Posted by & filed under Disaster Strategies, In-Home Preparations, Survival Mentality.

12v Battery Setup

Most people are unprepared for even short durations of power outages.  This is an easy and relatively inexpensive addition to your emergency preparedness kit.  A must have 12V (12 Volts) emergency power for several items that you may need to recharge/use if you are in a local power outage situation.  I describe local power outage as a couple of miles in any direction of your home and cell networks are probably still operational.  While this backup system will not power a home lighting or anything large scale, it can recharge lanterns, cell phones, and provide power for smaller objects.

In a local power outage, cell service should likely be functioning and nowadays, cell phones are a lifeline.  You don’t want to run your car or risk discharging your car battery to recharge 12V items.

The items for the backup 12V system for your emergency preparedness kit are the following:

  • 12V sockets (like the type you find in your car)
    photo 1
  • 12V deep cycle battery with threaded terminal ends photo 2
  • Volt meter or multi-meter, a means of recharging your battery
  • *for my example, I used a car battery charger from any auto parts store photo 5.  You can use solar, which is my preferred method in my emergency preparedness kit for numerous days without 3photo 4

Here is a step-by-step guide to assembling a backup 12V system together for your emergency preparedness kit.

Step 1:  Take your 12V sockets, which you can pickup in auto parts stores or good electronics store, need to have terminal ends crimped on the wire in order to connect to the battery.

photo 6

Match your size of the terminal ends to the battery studs.  Be careful as some battery manufacturers have 2 different size studs  so people do not accidentally swap the positive lead onto the negative terminal (reverse polarity), as you can burn your chargers out.

Step 2:  It is advisable to have red for positive, black for negative terminal ends, crimped to help identify it easily.  Positive on the 12V outlet is the CENTER pin or point, while the inside walls are the negative or ground on the on the outlet.


photo 7

You can confirm you have the correct leads by using a multi-meter.  This is  your finished 12V outlet or sockets..

photo 1

Step 3:  After confirming the leads/12V sockets are correct, connect it to the battery as shown in photo 2.  Check with a multi-meter from the center of the pin to the negative of the battery to confirm your polarity is correct.  Be careful not to touch the walls of the socket as it can be hot and burn your fingers!

Step 4:  If you are not sure if it is correct, my recommendation and easiest way is to connect a 12V fan to it.

photo 8

If it blows in the right direction, then you got it.  If it sucks backwards, then your leads are backwards.  Swap your leads and try the fan again.  Hook up your 12V phone charger and phone to watch it charge.

Now that you have a working 12V power source for your emergency preparedness kit, you run into two other issues.  You must monitor the voltage and must recharge the battery on occasion. 

Step 1:  Monitoring voltage can be accomplished with a multi-meter or a “stand alone” DC volt meter.

photo 3photo 4

Step 2:  If you use the volt meter, you will need to crimp on terminal ends the same as you did for the 12V sockets.  Remember – red positive and black negative!  Install it on the battery studs along with the 12V sockets.

photo 9

Step 3:  You should show a reading like this.

photo 10

Now a crash course on battery voltages –

  • 12.8v is at rest (no load) and roughly full.
  • 12.1-12.2 (no load) needs to be recharged.  You can go lower of course in emergencies, but it is not good for the endurance of the battery.

Charging the battery is the final component that needs to be addressed. 

Step 1:  We opted for the 110v battery charger.  If you live in sunny climates, I recommend getting a 30w 12V solar panel.

photo 5

Step 2:  Connect the red to positive, black to negative, plug in the unit and set it for 10 amps.  Watch the voltage rise.

photo 11

If you are using a NON smart charger, you will have to monitor the charging.

Step 3:  When the battery reaches 14.2v, set the charger for 2 amps to finish the charging process.  When the battery stabilizes (several hours) with the 2 amp charge at around 13.2v or more, you are pretty much done.  Disconnect the charging device from the outlet FIRST and then from the battery and watch the voltage hover around 12.8-12.9.

WARNING:  When charging batteries or under heavy loaded discharge, they produce a gas that is explosive and unhealthy.  Make sure the battery is in a well ventilated area, not near any ignition sources and that you are not breathing it in.

Avoid connecting or disconnecting anything when the voltage is in the high range, due to the fact you may make a spark.  Ten minutes after the charger is disconnected or when the batteries are idle or on a light load, (drawing less than 4 amps) the batteries still produce gas, but it is considered negligible for health and explosion hazard.  Nonetheless, you don’t want to be sleeping with the battery by your head.

The final product looks like this.

Do not keep the charger so close to the battery when 12


Some batteries require battery water occasionally.  Charge your battery once a month on the 2 amp setting for a couple of hours to make sure it is topped off.  Do not store the battery on concrete as it discharges the battery (insulating your battery with ½ inch or more of wood helps).  Also when charging, some battery acid may bubble out of the battery and damage floors.

One thing to consider when buying the battery, check the terminals orientation on your vehicle because if you purchase one that matches your vehicle, you will have a spare battery.  You can even swap your batteries and go on a 20+minute drive (the longer the better) to charge the battery you have been utilizing for power.

We utilize this system in our emergency preparedness kit and survival kit for charging flood light, cell phones, clip on 12V fan while sleeping, and lighting.  We usually go 3-4 days without recharging.  In fact, you can connect a 400w inverter to charge laptops/notebooks and any other load.  For approximately 150 dollars, the utility of this unit is wonderful because it is transportable and a necessity item for emergency preparedness kit.  Before a major storm hits your area, charge the battery to be prepared.

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