While I haven't had the chance to build the battery out yet the cells are pristine, voltages are near perfect and I see no issues ahead.
product description
EVE MB31 LiFePO4
EVE MB31 LiFePO4
314Ah Prismatic Cells
Grade A 3.2V 314Ah lithium iron phosphate prismatic cells supplied as a pack of 4 cells with busbars. This Shopify-ready page converts the live listing and MB31 specification into a professional, technical, chart-heavy description for customers comparing energy, voltage behavior, cycle life, thermal limits, pack architecture, and ESS suitability.
Pack of 4 Cells 314Ah LiFePO4 3.2V Nominal 3.65V Full Charge 0.5C / 157A Listing CDR M6 Stud + Busbars
314AhNominal Cell Capacity
1004.8WhNominal Energy Per Cell
4.02kWhApprox. Energy for 4 Cells
0.5CCharge / Discharge Class
8000+Cycle-Life Claim / 70% SOH Spec
≈5.6kgPer-Cell Datasheet Weight
EVE MB31 Grade A 3.2V LiFePO4 314Ah Prismatic Battery Cells (Pack of 4)
The EVE MB31 is a high-capacity LiFePO4 prismatic cell built for long-life energy storage, off-grid power, RV and marine battery systems, UPS modules, and large-format battery banks. Unlike high-drain cylindrical cells, this product is optimized around high stored energy, long cycle life, thermal stability, and pack-level serviceability.
The live listing is for a pack of 4 cells with busbars included. A common 4-cell series configuration creates a 12.8V nominal LiFePO4 module with approximately 314Ah capacity and about 4.02kWh nominal energy before BMS, wiring, enclosure, and usable-depth-of-discharge limits.
Design note: EVE’s MB31 specification defines the cell around constant-power 0.5P charge/discharge behavior.
| Brand / Model | EVE MB31 Grade A LiFePO4 prismatic cell |
|---|---|
| Listing Package | Pack of 4 cells with busbars included |
| Terminal | Single M6 stud |
| Chemistry | Lithium Iron Phosphate / LiFePO4 / LFP |
| Nominal Capacity | 314Ah |
| Nominal Energy | 1004.8Wh per cell |
| Nominal Voltage | 3.2V |
| End-of-Charge Voltage | 3.65V standard charge voltage |
| Discharge Cut-Off Voltage | 2.5V when cell temperature is above 0°C; MB31 spec also lists 2.0V when cell temperature is at or below 0°C |
| Listing CDR / Max Charge | 0.5C / 157A |
| Datasheet Power Rating | 0.5P standard and maximum continuous charge/discharge power; 502.4W per cell at 25°C |
| Initial AC Resistance | 0.18mΩ ± 0.05mΩ at AC 1kHz, delivery SOC, fresh cell |
| Cell Dimensions | 207.2mm ±0.5mm with terminal; 204.6mm ±0.5mm without terminal; 173.7mm ±0.5mm length; 71.7mm ±0.8mm thickness |
| Weight | 5600g ±300g datasheet value; retail listing approx. 5.4kg |
| Cycle Life | 8000 cycles at 25°C to 70% SOH in MB31 specification; live listing states 8000+ charge cycles |
| Operating Temperature | Charging 0°C to 60°C; discharging −30°C to 60°C in product table |
| Storage | 1 year: 0°C to 35°C; 1 month: −20°C to 45°C at delivery SOC status |
Electrical operating envelope at a glance.
These quick-reference visuals summarize the MB31’s voltage window, power/current interpretation, energy translation, and C-rate/P-rate mapping.
1. Cell Voltage Operating Window
LiFePO4 cells have a relatively flat discharge plateau between full charge and cut-off.
2. Power / Current Translation
EVE uses 0.5P constant-power ratings; the retail listing translates 0.5C to 157A.
3. Capacity and Energy Translation
Nominal watt-hours are calculated from nominal capacity and nominal voltage.
4. Common 4-Cell Configuration
A 4S1P pack configuration is a typical 12V-class LiFePO4 module topology.
| Cells Included | 4 individual MB31 cells with busbars |
|---|---|
| Example 4S Nominal Voltage | 12.8V nominal |
| Example 4S Full Charge | 14.6V full charge |
| Example 4S Capacity | 314Ah |
| Example 4S Energy | ≈4.02kWh nominal |
| Example 4S Cut-Off | 10.0V at 2.5V/cell above 0°C |
LiFePO4 voltage stays flat for most of the discharge curve.
