Power guide
Choose the right battery, inverter and lights.
Plain answers to the questions people ask in our showrooms, and a calculator to size your backup.
What do you want running in a power cut?
Suggested I-VOLT battery
How we worked this out
Battery size = load in watts × hours ÷ (system voltage × 0.85 for inverter losses × 0.8, so the battery is never drained flat). Inverter = load ÷ 0.8, plus 15% headroom, rounded up to a common size, and at least 900VA when a fridge is on the list, because a compressor draws several times its running power for a moment when it starts. Water pumps need more; ask us.
A starting point, not a quote. Show it at any ULTRA showroom and our team will confirm it.
Batteries
Choosing a battery
Start with what the battery is for. Each I-VOLT line is built for a different kind of work.
| You need power for | I-VOLT line | Sizes |
|---|---|---|
| Home or office backup with an inverter | Solar Tubular | 23–200Ah |
| A solar home system or solar inverter | Solar Tubular | 23–200Ah |
| A car, SUV or light commercial vehicle | Automotive Tubular | 65–110Ah |
| An electric rickshaw | E-Rickshaw Tubular | 185Ah |
What Ah means
Ah (amp-hours) is how much charge a battery holds. A 12V 150Ah battery stores about 1,800 watt-hours (12 × 150). After inverter losses, and without draining it flat, plan to use about two-thirds of that. So a 150Ah battery runs a 300W load for about four hours.
Tubular or flat plate
In a flat-plate battery the active material is pasted onto a grid, and a little of it sheds with every deep discharge. In a tubular battery it is packed into porous tubes around lead spines, so it stays in place. Tubular batteries handle long power cuts and daily solar charging better, which is why every I-VOLT battery is tubular.
12V, 24V or 48V
Small home inverters run on one 12V battery. Bigger inverters need two batteries (24V) or four (48V), wired in series. Batteries in one bank should be the same model and the same age.
Inverters
Choosing an inverter
The inverter turns battery power into the 230V your appliances use, and charges the battery when the grid is on. I-VOLT batteries work with standard home and solar inverters.
VA and watts
Inverters are rated in VA. As a rule, divide your total load in watts by 0.8 and leave some headroom. A 300W load needs at least 450VA; a 600VA inverter is the comfortable choice.
Pure sine wave
A pure sine wave inverter gives the same smooth power as the grid. Fans run quieter, and fridges, motors and electronics run cooler. It is the right choice for most homes.
Fridges, pumps and motors
Anything with a motor draws several times its running power for a moment when it starts. Size the inverter for that start-up surge, not only the running load.
Solar-ready inverters
A solar hybrid inverter charges your batteries from solar panels as well as from the grid. If you plan to add panels later, choose a solar-ready inverter now.
ULTRA showrooms stock home inverters, online UPS and solar hybrid inverters, and can match one to your I-VOLT battery.
Lighting
Choosing LED lights
Lumens, not watts
Watts tell you how much power a bulb uses. Lumens tell you how much light it gives. LEDs give far more light per watt than old bulbs, so compare lumens when you choose.
Warm white or cool daylight
Warm white (3000K) is soft and yellow, good for bedrooms and living rooms. Cool daylight (6500K) is crisp and bright, good for kitchens, study tables, shops and offices.
B22 or E27
B22 is the push-and-twist pin base. E27 is the screw base. Check your holder before you buy; I-VOLT makes both.
AC or 12V DC
AC bulbs run on mains power or through an inverter. 12V DC bulbs connect straight to a battery or solar home system with no inverter in between, so no power is lost converting it.
Street lights
I-VOLT street lights come in 50W and 100W, with or without a sensor that switches them on at dusk and off at dawn.
Care
Looking after your battery
- If your battery has top-up caps, check the level every month or two. Top up with distilled water only, up to the MAX line. Never use tap water or acid.
- Keep the terminals clean and tight. A thin layer of petroleum jelly stops corrosion.
- Give it air. Keep the battery in a dry, ventilated place, away from direct sun and open flames. Batteries give off gas while charging.
- Recharge soon after a long power cut. Leaving a battery flat for days shortens its life.
- Replace a bank together. Mixing old and new batteries, or different models, wears out the new ones faster.
Questions
Questions people ask
Will an I-VOLT battery work with my existing inverter?
In most cases, yes. I-VOLT Solar Tubular batteries are standard 12V lead-acid batteries. Check your inverter's battery voltage (12V, 24V or 48V) and its charging settings, or ask us.
How long will my backup last?
Use the calculator for an estimate. Real backup depends on the load, the battery's age and charge, and the temperature.
Where do I get help with warranty or service?
Call an ULTRA showroom or message us on WhatsApp +977 980-1006292 with your bill and the battery's details.
Do you sell outside Nepal?
We take export enquiries. Write to ggi@ultragroup.com.np with the models, quantities and destination.
