Hi everyone,
This is a project I've been working on for some time. As a bit of background I got a job in an electric bike shop. I live in Australia where there is plenty of sun and I want to do long distance touring with my bike. So for this project I need to have the solar panels charging while the motor is running.
The electric motor runs at 36V which gets its juice from a controller, which in turn gets its juice from a lithium ion battery. This battery is charged at about 42V. My biggest concern is what circuits to use between the panels and the battery.
One issue I forsee is that charging the battery and discharging it at the same time might cause problems. Lithium Ion batteries require a specific charge cycle and if you deplete it while it is charging it may damage the battery. One way around this would be to get a second battery and charge/use them separately. Another option would be to bypass the battery when the motor is running.
The other issue is the best way to power from the panels to the battery. For this project I need to use light weight flexible panels which I can only find in 12V. The battery needs 42V but the battery charger runs on mains voltage. What I'm wondering is how I can get the voltage up high enough while retaining efficiency. Three options come to mind.
1. Use a step up circuit to boost the voltage to the 42V and feed it directly into the battery.
2. Use a different curcuit to raise the voltage to mains level and use the mains charger.
3. Run several panels in series to increase the voltage.
I'm very keen to see wha tother people would do to get this working.
This is a project I've been working on for some time. As a bit of background I got a job in an electric bike shop. I live in Australia where there is plenty of sun and I want to do long distance touring with my bike. So for this project I need to have the solar panels charging while the motor is running.
The electric motor runs at 36V which gets its juice from a controller, which in turn gets its juice from a lithium ion battery. This battery is charged at about 42V. My biggest concern is what circuits to use between the panels and the battery.
One issue I forsee is that charging the battery and discharging it at the same time might cause problems. Lithium Ion batteries require a specific charge cycle and if you deplete it while it is charging it may damage the battery. One way around this would be to get a second battery and charge/use them separately. Another option would be to bypass the battery when the motor is running.
The other issue is the best way to power from the panels to the battery. For this project I need to use light weight flexible panels which I can only find in 12V. The battery needs 42V but the battery charger runs on mains voltage. What I'm wondering is how I can get the voltage up high enough while retaining efficiency. Three options come to mind.
1. Use a step up circuit to boost the voltage to the 42V and feed it directly into the battery.
2. Use a different curcuit to raise the voltage to mains level and use the mains charger.
3. Run several panels in series to increase the voltage.
I'm very keen to see wha tother people would do to get this working.
.