The MB31’s most important electrical behavior is not a dramatic voltage slope; it is the stable LiFePO4 plateau. This gives ESS and RV systems predictable voltage output over a wide state-of-charge range, but it also means SOC estimation should rely on coulomb counting and a calibrated BMS, not voltage alone.
The simplified discharge graph below visualizes typical LiFePO4 behavior: a fast drop from full-charge voltage, an extended flat plateau, and a steep knee near cut-off. Actual voltage depends on current, temperature, cell age, compression, busbar resistance, BMS calibration, and rest time.
Plateau interpretation
| 3.65V | Standard charge voltage limit |
|---|---|
| ≈3.35V–3.25V | Typical loaded/resting plateau region |
| 3.2V | Nominal voltage reference |
| 2.5V | Standard discharge cut-off above 0°C |
| 2.0V | MB31 data sheet low-temperature cut-off reference at or below 0°C |
5. Simplified Discharge-Curve Graph
Voltage vs. capacity illustration for LiFePO4 plateau behavior. Simplified for product-page visualization.
6. Low Resistance / High Energy Scale
The MB31 is a large-format storage cell with very low AC resistance.
Thermal, storage, cycle-life, and mechanical-control visuals.
Large prismatic LFP cells should be treated as structural energy-storage components. Temperature, compression, terminal connection, balancing, and BMS logic are all part of safe pack integration.
7. Charge Power vs. Temperature
Continuous charge modes by cell temperature, expressed as P-rate in the MB31 data sheet.
8. Discharge Temperature Envelope
Continuous discharge P-rate remains 0.5P through most of the usable temperature range.
9. High / Low Temperature Performance
Published discharge-energy performance versus 25°C reference energy E0.
10. Cycle-Life Visualization
MB31 specification: 8000 cycles at 25°C to 70% SOH under the specified 0.5P cycle test.
11. Storage & Self-Discharge
Storage windows and self-discharge values from the MB31 product specification.
| 1 Year Storage | 0°C to 35°C at delivery SOC status |
|---|---|
| 1 Month Storage | −20°C to 45°C at delivery SOC status |
| Self-Discharge First Month | ≤3.5% per month at delivery SOC, 25°C ±2°C |
| After First Month | ≤3.0% per month at 25°C ±2°C storage |
| 50% SOC Recovery | ≥98% E0 after 25°C / 28 days; ≥97% E0 after 45°C / 28 days |
12. Swelling Force & Compression Context
Large-format prismatic cells require mechanical attention over cycle life.
Prismatic cell dimensional envelope and pack architecture.
Use the larger datasheet dimensional envelope for CAD, busbar clearance, enclosure design, and terminal-stack planning. The live listing rounds the size to 72mm × 174mm × 207mm.
13. Cell Dimension Diagram
Mechanical envelope based on MB31 specification dimensions.
14. Pack Scaling Formulas
Common LiFePO4 pack math for series/parallel planning.
Pack Voltage ≈ Series Count × 3.2V
Pack Capacity ≈ Parallel Count × 314Ah
Pack Energy ≈ S × P × 1004.8Wh
Listing Current Class ≈ Parallel Count × 157A
15. Series Voltage Examples
Nominal and full-charge values for common LFP architectures.
| 4S1P | 12.8V nominal / 14.6V full / ≈4.02kWh |
|---|---|
| 8S1P | 25.6V nominal / 29.2V full / ≈8.04kWh |
| 16S1P | 51.2V nominal / 58.4V full / ≈16.08kWh |
| 16S2P | 51.2V nominal / 58.4V full / ≈32.15kWh |
| 20S1P | 64.0V nominal / 73.0V full / ≈20.10kWh |
16. Module Integration Checklist
Technical checks before installation into an ESS, RV, marine, or industrial system.
- Verify all cell QR codes, voltages, polarity, and physical condition on arrival.
- Use a LiFePO4-compatible BMS with cell-level voltage, current, and temperature protection.
- Balance cells before service and verify busbar contact resistance.
- Follow proper terminal hardware, torque, insulation, and anti-loosening practices.
- Use an enclosure that prevents shorts, moisture exposure, vibration damage, and terminal contact.
- Validate current path, conductor sizing, fuse selection, and heat rise at the actual load.
Designed for high-energy storage, not unmanaged loose-cell use.
