48v e-quadbike controller repair - Page 1
Forum section: electronics / repair

author: V_REDFOX
author_rank: Newbie
timestamp: June 14, 2025, 08:59:58 am
content: Greeting to all forum members, recently my neighbor asked me for help with his e-quadbike, The issue with the quad is that it does not charge (Tested with multiple chargers, and they are OK) As i opened the controller case the first thing that drove my eye was some shrink wrapped component, burned beyond recognition, one connection from it was soldered to pcb connection labeled SH together with the (+) wire from XLR charging port (checked for connectivity) the other end was connected to a wire leading to +P pcb connection and is connected to the battery (+) wire. Any ideas what this component might be?Additional info and the component in question in attached photos:Thanks in advance

author: voltsandjolts
author_rank: Unknown
timestamp: June 14, 2025, 10:59:13 am
content: Burned component looks like a diode.https://www.funsporthandel.de/ersatzteile/steuereinheit-1200-watt-48-volt-buerstenloser-elektro-motor-wygg12wf04-48_100799_6556

author: BILLPOD
author_rank: Frequent Contributor
timestamp: June 14, 2025, 02:30:08 pm
content: Good Morning V REDFOX, Welcome to the forum. You may get more answers if you post the make and model of E-bike and the charger. There are a lot of 48 volt chargers for sale on Amazon and other places, so maybe that is an alternate solution. Best of luck and keep us posted with your progress.

author: V_REDFOX
author_rank: Newbie
timestamp: June 14, 2025, 09:57:30 pm
content: Thanks for the reply, Forgot to mention, this one is the quad in questionhttps://www.high-per.com/midi-electric-renegade-1200w-atv-3ec-shaft-drive-product/and the controller is the exact model thatvoltsandjoltslinked to in his post.While browsing various e bike forums i stumbled upon a thread where one user mentioned that the SH connection is responsible for disabling the controller. Just a thought, could it be possible that the charger + is connected directly to the SH, and to the battery + via diode, when the charger is connected the battery will be charged through the diode and voltage will be applied to the SH connection (That would make sense because the vehicle should be disabled while charging) and when the charger is disconnected the diode will block voltage from SH connection

author: pcprogrammer
author_rank: Super Contributor
timestamp: June 15, 2025, 06:42:08 am
content: voltsandjolts thoughts on the component are my initial ones too. A diode, but this only makes sense if there is another connection from the battery + to the controller. There probably is, going on the size of the wire marked as battery + connection. It is to small to support the current for the motor.The diode as placed in your schematic allows the charging of the battery from the charger voltage as long as the voltage on the charge + wire is higher than the battery voltage. The presence of the charge voltage on SH (the controller) most likely disables the controller. The diode is there to prevent the battery voltage signaling the controller to disable it self after the charge voltage is disconnected.So yes, in that case it being a diode makes perfect sense. The question now is how high the maximum charge current is, as to find a suitable diode.

author: V_REDFOX
author_rank: Newbie
timestamp: June 15, 2025, 07:35:18 am
content: You are absolutely correct, my bad, i forgot to mention the wire from the component has connectivity to to the battery + but does not run to the battery directly, it runs to a PCB point labeled P+ and meets up with a cable multiple times thicker that is running directly to the battery connector plug, also this point is connected to massive solder traces running to what i assume are power transistors mounted on a heavy heatsink