LiFePO4 vs NMC batteries in power stations (cycles, weight, cold)

If you are shopping today the choice is mostly made for you: all 52 models we track list LiFePO4 cells, 49 of them sold new in the US, and none list NMC. The trade-offs still matter when you read an older listing, a used unit or a spec sheet that hides the chemistry, so this guide puts numbers on them.

What the two chemistries trade

Both are lithium-ion. The difference is the cathode, and Battery University's reference tables summarise what it changes at the cell level (BU-205, Types of Lithium-ion):

BU-205 notes that both cycle figures depend on depth of discharge and temperature, and describes LFP as very safe even when fully charged, with an elevated self-discharge. In a power station that means LFP buys a longer service life and more thermal margin, and pays for it in weight.

What a cycle rating actually promises

A cycle count only means something next to the capacity it ends at. Anker's spec page for the Anker SOLIX C2000 Gen 2 lists the battery as LFP with a lifespan of 4,000 cycles to 80% capacity (Anker SOLIX C2000 Gen 2 specs). So the rating describes a pack that still works after 4,000 cycles, holding a fifth less energy than new. A rating quoted to 70% would sound bigger for the same cells.

Worked example 1: lifetime energy from a cycle rating

Inputs: 2,048 Wh rated, KiloHour's 90% usable default, 4,000 rated cycles. To keep it simple we assume a straight-line fade from 100% to 80% health, so the average cycle runs at 90%. That is our simplification, not a curve Anker publishes. The engine computes usable energy at each health setting.

4,000 cycles × 1,659 Wh is about 6.6 MWh drawn from the battery before it reaches the end of its rating. For contrast, the same pack at BU-205's NMC range of 1,000 to 2,000 cycles would give 1.7 to 3.3 MWh. That gap matters if the station cycles daily on solar. Charge it a few times a year for camping and you will likely retire it for other reasons before it uses up either rating.

Worked example 2: what weight per watt-hour looks like

Inputs: 2,048 Wh and 18.9 kg from the dataset. 2,048 Wh ÷ 18.9 kg = 108 Wh/kg for the whole unit. That figure includes the inverter, chargers, case and ports, so a complete station always lands below its cells' specific energy. The median across LFP models we track is 82 Wh/kg, spanning 47 Wh/kg to 114 Wh/kg.

We don't convert this into an "NMC would weigh X" figure: with no NMC station in the dataset there is no measured pack to compare against, and cell ranges don't translate directly into finished units.

Worked example 3: the same laptop on a new and a worn pack

Inputs: a 50 W laptop on the SOLIX C2000 Gen 2's AC outlet, battery health at 100% and at the 80% end of its rating.

• New: 1,843 Wh ÷ 66.8 W from the battery = 27 h 35 min.
• At 80%: 1,475 Wh ÷ 66.8 W = 22 h 4 min.

Health scales runtime one for one. A chemistry with a longer rating keeps you near the first line for more years; it doesn't change the first line.

Every model we track, by chemistry

Counts, capacities and weights come from each maker's published spec as stored in our dataset. Wh/kg is capacity divided by weight, converted from pounds where only pounds are published.

The lightest and heaviest LFP stations per watt-hour, from the same data:

Since every row is the same chemistry, the spread comes from design: wheels, built-in handles, bigger inverters and home backup features add weight that has nothing to do with the cells. When weight decides it, compare finished units such as the SOLIX C2000 Gen 2 and Elite 200 V2 or the Power 2000 and DELTA 3 Max.

Cold, briefly

BU-205 says cold reduces performance for most batteries, and LFP is no exception. Charging is the stricter limit: Anker rates the SOLIX C2000 Gen 2 for charging at 0°C to 40°C (32°F to 104°F) on the same spec page. Check the charging temperature range on your own model's spec sheet, because it is set per product, not per chemistry.

What changes the answer

• How often you cycle it. Daily solar cycling turns a cycle rating into years of service; occasional use makes calendar age and storage matter more than cycles.
• The end point of the rating. Cycles to 80% and cycles to 70% aren't comparable. Read the capacity threshold before comparing two numbers.
• Carrying versus parking. Wh/kg matters for a unit you lift into a car each weekend, much less for one that sits by the fridge.
• Unlisted chemistry. When a spec page doesn't name the chemistry, treat cycle and cold claims as unknown until the maker states them.