Power source (battery and power source)


need help !

my project is to use that Low Loss PWRpath module to load a battery and run a load

It is mention in the specs that the PWRpath module need at least 13,8 Volts to load efficiently a battery.

I plan to use an computer ATX to be connected to the PWRpath in term of power supply.

Do you think i can use wire like this :

ATX -12V (blue wire) to be connected to the GND on the PWRPath power supply connectors (black)

ATX +12V (yellow wire) to be connected to the Power on the PWRPath power supply connectors (red)

Thus , i should have -12V ==> +12V , i should have 24V of power on the PWRPath ??

Please confirm


A simple schematic would help. It appears you want to charge a 12V battery with a 12V source, or you are placing two power supplies (+12 & -12)in series generating 24VDC. Sounds great but it will not work. To charge a battery you need to push current into it. To do that your voltage has to be higher than the terminal voltage of the battery. 13.8V is the voltage typically used for a lead acid or SLA battery. Check the battery specification to be sure. Applying 24V as you are suggesting will cause some nasty smelling smoke if left connected. You need to regulate the current to protect both the battery and power supply. You can get a buck or buck/boost module from your favorite china supplier that will do the job for a few bucks. The boost or sepic converters will allow you to do your thing with 12V. You also have a potential back feed problem via the mains ground.

Thanks maybe the better choice is to buy this card ?

Here is my schematic:

As you can see i want to detect (through the power good wire) if the main power is cut off
I want my arduino to be able to move from main power to battery power without disruption

What kind of device can i put for the "Battery charger" ?


To charge a 12V lead acid battery one needs 13.8V and to charge a 12V LiFePo4 ones needs between 13.8 and 14.8 volts. To start with you need a 13.8V supply.

For a lead acid battery if the volts across the battery is 13.8, wire the battery across the 13.8V line and let the battery act as a capacitor, until power loss.

For Li batteries you'll want a BMS, most have built in BMS, and a LiFePo4 charger. With the LiFePo4 and a charger, wired the battery to the output of the charger and use the 12V battery as a capacitor, until the power goes out.

Which battery are you going to use?

for the battery i don't know but if i purchase that card

it is mention lead acid battery

You will be using a solar cell to charge the battery?

As a note the 12V power supply will NOT charge a 12V battery.

i plan to use an adapter 220V / 14V

Are you using a solar cell?

No solar cell , but a plug adapter

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That card will work. There are inexpensive versions at your favorite china supplier. This is the one I use. DC 400W 15A Step up Boost Converter Constant Current Power Supply LED Driver 8.5 50V to 10 60V Voltage Charger Step Up Module|Integrated Circuits| - AliExpress It is less then $5.00. Look for SEPIC or step up charger module, you will find lots of them. These work because they actually boost the input voltage to whatever it needs to supply the output voltage you set it for. There are two trim pots, one sets the voltage (about 13.8 [your battery data sheet will tell you} and the other sets the current. It will then supply a constant current to the battery until it reaches the voltage you set then simply maintain the voltage.