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How to Build Your Own Uninterruptible Power Supply

Last updated on: February 7th, 2020

An unexpected power blackout comes with many downsides. Critical systems including medical and computer equipment should remain running at all costs. With a UPS system, you can do just that. Such a system have your establishment running even after your regular power supply cuts off.

By following this guide, you will be on your way to an efficient yet scalable UPS system. As well, you will have the option to extend this system with either power generation, wind or solar.

A common type of UPS is that which is sold with computers. The system comprises a small inverter, a switch, and DC batteries. The DC batteries supply the computer power in times of a blackout and the inverter is responsible for converting the direct charge to AC charge.

Accordingly, there are steps to creating such an uninterruptible power supply that fulfills the needs of your entire household or enterprise.

As safety is always the first concern, the preliminary step should always be: TO READ AND ADHERE TO ALL WARNINGS.

This will ensure the final system is safe to use.

Step 1. Choose the Charger

You want a charger whose capacity will be enough to supply your battery with sufficient charge. It should also be able to sustain the load from the inverter. With this in mind, here are some guidelines to consider when shopping for the appropriate, heavy-duty charger.

  • Uninterruptible Power SupplyCheck solar power suppliers for “large” house inverters and chargers that cater to the entire house and great power needs
  • Check RV suppliers too. Here, look for ‘Converters’ that are used on larger sized RV’s if you are looking to create a big UPS.
  • Confirm that the charger you purchase can handle the type of batteries you purchase.
  • If the converter you purchase comes with an in-built converter, confirm that it can be isolated from the power input.

Step 2: Choose the Right Type of Battery: Deep-Cycle Batteries

A truck or car battery will not do here. If your intention is to use a single battery, then a battery that is maintenance free will be perfect. For larger systems, that comprise deep-cycle batteries, go for AGM or Wet Cells only. Be sure to check the following too;

  • The batteries have enough ventilation to release the hydrogen gas created.
  • For wet cells, ensure the battery is one that can maintain an equalized charge.
  • The arrangement of the batteries. For more voltage, you should arrange the batteries in series. If you are looking to raise the amp-hours, arrange the batteries in parallel.
  • Do not mix new batteries with old ones for they will wear out quickly.
  • Shallowly drained batteries (cycled) have a longer lifespan while deep-cycled batteries have shorter lifespans.

Step 3: Choosing the Inverter

Ensure that its rated value for a continuous charge is a significantly higher power supply than what you estimate your normal usage to be. Its ‘peak’ current should also be enough to provide motor starting loads which are typically 3 – 7 times higher than the indicated running wattage.

Inverters are available in input voltages as follows: 12V, 24V, 36V, 48V, and 96V. There are some other, less known voltages but be advised to go for the higher rated voltages. Such inverters are bound to perform the job better especially if your power needs are significantly large.

The 12V inverter is the most commonly used option. This will, however, not do for a system that handles a power output greater than 2400 watts. As such a current is too high, a higher rated inverter will better handle your power needs.

As well, the highest quality inverters come built with a greatly simplified, 3-stage system comprising a battery charger that’s automatic and a transfer relay. Though these inverters cost a little extra money, you will benefit from the great functionality they represent and make significantly more savings with time as they are greatly efficient.

Step 4: Purchase Quality Fuses and Cables for the Connections

Look for cables that are well made and of a very heavy gauge. The cables should, also, not be unnecessarily long to cut down on the cable resistance. Instead of having ‘wires everywhere’ consider spending some money on a bus bar. It will help you maintain a tidy environment and accidental shorts. Removal of defective batteries will also be an easier process.

Step 5: Observe all the Safety Guidelines set and Wear Protective Gear too

A lot can go wrong while setting up the system. It is for this reason that you should always exercise every safety precaution set. To this end, wear protective clothing as you set up the system and carry out maintenance. Two such protective gear to consider are:

  • Eye Glasses – For acid splashing onto your eyes is never a good thing.
  • Non-Conductive gloves – For electrocution is never fun.

Remember, also, to remove any jewelry you might have on you before you start working on your UPS.

Step 6: Make the Connections

As you make the connections, ensure you securely attach the cables to the battery. Note the polarity too.

Step 7: Prepare Your Charging System

Once you have made all the necessary connections and confirmed the polarities, plug the charger into the wall. Next, turn on the power and ensure a proper charge cycle begins. Confirm, also, that the inverter is turned off. This will let the battery accumulate charge without losing any current.

Step 8: Test the Inverter

You will be looking to confirm that the inverter is indeed separate from the charger. To do this, turn on the inverter and use an AC load to test it. You will know everything is working perfectly when you fail to detect any smoke, sparks or fire at any point. If all is well, proceed to charge the batteries and leave the inverter on overnight while supporting a load similar to that which the UPS will be supporting. If you find the battery fully charged come morning then the load and the charger are a suitable match.

Step 9: Design a Suitable and Tidy Enclosure

Most people choose either some shelves in the garage or shed while others prefer to use a very large container. With either option, the most important factor to consider is the arrangement. The most important consideration is; don’t place the charger and/or the inverter too close to the batteries. This is because the batteries will frequently release gases that can tamper with the electronics connected or ignite when close to sparking vents.

As a solution, you could install some partitions and provide adequate air circulation vents for both the inverter and charger. Another idea would be to mount the inverter and/or charger on a separate compartment and the battery on another box.

Step 10: Make the Final Connections

Longer cables increase resistance to current. Accordingly, ensure your cables are not exceedingly long. Access to the batteries should also be fairly easy as this will allow quick maintenance of the same. For wet cell batteries, such access will enable you to check and top up fluid levels easily too.

The inverter should also be grounded. To do this, you can connect a grounding rod that drives into the soil or use the charger’s AC input.

Step 11: Look for Alternatives Where You Can

Where possible, you can replace components of your UPS with other alternatives. For instance; a solar or wind option might be good enough a supplement in place of the charger. Either of these two options will, also, see you save more on your utility bill. However, be sure to confirm the suitability and compatibility of any supplements to your system. One wrong component will put the whole system at risk of failing.

I’m a seasoned Interior Designer whose innovation, keen eye for detail and creativity have all earned me the reputation as a reliable go-to professional. Over the course of a decade, I’ve garnered extensive industry experience, successfully designing hundreds of bathrooms along the way. Additionally, I hold an Interior Design Certificate from College of Architecture and Design in Newark, New Jersey. Outside of my profession, I have an avid interest in all things related to fitness and cryptocurrency. If you are looking for a competent expert who can help you renovate your living space, then feel free to contact me today.

1 Comment
  1. Great information. Our whole lives depend on power supply. We’ve established alternate options like generators and solar panels and its really helpful to keep power running for a few days in case of emergencies. Having alternatives is a must whether its for your home or for office.

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