12v Solar Circuit Question

Thread Starter

RamboCircuits2020

Joined Dec 2, 2020
5
Hi everyone newbie here with a question. I have a 12v solar panel, battery, fan and temperature sensor. Okay so I ran into the problem with the charging system were you cannot charge and discharge at the same time. Solution add another battery right ? Well problem with adding another battery I do not know how to switch between both batteries. Let me explain so if I have one battery charging by solar then I can use the charged battery to power the system. That’s my problem I do not know have to switch between both batteries to use one at a time. Anyone have any idea how how can make this work without having to go unplug the discharged battery and re-hook up the charged battery? Thanks again.
 

BobTPH

Joined Jun 5, 2013
2,721
You cannot charge and discharge at the same time because current can only flow in one direction, but you can have the charger connected to the battery and the battery connected to the load. There might be a problem with the battery back-feeding the panel, this can be overcome with a diode.

Bob
 

Thread Starter

RamboCircuits2020

Joined Dec 2, 2020
5
Thanks bob for you response like I said a noob at circuits, so what about having 2 batteries a&b and having some kind of switch too to disconnect and reconnect between a&b? Example of that would be if the solar is charging batt A then batt B is being used as the source of power and when gets to the point of needing to be charged then switches back to batt A. Is there a way to switch them as described above?
 

crutschow

Joined Mar 14, 2008
25,980
Is there a problem connecting the load to the battery while it is charging?
That's the usual way to connect such a system.
 

BobTPH

Joined Jun 5, 2013
2,721
Let's go back to square one. What is the problem you are seeing when you try to have both the load and the charger connected?

Bob
 

BobaMosfet

Joined Jul 1, 2009
1,290
Hi everyone newbie here with a question. I have a 12v solar panel, battery, fan and temperature sensor. Okay so I ran into the problem with the charging system were you cannot charge and discharge at the same time. Solution add another battery right ? Well problem with adding another battery I do not know how to switch between both batteries. Let me explain so if I have one battery charging by solar then I can use the charged battery to power the system. That’s my problem I do not know have to switch between both batteries to use one at a time. Anyone have any idea how how can make this work without having to go unplug the discharged battery and re-hook up the charged battery? Thanks again.
Title: Understanding Basic Electronics, 1st Ed.
Publisher: The American Radio Relay League
ISBN: 0-87259-398-3
 

Thread Starter

RamboCircuits2020

Joined Dec 2, 2020
5
Brief run down on my circuit. 12v 10w solar panel - 12v 3000mah battery with on/off switch - 12v thermostat - pwm solar charger - 120mm fan.



Okay so let’s take a box for example an we put it outside In the sun. Once the sun has raised the inside temp to 90oF the fan needs to come on and cool it off too 85oF. Now all my components are inside the box so I have to keep them cool too. Okay once everything is connected I noticed on my PWM charger after hooking everything up my power light was on but not my charge light. Turn the power switch off on the battery and charge light came on. Is the battery charging when everything is connected ? Not sure. So that’s my road block charging and using power to control my temp sensor.
 

Attachments

Top