diff --git a/cue/src/lsv_analysis.rs b/cue/src/lsv_analysis.rs
index 0fe8ba9..b6bc244 100644
--- a/cue/src/lsv_analysis.rs
+++ b/cue/src/lsv_analysis.rs
@@ -91,6 +91,69 @@ pub fn detect_qhq_peak(points: &[LsvPoint]) -> Option<f32> {
         .map(|&(idx, _)| v_vals[idx])
 }
 
+#[derive(Debug, Clone, Copy)]
+pub struct ClPotentials {
+    pub v_free: f32,
+    pub v_free_detected: bool,
+    pub v_total: f32,
+    pub v_total_detected: bool,
+}
+
+pub fn derive_cl_potentials(points: &[LsvPoint]) -> ClPotentials {
+    let default = ClPotentials {
+        v_free: 100.0,
+        v_free_detected: false,
+        v_total: -200.0,
+        v_total_detected: false,
+    };
+    if points.len() < 5 {
+        return default;
+    }
+
+    let i_vals: Vec<f32> = points.iter().map(|p| p.i_ua).collect();
+    let v_vals: Vec<f32> = points.iter().map(|p| p.v_mv).collect();
+
+    let window = 5.max(points.len() / 50);
+    let smoothed = smooth(&i_vals, window);
+
+    let i_min = smoothed.iter().copied().fold(f32::INFINITY, f32::min);
+    let i_max = smoothed.iter().copied().fold(f32::NEG_INFINITY, f32::max);
+    let prominence = (i_max - i_min) * 0.05;
+
+    let extrema = find_extrema(&v_vals, &smoothed, prominence);
+
+    // v_free: most prominent cathodic peak (is_max==false) in +300 to -300 mV
+    let free_peak = extrema.iter()
+        .filter(|&&(idx, is_max)| !is_max && v_vals[idx] >= -300.0 && v_vals[idx] <= 300.0)
+        .min_by(|a, b| smoothed[a.0].partial_cmp(&smoothed[b.0]).unwrap_or(std::cmp::Ordering::Equal));
+
+    let (v_free, v_free_detected, free_idx) = match free_peak {
+        Some(&(idx, _)) => (v_vals[idx], true, Some(idx)),
+        None => (100.0, false, None),
+    };
+
+    // v_total: secondary cathodic peak between (v_free - 100) and -500 mV, excluding free peak
+    let total_lo = -500.0_f32;
+    let total_hi = v_free - 100.0;
+    let total_peak = extrema.iter()
+        .filter(|&&(idx, is_max)| {
+            !is_max
+                && v_vals[idx] >= total_lo
+                && v_vals[idx] <= total_hi
+                && Some(idx) != free_idx
+        })
+        .min_by(|a, b| smoothed[a.0].partial_cmp(&smoothed[b.0]).unwrap_or(std::cmp::Ordering::Equal));
+
+    let (v_total, v_total_detected) = match total_peak {
+        Some(&(idx, _)) => (v_vals[idx], true),
+        None => (v_free - 300.0, false),
+    };
+
+    let v_total = v_total.max(-400.0);
+
+    ClPotentials { v_free, v_free_detected, v_total, v_total_detected }
+}
+
 pub fn detect_peaks(points: &[LsvPoint]) -> Vec<LsvPeak> {
     if points.len() < 5 {
         return Vec::new();