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# Feasability of a solar bike charger ? Answered

Hello,

I have an electric bike and I would like to mount a solar charger on the bike to extend its life while in use.

I have no experience with solar chargers. Is this possible ?

I'am afraid charging while in use might be a problem.
Though, the battery has 2 connectors, different for charging and using,
I'am also afraid the limited Amperage due to the power of the solar panel (max ~0.2 m²)

bike battery : Li-Ion 25.2VDC 10Ah
battery charger output : 29.4V 2A

Any ideas / recommendations are indeed welcome :)

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## Discussions

Problem is it is going to be very big.

25.2 * 10 = 252 watt hours for the battery capacity.

A solar panel about 1500mm x 1000 puts out about 250 watts - at 35 volts. Not cheap either.

I was thinking more in terms of the power of the wall outlet charger I have, since I'am going to use the same connector.

It outputs 29.4V * 2A ~= 60 Watt.

So why would I need a panel that outputs 250 W ?

Tell me if I'am wrong, but wouldn't charging at 250W / 29.4V = 8.5A burn the battery ?

Isn't it a requirement to keep the voltage steady at 29.4V and the current under 2A ?

I assumed your going to use some kind of charger - actually you have to or you will destroy the battery.

I was illustrating how much power the pnls produce,

Your 2 A charger will take nominally 5 hours to charge your 10 A.hr battery - If that's is satisfactory then a panel that provides a similiar output FROM A REGULATED CHARGING CIRCUIT will do the same.

You must NOT connect the pnl direct to the Lion battery.

depending on the input the charge expects - the wattage remains the same.

I'm afraid I'm lost. What solar power should I get and where should I connect these panels ?

I suspect you would need rather large panels to make any noticeable difference in your run time on the bike. The size of the panels may make it difficult to ride the bike as well as adding significant weight. Then you have to consider the cost of the whole thing.