This was sent to me be an electrical engineering friend in Denmark. He had been asked to help a friend with her bike. He was concerned that batteries on bikes run down and appear not to work, so one buys a new one, and so on ad infinitum. He reckons this is a con and it is perfectly possible to revive the battery if you know what to do. Read on .........
If the battery on your electrical bike doesn’t work – here is a way to possible revive it.
Being an electronic engineer, I have just investigated a 10 Ah 29,4 V battery of the type GX-L024010-H3C. The battery had been discharged and could not be recharged with the original charger. It appeared that the charge current into the battery is controlled by a MOSFET transistor, which in turn is controlled by a micro processor, which in turn is supplied by the very same battery it is supposed to control. Hence, if the battery is discharged below a certain level the micro- processor cannot switch on the MOSFET transistor, hence the battery cannot be charged. The customer / the user will perceive it as if the battery is faulty and buy another battery!
You can save the battery by recharging it. Not knowing the schematic I took the battery pack apart and applied plus to the red wire going to the 10 A fuse holder and minus to the black wire connecting the battery and the printed circuit board. After having charged for an hour with a current of 250 mA the battery voltage had raised to approx. 20 V, and the original charger could function again. I used an adjustable bench power supply with a current limiter. The voltage was adjusted to 29,4V and the current to 250 mA.
If you don’t have access to a bench power supply a cheap 12 V charger for a car might do the job. To provide the current limiting a 25 W or 40 W / 230V incandescent lamp should be wired in series with the power supply.
You don’t have to dismantle the battery pack. You can electrically access the battery through the four terminal female plug at the end of the battery pack (two metal paper clips can slide into the two outer terminals of the plug). Doing so the charge current to the battery will be passing through the two MOSFET transistors, designed to drive the motor. To prevent excessive power dissipated in these MOSFET transistors during charging the charge current should be limited to 100 mA.
Watch out!! Plus and minus must not be interchanged!
Plus is the outmost terminal (nearest to the 10A fuse) in the four-terminal plug (connecting to the bike). Minus is the outmost terminal in the opposite side (the side where the red battery test switch is located).
Warning!!! Lithium batteries can be lethal! They can burn and they can explode. Hence, if you are in any doubt of what to do – leave it to others!
If the battery on your electrical bike doesn’t work – here is a way to possible revive it.
Being an electronic engineer, I have just investigated a 10 Ah 29,4 V battery of the type GX-L024010-H3C. The battery had been discharged and could not be recharged with the original charger. It appeared that the charge current into the battery is controlled by a MOSFET transistor, which in turn is controlled by a micro processor, which in turn is supplied by the very same battery it is supposed to control. Hence, if the battery is discharged below a certain level the micro- processor cannot switch on the MOSFET transistor, hence the battery cannot be charged. The customer / the user will perceive it as if the battery is faulty and buy another battery!
You can save the battery by recharging it. Not knowing the schematic I took the battery pack apart and applied plus to the red wire going to the 10 A fuse holder and minus to the black wire connecting the battery and the printed circuit board. After having charged for an hour with a current of 250 mA the battery voltage had raised to approx. 20 V, and the original charger could function again. I used an adjustable bench power supply with a current limiter. The voltage was adjusted to 29,4V and the current to 250 mA.
If you don’t have access to a bench power supply a cheap 12 V charger for a car might do the job. To provide the current limiting a 25 W or 40 W / 230V incandescent lamp should be wired in series with the power supply.
You don’t have to dismantle the battery pack. You can electrically access the battery through the four terminal female plug at the end of the battery pack (two metal paper clips can slide into the two outer terminals of the plug). Doing so the charge current to the battery will be passing through the two MOSFET transistors, designed to drive the motor. To prevent excessive power dissipated in these MOSFET transistors during charging the charge current should be limited to 100 mA.
Watch out!! Plus and minus must not be interchanged!
Plus is the outmost terminal (nearest to the 10A fuse) in the four-terminal plug (connecting to the bike). Minus is the outmost terminal in the opposite side (the side where the red battery test switch is located).
Warning!!! Lithium batteries can be lethal! They can burn and they can explode. Hence, if you are in any doubt of what to do – leave it to others!
