# Solar Charging Batteries on BlueROV2

**URL:** <https://discuss.bluerobotics.com/t/solar-charging-batteries-on-bluerov2/4879>\
**Category:** DIY ROVs\
**Created:** [April 19, 2019, 1:27am UTC](https://discuss.bluerobotics.com/t/solar-charging-batteries-on-bluerov2/4879 "2019-04-19T01:27:27Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Brent](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/brent/32/3952_2.png) [@Brent](https://discuss.bluerobotics.com/u/Brent)\
**Post date:** [April 19, 2019, 1:27am UTC](https://discuss.bluerobotics.com/t/solar-charging-batteries-on-bluerov2/4879/1 "2019-04-19T01:27:27Z")

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Covering a BlueROV2 with solar panels, to extend operational duration in sunlight, requires a power connector to charge up the batteries. There are earlier forums about the lack of battery protection from under charging (in February). Does one of its subsystems already include a battery charging connector that this project could use?

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**Author:** ![williangalvani](https://avatars.discourse-cdn.com/v4/letter/w/6f9a4e/32.png) [@williangalvani](https://discuss.bluerobotics.com/u/williangalvani)\
**Post date:** [April 19, 2019, 3:18pm UTC](https://discuss.bluerobotics.com/t/solar-charging-batteries-on-bluerov2/4879/2 "2019-04-19T15:18:02Z")

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Hello Brent,

Welcome to the Blue Robotics forums!

Do you plan to just leave it floating and charging?  
The Rov has an area of 457 mm x 338 mm = 0.154 m²  
Maximum sun radiance is 1120 W/ m²  
Maximum efficiency solar cell I could find is 22%.  
So covering the top of the ROV with these solar cells would output 0.154\*1120\*0.22 = 40 W  
In this best case scenario our battery would take 6h to charge.

If you want to increase autonomy and don’t want to deal with multiple batteries, maybe power over tether is a better solution.

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**Author:** ![Brent](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/brent/32/3952_2.png) [@Brent](https://discuss.bluerobotics.com/u/Brent)\
**Post date:** [April 19, 2019, 3:29pm UTC](https://discuss.bluerobotics.com/t/solar-charging-batteries-on-bluerov2/4879/3 "2019-04-19T15:29:58Z")

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William,

I appreciate that and this is just an experiment with some new solar cells that are conformal and a bit higher efficiency. My main question is whether I need to add a separate charging circuit or if that connection is already built in.

Regards,  
Brent

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**Author:** ![williangalvani](https://avatars.discourse-cdn.com/v4/letter/w/6f9a4e/32.png) [@williangalvani](https://discuss.bluerobotics.com/u/williangalvani)\
**Post date:** [April 19, 2019, 3:34pm UTC](https://discuss.bluerobotics.com/t/solar-charging-batteries-on-bluerov2/4879/4 "2019-04-19T15:34:59Z")

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Yes, you should add your own circuit to charge the battery. Currently we only monitor total voltage and an estimated charge state integrating the current passing through the power module.