So, I have a 6V solar panel, however I need about 9V to charge two 18650 batteries in series (with a 2s charger circuit). Is it possible to put a boost converter in there or it would cause damage to the solar panel?
A solar panel is just a bunch of enormous diodes exposed to light, its going to survive!
You might need some capacitance on the solar panel output to keep the boost converter happy.
You are likely to have issues as the light fades and the converter keeps cutting out, then cutting in,
then cutting out - a larger capacitor might help with that too, not sure.
It would probably be a good idea to tell us more about your solar panel.
Do you have a link to the spec sheet for it? Do you know how much current it can provide in optimal light?
Also a link to your charger. What input voltage range can it accept? How much current does it draw?
Just be aware that you can't boost the power (wattage). Power is calculated as voltage X current so when you boost the voltage you reduce the current (or more current goes-into the boost converter than comes-out).
That's an awfully puny solar cell. After you boost it to 12V and accounting for inefficiencies in the converter, you would be lucky to get 25mA in full sunlight. I would be rather dubious that you would be able to charge the batteries.
Why not just start with a 12V panel with enough current capability to power your charger circuit?
SteveMann:
That's an awfully puny solar cell. After you boost it to 12V and accounting for inefficiencies in the converter, you would be lucky to get 25mA in full sunlight. I would be rather dubious that you would be able to charge the batteries.Why not just start with a 12V panel with enough current capability to power your charger circuit?
I have ordered a 12V 4.2W solar panel, but it doesn't seem to arrive in the coming days/weeks. That would be the ideal solution, but if it does not arrive I have to work with what I have right now.