diff --git a/frontend/optmath.lua b/frontend/optmath.lua
index 178ebdb0d..7a22612a3 100644
--- a/frontend/optmath.lua
+++ b/frontend/optmath.lua
@@ -3,6 +3,7 @@ Simple math helper functions
 ]]
 
 local bit = require("bit")
+local dbg = require("dbg")
 
 local Math = {}
 
@@ -102,4 +103,26 @@ function Math.tmax(tab, func)
     return tmin_max(tab, func, "max")
 end
 
+--[[--
+Restricts a value within an interval.
+
+@number value
+@number min
+@number max
+@treturn number value clamped to the interval [min,max]
+]]
+function Math.clamp(value, min, max)
+    if value <= min then
+        return min
+    elseif value >= max then
+        return max
+    end
+    return value
+end
+dbg:guard(Math, "minmax",
+    function(value, min, max)
+        assert(min ~= nil and max ~= nil, "Math.clamp: min " .. min .. " and max " .. nil .. " must not be nil")
+        assert(min < max, "Math.clamp: min .. " .. min .. " must be less than max " .. max)
+    end)
+
 return Math
diff --git a/frontend/ui/widget/datetimewidget.lua b/frontend/ui/widget/datetimewidget.lua
index fe89d4f43..fbc570ed9 100644
--- a/frontend/ui/widget/datetimewidget.lua
+++ b/frontend/ui/widget/datetimewidget.lua
@@ -19,6 +19,7 @@ local VerticalSpan = require("ui/widget/verticalspan")
 local WidgetContainer = require("ui/widget/container/widgetcontainer")
 local _ = require("gettext")
 local Screen = Device.screen
+local T = require("ffi/util").template
 
 local DateTimeWidget = InputContainer:new{
     title_face = Font:getFace("x_smalltfont"),
@@ -64,33 +65,34 @@ function DateTimeWidget:init()
     end
 
