The Honda 300 FourTrax typically uses a 12-volt sealed lead-acid battery around 9 amp-hours (9Ah). Replacement is commonly the YTX9-BS or an equivalent that fits the bike’s battery tray. Always verify the exact spec for your model year.
Battery basics for the Honda 300 FourTrax
Voltage, capacity, and form factor
The TRX300 family runs on a standard 12-volt electrical system and uses a maintenance-free, sealed lead-acid battery. The typical replacement capacity is about 9Ah, with some year-to-year variation within a small range. Batteries are usually two-post units compatible with automotive-style post terminals.
Before buying, note that several model years may differ slightly in the exact footprint or terminal layout. Checking the owner’s manual or the OEM battery part number for your specific year is the best way to confirm fit.
- Voltage and type: 12-volt sealed lead-acid (maintenance-free).
- Typical capacity: around 9Ah (some years may vary within a 7–10Ah range; confirm for your bike).
- Terminal configuration: two post terminals compatible with standard 6.3 mm (1/4 inch) posts.
- Common replacement option: YTX9-BS or an equivalent 12V 9Ah battery that fits the TRX300 tray.
When replacing, ensure the replacement matches the physical footprint and terminal layout of the original. If in doubt, compare the dimensions and posts to the current battery or consult the OEM part number for your year.
How to verify the exact fit for your year
Because Honda sometimes updated specs across model years, use these steps to confirm the correct battery for your specific bike.
- Consult the owner’s manual or the OEM battery part number for your year and trim.
- Measure the current battery’s dimensions (length, width, height) and compare with the replacement’s specs.
- Verify terminal orientation and polarity; ensure the positive and negative posts align with the bike’s cables.
- Choose a 12V, approximately 9Ah sealed lead-acid battery that lists compatibility with Honda TRX300 FourTrax models.
With the correct fit, the FourTrax should start reliably and power lights and accessories without cranking issues. If you cannot find an exact compatibility note, contact a Honda dealer or ATV parts retailer with your VIN or model year for the precise OEM battery specification.
Shopping tips and replacement options
To shop confidently, keep these recommendations in mind and avoid mismatched batteries that won’t fit or connect properly.
- Look for 12V sealed lead-acid batteries labeled as YTX9-BS or equivalent; these are the common fits for the TRX300.
- Prefer maintenance-free or AGM variants if you ride in vibration-heavy conditions or store the bike for long periods.
- Ensure the replacement’s dimensions and terminal posts match the stock configuration; check the product spec sheet or vendor diagrams.
- Consider reliability and warranty from reputable brands (Yuasa, Interstate, and other established manufacturers).
By sticking to a 12V 9Ah class battery with the correct post layout, you’ll maintain reliable starts and electrical performance on your Honda 300 FourTrax. For exact fit, always confirm with the model-year documentation or a dealer.
Summary
The Honda 300 FourTrax typically uses a 12V sealed lead-acid battery around 9Ah, with the common replacement being a YTX9-BS or equivalent. Verify your exact model year’s OEM specification, measure the tray and posts, and choose a battery that matches voltage, capacity, and terminal arrangement for a proper fit and dependable starting power.