D
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I've spotted a number of posts around the web about these entry level e-bikes that have been left over winter or other long periods of disuse without charging the batteries. The batteries are described as 'dead'. They won't charge and they won't run the bike. The posters often lament that Halfords simply shrug and offer them a new battery for about £300.
The other day, my partner bought a bike that had a 'dead' battery. The bike was little used - immaculate really, and had been left unused and uncharged for over a year. The seller told us she could not charge the battery, and that the charger light just stayed green. We knew there was a risk we would need to spend a significant amount on a new battery, but after some investigation on line, I saw a technique described as 'jump starting' the dead battery by briefly and cautiously charging it through its output or motor port. It would probably better be described as 'jumps starting the BMS', but more of that later.
We got the bike and battery home and I took some voltage measurements. There was 0 volts on the charging port pins and about one volt on the motor or output port. I concluded that the BMS was shut down and that the battery cells were probably very very low, possibly with completely dead cells. Since the BMS can cut off the charging and output port, these readings are not necessarily those of the actual cells, but they were very low indeed. I did not have much hope for the battery.
I double checked the output port polarity and connected appropriately coloured wires to the contacts and connected a non Pendleton 36v Lithium charger to the wires - double checking polarity and watching carefully for any adverse reaction. I used a different charger because it was easier to connect it to the wires I was using, than it would have been with the din plug output on the Pendleton one. The connection was in parallel to my multi meter set on DC voltage measurement. At first the non Pendleton charger light stayed green, but the voltage measurement slowly raised to about 20volts and then the red light came on on the charger. Over couple of minutes the now charging battery voltage rose to about 30 volts, and I then disconnected the charger from the output port and inserted the correct charger in the correct port, and it switched on and began charging.
We kept the charging battery under supervision and over five hours or so, it charged normally and cut off at 41.8 volts. I left the voltmeter connected and went to bed. Next morning, the voltage remained at 41.6 volts, and on reinstalling the battery on the bike, it performed flawlessly with strong power in the high assistance settings, pushing the bike up steep hills with considerable pep. My partner and I then went for a sixteen mile ride on our bikes and the Pendleton was great. All the battery lights were still lit at the end of the ride, but after an hour for cooling down, I re-charged it and after two hours the charger cut off and the bike is ready for its next adventure.
I wonder how many perfectly good Pendleton batteries are lying in land fill right now. Halfords could probably easily recover most of them, but perhaps that would not suit their bottom line quite as much as shaking their heads, shrugging their shoulders and offering the customer a £300 replacement. Given that Lithium and cobalt used in these batteries are rather scarce elements, it's a heck of a waste.
If you are not used to electrical work, DO take care if you use this method. You must not create short circuits on the output port and you MUST NOT try to fully charge a battery on this port. The battery would be completely unprotected from over charging and there might be a risk of damage and fire if a charger was left connected to this port. The method is purely to kick the BMS back into life. As soon as the voltage has raised so it can charge on the correct port, use the correct port.
The other day, my partner bought a bike that had a 'dead' battery. The bike was little used - immaculate really, and had been left unused and uncharged for over a year. The seller told us she could not charge the battery, and that the charger light just stayed green. We knew there was a risk we would need to spend a significant amount on a new battery, but after some investigation on line, I saw a technique described as 'jump starting' the dead battery by briefly and cautiously charging it through its output or motor port. It would probably better be described as 'jumps starting the BMS', but more of that later.
We got the bike and battery home and I took some voltage measurements. There was 0 volts on the charging port pins and about one volt on the motor or output port. I concluded that the BMS was shut down and that the battery cells were probably very very low, possibly with completely dead cells. Since the BMS can cut off the charging and output port, these readings are not necessarily those of the actual cells, but they were very low indeed. I did not have much hope for the battery.
I double checked the output port polarity and connected appropriately coloured wires to the contacts and connected a non Pendleton 36v Lithium charger to the wires - double checking polarity and watching carefully for any adverse reaction. I used a different charger because it was easier to connect it to the wires I was using, than it would have been with the din plug output on the Pendleton one. The connection was in parallel to my multi meter set on DC voltage measurement. At first the non Pendleton charger light stayed green, but the voltage measurement slowly raised to about 20volts and then the red light came on on the charger. Over couple of minutes the now charging battery voltage rose to about 30 volts, and I then disconnected the charger from the output port and inserted the correct charger in the correct port, and it switched on and began charging.
We kept the charging battery under supervision and over five hours or so, it charged normally and cut off at 41.8 volts. I left the voltmeter connected and went to bed. Next morning, the voltage remained at 41.6 volts, and on reinstalling the battery on the bike, it performed flawlessly with strong power in the high assistance settings, pushing the bike up steep hills with considerable pep. My partner and I then went for a sixteen mile ride on our bikes and the Pendleton was great. All the battery lights were still lit at the end of the ride, but after an hour for cooling down, I re-charged it and after two hours the charger cut off and the bike is ready for its next adventure.
I wonder how many perfectly good Pendleton batteries are lying in land fill right now. Halfords could probably easily recover most of them, but perhaps that would not suit their bottom line quite as much as shaking their heads, shrugging their shoulders and offering the customer a £300 replacement. Given that Lithium and cobalt used in these batteries are rather scarce elements, it's a heck of a waste.
If you are not used to electrical work, DO take care if you use this method. You must not create short circuits on the output port and you MUST NOT try to fully charge a battery on this port. The battery would be completely unprotected from over charging and there might be a risk of damage and fire if a charger was left connected to this port. The method is purely to kick the BMS back into life. As soon as the voltage has raised so it can charge on the correct port, use the correct port.