     -- Actually the widget layout
-    self:update()
+    self:layout()
 end
 
-function DateTimeWidget:update()
-    local year_widget = NumberPickerWidget:new{
+local year_widget, month_hour_widget, day_min_widget
+function DateTimeWidget:layout()
+    year_widget = NumberPickerWidget:new{
         show_parent = self,
         value = self.year,
         value_min = 2021,
         value_max = 2041,
         value_step = 1,
-        value_hold_step = 4,
+        value_hold_step = self.year_hold_step or 4,
     }
-    local month_hour_widget = NumberPickerWidget:new{
+    month_hour_widget = NumberPickerWidget:new{
         show_parent = self,
         value = self.is_date and self.month or self.hour,
-        value_min = self.is_date and 1 or 0,
-        value_max = self.is_date and 12 or self.hour_max,
+        value_min = self.hour_min or self.month_min or (self.is_date and 1 or 0),
+        value_max = self.hour_max or self.month_max or (self.is_date and 12 or 24),
         value_step = 1,
-        value_hold_step = 3,
+        value_hold_step = self.hour_hold_step or self.month_hold_step or 3,
     }
-    local day_min_widget = NumberPickerWidget:new{
+    day_min_widget = NumberPickerWidget:new{
         show_parent = self,
         value = self.is_date and self.day or self.min,
-        value_min = self.is_date and 1 or 0,
-        value_max = self.is_date and 31 or 59,
+        value_min = self.min_min or self.day_min or (self.is_date and 1 or 0),
+        value_max = self.min_max or self.day_max or (self.is_date and 31 or 59),
         value_step = 1,
-        value_hold_step = self.is_date and 5 or 10,
+        value_hold_step = self.day_hold_step or self.min_hold_step or (self.is_date and 5 or 10),
         date_month_hour = month_hour_widget,
         date_year = year_widget,
     }
@@ -146,49 +148,59 @@ function DateTimeWidget:update()
     else
         date_info = VerticalSpan:new{ width = 0 }
     end
-    local buttons = {
-        {
-            {
-                text = self.cancel_text,
-                callback = function()
-                    self:onClose()
-                end,
-            },
+
+    local buttons = {}
+    if self.default_value then
+        table.insert(buttons, {
             {
-                text = self.ok_text,
+                text = self.default_text or T(_("Default value: %1"), self.default_value),
                 callback = function()
-                    if self.callback then
-                        self.year = year_widget:getValue()
-                        if self.is_date then
-                            self.month = month_hour_widget:getValue()
-                            self.day = day_min_widget:getValue()
-                        else
-                            self.hour = month_hour_widget:getValue()
-                            self.min = day_min_widget:getValue()
-                        end
-                        self:callback(self)
+                    if self.default_callback then
+                        self.default_callback(year_widget:getValue(), month_hour_widget:getValue(),
+                            day_min_widget:getValue())
+                    end
+                    if not self.keep_shown_on_apply then -- assume extra wants it same as ok
+                        self:onClose()
                     end
-                    self:onClose()
                 end,
             },
-        }
-    }
+        })
+    end
     if self.extra_text then
-        table.insert(buttons,{
+        table.insert(buttons, {
             {
                 text = self.extra_text,
                 callback = function()
-                    if self.extra_callback then
-                        self.extra_callback(year_widget:getValue(), month_hour_widget:getValue(),
-                            day_min_widget:getValue())
-                    end
-                    if not self.keep_shown_on_apply then -- assume extra wants it same as ok
-                        self:onClose()
-                    end
+                    self.extra_callback(self)
                 end,
             },
         })
     end
+    table.insert(buttons, {
+        {
+            text = self.cancel_text,
+            callback = function()
+                self:onClose()
+            end,
+        },
+        {
+            text = self.ok_text,
+            callback = function()
+                if self.callback then
+                    self.year = year_widget:getValue()
+                    if self.is_date then
+                        self.month = month_hour_widget:getValue()
+                        self.day = day_min_widget:getValue()
+                    else
+                        self.hour = month_hour_widget:getValue()
+                        self.min = day_min_widget:getValue()
+                    end
+                    self:callback(self)
+                end
+                self:onClose()
+            end,
+        },
+    })
 
     local ok_cancel_buttons = ButtonTable:new{
         width = self.width - 2*Size.padding.default,
@@ -242,6 +254,15 @@ function DateTimeWidget:update()
     end)
 end
 
