Bigger Battery Mod

Hi everyone,

I’m looking into a Hornet S1 scooter battery upgrade and wanted to sanity-check the idea before I touch anything. The goal is pretty simple: more range, not more speed. I’ve seen people talk about fitting a larger-capacity battery or parallel pack, but I want to do this safely and in a way that actually works long-term.

From what I understand so far, the big concerns are battery voltage compatibility, BMS limits, and whether the stock controller can handle the extra capacity without stressing components. I’m not planning to change the nominal voltage, just increase Ah capacity so the scooter runs longer per charge.

My rough plan is to keep the same voltage rating, use a quality lithium pack with a proper BMS, and make sure wiring, fusing, and connectors are upgraded if needed. I also plan to secure the pack properly and watch heat buildup during longer rides.

For those who’ve done scooter or e-mobility battery mods:

Is running a higher-capacity pack at the same voltage generally safe with stock controllers? Any common mistakes that cause premature controller or BMS failure? Would you recommend parallel packs, or is a single larger pack usually the better approach?

I’m comfortable with basic wiring and measurements, but I’m trying to avoid “learning the hard way.” Any real-world advice would be appreciated.