The Honda Grom uses a small 12-volt sealed lead-acid (SLA) maintenance-free battery, typically around 5 Ah. It's a compact unit designed to fit under the seat; many riders upgrade to lighter lithium options, but stock is SLA.
Stock battery: the standard Grom setup
The following details describe the core characteristics you can expect from the Grom's factory battery across most model years.
- Type: 12-volt sealed lead-acid (SLA), maintenance-free
- Capacity: commonly around 5 Ah (rated near 4.5–5.0 Ah depending on model year)
- Construction: compact motorcycle battery designed to fit under the seat
- Terminals: standard positive/negative posts oriented for motorcycle wiring
- Typical brands used by dealers and aftermarket suppliers: generic SLA/AGM variants sourced for small bikes
In short, the Grom's stock battery is a small 12V SLA unit around 5 Ah, with an AGM-style construction common in motorcycles.
Upgrading and alternatives
Many riders consider lighter alternatives or longer-lived options to reduce weight or extend maintenance intervals. Here are the common paths people take.
- AGM 12V batteries rated around 4–5 Ah (sealed, maintenance-free, similar footprint to stock)
- LiFePO4 (lithium) 12V packs in the 4–8 Ah range for significant weight savings
- Battery management considerations: LiFePO4 requires compatible charging/monitoring and may need a different regulator/charger setup
When upgrading, ensure the replacement physically fits under the seat, matches the terminal layout, and does not overload the Grom's charging system.
Choosing the right battery for your Grom
To pick the right battery, verify the vehicle's requirements, dimensions, and electrical system compatibility. Use the owner's manual or a trusted parts catalog to confirm exact specs for your year and market.
- Voltage: 12V
- Capacity: 4–6 Ah (stock is around 5 Ah)
- Size/fit: ensure the battery fits under the seat with room for wiring and venting
- Terminals: confirm positive and negative post orientation matches your bike's harness
- Charging compatibility: ensure the charger and alternator can safely handle the chosen technology (SLA vs LiFePO4)
Assessing these factors helps avoid starting or charging issues and ensures reliable performance.
Maintenance and care tips
Keep the battery charged, check for corrosion on terminals, and store the bike with a trickle charger connected if it will sit for extended periods. If you switch to LiFePO4, follow the supplier's charging recommendations to preserve the battery life.
Conclusion
The Honda Grom ships with a compact 12-volt sealed lead-acid battery around 4–5 Ah, and many riders upgrade to heavier-duty or lighter options based on preference and riding needs. Stock SLA is adequate for normal commuting, while LiFePO4 can offer weight savings and longer cycle life with proper charging compatibility.
Summary
Stock Grom battery: 12V SLA, ~5 Ah. Upgrades: AGM or LiFePO4 options exist; check fit and charging compatibility. Always refer to model-year specifics for exact dimensions and terminals.