The MB31 is a large-format energy-storage cell. It is intended for protected battery packs and modules, not loose-cell consumer use. A suitable BMS, enclosure, compression/module design, and LiFePO4 charger are required.
17. ESS Protection Threshold Map
Recommended system-level controls derived from the product/specification values.
| Charge upper limit | 3.65V per cell standard; absolute charging voltage max 3.8V in data sheet protection language |
|---|---|
| Discharge floor | 2.5V per cell above 0°C; special low-temperature cut-off handling required at ≤0°C |
| Charge temperature gate | 0°C to 60°C cell temperature |
| Discharge temperature gate | Product table: −30°C to 60°C; absolute discharge temp in spec: −35°C to 65°C |
| Cycle design point | 0.5P charge/discharge at 25°C for 8000-cycle / 70% SOH specification |
| Mechanical control | Consider compression, swelling force, busbar resistance, vibration, and thermal expansion |
18. Safety Checklist
Use in protected LiFePO4 systems only.
- Use only with a LiFePO4-compatible charger and BMS.
- Do not short circuit, puncture, crush, disassemble, incinerate, or expose to water.
- Do not connect series/parallel modules without balancing and a proper protection system.
- Do not use cells with swelling, leakage, crushed cases, terminal damage, or abnormal voltage.
- Do not solder directly to terminals; use proper mechanical terminal hardware and busbars.
- Use correct fusing and disconnects for pack-level fault protection.
- Store in a dry, cool place away from direct sunlight and heat sources.
- Only qualified users should assemble large LiFePO4 battery packs.
Best suited for ESS, RV, marine, and industrial energy-storage systems.
Solar ESS
- Strong fit for off-grid and hybrid solar battery banks.
- High cycle life supports daily cycling when properly managed.
Home Backup
- Useful for 12V, 24V, and 48V backup power modules.
- Requires a suitable BMS, enclosure, fusing, and charger/inverter settings.
RV / Van Power
- High capacity per cell reduces part count for mobile power systems.
- Mechanical mounting and vibration control are important.
Marine Systems
- LiFePO4 chemistry offers stable energy storage for protected marine packs.
- Moisture protection and terminal insulation are mandatory.
Industrial UPS
- Suitable for large backup systems where long calendar and cycle life matter.
- BMS telemetry and cabinet-level monitoring are recommended.
DIY Battery Builds
- Appropriate only for experienced builders with LiFePO4 pack knowledge.
- Pre-balance, BMS validation, and safe busbar assembly are required.
19. Selection Bias: Energy Storage vs. Power Cell
MB31 is optimized for stored energy and long cycle life, not compact high-drain cylindrical use.
20. Application Suitability Matrix
Simple product-page fit guidance.
| Solar ESS | Strong fit |
|---|---|
| Home backup | Strong fit |
| RV / marine | Strong fit with enclosure |
| EV / mobility modules | Engineer carefully |
| Loose-cell consumer use | Not appropriate |
| High-current compact tools | Use cylindrical power cells |
Receiving-inspection notes.
Receiving checklist
- Record serial numbers and QR codes.
- Measure and log resting voltage for every cell.
- Inspect terminals, cases, vents, and corners for shipping damage.
- Verify busbars and terminal hardware are present.
- Top-balance or pre-balance before building a series pack.
- Confirm BMS cell-count and LiFePO4 settings before energizing the system.
Do not skip
- Do not build a pack without cell balancing.
- Do not operate without a BMS or equivalent protection controller.
- Do not exceed voltage, current, temperature, or compression limits.
- Do not allow terminals or busbars to contact conductive enclosures.
- Do not install in wet, vibrating, or high-heat environments without protection.
- Do not assume charger settings for lead-acid batteries are LiFePO4 compatible.
Common technical questions about the EVE MB31.
Is the listing for one cell or four cells?
The live product listing states that the price is for a pack of 4 cells with busbars included.
What is the nominal voltage?
Each MB31 cell is 3.2V nominal. Four cells in series make a 12.8V nominal LiFePO4 battery module.
How much energy is in one cell?
The MB31 data sheet lists nominal energy of 1004.8Wh per cell. A 4-cell set is approximately 4019Wh, or about 4.02kWh nominal.
What is the correct full-charge voltage?
The standard end-of-charge voltage is 3.65V per cell. A 4S pack charges to 14.6V, while a 16S pack charges to 58.4V.
What is the discharge cut-off voltage?
