diff --git a/docs/nmea/init-cool.lua b/docs/nmea/init-cool.lua
index 5f5e493..4ddbd40 100644
--- a/docs/nmea/init-cool.lua
+++ b/docs/nmea/init-cool.lua
@@ -167,11 +167,11 @@ function PrintUart()
         fail_cnt = fail_cnt + 1
     end
     if (sync_att >= 2 or fail_cnt >= 3) then
-        print("going to deep sleep mode")
+        print("going to deep sleep for " .. math.floor((node.dsleepMax()-1e8)/1e6/60) .. " min")
         tmr.create():alarm(3000, tmr.ALARM_SINGLE, function()
     	    -- !! rtctime.dsleep() breaks NTP, using node.dsleep() instead
             -- node.dsleep(1810e6); -- ~30 min sleep, will be rebooted (32-bit value for "integer" fw)
-            node.dsleep(36000e6) -- >3 hrs sleep, will be rebooted (64-bit value for "float" fw)
+            node.dsleep(node.dsleepMax()-1e8) -- >3 hrs sleep, will be rebooted (64-bit value for "float" fw)
         end)
     end
 end
diff --git a/docs/nmea/nmea_howto.txt b/docs/nmea/nmea_howto.txt
index 3bc00b0..1b74465 100644
--- a/docs/nmea/nmea_howto.txt
+++ b/docs/nmea/nmea_howto.txt
@@ -88,11 +88,11 @@ so USB-TTL +5V line shouldn't be connected when powered from the clock!
 
   - uses DHCP mode by default (can be disabled with DHCP=0)
   - has no http server
-  - after 2 successfull sync attempts it goes to deep sleep for 10 hrs.
+  - after 2 successfull sync attempts it goes to deep sleep for ~3.5 hrs.
     so it consumes much less power and generates almost no heat.
     just rename it to init.lua before uploading to ESP866.
-  - script uses node.dsleep() for 10 hrs by default.
-    please change value to 30 min if you're using "integer" nodemcu FW.
+  - script uses node.dsleep() for ~3.5 hrs (max for nodemcu) by default.
+    please change value to less than 36 min if you're using "integer" nodemcu FW.
 
   notice: deep sleep function can only be used when
   ESP8266 PIN32(RST) and PIN8(XPD_DCDC aka GPIO16) are connected together.