Home Inverter UPS and battery-Purchase guide, points to consider

We got inverter installed at our home recently. This post shares my experience and serves as a guide to select right model of UPS and Battery for your usage.

In this post following critical aspects of a home inverter purchase has been explained in easy steps:

1. Setting right expectations from home inverter investment
2. Calculating power needs
3. Selecting right UPS and battery - brand and specifications
4. Current Pricing & seller traps to avoid
5. Maintenance Tips

Step 0: Setting expectations right.

Inverter helps run some appliances in the event of a power cut. Inverter can't power your home non-stop. It has its limitations depending on which kind of appliances you run and how long. Typical objectives for domestic usage are

• We want to run ceiling fan whole night so that we can sleep peacefully
• Want to run a few lights in the evening for couple of hours
• Need to charge laptop for urgent work
• Need to run mixie for 5 mins

Set your expectations right. If you are expecting to use heavy duty appliances or expecting longer backup, you have to plan for additional batteries- more investment. Discuss with your family, get into consensus on how much backup you would need. 

Step 1: Rewiring home: You will have to consult an electrician to check readiness of your home for an inverter. Electricians can separate heavy load appliances like Refrigerator, AC, Geyser, Washing Machine etc into a separate line that doesn't draw power from inverter. This change ensures you don't accidentally drain inverter setup by running non critical heavy duty appliances when there's no live AC.  Electrician may charge 2-5k for his efforts, depending on materials used and effort involved.

If your house already has suitable wiring then this step can be avoided.

Step 2: Analyzing your usage/needs and deciding Inverter Specifications 

Inverter has two components: UPS and Battery.

2A: Power (UPS): UPS provides the power to run appliances and they are rated in VA (Power = Voltage * Amps). Cheapest of the UPS models have around 600-850 VA. Whereas generic guideline is to use more than 1 kilo watt (1000 VA or above) UPS for slightly better experience.

Combined load of all appliances you intend to run must be lesser than UPS's VA rating.

Typical Wattage of various appliances for reference.

#	Appliance	Typical Wattage	Remarks
1	Fans-ceiling, table	50 to 75 Watts
2	Tubelights	20 to 60 watts
3	LED/CFL Bulbs	5 to 30 watts	depending on rating
4	Mixer Grinder	550-750 watts	(Can be powered with domestic inverter but will drain battery fast, so emergency few mins usage possible)
5	Water Heater	2000 Watts+	(Can't power with domestic inverter)
6	TV	60-100 watts	Depends on size, CRT/LED etc
7	CCTV	100 Watts
8	AC	1000-2200 Watts	Depending on star rating, tonnage, regular/inverter etc, hard to power with domestic inverters
9	Laptops/Desktop etc	100-200 watts
10	Refrigerator	300-500 watts	Depends on size & star rating etc. Can be supported but avoided usually as cooling will sustain for couple of hours till power returns
11	Washing Machine	1000 Watts	Avoid

If you need back up for 3 fans, 5 lights, 1 laptop and 1 TV, you are looking at about 500 Watts. If this is all your requirements at 850 VA UPS is enough. But you might want to run few more lights and fans, charge mobiles, run mixie for some emergency cooking so total can come close to a kilo watt. So UPS above 1000 VA is usually recommended.

Your load determines UPS Specification. This tool is useful to calculate load.

https://www.luminousindia.com/load-calculator

2B: Backup (Battery): Batteries are rated in AH or Ampere Hours. Battery provides current and determines "How long" you can run above appliances. Depending on backup duration needed, battery rating and number of batteries will have to be decided.

Multiply load wattage (Ex: 500 watts) by number of hours of backup required- let us say 3 hours.

500 * 3 = 1500 Watt Hours. Your inverter will loose its efficiency over time, so you should factor 20-30% more for all practical purposes. So let us assume 1800 Watt Hours. Most inverter batteries are 12 volt batteries. 1800 Watt Hours = 1800 Volt * Amp Hours/12 Volts = 150 Amp Hours. This is the battery rating you should aim for.

