Grin Cycle Analyst V3
The data nerd's e-bike display and the gold standard for DIY builds. The Cycle Analyst shows everything — volts, amps, watts, amp-hours used, range — and can actively limit speed and current to protect your system.
The Cycle Analyst (CA) from Grin Technologies is the long-running benchmark for monitoring and controlling a DIY e-bike. Wired inline with a shunt, it gives you a true picture of what your system is doing: instantaneous power, battery voltage under load, amp-hours consumed, efficiency in Wh/mile, and a genuinely useful range estimate. For diagnosing a build or babysitting battery health, nothing off-the-shelf comes close.
Beyond monitoring, the V3 can actively govern your bike — capping speed, limiting current, and shaping throttle response — and it pairs with Grin's Phaserunner and other controllers for torque/PAS throttle modes. The hardware looks dated next to a color smart display, but for builders who want real numbers and real control, it remains the one to beat.
Where to buy
Two paths — match your spend to the build. Quality picks last longer and come with real support; affordable picks get you rolling for less. Always confirm fitment, voltage, and connectors for your bike first.
Quality picks
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Pro tips from our test team
- Watch voltage sag — battery voltage under load tells you far more about pack health than a 5-bar gauge.
- Use the amp-limit to protect a small controller or a tired battery from overcurrent.
- Get the direct-plug (DP) version if your controller has a matching CA connector — it saves wiring the shunt.