3.7V 500mA Solar LiPo Battery Charger

Lynxmotion Electronics & Software
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I think I will be fine with a 6v 1w solar panel

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Hi @Leyland

Yes, you can use a 6V 1W solar panel

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Just to clear up things for @Leyland the OP - this “fact” has absolutely nothing to do with the question asked “What is the max amps input to the charger?”

That quote from the datasheet is the control chip’s operating current - meaning that the cost of controlling the charging is around 0.6 milli-amps of the maximum 500 milli-amps of charging current. Interesting and valuable, but has nothing to do with the question.

The answer to the OPs question is in this graphic:
35%20AM

In other words - pick a solar cell or bank of solar cells that output between 4.4 to 6 volts and produce a maximum of 500mA (0.5 Amp).

And for reference - a 6V 1W solar cell can be expected to deliver a maximum of 1W/6v = .167 Amps or 167mA (milli-amps) which is below the maximum allowed. It would appear that three of these cells in parallel can be utilized at peak sun conditions, and might even be necessary depending on the user’s requirements.

Designing a solar charging circuit is additionally complicated by how much sun can be expected on average, and how much power the system needs to operate for what periods.

@geraldinebc15, I apologize for butting into this thread.

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Hi @alanmcd, no need to apologize! You’re absolutely right, that is why I said this later on


I think I misunderstood your question, if you are asking for the charging current then that is the “BAT pin Current” on the datasheet, so Min: 400, Typ: 500, Max: 600 mA (milliamperes) @VBAT3.6V and Min: 25, Typ: 50, Max: 75 mA @VBAT2.4V

Anyways, thank you for clearing things out :grin:

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So I will need a minimum of 3 6v 1w solar panels which are also 60 x 100mm