The live listing states 2.5V. The MB31 data sheet lists 2.5V when cell temperature is above 0°C and 2.0V when cell temperature is at or below 0°C. Pack designers typically select a conservative cut-off based on the BMS, operating temperature, and desired cycle life.
What is the continuous discharge current?
The live listing states 0.5C, or 157A. The MB31 data sheet uses 0.5P constant-power language, equal to 502.4W standard and maximum continuous discharge power at 25°C reference conditions.
Can these be used for a 12V battery?
Yes. Four cells in series are commonly used to build a 12.8V nominal LiFePO4 battery, but the cells must be used with a proper BMS, fusing, enclosure, balancing, and LiFePO4-compatible charger.
Can I connect cells directly without a BMS?
No. These cells should be used in a protected battery system with cell-level voltage, temperature, and current monitoring.
What are the dimensions?
The live listing gives 72mm × 174mm × 207mm. The MB31 data sheet lists 207.2mm height with terminal, 204.6mm without terminal, 173.7mm length, and 71.7mm thickness.
How long do they last?
The product listing states 8000+ cycles. The MB31 data sheet specifies 8000 cycles to 70% SOH at 25°C under its listed 0.5P cycling procedure.
Do the cells need compression?
Large prismatic cells should be mechanically supported in a proper module or enclosure. The data sheet includes thickness conditions under 300kgf ±20kgf compression and swelling-force criteria, so pack mechanical design should not be ignored.
Can these be used in cold weather?
Discharging is listed down to −30°C in the product table, but charging is 0°C to 60°C. A BMS should prevent charging below allowed temperature limits and should enforce low-temperature cut-off logic.
What charger should be used?
Use a LiFePO4-compatible charger or inverter/charger profile. Do not use an incompatible lead-acid or lithium-ion profile that exceeds the correct cell or pack voltage.
Are busbars included?
Yes. The product listing states that busbars are included and that the terminal is a single M6 stud.
Customer Reviews
Overall rating: 4.9 / 5 from 60 reviews.
I really like these batteries.
Shipped fast and we’re packed perfectly. Cells all arrives at exactly 3.2v. Have them charging on the bench and can’t wait to put them to work! Can’t find prices like this anywhere else for guaranteed great quality and without shipping delays.
Batteries arrived in perfect condition. Wired eight together with a BMS and put in service as a 24v package for my RV inverter system. Power throughout the night and solar charges every day. Very happy with the purchase.
Arrived Dangerously Swollen - Ghosted by Customer Service Three out of the eight 314Ah cells arrived severely swollen and out of factory tolerance (exceeding 1.6mm gaps verified face-down on a cast-iron table saw). I reached out multiple times with immediate photo and video proof of the defects and the laser-etched QR codes. The company has completely ghosted my emails and phone calls. Per US DOT regulations (49 CFR 173.185(f)), it is illegal to mail swollen lithium batteries back, yet customer service has abandoned all communication. I have been forced to escalate a formal claim through PayPal to freeze the funds and demand a full refund. Atrocious quality control and nonexistent support. And while I don’t usually do this, I’m pretty upset with the way. This company has treated me. I have a list of all DIY forums. I have composed a complete factual letter of my experience with 18650.com. And I’m about to post my experience on these forms. I would hope upper management could take care of this situation, maybe you guys don’t know what’s going on at the Support level?
Ordered online and the order arrived in well packaged boxes. The cells tested 3.23 to 3.25 volts on each cell. No problems so far. The only issue I have with the 18650 Store is that I can't pick these cells up myself. For the cost of the shipping, I could have traveled to Atlanta, rented a room, and had a good meal. The other issue I have is the email I sent regarding this issue was neither acknowledged or answered. That leaves one of 2 options: 1. The person who is supposed to handle communications is overworked, or 2. The people who work here just don't care.
(Pack of 4) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery
Great service again, this is my fourth set of 16 cells to compleat My 48 volt 64.3kWh battery bank. I only order from 18650 because I know I will get a good price and fast shipping.
(Pack of 4) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery
Voltage at 3.2 looks new. QR code matches what the cell says.
(Pack of 4) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery
Overall it was a good purchase, and a good price. Bought 4x boxes of 4 cells each, none of the boxes came with matched cells - they had random manufacture dates ranging from May 25 - Oct 25. Voltage is good on them, physical inspection is good, packaging was good. Thanks
(Pack of 4) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery
Awesome cells . Love doing business with you guys , never disappoint... Thanks again..
