diff --git a/goodwe_controller/DOCS.md b/goodwe_controller/DOCS.md
index 6523d3f..7c46df8 100644
--- a/goodwe_controller/DOCS.md
+++ b/goodwe_controller/DOCS.md
@@ -1672,7 +1672,8 @@ balances, so it need not reach `maintenance_soc_target`. The charge counts as
 done when the battery is within 3 points of the target and has taken no more
 charge for 60 minutes of charging time, or when the charging time (36 hours) runs
 out within 3 points of the target. Only the minutes the cheap-hours gate let the
-battery charge count. Then the usual hold follows.
+battery charge count, and the charge ends after 7 days at the
+latest. Then the usual hold follows.
 
 **When a cycle fails.** If the battery does not empty in 12 hours, or does not
 get within 3 points of the target in 36 hours of charging time, the cycle
diff --git a/goodwe_controller/test_maint13.py b/goodwe_controller/test_maint13.py
index c2bf93b..07881ed 100644
--- a/goodwe_controller/test_maint13.py
+++ b/goodwe_controller/test_maint13.py
@@ -240,6 +240,10 @@ check("a gap in the ticks (add-on down) counts for exactly 5 minutes (the cap)",
       abs(m._trk["open_min"] - before - 5.0) < 1e-9)
 m.tick(t + 2 * timedelta(hours=1) + 2 * MIN, 70.0)
 check("...and a 2 minute step counts 2", abs(m._trk["open_min"] - before - 7.0) < 1e-9)
+_t = t + 2 * timedelta(hours=1) + 2 * MIN
+m.tick(_t - 10 * MIN, 70.0)          # the clock steps back 10 min
+check("...and a step back in time counts nothing (not minus)",
+      abs(m._trk["open_min"] - before - 7.0) < 1e-9)
 
 print("6. restarts and old state files")
 with tempfile.TemporaryDirectory() as d:
@@ -286,6 +290,19 @@ with tempfile.TemporaryDirectory() as d:
     res, _, out = run(mo, T0 + MIN, 120, 70.0)
     check("...so it fails when the 36 h are up, as before",
           out and out[0].failed == "charge")
+    # A record left by another charge (an add-on rolled back and forward
+    # again does not clear it) must not be read as this charge's.
+    stale = {"phase": "charge",
+             "phase_started": (T0 - timedelta(hours=2)).isoformat(),
+             "charge_track": {"since": (T0 - timedelta(days=30)).isoformat(),
+                              "open_min": 2000.0, "flat_min": 59.0,
+                              "best": 99.0, "at": None}}
+    ms = Maintenance(CFG, Mem(stale))
+    r = ms.tick(T0, 98.0)
+    check("a charge record from another charge is ignored: this charge counts "
+          "its own 2 h and its own best",
+          r.phase == CHARGE and 119 < ms._trk["open_min"] < 121
+          and ms._trk["flat_min"] == 0.0 and ms._trk["best"] == 98.0)
     mi = Maintenance(CFG, Store(os.path.join(d, "none.json")))
     check("no state file: due, no back-off", mi.due(T0) and mi.backoff_until(T0) is None)