Charge battery from solar panel and use it at the same time

Projects General Guidance
1

I use Arduino MEGA 2560 + a circuit of sensors.

I want to charge the battery from solar panel using this circuit:

Because I haven't done this before. Can I use the battery for supplying Arduino and the rest of the circuit, when at the same time I charge it?

The solar panels have output 12 Volt, 600 mA.

Shouldn't I make the Arduino+circuit use less than 600 mA in order to let the battery charging?
Otherwise when I use, for example, 800mA to the Arduino and the circuit, and at the same time the battery is being charged with 600mA it will never be charged. Am I correct?

(When I say "the rest of the circuit" I mean my circuit with the sensors that Arduino supports, not the circuit for charging the battery, obviously)

2

Can I use the battery for supplying Arduino and the rest of the circuit, when at the same time I charge it?

Yes. Your phone works while you are charging it, doesn't it?

The solar panels have output 12 Volt, 600 mA.

Rubbish. That MIGHT be the maximum output on a very sunny day.

Shouldn't I make the Arduino+circuit use less than 600 mA in order to let the battery charging?

You can't make it use less current. Or more current. The only way to control how much power it uses is to turn off things that it powers.

If the Arduino draws more current that the charger provides, the battery needs to supply the rest.

3

You seem to have started at the wrong end.

First you set up your arduino and sensors then you measure the current and find out how much you use in an hour.
Times by 24 hours and there is your current to run your arduino for a day.

Rule of thumb is allow for 3 days without sun and there is your battery capacity.

Remember if you do not want to damage your battery never discharge it below the recomended amount.
Eg. A deep cycle lead acid is around 60% discharge (Check the battery specs) so if you have a 10 Amp hour battery you should only use 6 amps before recharging.

For charging from a solar panel you should allow about 6 hours of full sun on a good day as your recharge so you would need one amp for 6 hours from the panel to recharge your battery.

Remember you will be working on 6 hours of sun to replace up to 72 hours (3 days) of use!

There is a lot more involved but that should get you started.

Daz

4

Daz1712:
Remember you will be working on 6 hours of sun to replace up to 72 hours (3 days) of use!

I'm used to calculating at 1:10: 1W of load requires 10W of solar panels for mostly continuous operation. Works quite well in my climate - higher latitudes may need more rated solar wattage per load wattage.

About half of the day there's sunlight, but less than half of that is at maximum strength (the hours around midday), and less than half of that is actual enough to get near rated power from the solar panels (clear sunny skies).

5

Im in Victoria, Australia so 6 hours works for me and i agree you dont get 12 watts from a 12 watt solar panel, unless you run a GOOD MPPT system.

Re the 1 for 10 watts i have read the same from quiet a few RV people.

Daz

6

Daz1712:
Im in Victoria, Australia so 6 hours works for me and i agree you dont get 12 watts from a 12 watt solar panel, unless you run a GOOD MPPT system.

Re the 1 for 10 watts i have read the same from quiet a few RV people.

Daz

So, this circuit will work when I have peak sun light, right? And if I have ambient sun light, not directed to the solar panel, what happens? For example when the solar panel provide me 10 Volt instead of 12 Volt?

https://www.electroschematics.com/4746/solar-charger-circuit/

7

And if I have ambient sun light, not directed to the solar panel, what happens?

The current supplied by the panel drops dramatically. Current is proportional to light intensity.

It would be a good idea to buy the panel, and use your multimeter to investigate the voltage and current produced under different lighting conditions.