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Before lithium took over, most portable power packs and many DIY backup systems ran on sealed lead-acid batteries, usually AGM or gel. They are still sold today because they are cheap upfront, and some budget jump-starter power packs and homemade inverter carts still use them. LiFePO4, or lithium iron phosphate, now dominates quality power stations. The question of which lasts longer has a clear answer, but the size of the gap surprises most people, and so does the way it changes the real cost of each battery.
Why cycle life depends on how deep you drain
Every battery wears out a little with each charge and discharge cycle. Lead-acid batteries are extremely sensitive to how deeply they are discharged. Draining one to 80 percent depth regularly can wear it out in a few hundred cycles. LiFePO4 tolerates deep discharges far better.
Typical cycle life by depth of discharge
These are general industry ranges; individual products vary.
| Depth of discharge | Sealed lead-acid (AGM) | LiFePO4 |
|---|---|---|
| 30% | ~1,000-1,200 cycles | 6,000+ cycles |
| 50% | ~500-600 cycles | ~5,000 cycles |
| 80% | ~300-400 cycles | ~3,500-4,000 cycles |
| 100% | ~150-250 cycles | ~2,500-3,500 cycles |
At the depth most people actually use a power station, 70 to 100 percent, LiFePO4 typically lasts roughly 8 to 15 times as many cycles.
Usable capacity is not the same
A 100Ah, 12V lead-acid battery is nominally 1,200Wh, but to keep it healthy you should use only about 50 percent, around 600Wh. A 100Ah LiFePO4 battery at 12.8V is nominally 1,280Wh, and you can routinely use 90 percent or more. So for the same usable energy, you need about twice the lead-acid capacity.
Voltage sag and the Peukert effect
Lead-acid voltage drops steadily as it discharges and sags further under heavy loads. High-draw appliances like microwaves reduce its effective capacity, a behavior described by the Peukert effect. LiFePO4 holds a nearly flat voltage until close to empty and delivers close to its rated capacity even at high draw. That makes inverters run more reliably from start to finish.
Weight and size
For the same usable energy, lead-acid weighs roughly three to four times as much. A 1kWh usable lead-acid bank can weigh 60 to 70 pounds; a LiFePO4 power station with similar usable capacity typically weighs 22 to 30 pounds. For anything portable, this alone settles the question.
Cost per usable kilowatt-hour over the battery’s life
| Metric | Sealed lead-acid | LiFePO4 |
|---|---|---|
| Upfront cost per usable kWh | Lower, often 40-60% of LiFePO4 | Higher |
| Cycles at 80% depth | ~300-400 | ~3,500-4,000 |
| Lifetime energy delivered per usable kWh | ~0.3-0.4 MWh | ~3.5-4 MWh |
| Cost per kWh delivered over life | High | Very low |
Even though lead-acid costs less upfront, LiFePO4 delivers several times more energy over its life for each dollar spent.
Storage behavior
Lead-acid batteries self-discharge and sulfate if left partially charged, meaning they need regular charging or a float charger. LiFePO4 self-discharges slowly, typically a few percent per month, and prefers storage around 50 to 60 percent charge.
Cold-weather differences
Lead-acid can be charged in cold temperatures but loses substantial capacity when cold. LiFePO4 discharges reasonably well in cold weather but usually must not be charged below freezing unless the product has internal heating. For winter use, look for self-heating LiFePO4 or keep the battery in a warm space while charging.
When lead-acid still makes sense
Lead-acid remains reasonable for low-cycle standby uses that almost never discharge, such as small computer UPS units, alarm panels, or emergency lighting, where the battery floats at full charge and replacement every 3 to 5 years is acceptable. It also tolerates simple chargers and very cold charging better, which is why it persists in some vehicle and equipment roles. For anything you cycle weekly or daily, though, the replacement costs add up quickly.
FAQ
How many years does a LiFePO4 power station last compared with lead-acid?
With regular use, LiFePO4 commonly lasts 8 to 15 years or more, while lead-acid in the same deep-cycle duty often needs replacement in 2 to 5 years.
Can I replace a lead-acid battery with LiFePO4 in my setup?
Often, but the charger and inverter must support LiFePO4 charging profiles. Check compatibility before swapping.
Bottom line
LiFePO4 lasts far longer than lead-acid in any application that regularly discharges the battery, typically by 8 to 15 times the cycles, while weighing a third as much. Lead-acid only wins on upfront cost for standby uses that rarely cycle. For a power station you will actually use, LiFePO4 is the clear choice.
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