+function DateTimeWidget:update(left, mid, right)
+    year_widget.value = left
+    year_widget:update()
+    month_hour_widget.value = mid
+    month_hour_widget:update()
+    day_min_widget.value = right
+    day_min_widget:update()
+end
+
 function DateTimeWidget:onCloseWidget()
     UIManager:setDirty(nil, function()
         return "ui", self.date_frame.dimen
diff --git a/frontend/util.lua b/frontend/util.lua
index 51ff1e46d..7f81916f0 100644
--- a/frontend/util.lua
+++ b/frontend/util.lua
@@ -111,7 +111,7 @@ Source: <a href="https://gist.github.com/jesseadams/791673">https://gist.github.
 ---- @int seconds number of seconds
 ---- @bool withoutSeconds if true 00:00, if false 00:00:00
 ---- @treturn string clock string in the form of 00:00 or 00:00:00
-function util.secondsToClock(seconds, withoutSeconds)
+function util.secondsToClock(seconds, withoutSeconds, withDays)
     seconds = tonumber(seconds)
     if not seconds then
         if withoutSeconds then
@@ -127,7 +127,14 @@ function util.secondsToClock(seconds, withoutSeconds)
         end
     else
         local round = withoutSeconds and require("optmath").round or passthrough
-        local hours = string.format("%02d", seconds / 3600)
+        local days = "0"
+        local hours
+        if withDays then
+            days = string.format("%d", seconds / (24*3600)) -- implicit math.floor for string.format
+            hours = string.format("%02d", (seconds / 3600) % 24)
+        else
+            hours = string.format("%02d", seconds / 3600)
+        end
         local mins = string.format("%02d", round(seconds % 3600 / 60))
         if withoutSeconds then
             if mins == "60" then
@@ -135,10 +142,10 @@ function util.secondsToClock(seconds, withoutSeconds)
                 mins = string.format("%02d", 0)
                 hours = string.format("%02d", hours + 1)
             end
-            return hours .. ":" .. mins
+            return  (days ~= "0" and (days .. "d") or "") .. hours .. ":" .. mins
         else
             local secs = string.format("%02d", seconds % 60)
-            return hours .. ":" .. mins .. ":" .. secs
+            return (days ~= "0" and (days .. "d") or "") .. hours .. ":" .. mins .. ":" .. secs
         end
     end
 end
@@ -147,8 +154,9 @@ end
 ---- @int seconds number of seconds
 ---- @bool withoutSeconds if true 1h30', if false 1h30'10''
 ---- @bool hmsFormat, if true format 1h30m10s
+---- @bool withDays, if true format 1d12h30m10s
 ---- @treturn string clock string in the form of 1h30'10'' or 1h30m10s
-function util.secondsToHClock(seconds, withoutSeconds, hmsFormat)
+function util.secondsToHClock(seconds, withoutSeconds, hmsFormat, withDays)
     local SECONDS_SYMBOL = "\""
     seconds = tonumber(seconds)
     if seconds == 0 then
@@ -189,7 +197,7 @@ function util.secondsToHClock(seconds, withoutSeconds, hmsFormat)
             end
         end
     else
-        local time_string = util.secondsToClock(seconds, withoutSeconds)
+        local time_string = util.secondsToClock(seconds, withoutSeconds, withDays)
         if withoutSeconds then
             time_string = time_string .. ":"
         end
@@ -198,15 +206,15 @@ function util.secondsToHClock(seconds, withoutSeconds, hmsFormat)
             time_string = time_string:gsub(":", _("h"), 1)
             -- @translators This is the 'm' for minute, like in 1h30m30s. This is a duration.
             time_string = time_string:gsub(":", _("m"), 1)
-            -- @translators This is the 's' for second, like in 1h30m30s. This is a duration.
-            time_string = time_string:gsub("00" .. _("h"), "") -- delete leading "00h"
+            time_string = time_string:gsub("^00" .. _("h"), "") -- delete leading "00h"
             time_string = time_string:gsub("^0", "") -- delete leading "0"
+            -- @translators This is the 's' for second, like in 1h30m30s. This is a duration.
             return withoutSeconds and time_string or (time_string .. _("s"))
         else
             -- @translators This is the 'h' for hour, like in 1h30m30s. This is a duration.
             time_string = time_string:gsub(":", _("h"), 1)
             time_string = time_string:gsub(":", "'", 1)
-            time_string = time_string:gsub("00" .. _("h"), "") -- delete leading "00h"
+            time_string = time_string:gsub("^00" .. _("h"), "") -- delete leading "00h"
             time_string = time_string:gsub("^0", "") -- delete leading "0"
             return withoutSeconds and time_string or (time_string .. SECONDS_SYMBOL)
         end
@@ -218,13 +226,14 @@ end
 ---- @string Either "modern" for 1h30'10" or "classic" for 1:30:10
 ---- @bool withoutSeconds if true 1h30' or 1h30m, if false 1h30'10" or 1h30m10s
 ---- @bool hmsFormat, modern format only, if true format 1h30m or 1h30m10s
+---- @bool withDays, if hours>=24 include days in clock string 1d12h10m10s
 ---- @treturn string clock string in the specific format of 1h30', 1h30'10" resp. 1h30m, 1h30m10s
-function util.secondsToClockDuration(format, seconds, withoutSeconds, hmsFormat)
+function util.secondsToClockDuration(format, seconds, withoutSeconds, hmsFormat, withDays)
     if format == "modern" then
-        return util.secondsToHClock(seconds, withoutSeconds, hmsFormat)
+        return util.secondsToHClock(seconds, withoutSeconds, hmsFormat, withDays)
     else
         -- Assume "classic" to give safe default
-        return util.secondsToClock(seconds, withoutSeconds)
+        return util.secondsToClock(seconds, withoutSeconds, withDays)
     end
 end
 
