How many years does a home solar battery last?

By type: lithium LFP typically ~8–15 years (thousands of cycles), lead-acid ~1.5–3 years, gel/AGM ~3–5 years. The big variables are how deeply you discharge (DoD), temperature and cycles per day. Budget for replacement on this horizon — don't look only at the purchase price; go by the model's warranty for real figures.

I have on-grid solar — can I use panel power during an outage?

Not with pure on-grid — when the grid drops, the inverter shuts itself off under the anti-islanding standard for safety, so the panels stop even in full sun. To have power during an outage you must move to a hybrid system with a battery that supports islanding. See the system differences on on/off/hybrid.

Is a 5 kWh battery enough for the whole house?

Depends what it feeds. A 5 kWh battery (~3.8 kWh usable) covers "critical loads" — lights, fridge, fan, Wi-Fi — for many hours or overnight, but air-con and water heaters drain it fast (a ~1,500 W air-con running flat-out empties it in ~2–3 h). Plan a backup circuit for essentials only, and use the hours table above.

Can I use a car or golf-cart battery with solar?

A car starter battery (SLI) is unsuitable — it is built for a short high-current burst at start-up, not repeated deep discharge, and will fail fast. Use a battery designed for deep cycling: deep-cycle lead-acid or LFP. Some golf-cart batteries are genuine deep-cycle and can work, but check the spec says deep-cycle, not starter.

Home Solar Guide

Home Solar Batteries — Lithium vs Lead-Acid, Hours, and Whether It's Worth It

Name: CapSolar
Address: 429/44 Sukhonthasawat Rd, Lat Phrao, Bangkok, 10230, TH
Telephone: +66 2 124 5414
Price range: $$$$

Which chemistry, how many kWh is enough, how long a 100Ah battery runs, how many years it lasts, whether it is safe — and the question that saves the most money: does a home that already has grid power even need a battery? Answered on real principles, with no invented prices.

8 min readLast updated: 23 Aug 2026Data as of: Aug 2026

The short version: a home with normal grid power on an on-grid system usually does NOT need a battery — the grid already acts as your supply, and selling surplus back pays off better than storing it. A battery earns its place when you go off-grid (no utility line) or want backup during outages (which requires a hybrid system). If you are buying, a home's two realistic choices today are lithium LFP (long life, light) and lead-acid (cheaper up front, wears out faster). Size it by "usable kWh", not just Ah — everything is below. (How on/off/hybrid systems differ is a separate read.)

How much does a home solar battery cost (per kWh)?

No utility publishes an official "home-battery price" — the real number depends on several factors, so we print no rumoured figure and instead give you the cost drivers to compare quotes yourself. The key trick: compare on baht per "usable kWh", not per nameplate kWh, because a lead-acid battery only delivers about half of its rating.

What moves the price

① Capacity (kWh / Ah × voltage) — more stored energy costs more. ② Cell type — lithium LFP costs more up front than lead-acid but less once divided by cycles and years. ③ Whether a hybrid inverter / BMS is in the kit — a bare battery is not a ready system. ④ Brand and warranty (years / cycles). ⑤ Install labour, enclosure and cabling. For a grid-connected home, PEA Solar itself notes a battery system "has high cost" — the cheaper route is to do an on-grid system with no battery first, and add a battery later only if you need one.

To compare fairly: ask for the quote in baht per usable kWh plus the warranted cycle count, then divide → a "cost per cycle" you can actually compare across brands. PEA's official on-grid packages (PEA Solar package) work as a no-battery price anchor.

How many hours does a 100Ah / 5kWh battery run?

Two steps: (1) convert Ah to kWh first — kWh = Ah × voltage ÷ 1000, so 100Ah at 12V = 1.2 kWh but 100Ah at 48V ≈ 4.8 kWh (wildly different!). (2) Then usable kWh ÷ load power (kW) = hours, where "usable" = nameplate × DoD × efficiency.

Example: a 5 kWh LFP battery (assume DoD 80% × ~95% efficiency → ~3.8 kWh usable) powering various loads for roughly

Load (approx.)	Power	Runs for about
LED lights + fan + phone charging	~100 W	~38 hours
Fridge + house lights	~200 W	~19 hours
Fridge + TV + lights + Wi-Fi	~500 W	~7–8 hours
Whole-home light load	~1,000 W	~3.8 hours
One small air-con running	~1,500 W	~2.5 hours

These are computed from the assumptions above; real runtime is shorter with heat, battery age, and the surge when motors start (a fridge/air-con/water-pump draws several times its average at start-up). Read each appliance's real power off its label — compare per-device draw on the appliance power table.

