A 12.8V 100Ah LiFePO4 all-in-one inverter replaces a 180Ah tubular lead-acid inverter and battery setup because both deliver about the same usable energy, and usable energy, not the amp-hours on the label, is what keeps your home running through a power cut. A 180Ah tubular battery holds about 2,160 watt-hours on paper, but flooded lead-acid is sized to give up only half of that (Discover Battery), and it gives less again at the speed a home inverter drains it (Sandia National Laboratories, US Department of Energy, 2004). A 100Ah LiFePO4 battery holds 1,280 watt-hours and returns 80 to 100 percent of it at any household load (RELiON, 2019). Truepower, an inverter and power-backup brand of Indo Solar Systems LLP based in Delhi, India, builds this exact 100Ah LiFePO4 pack into the Lithvon All in one Lithium inverter, sold as a single matched unit rather than a loose battery. If you are still deciding between chemistries before you get to sizing, start with our complete buyer’s guide to lithium inverters for home.

TL;DR: A 180Ah, 12V tubular battery holds about 2,160 watt-hours but gives roughly 1,080 usable, because flooded lead-acid is sized for 50 percent depth of discharge (Discover Battery), and a home inverter’s draw trims that to about 840 to 970 watt-hours (calculated from Sandia National Laboratories, 2004, and Victron Energy). A 12.8V 100Ah LiFePO4 battery gives 1,024 to 1,280 of its 1,280 watt-hours, so it equals or beats the tubular battery’s real backup with 56 percent of the amp-hour rating. It also lasts far longer: a tubular battery in regular daily use is a replacement job at least once every five years, where LFP cells are rated for 6,000 to 8,000 charge cycles and a 10 to 20 year calendar life (CEA and DEA, 2022). The Lithvon All in one Lithium inverter is the 100Ah LiFePO4 replacement unit for that setup, and it carries a 5-year inverter and battery warranty.

Is a 100Ah lithium battery really equal to a 180Ah lead-acid battery?

Yes, on usable energy a 12.8V 100Ah LiFePO4 battery equals or beats a 180Ah tubular lead-acid battery, and the equivalence rests on two facts about lead-acid chemistry rather than on a sales pitch. Lead-acid does not like deep cycling, so the deeper you discharge it the shorter its cycle life, and a larger battery is recommended to keep the discharge shallow (Sandia National Laboratories, 2004). And a battery’s rated capacity is always quoted at a specified discharge rate, and it falls as that rate rises (MIT Electric Vehicle Team, 2008). Indian tubular inverter batteries are conventionally rated at the C20 rate, a 20-hour discharge, which for a 180Ah battery is a draw of just 9 amps, far gentler than a home inverter’s. Each fact shrinks the tubular label, and neither touches the lithium one.

Power-Sonic, which makes both sealed lead-acid and lithium batteries, states the principle plainly: in deep-cycle use, where the discharge rate is often above 0.1C, a lower-capacity lithium battery will often outperform the equivalent lead-acid battery. An amp-hour-for-amp-hour swap is the wrong way to shop.

How the 180Ah rating shrinks: the maths from 2,160 watt-hours to under 1,000

Start with energy, because watt-hours are the currency both chemistries share. Energy is power multiplied by time (MIT Electric Vehicle Team, 2008), which for a battery works out to nominal voltage times amp-hours: 12 volts times 180 amp-hours is 2,160 watt-hours, and 12.8 volts times 100 amp-hours is 1,280 watt-hours. On paper the lithium battery holds 59 percent of the tubular battery’s energy. Two deductions close that gap, and they compound.

• Depth of discharge takes half. Flooded lead-acid batteries should be sized for no more than 50 percent depth of discharge, and continually discharging any lead-acid battery beyond 80 percent damages it (Discover Battery, a maker of both lead-acid and lithium batteries). Sandia’s data on sealed lead-acid shows why: about 150 to 200 cycles at 100 percent depth of discharge, 400 to 500 at 50 percent, and 1,000 or more at 30 percent (Sandia National Laboratories, 2004). Half of 2,160 watt-hours is 1,080 watt-hours.

