More and more people are warming up to the idea of building their own power banks at their homes. These do-it-yourself ideas were first demonstrated by some folks who uploaded their attempts on YouTube. Granted, those that have been built are rudimentary and made out of laptop batteries, but it showed that it is possible to make a power bank out of spare batteries at home.
This article aims to impart instructions for building a battery bank for home, and who knows, further improvements could even rival the Tesla Powerwall. So gather up your materials and ready your tools, because we will be building an alternative power source for your home or business in case of main power outage.
What Materials Do You Need To Build a Battery Bank System?
I will list here the bare minimum of materials that will be needed in building your very own battery bank for home and business use. Of course, first you will need a sealed, deep cycle battery. Absorbed glass mat (AGM) batteries will work best for our purposes, although other battery types cannot be dismissed. Theoretically, one would be enough, but more batteries means more energy, and that is always a good thing.
Next thing, you will also need a power inverter that will convert DC to AC. To provide all the power for your batteries, you will also need a charger. A smart model that will be able to maintain a “trickle” charge is preferable, as this charger will know to stop when the battery is full. It will also be able to provide little bursts of charging should your batteries drop below capacity.
If you are going to be using more than one battery, you will need battery cables to connect them all. An assortment of cables will also be needed to connect the inverter to the whole system.
What Are The Steps Involved In Making The Reserve Power System?
First, find the right wattage for your power inverter. This choice largely depends on how much load your power bank will be receiving. Your inverter must always be able to provide more wattage than what you need. Because of this, it will be best of the wattage rating of your inverter is well above what you require for your purposes. There is no harm in inverter wattage overkill— the only bad thing is when your inverter cannot provide enough power for all the appliances and devices you will plug into your reserve power system.
For example, if the combined wattage that your phone and laptop charger requires is 100 watts, your inverter should be able to provide at least 150 watts. If you add a blended to this — which typically consumes 300 watts — then that would be 100 W plus 300 W or 400 watts. In this case, your inverter must be able to provide at least 500 watts. The general rule is that oversizing your inverter is never a bad thing.
Below i will list common applications and the wattage typically required to run them, in order of least demanding to greatest.
A List Of Common Devices And Applications, And Their Typical Wattage Requirement
● 20-inch television and VCR combo – 300 watts
● Blender – 500 watts
● Flood light – 500 watts
● Portable vacuum cleaners – 525 watts
● Small refrigerator, 1.7 cubic feet – 585 watts
● Coffee maker – 600 watts
● Reciprocating saw – 720 watts
● Submersible pump, 1/3 horsepower – 1000 watts
● Iron (for clothes) – 1000 watts
● Small microwave – 1000 watts
● Chest freezer – 1200 watts
● Hair dryer – 1300 watts
● Standard microwave oven – 1400 watts
● Electric circular saw – 1600 watts
● Electric chainsaw – 1700 watts
● Well water pump – 2400 watts
● Large household appliances – 2500 watts
Choose The Right Battery
There are many battery types created for different purposes, and you must find one that will suit your purposes. For a home battery bank, perhaps the best type to use is the Absorbed Glass Mat (AGM) battery that can be cycled deep. AGM deep cycle batteries fir the purposes of a reserve power systems for several reasons.
First, they can be cycled deeply. This is important, as this contributes to the long life of a battery type. If you use lead acid batteries like the one used in cars, those would easily deteriorate when cycled deep. It will be out of service earlier, unlike deep cycle types which can withstand charging and discharging way below 50 percent of their capacity.
What’s more, unlike flooded lead acid batteries, AGM does not require as much maintenance procedures. With flooded lead acid, you will need to check water levels regularly so that sulfation will not build up in the internal battery plates. However, the composition of AGM is sealed, and with this technology, frequent checking of water levels have become unnecessary (and actually a hassle).
Deep cycle AGM is recommended but if you have better ideas, then by all means, use them. Anyway, the more important part is if your battery can provide enough power for the amount of time you need it to. To find the right capacity, first check your required load. For example, let me say you need to power a TV and VCR combo for 5 hours. As we see in the list above, the TV/VCR combo needs 300 watts of power.
Now, multiply the wattage requirement by the number of hours and you get:
300 watts x 5 hours – 1500 watt-hours.
This is the amount of watt hours you need.
Now, do not rush ahead and but a battery that will provide 1500 watt-hours – remember that you need more than this value so that your battery will not be as deeply-cycled every time you use them. If you buy a 1,500 watt-hour battery for a system that requires the same value, then your battery will almost always be at zero percent charge when its job is done.
This is why you need your battery to provide at least double the watt-hours required. If you install a 3000 watt-hour battery for a system that requires 1,500, then at the end of the job your battery will still have about 50 percent of its capacity left— just enough for another recharge cycle.
What’s more, you will have allowance, an excess of spare energy in case of emergencies.
Find A Suitable Charger
As mentioned earlier, a smart charger is preferable for this system because these kinds of chargers will be able to detect the three different stages of charging.
First, there is bulk charging stage, where a constant amount of voltage is being pumped into the battery. Then, there will be the absorption stage, wherein the internal resistance increases and the voltage being provided to the battery decreases accordingly.
Finally, the float charge stage occurs when the battery is full. While idle, the charger will provide a “trickle” charge as needed when the battery drops in voltage. These are short bursts of energy that will keep the battery in full charge even when idle.
Smart chargers will keep your battery from being overcharged. They will also maintain a steady charge for your battery, as well, avoiding cases wherein the battery will be discharged even if it is not even actually in use.
Find Quality Cables
Find the positive and negative terminals of your battery, and connect your cables accordingly. Your ed cables will go into the positive terminals, and the black will connect into the negative ones.
You will need an assortment of wrenches and clamps for this, and do not forget to wear your gloves as well so as to nullify the risk of electrocution. Keep in mind that you should connect multiple batteries first, before connecting to the charger, inverter, and the rest of the stuff.
An Uninterrupted Power Supply System Will Go A Long Way
This step is optional, but if you have devices that require little energy like printers and servers, then you might want to invest in an uninterruptible power supply, or UPS. This has the advantage of keeping your device running even when the power runs out. All you need to do is order a UPS and you will get a black, heavy box with several outlets in the back.
Find one that says “battery” and plug the device that you want in there. In turn, plug the UPS to charge its built in battery. When power is cut off, the UPS will automatically switch to battery power to provide the energy required for the devices you plugged in its “battery socket”. Using a UPS will actually lessen the load on the reserve power system for your home that you just built, so it can provide spare power for other devices longer.
These are pretty much all the basics you need to know about how to build a battery bank for home or business use. You can always consult the manual on your battery for additional tips, and observe the performance of each component so that you can make informed judgments on how to improve your system.