Lithium or lead-acid — which should you choose?

For a home cycling almost daily with solar, lithium LFP wins over the long run — deeper usable depth (DoD ~80–90% vs ~50% for lead-acid), several times the lifespan, and almost no maintenance. Lead-acid suits a tight budget or occasional use. The table below is typical manufacturer-spec figures for direction; always confirm against the real model's datasheet.

Metric	Lithium LFP	Lead-acid	Gel / AGM
Usable depth (DoD)	~80–90%	~50%	~50%
Cycle life	~3,000–6,000+	~300–500	~500–800
Typical lifespan	~8–15 years	~1.5–3 years	~3–5 years
Round-trip efficiency	~95%+	~80–85%	~85%
Maintenance / weight	Almost none · light	Top up water/vent gas · heavy	Sealed but still heavy
Up-front cost (relative)	Highest, cheapest per cycle	Cheapest	Middle

⚠️ The table shows "typical" values that vary widely by brand, model, temperature and usage — for a real buying decision, go by that specific model's datasheet and warranty terms.

Does a grid-tied home need a battery — and when is it worth it?

If your home has normal grid power and an on-grid system, in principle you do not need a battery — use daytime output, and sell the surplus back at 2.20 THB/unit, which pays off better than storing it in an expensive battery. A battery becomes "necessary" only in these three cases.

1) Off the grid (no utility line)
An orchard, field or cabin with no utility line — PEA Solar states an off-grid system "must have a battery connected" to store power for night use.
2) Backup during outages (needs hybrid)
Crucial: an ordinary on-grid system does NOT supply power during an outage — the anti-islanding standard forces the inverter to shut off immediately for line-worker safety. To keep power when the grid is down you need a hybrid system + battery designed to island.
3) Areas with frequent outages/sags
A home with frequent outages or unstable voltage can use a battery as a buffer for critical loads — but weigh it against "the value of having power", not just the payback number.

On worth: a battery adds cost but adds no generation, so it usually lengthens the whole system's payback. If the goal is purely a lower bill, on-grid + sell-back is usually the better deal. For real numbers, run the solar payback page; after install, track your used/sold units on the bill and the PEA Smart Plus / MEA Smart Life utility apps.

Can a lithium solar battery explode or catch fire?

Any energy storage carries some risk, but LFP lithium (lithium iron phosphate) is far more thermally stable than the NMC lithium used in phones and EVs — it tolerates heat and does not run away easily, which is why it is the popular home choice. Safety comes down to a good BMS, correct installation, and not using low-grade or unknown second-hand cells.

Make it safer

• Choose a battery with a BMS that cuts off on over-charge/over-discharge/over-temperature. • Install it in a well-ventilated spot, away from heat and water (lead-acid vents hydrogen, so ventilation matters even more). • Use standards-compliant inverters/gear and a knowledgeable installer. • Avoid cheap second-hand batteries whose used cycle count is unknown.

Who wrote this page

Compiled by the CapSolar team, a commercial solar provider in Thailand, reviewed by Frank Lee (Founder). The system/battery principles cite official PEA Solar / MEA material whose accessibility we verified as of Aug 2026 (links below); the technical figures (DoD/cycles/lifespan) are typical manufacturer-spec ranges we explicitly tell you to confirm against the real model, and we print **no invented battery price** — because no utility publishes one.

FAQ

Riskier than it looks: you usually cannot tell how many cycles it has done or how much cell health remains. It is cheap up front, but real usable capacity may be low and fade fast. If you must, insist on a measured-capacity test and usage history first — but overall, a new LFP battery with a warranty is usually cheaper per cycle.

Want to cut the bill with solar (with or without a battery)?

For buildings and factories, CapSolar assesses free whether on-grid, hybrid or added storage fits — no obligation.

Talk to CapSolaror call +66 2 124 5414

Home Solar Batteries — Lithium vs Lead-Acid, Hours, and Whether It's Worth It

How much does a home solar battery cost (per kWh)?

What moves the price

How many hours does a 100Ah / 5kWh battery run?

Lithium or lead-acid — which should you choose?

Does a grid-tied home need a battery — and when is it worth it?

1) Off the grid (no utility line)

2) Backup during outages (needs hybrid)

3) Areas with frequent outages/sags

Can a lithium solar battery explode or catch fire?

Make it safer

Who wrote this page

FAQ

Keep reading

On-grid / Off-grid / Hybrid

Solar Payback: Is It Worth It?

Sell Power Back to the Grid

Factory Battery / BESS

Want to cut the bill with solar (with or without a battery)?