A deep dive into the real cost of lithium iron phosphate batteries vs lead-acid — and why most people are still buying wrong.
When you factor in cycle life, the cost per kWh for 48V LFP batteries is about one-third that of lead-acid. But most people are still buying lithium batteries with the same mindset they use for lead-acid.
— Originally posted on DIY Solar Forum, widely shared
A lot of people don't do the math this way. I know solar business owners — people from my father-in-law's generation — who still think lithium batteries are "expensive." Installation technicians consider a 48V 100Ah battery pack priced at five or six thousand yuan to already be "quality goods."
In reality, a 48V 100Ah LFP battery pack has a capacity of 4.8kWh. Decent quality units are priced between three to five thousand yuan. I personally use EVE LF280K cells; a 16-series configuration costs around 4,200 yuan. That's the price as of early 2024.
LFP battery cycle life is calculated at 4,000 cycles, 80% DOD — that's a conservative number. EVE's datasheet states 6,000 cycles; in actual use, I apply a discount. 4.8kWh multiplied by 0.8, then multiplied by 4,000 cycles, gives a total discharge of 15,360 kWh. Divide 4,200 yuan by 15,360, and you get a storage cost of 0.27 yuan per kWh.
Lead-acid battery: A 48V 100Ah pack costs around 1,600 yuan. Cycle life is 300 to 500 cycles; let's call it 400. 4.8kWh multiplied by 0.5 (lead-acid DOD should be 50%), then multiplied by 400, gives a total discharge of 960 kWh. Divide 1,600 by 960, and you get a cost of 1.67 yuan per kWh.
Energy storage salespeople like to compare LFP batteries to diesel generators. They say generators cost two to three yuan per kWh — look how much more cost-effective energy storage is.
This comparison is flawed. Diesel generators are for emergency backup power; they don't run more than a few times a year. Taking a device with a ten-year design life that runs only a few dozen hours annually and comparing its cost per kWh to an energy storage battery that cycles daily — that's not an apples-to-apples comparison.
A more reasonable comparison is peak-valley electricity price differential. I'm in Jiangsu, where the peak-valley price difference is around 0.7 yuan. My system cycles once daily: 4.8kWh × 0.8 × 0.7 = 2.69 yuan saved per day. Battery cost is 4,200 yuan; ignoring the inverter and other components, the battery-only payback period is 1,561 days — just over four years.
This is the calculation consumers should be doing.
Many people don't realize that rated capacity and actual usable capacity are two different things.
48V 100Ah has a rated capacity of 4.8kWh. LFP batteries are normally used between 10% and 90% state of charge, which is 80% DOD. Actual usable capacity is 3.84kWh.
Some manufacturers are even worse. I once bought cells on 1688 that were labeled 280Ah but actually only delivered 260Ah*. One capacity test and the truth comes out — a 4.8kWh rated pack that can only discharge 3.5kWh. This is common when buying loose cells.
Full charge: 57.6V
Empty: 44.8V
✓ Standard configuration
Full charge: 54V
Empty: 41.25V
⚠ May not fully charge with 16S inverter
There's another thing. Batteries both called "48V" can have different voltage platforms. Some are 16-series: full charge 57.6V, empty 44.8V. Some are 15-series: full charge 54V, empty 41.25V. If your inverter is designed for 16-series, connecting a 15-series battery might prevent it from fully charging. Salespeople won't proactively tell you these details.
Battery sellers will tell you LFP is safe, long-lasting, with many cycles.
They won't tell you there are other costs. A good BMS costs five to six hundred yuan; Bluetooth-enabled ones are more expensive. Cables and busbars are a few hundred yuan. Battery cabinet is three to four hundred yuan. Shipping is over a hundred — a 48V 100Ah unit weighs about 50kg. Installation is extra.
| Component | Cost (CNY) |
|---|---|
| Battery Cells | ¥4,200 |
| BMS | ¥580 |
| Cables & Busbars | ¥380 |
| Metal Enclosure | ¥320 |
| Shipping | ¥160 |
| Total | ¥5,640 |
That's 34% higher than the cell cost alone.
If you buy a complete battery pack, like Pylontech's US3000C or those Pylon units — 4.8kWh rated with 3.55kWh actually usable — retail prices are eight to ten thousand yuan. That's 40% to 80% more expensive than DIY, but saves two weekends of time. Weigh that time cost yourself.
Based on 2024 market conditions, the reasonable price range for 48V LFP batteries is 0.6 to 0.9 yuan per Wh. Below 0.5? Be careful — it's either recycled cells, capacity misrepresentation, or no-name cells. Above 1.0? You're paying a brand premium, unless there are special features.
For a 4.8kWh battery pack, 2,900 to 4,300 yuan is the normal range. Above 5,500 yuan, ask yourself what you're getting for the extra money.
I've seen someone spend 12,000 yuan on a "smart energy storage battery" with a 7-inch touchscreen that displays charge/discharge curves. A phone app shows the same thing. That screen costs maybe 200 yuan tops. Where did the extra money go? Hard to say.
BloombergNEF data shows that in 2024, LFP cell prices have dropped to $78 per kWh, and pack-level prices are $115. Converting to RMB, cells are under 0.6 yuan per Wh. If the price you're paying is significantly higher than this, it's worth thinking about where that price difference is going.