diff --git a/plugins/autosuspend.koplugin/main.lua b/plugins/autosuspend.koplugin/main.lua
index d2963583e..915f6c3e1 100644
--- a/plugins/autosuspend.koplugin/main.lua
+++ b/plugins/autosuspend.koplugin/main.lua
@@ -17,10 +17,11 @@ local WidgetContainer = require("ui/widget/container/widgetcontainer")
 local logger = require("logger")
 local util = require("util")
 local _ = require("gettext")
+local Math = require("optmath")
 local T = require("ffi/util").template
 
-local default_autoshutdown_timeout_seconds = 3*24*60*60
-local default_auto_suspend_timeout_seconds = 60*60
+local default_autoshutdown_timeout_seconds = 3*24*60*60 -- three days
+local default_auto_suspend_timeout_seconds = 15*60 -- 15 minutes
 
 local AutoSuspend = WidgetContainer:new{
     name = "autosuspend",
@@ -107,8 +108,10 @@ end
 function AutoSuspend:init()
     logger.dbg("AutoSuspend: init")
     if Device:isPocketBook() and not Device:canSuspend() then return end
-    self.autoshutdown_timeout_seconds = G_reader_settings:readSetting("autoshutdown_timeout_seconds") or default_autoshutdown_timeout_seconds
-    self.auto_suspend_timeout_seconds = G_reader_settings:readSetting("auto_suspend_timeout_seconds") or default_auto_suspend_timeout_seconds
+    self.autoshutdown_timeout_seconds = G_reader_settings:readSetting("autoshutdown_timeout_seconds",
+        default_autoshutdown_timeout_seconds)
+    self.auto_suspend_timeout_seconds = G_reader_settings:readSetting("auto_suspend_timeout_seconds",
+        default_auto_suspend_timeout_seconds)
 
     UIManager.event_hook:registerWidget("InputEvent", self)
     -- We need an instance-specific function reference to schedule, because in some rare cases,
@@ -169,87 +172,121 @@ function AutoSuspend:onPreventStandby()
     self.standby_prevented = true
 end
 
