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solar panel battery charge

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Alehandro

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Hi, I'm making a solar project and I have a 7.5V solar panel (250mA & 1.9w) and a 6V battery (4.5Ah) .. Is it possible to charge the battery with this panel and have a protection cut-off circuit? I searched and the only circuit that I found thats close is this one but its a 12v solar panel charging a 6V battery 4.5Ah.**broken link removed**.. If I make the same circuit and change the LM317 and the resisters will it work or will I not have enough volts to charge my 6V battery?? If not is there a way not to loose the volts at the output? thank you..
 
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With 2 diodes and a regulator, you will not get 6V on the battery from 7.5V panel. The panel may be able to rise voltage to 8V, but then it'll lose a lot of power.
 
So the solution is to put only one diode and directly charge the battery or to put lets say a 2V panel in series with my 7.5V solar panel??
 
With 2 diodes and a regulator, you will not get 6V on the battery from 7.5V panel. The panel may be able to rise voltage to 8V, but then it'll lose a lot of power.
So the solution is to put only one diode and directly charge the battery or to put lets say a 2V panel in series with my 7.5V solar panel??
 
So the solution is to put only one diode and directly charge the battery or to put lets say a 2V panel in series with my 7.5V solar panel??

You can try to design something with low voltage drop. Big mosfet for control, mechanical relay or manual switch for the night time.

If you put two panels in series they must be rated for the same current, because the panel with the least current will bring down the combined current to its level.

What kind of battery do you have?
 
You can try to design something with low voltage drop. Big mosfet for control, mechanical relay or manual switch for the night time.

If you put two panels in series they must be rated for the same current, because the panel with the least current will bring down the combined current to its level.

What kind of battery do you have?
The battery I have is like this one https://www.indiamart.com/suvidha-electronics/smf-battery.html .. My project wont work at night time.. I'm just making a solar tracker which will charge the baterry for the cloudy days..
 
The battery I have is like this one https://www.indiamart.com/suvidha-electronics/smf-battery.html .. My project wont work at night time.. I'm just making a solar tracker which will charge the baterry for the cloudy days..

With flooded battery, you could simply connect it directly to the battery through a diode. The worst think that could've happen is some loss of electrolyte that is easily replenished. With sealed battery it's not a good idea to expose it to long periods of elevated voltage. So, you probably do need some sort of controller to limit voltage and to disconnect when it's fully charged. But you can make a really simple one. A mosfet which you turn on when battery voltage gets higher than your set point and off otherwise will work fine.
 
A mosfet which you turn on when battery voltage gets higher than your set point and off otherwise will work fine.
.... provided it's a 'logic-level' type, to ensure it can be turned on fully by a Vgs of 6V.
 
Oh what do you mean by saying "logic level" type?
Many FETs require a Vgs of around 10V to turn them on fully. Logic-level ones need only 5V or less.
 
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