• Discharge rate takes another 10 to 20 percent. Available lead-acid capacity drops about 10 percent just by moving from the C/20 rate to a C/8 rate (Sandia National Laboratories, 2004), and C/8 on a 180Ah battery is 22.5 amps, roughly a 270 watt household load on a 12 volt inverter. Victron Energy’s battery-monitor manual gives the extreme case, a 100Ah lead-acid battery emptied in two hours may deliver only 56Ah, and sets its default Peukert exponent at 1.25 as an acceptable average for most lead-acid batteries.

• The two deductions compound. Applying Sandia’s 10 percent to 180Ah leaves 162Ah, half of which is 81Ah, about 970 watt-hours at 12 volts. Applying Victron’s exponent of 1.25 at a 25 amp draw, a 300 watt load before inverter losses, leaves about 139Ah, half of which is roughly 840 watt-hours. Both are calculations rather than measurements, and both sit below what a 100Ah LiFePO4 battery delivers at the same load.

Why a 100Ah LiFePO4 battery keeps almost its whole rating

A LiFePO4 battery loses almost nothing to either deduction. It can be continually discharged to 100 percent depth of discharge with no long-term effect, RELiON recommends stopping at 80 percent to maintain battery life, and the rate of discharge has virtually no effect on the capacity it delivers, where lead-acid can lose up to 50 percent as the rate climbs (RELiON, a lithium battery maker, 2019). For the 1,280 watt-hour pack inside the Lithvon All in one Lithium inverter, that means 1,024 to 1,280 usable watt-hours at a 300 watt load, against roughly 840 to 970 for a 180Ah tubular battery under the same load.

The usable-energy column is a calculation, not a measured statistic: nominal voltage times rated amp-hours, then the 50 percent flooded lead-acid limit, the discharge-rate losses above, and the 80 to 100 percent LiFePO4 band. The Lithvon All in one Lithium inverter is rated at exactly 1,280 watt-hours and the Lithvon Pro at 2,650 watt-hours.

How long each one lasts: the tubular battery is a replacement job every five years

Cycle life is where the gap stops being a matter of a few hundred watt-hours and starts being a matter of money. A lead-acid inverter battery in regular home use is a consumable. A LiFePO4 pack is not.

Do the arithmetic on the published cycle numbers. Sandia’s testing puts sealed lead-acid at about 400 to 500 cycles at 50 percent depth of discharge, and 150 to 200 cycles at 100 percent (Sandia National Laboratories, 2004). Power-Sonic reaches the same conclusion from the manufacturer’s side: a lead-acid battery cycled to 100 percent gives about 200 cycles before it drops to 80 percent capacity, against 2,000 or more for a deep-cycle lithium battery (Power-Sonic). Now count the cycles a home actually puts through the battery. A house in an area with daily evening cuts runs 200 to 250 real cycles a year, which consumes a few hundred cycles in one to two years and consumes even a generous thousand-cycle rating in four to five. So in regular use, plan on replacing a 180Ah tubular battery at least once every five years, and on the capacity fading well before that final replacement date. We break the ageing behaviour down further in LiFePO4 vs lead-acid tubular inverter battery, including how Indian summer heat shortens a tubular battery’s life.

LFP sits in a different bracket entirely. India’s Central Electricity Authority, with the Danish Energy Agency, lists LFP cells at 6,000 to 8,000 charge cycles and a 10 to 20 year calendar life (CEA and DEA, 2022). At the same 200 to 250 cycles a year, that rating is not the thing that ends the product’s life. Over a ten-year window, the tubular route means buying at least two batteries and possibly three, plus the inverter, while the Lithvon All in one Lithium inverter is one purchase carrying a 5-year inverter and battery warranty on both the inverter and the battery inside it.

