I built this DC power pack for about $100. When power goes out where I live it can be out for a day or more. So I wanted a way to charge cell phones, tablets, laptops and provide light at night if needed. This is what I came up with. It has USB ports for phones and tablets and a cigarette port for my laptop or an inverter if you want to power a small AC load. I charge it over night about once every 3 months with a trickle charger to keep it topped off. I am looking for a 50 watt solar panel to charge it when the power may be out for days at a time.
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Step 1: Supplies
Gather your supplies. You will need the following.
NOCO HM318KS battery box I purchased from Walmart. https://www.walmart.com/ip/NOCO-Snap-Top-HM318BK-...
Car DC 12V power socket 3 hole panel this comes with 2 usb sockets, cigarette socket and a digital voltmeter. Amazon https://www.amazon.com/AOTOMIO-Voltmeter-Waterpro...
UB12350 sealed lead acid battery 35AH Walmart https://www.walmart.com/ip/New-12V-35Ah-AGM-Sealed-Lead-Acid-Battery-UB12350-Group-U1-Free-Shipping/168009742
1 1/8 drill bit
Inline fuse holder and 7.5 amp fuse. any fuse holder will do. I had one already
Battery tender or any trickle charger
Toggle switch I wired the usb and volt meter through the switch so they would not be a constant drain on the battery.
I purchased a Sunjack camp light 340 lumens to use with my power pack, but it is not needed.
I got the chance to use it due to an extended power outage. I powered my light and charged two phones over the course of about 18 hours. When I started using it it had 12.7 volts. When I finished using it it was still at 12.3 volts. That equates to about 30% of the charge used.
Step 2: Drilling the Holes
The 12V DC power socket comes with a cover I used this as a template for the hole locations. I used a 1 1/8 inch drill bit to make my holes and they are perfect. My friend used a 1 1/4 inch bit and his are a little loose but not to bad. Drill the three holes. Then drill a hole for the toggle switch.
Step 3: Installing the Panel and Switch
Install the toggle switch and the 12V DC panel in the battery box. They just use a nut on the back to hold them in place.
Step 4: Wiring
I wired two of the ground wires that came with the panel back straight to the battery. The third I wired to my toggle switch because it is lighted and needs a found to power the light. I then used a small jumper from the toggle switch to the voltmeter.
For power wires I ran the one for the cigarette socket straight to the battery. The ones for the USB socket (because it has a light on it) and the voltmeter I ran through the toggle switch so it would not drain the battery. From the toggle switch to the USB socket and the voltmeter I put in an inline fuse holder with a 7.5 amp fuse.
I also attacked a SAE ring adapter to the battery so I could charge it without having to take the top off.
Step 5: Secure the Battery
I did not do this at first. I decided it would be better to have the battery more secure after I tried moving it a few times. I took a small piece of plywood and cut it to fit the bottom of the battery box. I then screwed a strap to each side of the board and ran it over the top of the battery.