+function AutoSuspend:setSuspendShutdownTimes(touchmenu_instance, title, info, setting,
+        default_value, range, is_day_hour)
+    -- Attention if is_day_hour then time.hour stands for days and time.min for hours
+
+    local InfoMessage = require("ui/widget/infomessage")
+    local DateTimeWidget = require("ui/widget/datetimewidget")
+
+    local setting_val = self[setting] > 0 and self[setting] or default_value
+
+    local left_val = is_day_hour and math.floor(setting_val / (24*3600))
+        or math.floor(setting_val / 3600)
+    local right_val = is_day_hour and math.floor(setting_val / 3600) % 24
+        or math.floor((setting_val / 60) % 60)
+    local time_spinner
+    time_spinner = DateTimeWidget:new {
+        is_date = false,
+        hour = left_val,
+        min = right_val,
+        hour_hold_step = 5,
+        min_hold_step = 10,
+        hour_max = is_day_hour and math.floor(range[2] / (24*3600)) or math.floor(range[2] / 3600),
+        min_max = is_day_hour and 23 or 59,
+        ok_text = _("Set timeout"),
+        title_text = title,
+        info_text = info,
+        callback = function(time)
+            self[setting] = is_day_hour and (time.hour * 24 * 3600 + time.min * 3600)
+                or (time.hour * 3600 + time.min * 60)
+            self[setting] = Math.clamp(self[setting], range[1], range[2])
+            G_reader_settings:saveSetting(setting, self[setting])
+            self:_unschedule()
+            self:_start()
+            if touchmenu_instance then touchmenu_instance:updateItems() end
+            local time_string = util.secondsToClockDuration("modern", self[setting], true, true, true)
+            time_string = time_string:gsub("00m","")
+            UIManager:show(InfoMessage:new{
+                text = T(_("%1: %2"), title, time_string),
+                timeout = 3,
+            })
+        end,
+        default_value = util.secondsToClockDuration("modern", default_value, true, true, true):gsub("00m$",""),
+        default_callback = function()
+            local hour = is_day_hour and math.floor(default_value / (24*3600))
+                or math.floor(default_value / 3600)
+            local min = is_day_hour and math.floor(default_value / 3600) % 24
+                or math.floor(default_value / 60) % 60
+            time_spinner:update(nil, hour, min)
+        end,
+        extra_text = _("Disable"),
+        extra_callback = function(_self)
+            self[setting] = -1 -- disable with a negative time/number
+            self:_unschedule()
+            if touchmenu_instance then touchmenu_instance:updateItems() end
+            UIManager:show(InfoMessage:new{
+                text = T(_("%1: disabled"), title),
+                timeout = 3,
+            })
+            _self:onClose()
+        end,
+        keep_shown_on_apply = true,
+    }
+    UIManager:show(time_spinner)
+end
+
 function AutoSuspend:addToMainMenu(menu_items)
     menu_items.autosuspend = {
         sorting_hint = "device",
+        checked_func = function()
+            return self:_enabled()
+        end,
         text_func = function()
-            if self.auto_suspend_timeout_seconds  then
-                local duration_format = G_reader_settings:readSetting("duration_format", "classic")
-                return T(_("Autosuspend timeout: %1"),
-                    util.secondsToClockDuration(duration_format, self.auto_suspend_timeout_seconds, true))
+            if self.auto_suspend_timeout_seconds and self.auto_suspend_timeout_seconds > 0 then
+                local time_string = util.secondsToClockDuration("modern",
+                    self.auto_suspend_timeout_seconds, true, true, true):gsub("00m$","")
+                return T(_("Autosuspend timeout: %1"), time_string)
             else
                 return _("Autosuspend timeout")
             end
         end,
         keep_menu_open = true,
         callback = function(touchmenu_instance)
-            local InfoMessage = require("ui/widget/infomessage")
-            local SpinWidget = require("ui/widget/spinwidget")
-            local autosuspend_spin = SpinWidget:new {
-                value = self.auto_suspend_timeout_seconds / 60,
-                value_min = 5,
-                value_max = 240,
-                value_hold_step = 15,
-                ok_text = _("Set timeout"),
-                title_text = _("Timeout in minutes"),
-                callback = function(autosuspend_spin)
-                    self.auto_suspend_timeout_seconds = autosuspend_spin.value * 60
-                    G_reader_settings:saveSetting("auto_suspend_timeout_seconds", self.auto_suspend_timeout_seconds)
-                    UIManager:show(InfoMessage:new{
-                        text = T(_("The system will automatically suspend after %1 minutes of inactivity."),
-                            string.format("%.2f", self.auto_suspend_timeout_seconds / 60)),
-                        timeout = 3,
-                    })