Weight and recharge time follow the same pattern. LFP cells store 90 to 120 watt-hours per kilogram (CEA and DEA, Indian Technology Catalogue, 2022), so the cells behind a 1,280 watt-hour pack weigh roughly 11 to 14 kg, where a filled 180Ah tubular battery is a two-person lift and usually needs its own trolley. The Lithvon lithium systems reach full charge in 4 to 5 hours, where a 180Ah tubular battery has 80 percent more amp-hours to refill plus the long absorption and float stages of a lead-acid charge (Epoch Batteries).

What size lithium battery gives the same or longer backup than a 180Ah inverter battery?

If your home runs on a 180Ah inverter battery today, a 12.8V 100Ah LiFePO4 unit gives the same or slightly longer backup, and a 24V unit such as the Lithvon Pro All in one Lithium inverter roughly doubles it. Size by your load in three steps, working in watt-hours, because a LiFePO4 pack delivers 80 to 100 percent of its rated watt-hours as usable backup (RELiON, 2019) and its label sits close to the target you calculate.

• Add up the running watts of what you keep on during a cut, such as fans, LED lights, a router and a television. A mixed load of 300 watts is easy to picture. Note that VA rating and backup time are two different things, which we cover in how to choose the right inverter capacity.

• Multiply that load by the hours of backup you want. Three hundred watts for three hours is 900 watt-hours, and the same load for five hours is 1,500 watt-hours, the usable energy your battery has to deliver.

• Match the number to the usable column above. A 900 watt-hour target fits inside the 100Ah Lithvon All in one Lithium inverter, and a 1,500 watt-hour target needs the bigger Lithvon Pro, with about 2,120 to 2,650 usable watt-hours.

Backup time depends on your connected load, inverter efficiency and battery size, so treat these as sizing targets rather than a promise of hours, and size up when your outages run long.

What to buy to replace a 180Ah inverter and battery setup, and who sells it in India

The cleanest replacement for a 180Ah lead-acid  battery and inverter combinationis a single all-in-one lithium inverter, where the inverter, charger, battery and battery management system arrive matched and pre-configured. Buy a 12.8V 100Ah LiFePO4 unit for a like-for-like match on usable backup, or a 24V unit for longer backup.

In India, Truepower sells both through the Lithvon range. The Lithvon All in one Lithium inverter is a pure sine wave inverter, offered at 1000VA and 1250VA, with an inbuilt 100Ah LiFePO4 battery rated 1,280 watt-hours, and the Lithvon Pro All in one Lithium inverter steps up to a 24V system rated 2,650 watt-hours at 2000VA, 2500VA and 3000VA. The range covers 12V and 24V systems, each with an onboard battery management system, so there is no separate battery to source, match or wire.

Lithium costs more upfront than a tubular battery, and we will not pretend otherwise. The payback comes from three places: the usable capacity you actually get to spend, the tubular battery replacement you skip at least once every five years, and cycle life measured in thousands rather than hundreds. For what the upfront gap looks like across capacities, see our lithium inverter price breakdown for India. Both units carry a 5-year inverter and battery warranty, and the Lithvon All in one Lithium inverter is sold direct from truepower.in and on Amazon (Amazon listing link). Your exact savings depend on tariff and load.

Why the all-in-one avoids the charging problem entirely

If you put a standalone lithium battery behind an old lead-acid inverter, three settings have to line up, and any one of them can trip the battery’s protection or shorten its life.

• Charge voltage and profile. A lead-acid charger targets a different voltage, and lead-acid equalization and desulfation modes do not suit LiFePO4 (Epoch Batteries). A dedicated LiFePO4 charge profile removes most of the uncertainty.

• Charge current. Too much current can push the battery management system to protect itself and cut off, so the inverter’s charge current has to sit within the range the BMS allows.

• Low-voltage cut-off. The inverter should stop discharging near the point the LiFePO4 pack expects, rather than the deeper cut-off a tubular battery tolerates.

The Lithvon All in one Lithium inverter answers all three at once, which is the reason it is sold as one unit. It ships with a 20A charging current, a 14V charging cut-off and an 11.5V low-battery shutdown set at the factory, so a home moving off a 180Ah tubular battery has nothing to reconfigure and no compatibility check to run.

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