Mighty Max Battery 12V 35Ah Gel Battery Replaces JohnDeere Lawn Tractor-Riding Mower 108

What It Is

The Mighty Max Battery 12V 35Ah Gel Battery is a sealed, maintenance-free replacement battery designed for lawn tractors and riding mowers like the John Deere 108. It uses absorbed glass mat (AGM) gel technology, making it spill-proof and resistant to vibration, ideal for outdoor power equipment.

Fitment & Compatibility

Before buying, verify three things:

• Dimensions: This battery measures 7.68" L x 5.16" W x 6.14" H. Measure your existing battery tray to ensure it fits. The terminal layout (positive left, negative right when facing terminals) must match your mower’s cable routing.
• Voltage & Capacity: It’s a 12V, 35Ah (amp-hour) battery. This replaces standard lawn tractor batteries with similar Ah ratings (e.g., 28Ah–35Ah). Check your mower’s manual or old battery for CCA (cold cranking amps) requirements—this battery is not rated in CCA, so it may struggle in very cold starts.
• OEM & Cross-References: Replaces John Deere part numbers AM103636, AM105114, and many others. Also fits many Craftsman, Husqvarna, and MTD models with a BCI group U1 or U1R battery. Confirm your mower uses a U1 size group.

Key Things to Know

• Gel vs. Lead-Acid: This is a sealed gel battery, meaning no water topping and no acid leaks. It can be mounted in any position (except upside down) and has lower self-discharge than standard flooded batteries.
• Installation: Simple bolt-in swap—remove old battery, clean terminals, connect red to positive (+), black to negative (−). Use a battery charger with a gel/AGM setting; a standard charger can overcharge and damage it.
• Cold Weather Performance: Gel batteries lose starting power in freezing temps. If you mow in winter or store the mower in an unheated shed, consider a higher-CCA flooded battery instead.
• Lifespan: Expect 2–4 years with proper charging. If your mower sits for months, use a maintainer to prevent sulfation.

Should You Buy It

Buy this if you want a spill-proof, low-maintenance battery for a John Deere 108 or similar riding mower and don’t need extreme cold cranking power. It’s a solid value at $79.99 for casual to moderate use. Skip it if you mow in sub-freezing temperatures or need a high-CCA battery for a demanding engine.