Cell Review: Sodium-ion NaCR, 18650
NaCR Sodium-Ion 18650 Cell — Cold-Ready Power Without Lithium
Why this matters: These sodium-ion cells are a real alternative to lithium-ion. But which Sodium-ion is the right to choose? These cells use a NaCrO2-type layered-oxide cathode, they run at about 3.05 V nominal, and they can still discharge in deep cold where normal lithium cells struggle. They’re available in familiar cylindrical formats (like 18650), so you can build packs with normal tooling and normal holders.
What Is NaCR Chemistry?
“NaCR” refers to a sodium-ion layered-oxide cathode (NaCrO2-type). This chemistry gives you:
- Usable nominal voltage around 3.05 V per cell and a wide working window (about 1.8 V to 3.95 V per cell).
- Cold-weather performance that stays usable at sub-zero temperatures, including discharge down to −40 °C.
- Sodium instead of lithium, cobalt, etc. — more abundant materials and less supply chain drama.
Practically, that means you can design a multi-cell pack (12 V, 24 V, 48 V, etc.) almost the same way you’d design around LFP, but you get better low-temp behavior than typical LFP cells.
Cell Snapshot (NaCR18650-1.3ER)
- Form factor: 18650 cylindrical cell (Ø18.35 mm × 65.2 mm)
- Rated capacity: 1300 mAh (at 0.2C)
- Nominal voltage: 3.05 V
- Charge limit voltage: 3.95 V (CC/CV)
- Discharge cutoff: 1.8 V
- Burst discharge: up to ~7.8 A (≈6C) at 25 °C, full charge
- Operating temp: Charge −20 °C → 55 °C / Discharge −40 °C → 60 °C
- Weight: ~36.5 g
- In stock: Sold individually so you can prototype small packs before scaling up
Electrical & Mechanical Specs
| Parameter | Value |
|---|---|
| Chemistry | NaCR (NaCrO2-type layered-oxide sodium-ion) |
| Model | NaCR18650-1.3ER |
| Nominal Voltage | 3.05 V |
| Voltage Window | ~1.8 V (cutoff) to 3.95 V (charge limit) |
| Rated Capacity | 1300 mAh @ 0.2C |
| Standard Charge Current | 0.5C (≈650 mA), CV taper to ≤0.05C |
| Max Charge Current | 1.0C (≈1300 mA) |
| Standard Discharge Current | 0.5C (≈650 mA) |
| Max Burst Discharge | 7.8 A (~6C) at 25 °C, 100% SOC |
| Operating Temp (Charge) | −20 °C to 55 °C |
| Operating Temp (Discharge) | −40 °C to 60 °C |
| Dimensions | Ø18.35 ± 0.15 mm × 65.2 ± 0.2 mm |
| Weight | 36.5 ± 0.5 g |
| Storage Temp | 15 °C – 35 °C recommended |
How NaCR Compares to NFPP, NFM, and LFP
You’ll see a few different sodium and lithium chemistries in the store. Here’s the plain-English version of where NaCR sits:
-
NaCR vs NFPP (sodium iron fluorophosphate / “phosphate-style sodium”):
NFPP behaves like “the LFP of sodium-ion” — super stable, very forgiving, excellent safety. It’s incredibly good in the cold and has a nice flat discharge curve around ~3.0 V. NaCR is still sodium, but it’s a layered oxide instead of a phosphate. Result: NaCR tends to allow higher burst current and a slightly higher usable voltage window, while still working in sub-zero temps. -
NaCR vs NFM (layered sodium nickel / iron / manganese oxide):
NFM is the higher-energy, higher-voltage sodium layered oxide. It usually runs ~3.1 V nominal and can reach a higher top-of-charge voltage. If you care about squeezing out Wh/kg and don’t mind managing temperature more carefully, NFM is attractive. NaCR gives you a little less energy density than NFM, but still supports serious discharge current (multi-C bursts) and is very tolerant of cold-weather discharge. -
NaCR vs LFP (LiFePO4):
LFP is still the king for cycle life (often 4000–6000+ cycles in large prismatic cells) and maturity. But LFP hates being charged cold and doesn’t like to be discharged far below freezing. NaCR can discharge at extreme low temps (down to about −40 °C) and can even accept charge below 0 °C (with reduced current). If you’re building storage for an unheated shed, cabin, or outdoor enclosure in winter, that matters a lot.
Cell Testing Results
| Chemistry | Nominal V / Cell | Energy Density | Cycle Life Class | Cold Behavior | Typical Use Case |
|---|---|---|---|---|---|
| NaCR (NaCrO2-type) | ~3.05 V | Moderate | 1000+ cycles typical | Excellent (down to −40 °C discharge) | Outdoor / cold-climate packs that still need burst current |
| NFPP (sodium phosphate / fluorophosphate) | ~3.0 V | Lower to moderate | 3000–5000 cycle class | Excellent, very stable and safe | Long-life stationary storage, safety-first builds |
| NFM (layered Na-Ni-Fe-Mn oxide) | ~3.1 V | Higher for sodium-ion | ~3000 cycle class | Good, but not as forgiving as NFPP in deep cold | Energy-focused builds where Wh/kg matters |
| LFP (LiFePO4) | ~3.2 V | High for stationary cells | 4000–6000+ cycle class (large prismatics) | Fair: needs heat in winter, hates charging below 0 °C | Home ESS / off-grid banks where you can control temp |
Where These NaCR Cells Make Sense
- Cold-climate storage: Cabin, garage wall, outdoor box, van in winter. You don’t always get to keep the pack warm.
- DIY 12 V / 24 V / 48 V packs: You can build standard series/parallel packs because the nominal voltage is in the same general range as other Li-ion-style cylindrical cells.
- Prototyping sodium-ion: Because this is a normal 18650 can, you can spot-weld nickel strip and use off-the-shelf 18650 holders instead of designing compression plates like with big prismatics.
- Portable gear and test rigs: The ~6C burst rating means you can pull short high loads without the cell collapsing immediately.
Build Notes & BMS Settings
- Charge limit: ~3.95 V per cell max. Use CC/CV and stop when the taper current falls below ~0.05C.
- Low cutoff: ~1.8 V per cell. Going lower risks capacity loss and stress.
- Packs: Treat these like any other cylindrical cell pack: fuse or protect parallel groups, then series-stack those groups. Balance leads should go across each series group.
- Spot welding: Start with the lowest weld energy and shortest pulse your welder will do. Increase slowly only if the nickel tab doesn’t stick. Sodium-ion cans can be easier to damage with too much heat.
➜ Order NaCR Sodium-Ion Cylindrical Cells
Specs above are typical values from the NaCR18650-1.3ER datasheet and current store listing. Always confirm limits (voltage, cutoff, current, temperature) against the latest datasheet before finalizing your BMS settings.