At times calculations reveal that you may need much higher AH. Like if you are expecting 5 hour backup you may need 250 AH battery for above. In such cases you've to either invest in bigger capacity battery or two batteries of smaller capacity (like one 100 and one 150 AH battery) or reduce your expectation and decide to live with lesser wattage/backup duration. Dual battery setup should be avoided if possible- more expense, more space, more maintenance.

Step 3: Evaluating a brand for UPS and Battery

3A: Buying UPS: Microtek, V-Guard, Exide, Luminous are most popular UPS brands. UPS are available from 850 VA to 1200 VA (Microtek has 1700 VA also). 1000 VA+ is usually recommended unless your usage is very limited or if you're under severe cost crunch. 

Sine Wave vs Square wave: Pure Sine Wave inverters are more silent, safer but about 700-1000 INR more expensive than Square wave inverters. Square wave inverters make mild humming noise, little less safer but usually cheaper. Pay attention to this difference and prefer a Sine Wave Inverter.

Fancy features: V-Guard shows a battery water level low alert which looks cool but may give false positive most of the time and irritate you. Exide claims to have pure copper transformer. Some have LCD display, some inverters claim they can support AC also. 

It is hard to declare one brand as good and another brand as bad. You can decide based on following factors:

• How much you trust a brand
• Service availability in your area
• What does your trusted friends/electrician recommend
• Features that impress you
• Price and offers

3B: Battery: Exide, Powerpak, Luminous and V-Guard are popular inverter battery brands. These brands have dedicated websites to help you select right battery. You can compare specs, pricing, locate a dealer etc and better your understanding. Cheapest of inverter batteries start with 100 AH rating and costs about 7000 INR+ 150 AH battery is usually recommended to pair with 1KVA+ UPS. Even within 150 AH battery, there're options ranging from 10000 to 19000+ with different warranty, brand name, quality and from where you buy from. You will get these options only if you visit a dedicated battery shop and not a consumer durable shop (home appliance shops will only try to sell what they have). You've to decide the trade off.

Exidecare has a battery comparing tool- but works only on exide brands and that too within same category. I couldn't compare 150 AH Invatubular vs 180 AH Invatubular. https://www.exidecare.com/

Step 4: Avoiding selling traps

• Most consumer electronics shops try to push what they have. They will have two or three brands of UPS and battery options and will push you only those combinations. You have to do your research and decide on UPS and Battery brands and specifications that are best for you.
• Large consumer shops are often expensive compared to wholesale dealers. Do bit more research, identify exclusive dealers in your area. They might give a better deal and latest product. Large consumer durable shops inflate the price a bit because they have to pay lots of rent, staff salaries, freebies (like a stand) and give some offers.
• Online is risky. Because the batteries are heavy getting it shipped and dealing with after sales service, issues etc will be tricky. Best to deal with a local vendor who can come home and fix issues.
• Buyback offers: If you have an old battery, many sellers offer 1500-2000 Rs or more off depending on battery condition.
• Some minute difference between two options may not be explained to you voluntarily (like Exide has Long and Short models of same name, with about 2000 Rs price difference)

Below is current pricing for various Battery & UPS models (July 2020, near Udupi Karnataka). Use this for reference. Check prevailing price online or check with your local dealer for latest price and offers

#	UPS Brand	Model/Specs	Price	Source
1	Exide	1050 VA	5500	Exide dealer
2	ELCO	850 VA	7308	Harsha
3	Microtek	SEBZ 1200 VA	5400	Microtek site
4	Microtek	SEBZ 1100 VA	5200	Microtek site
5	Microtek	SEBZ 1000 VA	4700	Microtek site
6	V-Guard	1 KVA	5990	Harsha
7	Luminous	650 VA Eco Watt	3200	Amazon
8	Su-Kam (company doesn't exit now)	Falcon ECO 1 KVA	4200	Powerwale
9	Luminous	Zelio+ 1100 VA	5300	Amazon
10
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#	Battery Brand	Model/Specs	Price	Source
1	Exide	Invatubular 150 AH	17000	Exide dealer
2	Exide	Invamaster 150 AH (Long)	14500	Exide dealer
3	ELCO	180 AH	15565	Harsha
4	PowerPak	150 AH	12000+	Dealer
5	Luminous	150 AH	13500	Pai
6	V-Guard	VT160, 150 mAH VT165	15000 16150	Amazon, Harsha
7	Su-Kam	150 AH	15000+	Amazon
8	Amaron	150 AH	12500	Amazon
9	Exide	Invatubular 180 AH	22000	Exidecare
10	Exide	Invamaster 180 AH	20000	Exidecare
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Price can vary a bit depending on following factors

