diff --git a/core/site_optimizer.go b/core/site_optimizer.go
index cede325c5..12c8a5b3e 100644
--- a/core/site_optimizer.go
+++ b/core/site_optimizer.go
@@ -119,8 +119,11 @@ func (site *Site) optimizerUpdate(battery []types.Measurement) error {
 	if solarTariff != nil && len(solar) > 0 {
 		minLen = min(minLen, len(solar))
 	}
-	const expectedSlots = 8
-	if minLen < expectedSlots {
+
+	// limit to 2 days for sake of performance
+	minLen = min(96, minLen)
+
+	if expectedSlots := 8; minLen < expectedSlots {
 		if solarTariff != nil {
 			return fmt.Errorf("not enough forecast slots for meaningful optimization: %d < %d (grid=%d, feedIn=%d, solar=%d)", minLen, expectedSlots, len(grid), len(feedIn), len(solar))
 		}