiring. The charger light stays green. Maybe this will work from Amazon - The fuse here looks different shape than my fuse. Maybe I should check to see fuse is same amps or whatever the fuse measurements are. I’ve found the Emmo urban manual but couldn’t find the fuse amps. But found another Emmo model with higher voltage I think and that fuse in the manual said it was 30amps.


  • IMG_6972.jpeg
    166.8 KB · Views: 5
  • IMG_6969.jpeg
    134.4 KB · Views: 5
  • IMG_6973.jpeg
    183.6 KB · Views: 5
  • IMG_6974.png
    332.3 KB · Views: 4
Edit - I got in touch with Emmo and found out the amp of the fuse which is written on it - 20 amp, which makes this Amazon thing not workable. Emmo says they can replace all the housing , it is an hour away to pick it up . I’ve written back maybe they can mail it. It is nutty city driving in Toronto which is not fun.
Battery is fixed. Took it to shop. Paid 58 dollars. Seemingly, I’m a noob so who knows, they bypassed the fuse. So battery has no fuse now. But battery works and better than ever so far. New wiring seems to give it more power. I am very happy.