JIS 145G51 (N150) Battery¶
The 145G51 is a JIS N150 group-size automotive battery — a heavy-duty 12V lead-acid unit built for commercial vehicles operating in Japanese and Asian markets. It is the standard high-capacity starting battery for large trucks, buses, diesel generator sets, and construction or agricultural equipment that demand sustained cranking torque plus a stable reserve for accessory loads.
The model code unpacks the way JIS names its batteries. The prefix 145 is a performance rating tied to cranking capability, G51 is the terminal-and-case layout code (G denotes the terminal profile, 51 the case length class), and the group size N150 is the physical footprint reference. You'll see this same battery sold under aliases like 145G51, N150, or CMF145G51 depending on the supplier. See Standards Comparison for how JIS sizing compares to DIN and BCI.
Key Specifications¶
| Field | Value |
|---|---|
| Standard | JIS D 5301 (N-series) |
| Group Size | N150 |
| Voltage | 12V (6 cells) |
| Capacity (C20) | 150–160 Ah |
| CCA (reference) | 1050 A (SAE, −18°C) |
| Reserve Capacity | Confirm on inquiry |
| Terminal Type | JIS post — confirm polarity on inquiry |
| Application | Heavy trucks, buses, diesel gensets, construction/ag equipment |
CCA is a reference value, and it is test-method dependent. A number quoted on the JIS basis (−15°C) is not the same as one quoted on the SAE/EN basis (−18°C). The 1050 A figure above is an SAE-basis reference taken from a JIS N150 datasheet — always confirm the basis and the final value with the manufacturer before putting it into a product specification. See CCA Testing for the full methodology.
Electrical Performance¶
The N150 sits near the top of the JIS N-series. Its electrical profile is shaped for cold diesel starts, where thickened oil raises cranking resistance, and for extended accessory run time.
- Capacity (C20) — 150–160 amp-hours at the 20-hour rate. This is the stored-energy figure that keeps lights, climate control, and comms gear alive when the alternator output tapers.
- CCA — roughly 850–1050 A depending on the test basis and plate design. Vendor datasheets show a wide spread: some 145G51 units rate at 685 A on the JIS basis while maintenance-free variants reach 1050 A on the SAE basis.
- Reserve Capacity (RC) — published on inquiry; the manufacturer does not list a fixed RC because it shifts with the Ah rating and plate formula.
- Charging current — heavy N-series batteries accept a higher bulk charge than passenger-car units; confirm the recommended rate for the specific batch.
The relationship between Ah and CCA matters here: a diesel crane or long-haul tractor needs both — high CCA for the first cranking burst and high Ah to carry extended idle or hotel loads. See Capacity & Reserve.
Dimensions & Tolerance¶
Physical dimensions are confirmed against the production batch. Reference case dimensions are in the region of:
| Dimension | Reference value |
|---|---|
| Length | ~508–510 mm |
| Width | ~220–222 mm |
| Height | ~210–234 mm (varies with lid/handle configuration) |
| Wet weight | ~45 kg |
JIS N-series cases allow a small manufacturing tolerance on the case envelope. Even a few millimetres of overhang will stop the battery seating in the tray or clearing the hood, so verify the exact case size against your vehicle or a sample before committing. Height is the least forgiving figure: versions with an integrated handle or a raised lid ("扁頭"/flat-head variants) differ by up to 20 mm.
Terminal Type & Polarity¶
The N150 uses JIS posts. JIS terminals are the smaller, tapered posts common to Japanese and Asian vehicles — they do not interchange with the recessed DIN or the larger BCI/SAE top-post hardware without an adapter.
Polarity and terminal layout are not fixed at the group-size level. The same N150 is produced in right-positive and left-positive configurations, and orientation must be confirmed on inquiry against the vehicle's cable routing and hold-down. Getting this wrong means the cables will not reach, or worse, a reversed-connection fault at installation.
Compatible Vehicles & Applications¶
The N150/145G51 is a fleet workhorse for Asian-market heavy vehicles. Typical fitments include:
- Heavy trucks and tractor heads — Japanese and Asian OEM platforms (Hino, Isuzu, Fuso, UD Trucks, and equivalent) using the JIS N-series tray.
- Buses and coaches — city and intercity units with high accessory and door-pneumatic loads.
- Diesel generator sets — standby and prime-power gensets where a 12V bank must deliver a reliable cold start.
- Construction & agricultural equipment — excavators, wheel loaders, crawlers, and tractors that combine high cranking demand with constant vibration.
The N150 is a fuel-engine starting battery, not a deep-cycle or hybrid unit. For applications that cycle deeply or run lithium chemistries, a different platform is required.
N150 vs N200¶
Both are JIS N-series heavy-duty references. The N150 is the smaller of the two: ~160 Ah and a ~508 mm case, versus the N200's ~200 Ah and ~518 mm case. Where the N150 suits standard heavy trucks and gensets, the N200 steps up for the largest engines and the heaviest accessory loads. See the 190H52 (N200) page.
Source & Purchase¶
For high-volume OEM and private-label sourcing with full analytical documentation, browse the complete battery catalog on the main website.