Solar cell charging battery and load at the same time When there is Sun , When there is no sun , the battery take over and power up the Load

[HelpmeHelpme]

Hi 

Im currently doing a project using LabVIEW and myDAQ where i have to use the solar cell to charge the battery and turn on the load ( LED) when there is light

and once the the solar cell is unable to detect the light , the battery will power the load instead of the solar cell

i am having some problems with labview programing ( unable to work )

Does anyone has something similar that i could reference to ?

Thanks 

[PeterFoerster]

Hi HelpmeHelpme,

what exactly is your problem? Are you able to acquire data from the myDAQ? Does writing to the Output work? Do you get an error?

As a first guess I would say you are looking for something lika a case structure to decide wether or not to activate the LED.

[RTSLVU]

Most solar charge controllers have their battery and load connected in parallel with a simple transistor switch to turn the load off or on if desired.

So if the load is on it will be powered by the solar or battery or a little of both depending on how much solar power is available.

[_Bryan]

Good to see that you found the LabVIEW forum, but you have not added any more information than what you posted on the Reddit LabVIEW forum.  

The people here will also need more information about what is not working, be as specific as possible.  I will also repeat that you can replace the inputs with controls and the outputs to indicators so you have more control over the code to test it.  Then introduce the real IO when you have the code working like you want it to.

Spoiler

[HelpmeHelpme]

Just a qns  , my solar cell is connected to the input of myDAQ , i connect the output (line 7 ) to the relay but its unable to turn on the relay when i move the threshold (solar enegry lower limt) 

Should line 7 have the same voltage level as the solar cell ? when i use a multimeter to check it , it just shows a constant value od 2.1 + volt 

Thanks 

[Dennis_Knutson]

You should probably enlist the help of an electronic student for your project. There is a specification for output current for a digital line of only 4ma. Your relay coil certainly needs more than that and is pulling the voltage down. Add a current amplifier. You can buy a relay driver ic such as the ULN200x series.