- Distance from big cities (transport cost)

- Warranty period and type (replacement & service)

- Any offer dealer may be giving (like free trolley)

- Shipping cost included/excluded

- Dealer margin

- Brand premium (a brand that spends a lot on TV ads will obviously have to charge more)

- Other tricks (some online sellers might sell a refurbished unit or old stock)

Stand or Trolley for your home inverter setup: You would need a table or stand to keep inverter and battery. Battery can be kept on ground but for cleaning, mobility etc a proper stand will be good. Larger showrooms with high margins on UPS+Battery offer free trolley (usually worth between 600-1000 INR) while online shops, wholesale dealers may not give a free trolley as their pricing is cut throat. If you have an existing table at home with suitable dimensions you can use them. Note that a 150 AH battery are super heavy (weighs about 40-50 KG+) so table/trolley should be strong enough to support it.

Custom made inverter trolley can old acid spillage and prevent it from spreading on the ground. Many will also have a 5th leg in the centre to support heavy weight of the battery. Trolley is also available purpose built- single battery, double battery, long tubular battery, small size 100 AH battery etc.

Step 5: Purchase and Installation of home inverter UPS and Battery

Before finalizing cross check the following

1. Your home electric wiring is ready for inverter installation.
2. You've made a fair and reasonable estimate of your usage and backup requirements, keeping in needs of next 3-5 years minimum
3. You're convinced that UPS and Battery spec you've shortlisted meets above requirement. 
4. You've selected a brand and seller that you trust and are convinced about after sales service, warranty. 

Go ahead and make your purchase. Sellers often include free delivery and installation.

Step 6: Regular maintenance

Battery needs distilled water top up once every 6 months. Have at least one person in home learn how to care for batteries. Set reminder to check level every 4 months and top up as necessary. This will save lots of trouble later- an unattended battery drains fast and will loose backup ability even if topped up later. Distilled water can be purchased at petrol pumps- about 80-100 INR for 5 litre can. Or you can collect rain water or use boiled water- but be sure to filter multiple times for impurities. Battery life will deteriorate if water with impurities get inside.

Remember to register your UPS/Battery with manufacturer- this way you will know instantly if it is used and not new. Also warranty claim will be simplified.

Avoiding overload and physical damage. Check periodically for any acid spill.

Expected life span: UPS has 2 years and Battery gets 3 year warranty typically. After that few more years if you are lucky- depending on load, power fluctuation and usage. So your home inverter investment will last 3-4 years max for sure. Beyond that, depending on your luck, power conditions, usage and maintenance and other factors. A few have used home inverter setup for 10 + years with minimum repairs. Over time UPS power efficiency drops, battery backup duration drops so at some point in time down the years you will be forced to replace UPS/Battery or both. Better technology, more powerful equipment in market, increased consumption demand (more appliances, longer power cuts etc) and your increased financial position in future also may trigger an upgrade. So you can't really future proof your home inverter investments- just be sure not to spend too less on substandard brands/inefficient systems. But no need to go over the budget thinking this will last 10-15 years. Spend reasonably.

My Experience: After scouting 3 consumer electronics showrooms, I finally decided to visit an Exide dealer and finalize. Dealer gave wholesale price, Exide as a brand appeared more trustable than other options, was promised good service. I settled for Exide 1050 VA UPS and Invatubular 150 AH battery, costing 22500 total. I had tough time deciding between Invamaster 150 vs Inva Tubular 150- the difference was 2500 rupees with an extra 6 month warranty, promise of better performance and durability. I decided to invest a bit more in Inatubular.

Disclaimer: Post is drafted based on research done and information collected for our home inverter installation in July 2020. I am not an electrician or expert in inverter. Prices and other factors may change over time, from city to city. Please use your discretion.

Also read: 15+ FAQs related to home inverter purchase are answered here

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