The 2018 Grom uses a 12-volt sealed lead-acid motorcycle battery, usually around 5–6 Ah. The most common replacements are the YTZ7S or YTX7L-BS types, depending on market and mounting arrangement.
Battery basics for the 2018 Grom
The Grom’s electrical system operates on a standard 12-volt supply, with the battery tucked under the seat. A compact sealed lead-acid (SLA) battery provides reliable cranking power for this small motorcycle. While many riders stick with the stock type, there are lithium-based upgrade options available, though they require attention to charging compatibility and a suitable Battery Management System (BMS).
Replacement options
Below are common battery families that fit the Grom’s size and electrical needs. These are widely sold as direct replacements or OEM-equivalents, but you should verify the exact dimensions and terminal layout before purchasing.
- YTZ7S-style 12V sealed lead-acid motorcycle battery (roughly 6 Ah capacity).
- YTX7L-BS-style 12V sealed lead-acid motorcycle battery (similar capacity, different terminal arrangement).
In practice, either option will power the Grom’s starter and electricals, but confirm the terminal orientation (positive/negative) and tray fit for your exact model.
Notes on compatibility
Battery size and terminal positions can vary slightly by market and production year. If unsure, compare the new battery to your old unit or bring both to a parts retailer to verify fitment and mounting clearance. Your owner’s manual also provides the recommended specification for your VIN.
Upgrading considerations
Some riders upgrade to lithium-based 12V batteries (often LiFePO4) for weight savings and longer life. These can be compatible with the Grom, but they typically require a BMS-equipped unit and may demand attention to the bike’s charging system and voltage regulation. Always choose a battery designed for motorcycles and ensure proper charging compatibility and wiring the positive/negative terminals correctly.
Summary
For the 2018 Honda Grom, the stock battery is a compact 12-volt sealed lead-acid type in the 5–6 Ah range, with common replacements including YTZ7S or YTX7L-BS. Check fitment for your market and consider professional guidance if upgrading to lithium-based packs. Regular inspection and proper terminal maintenance help ensure reliable startup power.