Circuit for charging accumulators with solar panel

Other Hardware General Electronics
1

Hi

So I have 5W solar panel with an maximum output of 13.63V on its regulator and a 12V/7.2Ah gel accumulator. Is it possible to charge this accumulator up with this panel? If it is, is it possible to make a circuit that would have a maximum of 1V drop across the charger so that I would have at least this 12V to charge the accumulator up?

I have come across this and I was thinking is it possible to make such circuit with an LDO? Also, I would like to check the voltage level on accumulator with Arduino, how can I do that?

I am not the best at this so go easy on me.

Any help greatly appreciated!

2

I think you'll find the regulator might be already designed to do this. 13.8V is the nominal max charge voltage
for 12V lead-acid.

Perhaps if you posted details of the panel and regulator we could be more certain?

3

I asked it also somewhere else and yes, panel is made to charge those 12V baterries. I am now looking for a circuit that could let me do this. Anyone has a clue how to google this?

4

If by this, you mean adjust the operating point for maximum efficiency,
its not worth doing as your system is too small.

There was a discussion here about this a few months ago.

Search term for this is MPPT controller

5

Are you asking for an undervoltage shutdown for the battery to protect it from
over-discharge?

6

I am given PV with such parameters:

And it is directly wired to such regulator:

What I would like to achieve is that I could wire this PV, 12V battery and Arduino in one circuit. I know that I need LR between battery and Arduino to lower the voltage but what I would like to do aswell is that I could check the the battery level with Arduino so that I could warn the user if it is too low on power.

I am not sure if it is necessary to use MPPT once I have this regulator...?

EDIT: Drawing of the circuit. Is this valid?

7

check the the battery level with Arduino so that I could warn the user if it is too low on power.

Use a voltage divider to reduce the battery voltage to the range 0-5 V for input to the Arduino ADC.
Suitable resistor values would be 10K ohm and 4.7 K ohm, or 100K and 47K, for a ratio of 0.32 Voltage Divider

8

jremington:
Use a voltage divider to reduce the battery voltage to the range 0-5 V for input to the Arduino ADC.
Suitable resistor values would be 10K ohm and 4.7 K ohm, or 100K and 47K, for a ratio of 0.32 Voltage Divider

According to the calculator I would have 3.83V on the output if I use such resistors. Shouldn't I use resistors like 4.7k and 3.3k so I would have a maximum of 4.95V? Voltage input is 12V of course from battery.

9

Voltage input is 12V of course from battery.

Lead acid batteries often have over 14V across the terminals. Plan for even higher to protect the Arduino ADC input.

10

whoru:
I am not sure if it is necessary to use MPPT once I have this regulator...?

MPPT is only an advantage for larger systems.

Your unit is fine for charging a Lead acid accumulator without further modification.

You can run an arduino off a 12v scource PROVIDED its just the arduino and nothing added on.

The link you refer to , the op is asking about running a cooler.

If that is your intention then your system is woefully inadequate, coolers draw 30 watts upwards, and your battery will be lucky to last 2 hours.

What is your "bigger picture".

The circuit shown appears to be designed for variable voltage , perhaps for charging other batteries.