A while back I took an old fluorescent lantern I had stuffed in a box of junk and converted it to a lithium battery powered lantern after removing the D battery clips that I installed in the unit not too long ago in order to resurrect the light since it was indeed over 35 years old. Now, I have another old item that has been defunct for a while due to the battery having long since died. This device is a simple power supply box. It started life off as a box with a couple of 6v lead acid batteries inside and two cigarette lighter/12v receptacles. One delivered a constant 12v at 15 amps max and the other jack delivered a variable 3/6/9/12v at 1 amp max, and included a plug that had multiple plugs for devices that would normally be plugged up to an AC adapter that came with said device.
This power supply box has had batteries replaced in it a couple of times already and after the 2nd time I never replaced the batteries but instead stuck the box in a corner in our junk room among other junk until I finally decided to do something with the box. After making the lantern using a simple lithium battery pack that was a fraction of the size of the 12v lead acid batteries of equivalent power output, I bought another of the same battery pack and commenced to remake the power supply with this newer battery. The first thing I had to do was open up the box to see what I was working with. The box comes with a circuit board that regulates the charging power for the old batteries as well as the regulator for the 3/6/9/12 socket on the unit. For all intents and purposes we won't be using this circuit board but at this time I won't remove it just in case I do decide to resurrect that multi-voltage part of the power supply. Instead I wanted to utilize the charging port on the box. Conveniently, the charging plug that came with the battery fits the socket on the power supply box. As a result, instead of trying to adapt the female plug on the battery to the box, I just cut that plug off and wired the box's charging port into the wire coming from the battery, allowing me to keep the flush original charging port of the power supply. With the battery wired into the box's charging port the next thing was to hook the power output cable to the two 12v sockets on the box. This was pretty simple as I just cut the male plug from the battery and using some male/female crimp terminals, wired the battery's wires into the wires coming from the 12v receptacles on the box. At this point the power supply will have two constant 12v outlets on board for powering multiple items/devices. With the battery fully wired up to the power supply box, the next thing was to hot glue the battery pack to the base inside the box so I can wrap things up. Since I want to be able to easily remove the battery pack if/when it dies for replacement, I didn't use a lot of glue, just enough to ensure that the pack was anchored in the cavity where the original lead acid batteries rested. With the battery pack glued in place the next thing I had to do was cut a little access port on the box to allow me to access the built in rocker switch that turns power on to the battery pack's output cable. This was as simple as using a rotary tool and cut off wheel to cut the plastic away to make it big enough to stick a finger inside to flip the switch when necessary. With the battery completely situated in the box, I was able to put the other half of the box back on, closing things up and securing with the screws I had available with the box. Plugging the charger up to the port on the box allowed for charging of the battery pack but because power is not going through the original charging circuit, there is no way to know that the battery is taking power other than the LED light on the rocker switch, which means looking at the switch under the box to confirm power is going into the battery. When the switch is turned out to allow power out from the battery to the sockets, a light on the LED display on the box will come on indicating the charge state since the 12v receptacles are still wired into the circuit board. Another little feature of this power supply is an area light built into the back of the box. This light is a simple incandescent lamp, showing just how old this unit is. I bought this unit back in the middle 90's well before LED lights became mainstream. Now, this light does work like its supposed to, but after being exposed to so many super bright LED lights, the weak incandescent lamp in this unit needs to be replaced. There are generic LED lamps that have adapters for different plugs in 12v/automotive applications that will literally blow this little weak bulb out of the water. I'll be upgrading to an LED lamp in this unit first thing. Another thing I may add to this unit to bring this thing up to date is a small power inverter unit to allow this power supply the ability to deliver limited 110vac power in the field from the small package. Also I have the ability to charge USB/5v devices is easy with a simple little plug in flush phone charger that I can plug into one of the 12v receptacles and just leave it there. Of course it would be even more unique to just get a 12v-5v circuit, or just install the right resistor on the 12v output line from the battery pack and hot glue a USB plug into a spot somewhere on the box to allow the box to keep its two 12v receptacles AND have a USB power port on board. A USB plug can be had from any adapter that has a female USB end on it, or salvaged from any old phone charger that went bad and I have plenty of resistors from my early electronics hobby days. A small inverter like the little units that plug directly to a 12v receptacle will probably yield a circuit board that is small enough to glue in place somewhere inside the box and the outlet glued in another suitable spot. Most of these items are small and low profile enough to allow for cramming into the small spaces of this power supply's casing. When I make those upgrades they will be posted here.
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