(Pack of 4) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery
This is my third set of 16 and never had any problem with quality or delivery. soon as I have the extra cash I will get 16 more to complete my off grid 48 volt system
(Pack of 4) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery
exactly what I ordered and 1 day early
(Pack of 4) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery
James & Charles are excellent people to work with. We usually buy form a local vendor but they stopped carrying the eve terminal cells, for this project our end user required Eve terminal cells and 18650 was able to deliver. Thanks!
(Pack of 4) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery
Cell came matched well. Been 30 days since I built my 24 volt battery and cells are within .003 volts of each other with being discharged to 30% daily. Recharging with 2400 watts of solar at around 55 amps. So far very happy with purchase will be buying 8 more in next month or so.
(Pack of 4) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery
Arrived in great condition. Box took a bit of a hit and could use some better packaging. But overall satisfied with these new LFP cells for our camper trailer battery system!
(Pack of 4) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery
These batteries have been a game changer for living off grid. After 20 years of dealing with flooded lead acid L16’s, we made the switch after building a smaller 105 Ah 48 volt bank for our golf cart a year ago. It’s fantastic to see each cells voltage through the BMS (a Daly) and be able to have more control over the charging profile. The price point can’t be beat. Also nice (especially for my back) is that the entire 24v 314 Ah battery plus the BMS and redundant Epoch charger weighs less than one old school 6v L16. Have already started building similar battery banks for our neighbors. 18650 Battery Store are great to deal with and we will be ordering again soon. Thanks!
(Pack of 4) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery
Worth every penny, best cells out there.
(Pack of 4) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery
The batteries look perfect. Great quality and they all have full capacity.
(Pack of 4) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery
Excellent product and fast shipping!
(Pack of 4) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery
More than expected.314 eve battery I made a mistake thinking of ordering 280s. But for this price it was fantastic what I got
Purchased 8 cells. Quick ship, arrived quickly and in good condition. Cell voltages were within 2 mV. I built these into a 12V pack , charged to 3.65 highest cell V, placed in parallel. top balanced at 3.65V, reformed into a single 12V pack then ran several charge/discharge cycles between 3.55V/cell & 2.75V/cell. Capacity tested around 320AH. Very happy.
Well packaged and ships in reasonable time👍👍
Excellent shipment and all same Voltage.
The cells arrived in pristine condition, very well packed. No swelling, scratches or anything wrong at all. All 8 cells measured 3.295 V, so very well balanced.
Arrived promptly in excellent condition and all at same voltage as expected . great store .
Great batteries; great price!
Fast, efficient, and great old school customer service!
Perfect fit
Prompt shipping, well packaged, beautiful cells. Nice flexible busbars. Great price.
These are the best prismatic Grade A cells available and 18650Battery Store consistently provides the highest quality. The packaging is starting to slide from my first set purchased in August of 2024. They had been fully enclosed in high quality Styrofoam pacing but now the top just has a strip across the 4 pack of cells. This is likely from the manufacturer as the boxes are marked in Chinese. My latest shipment arrived without damage though.
Nice
(PRE-ORDER) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery - ETA FEB 21
Some damage to the boxes but the batteries were padded so well they were perfect. I was going to top balance them until i saw the voltage readings. Put a 16S together with a JK 2A bms and just charged them up. Had to sit for a while at 98% but then they were perfect. There is that word again. And flex buss bars..........smiley face.
The battery arrived, well packaged, and in perfect shape. After charging, the battery has worked perfectly as expected.
(PRE-ORDER) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery - ETA FEB 21
18650 BatteryStore does it again! Outstanding packaging as always and cells perfectly matched. I do not buy batteries anywhere else and will soon add 12 more.
(PRE-ORDER) EVE MB31 Grade A Cells - 3.2V LiFePO4 314Ah Battery - ETA FEB 21
En muy buen estado todo bien muy satisfecho
😅😅
love how they arrive with unmatched serious packaging keeping them in perfect shape and all at the same voltage not to mention the included bus bars in both aluminum and flexible copper plus all the screws to tie them together. third purchase with more possible in the future
These cells were great looking and all balanced. Couldn't be more happier
Excellent product and shipping. Will be buying more.
Excellent service ,communication and delivery! Cell on my doorstep in 7 days from order!