Jonway Moped Battery Voltage Conundrum

dithian

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Joined
May 14, 2024
Messages
2
Location
Hawaii
Hi Everyone!

I have a 2011 Jonway electric moped with 48v 1500w hub motor. I bought it used, and a previous owner had modified it to accommodate a lithium battery setup. The batteries have now died (after several years of good use). I've run into some issues trying to get new batteries and I'm very confused by what I've pulled out of the machine so far.

The batteries I've taken out of the bike are 4x 20v 4.4 Ah lithium-ion (as per info printed on side) wired in series, assuming resulting in 80v. The paperwork that came with the bike says the charger I have is a nominal 48v charger. Inside the bike I found a 72v-12v DC to DC converter (assuming this is for the lights, etc.). The battery bank was going through a 48v 63amp DC breaker. I haven't found a 80v or 72v to 48v DC converter, but I also haven't stripped the bike.

Is it possible I was charging an 80v battery bank with a 48v charger? Or is it possible the batteries are mislabeled? Maybe they are actually 4x 12v batteries wired in series to create 48v? When I tested the charge of each battery individually, 2 of them read at 13.5v and 2 read at 9.3v.

So, the million dollar question is, what battery voltage should I buy? 48v? 72v? Flux capacitor? I'm inclined to go with 48v, but the bike was working really well with good power with the modified setup. Will I need to change the existing 72v-12v converter with a 48v-12v converter?

Can anyone help me decode what's going on here?

Bonus question: LiFePo4, or Lithium-ion?

Thank you!
 
4.4Ah is a too small for any practice use to be on an ebike. If I was to guess they were probably 2 in series and two in paralell for a 40V 8.8 ah pack but that doesn't work if you charger is in-fact for 48V. Do you have a photo of the batteries in question?

If you have the charger and it was working; try measuring the output voltage of it.

Check the motor controller to see if there are any voltage ratings on it. You can pop open the case and check the capacitors if you need to.
 
4.4Ah is a too small for any practice use to be on an ebike. If I was to guess they were probably 2 in series and two in paralell for a 40V 8.8 ah pack but that doesn't work if you charger is in-fact for 48V. Do you have a photo of the batteries in question?

If you have the charger and it was working; try measuring the output voltage of it.

Check the motor controller to see if there are any voltage ratings on it. You can pop open the case and check the capacitors if you need to.
Thanks for the reply! I'll pull apart the bike this weekend to look at the motor controller. Until then, here are photos of one of the batteries, as well as the DC-DC controller (presumably to reduce voltage for lights).

The batteries were definitely wired all in series. When fully charged, the bike could go approximately 24 miles (roughly one hour of ride time). I'm trying to figure out how to test the charger. I plugged it in and put multimeter leads into the plug, but it didn't give me a real reading. Maybe it needs a battery to draw the power and kick it on?

IMG_2054.jpegIMG_2055.jpeg
 
I plugged it in and put multimeter leads into the plug, but it didn't give me a real reading. Maybe it needs a battery to draw the power and kick it on?
Yes, some do require a load before it outputs full voltage. If the battery pack is dead; you can remove the shrink wrap and any other layers to see what kind of cells are inside. If they have specifications on them or have a model number that can be found; that will tell you what the actual configuration was.
 
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