Mighty Max Battery YTX4L-BS Replacement for Snapper Push Lawnmower Walk Behind Lawn Mower

What It Is

The Mighty Max YTX4L-BS is a sealed lead-acid (AGM) battery designed to replace the original battery in Snapper push lawn mowers and certain walk-behind models. It provides the 12V power needed for electric-start engines, eliminating pull-start effort.

Fitment & Compatibility

Before buying, verify these three things:

1. Battery size: The YTX4L-BS measures 4.5" L x 2.8" W x 3.4" H. Measure your battery tray to confirm it fits—this is smaller than typical riding mower batteries.
2. Terminal layout: This battery has left positive (+) and right negative (-) terminals (viewed from the front). Check that your mower’s cable routing matches this orientation.
3. Model compatibility: Works with Snapper walk-behind mowers using electric start (e.g., models with 6.75–9.5 ft-lb engines). Not for riding mowers or zero-turns. Confirm your mower’s model number against Mighty Max’s fitment list—OEM part numbers include Snapper 702158, 7022158, or 7022158YP.

OEM vs aftermarket: This is a non-OEM replacement. It lacks the Snapper branding but uses the same AGM chemistry and terminal design.

Key Things to Know

• Quality: AGM construction is spill-proof and vibration-resistant, but some users report shorter lifespan (2–3 years) compared to premium brands like Yuasa or Deka. Expect reliable performance in moderate climates; extreme heat may degrade it faster.
• Installation difficulty: Easy—remove old battery (usually two wing nuts), connect red to positive (+), black to negative (-), and secure with the hold-down bracket. No fluid filling or activation required.
• Common gotchas:
  • The battery arrives with a “storage charge” (about 12.4V). For best cranking, charge it fully (12.7–12.8V) before first use—a standard 1-amp charger works.
  • If your mower sits unused for months, use a battery maintainer to prevent sulfation. This battery can self-discharge faster than premium options.
  • The terminal bolts are M5 x 0.8; ensure your cables have ring terminals that fit (most Snapper cables do).

Should You Buy It

If you need a budget-friendly, drop-in replacement for a Snapper walk-behind mower and don’t mind a slightly shorter lifespan than premium brands, this battery is a solid value. It’s ideal for occasional users who want reliable starts without the cost of OEM batteries. For heavy daily use or harsh climates, consider a higher-end AGM battery.