-                    self:_unschedule()
-                    self:_start()
-                    if touchmenu_instance then touchmenu_instance:updateItems() end
-                end
-            }
-            UIManager:show(autosuspend_spin)
+            -- 60 sec (1') is the minimum and 24*3600 sec (1day) is the maximum suspend time.
+            -- A suspend time of one day seems to be excessive.
+            -- But or battery testing it might give some sense.
+            self:setSuspendShutdownTimes(touchmenu_instance,
+                _("Timeout for autosuspend"), _("Enter time in hours and minutes."),
+                "auto_suspend_timeout_seconds", default_auto_suspend_timeout_seconds,
+                {60, 24*3600}, false)
         end,
     }
     if not (Device:canPowerOff() or Device:isEmulator()) then return end
     menu_items.autoshutdown = {
         sorting_hint = "device",
+        checked_func = function()
+            return self:_enabledShutdown()
+        end,
         text_func = function()
-            if self.autoshutdown_timeout_seconds  then
-                local duration_format = G_reader_settings:readSetting("duration_format", "classic")
-                return T(_("Autoshutdown timeout: %1"),
-                    util.secondsToClockDuration(duration_format, self.autoshutdown_timeout_seconds, true))
+            if self.autoshutdown_timeout_seconds and self.autoshutdown_timeout_seconds > 0 then
+                local time_string = util.secondsToClockDuration("modern",
+                    self.autoshutdown_timeout_seconds, true, true, true):gsub("00m$","")
+                return T(_("Autoshutdown timeout: %1"), time_string)
             else
                 return _("Autoshutdown timeout")
             end
         end,
         keep_menu_open = true,
         callback = function(touchmenu_instance)
-            local InfoMessage = require("ui/widget/infomessage")
-            local SpinWidget = require("ui/widget/spinwidget")
-            local autosuspend_spin = SpinWidget:new {
-                value = self.autoshutdown_timeout_seconds / 60 / 60,
-                -- About a minute, good for testing and battery life fanatics.
-                -- Just high enough to avoid an instant shutdown death scenario.
-                value_min = 0.017,
-                -- More than three weeks seems a bit excessive if you want to enable authoshutdown,
-                -- even if the battery can last up to three months.
-                value_max = 28*24,
-                value_hold_step = 24,
-                precision = "%.2f",
-                ok_text = _("Set timeout"),
-                title_text = _("Timeout in hours"),
-                callback = function(autosuspend_spin)
-                    self.autoshutdown_timeout_seconds = math.floor(autosuspend_spin.value * 60 * 60)
-                    G_reader_settings:saveSetting("autoshutdown_timeout_seconds", self.autoshutdown_timeout_seconds)
-                    UIManager:show(InfoMessage:new{
-                        text = T(_("The system will automatically shut down after %1 hours of inactivity."),
-                            string.format("%.2f", self.autoshutdown_timeout_seconds / 60 / 60)),
-                        timeout = 3,
-                    })
-                    self:_unschedule()
-                    self:_start()
-                    if touchmenu_instance then touchmenu_instance:updateItems() end
-                end
-            }
-            UIManager:show(autosuspend_spin)
+            -- 5*60 sec (5') is the minimum and 28*24*3600 (28days) is the maximum shutdown time.
+            -- Minimum time has to be big enough, to avoid start-stop death scenarious.
+            -- Maximum more than four weeks seems a bit excessive if you want to enable authoshutdown,
+            -- even if the battery can last up to three months.
+            self:setSuspendShutdownTimes(touchmenu_instance,
+                _("Timeout for autoshutdown"),  _("Enter time in days and hours."),
+                "autoshutdown_timeout_seconds", default_autoshutdown_timeout_seconds,
+                {5*60, 28*24*3600}, true)
         end,
     }
 end
diff --git a/spec/unit/optmath_spec.lua b/spec/unit/optmath_spec.lua
index d7f316cce..a9aab5cce 100644
--- a/spec/unit/optmath_spec.lua
+++ b/spec/unit/optmath_spec.lua
@@ -58,4 +58,16 @@ describe("Math module", function()
         assert.are.same("even", Math.oddEven(0))
     end)
 
+    describe("minmax", function()
+        it("should return a value within a range", function()
+            assert.are.same(-1, Math.clamp(-2, -1, 10))
+            assert.are.same(-1, Math.clamp(-1, -1, 10))
+            assert.are.same(0, Math.clamp(0, -1, 10))
+            assert.are.same(5, Math.clamp(5, -1, 10))
+            assert.are.same(9, Math.clamp(9, -1, 10))
+            assert.are.same(10, Math.clamp(10, -1, 10))
+            assert.are.same(10, Math.clamp(11, -1, 10))
+        end)
+    end)
+
 end)