Mighty Max Battery Y50-N18L-A3 Replacement Battery for MTD 700 Series Riding Lawn Mower

What It Is

The Mighty Max Battery Y50-N18L-A3 is a sealed lead-acid (AGM) replacement battery designed to start and power the electrical system on MTD 700 Series riding lawn mowers and compatible garden tractors. It delivers 12V with 275 cold cranking amps (CCA) for reliable starting, even in cooler weather.

Fitment & Compatibility

Before buying, confirm your mower uses a Group U1 battery size. The Y50-N18L-A3 measures approximately 7.7" L x 5.1" W x 6.2" H. It directly replaces MTD OEM battery part numbers 725-04064, 725-04064A, 725-04117, and 725-04117A. It fits most MTD 700 Series models (e.g., 13A-325-190, 13AC762G755) and many 600/800 series. Check your owner’s manual or existing battery label for “Y50-N18L-A3” or “U1L” compatibility. Verify terminal orientation: positive terminal should be on the right when facing the battery (standard for MTD).

Key Things to Know

• AGM vs. flooded: This is an absorbed glass mat (AGM) battery—spill-proof, maintenance-free, and vibration-resistant. No need to add water.
• Installation: Simple DIY swap—disconnect negative terminal first, remove hold-down bracket, replace, and reconnect positive then negative. Expect about 20 minutes.
• CCA rating: 275 CCA is adequate for most single-cylinder lawn tractor engines (12–20 HP). For larger twin-cylinder engines or cold climates, consider a higher CCA battery.
• Charging: Use a charger compatible with AGM batteries (typically 2–10 amps). Overcharging can damage the sealed design.

Should You Buy It

If you need a direct, no-fuss replacement for an MTD 700 Series mower and want the durability of a sealed AGM battery without the spill risk of traditional flooded batteries, this is a solid choice. The low price and 1-year warranty make it a good value for standard residential use, but if you have a high-horsepower engine or mow in freezing temps, you might prefer a battery with higher CCA.