diff --git a/.gitignore b/.gitignore
index c6d17b3..f117536 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@ mini-beieli-web
 nohup.out
 database/
 node_modules/
+check_mini_beieli_nodes/check_mini_beieli_nodes
diff --git a/check_mini_beieli_nodes/main.go b/check_mini_beieli_nodes/main.go
new file mode 100644
index 0000000..e80c035
--- /dev/null
+++ b/check_mini_beieli_nodes/main.go
@@ -0,0 +1,358 @@
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"github.com/gomodule/redigo/redis"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"net/smtp"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func sendEmailAccu(username string, alias string, deveui string, accu_percent string) {
+	c, err := smtp.Dial("127.0.0.1:25")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer c.Close()
+	// Set the sender and recipient.
+	c.Mail("info@mini-beieli.ch")
+	c.Rcpt(username)
+	// Send the email body.
+	wc, err := c.Data()
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer wc.Close()
+	mail_message := "To: " + username + `
+Subject: mini-beieli.ch: Bitte Akku laden (` + alias + `)
+
+Lieber Benutzer von mini-beieli.ch
+
+Der Akku von "` + alias + `" (DevEUI: ` + deveui + `) ist nur noch zu ` + accu_percent + ` Prozent geladen.
+
+Bitte bei nächster Gelegenheit laden.
+
+Mit freundlichen Grüssen
+--
+mini-beieli.ch`
+
+	buf := bytes.NewBufferString(mail_message)
+	if _, err = buf.WriteTo(wc); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func sendEmailAbo(username string, alias string, deveui string, days_left int) {
+	c, err := smtp.Dial("127.0.0.1:25")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer c.Close()
+	// Set the sender and recipient.
+	c.Mail("info@mini-beieli.ch")
+	c.Rcpt(username)
+	// Send the email body.
+	wc, err := c.Data()
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer wc.Close()
+	mail_message := "To: " + username + `
+Subject: mini-beieli.ch: Abo laeuft ab (` + alias + `)
+
+Lieber Benutzer von mini-beieli.ch
+
+Das Abo von "` + alias + `" (DevEUI: ` + deveui + `) laeuft in ` + strconv.Itoa(days_left) + ` Tagen ab.
+
+Bitte Abo verlaengern auf https://mini-beieli.ch
+
+Mit freundlichen Grüssen
+--
+mini-beieli.ch`
+
+	buf := bytes.NewBufferString(mail_message)
+	if _, err = buf.WriteTo(wc); err != nil {
+		log.Fatal(err)
+	}
+}
+
+var globalPool *redis.Pool
+
+const userPrefix string = "user:"
+const devPrefix string = "dev:"
+const confirmPrefix string = "confirm:"
+
+func newPool() *redis.Pool {
+	return &redis.Pool{
+		// Maximum number of idle connections in the pool.
+		MaxIdle: 80,
+		// max number of connections
+		MaxActive: 12000,
+		// Dial is an application supplied function for creating and
+		// configuring a connection.
+		Dial: func() (redis.Conn, error) {
+			c, err := redis.Dial("tcp", ":6379")
+			if err != nil {
+				panic(err.Error())
+			}
+			return c, err
+		},
+	}
+}
+
+// ping tests connectivity for redis (PONG should be returned)
+func ping(c redis.Conn) error {
+	// Send PING command to Redis
+	// PING command returns a Redis "Simple String"
+	// Use redis.String to convert the interface type to string
+	s, err := redis.String(c.Do("PING"))
+	if err != nil {
+		return err
+	}
+
+	logit("PING Response = " + s)
+	// Output: PONG
+
+	return nil
+}
+
+type Dev struct {
+	Deveui      string
+	Alias       string
+	Alarmactive string
+	Smsnumber   string
+	ActiveUntil string // Abo bezahlt bis TT.MM.YYYY
+}
+
+func initDB() {
+
+	// newPool returns a pointer to a redis.Pool
+	pool := newPool()
+	// get a connection from the globalPool (redis.Conn)
+	conn := pool.Get()
+	defer conn.Close()
+
+	globalPool = pool
+
+	// wir machen einen Connection Test
+	ping(conn)
+}
+
+func closeDB() {
+	globalPool.Close()
+}
+
+func getUsers() []string {
+	res := []string{}
+
+	conn := globalPool.Get()
+	defer conn.Close()
+
+	//logit("getUsers")
+	users, err := redis.Strings(conn.Do("KEYS", userPrefix+"*"))
+	if err == nil {
+		//logit("getUsers successful!")
+		res = users
+	} else {
+		log.Print(err)
+	}
+
+	return res
+}
+
+func getMyDevs(username string) []string {
+	res := []string{}
+
+	if username == "" {
+		return res
+	}
+
+	conn := globalPool.Get()
+	defer conn.Close()
+
+	//logit("getMyDevs: User: " + username)
+	mydevs, err := redis.String(conn.Do("HGET", userPrefix+username, "my_devs"))
+	if err == nil {
+		//logit("getMyDevs: mydevs: " + mydevs)
+		res = strings.Split(mydevs, ",")
+	} else {
+		log.Print(err)
+	}
+
+	return res
+}
+
+func getDevAlias(deveui string) string {
+	res := deveui
+
+	if deveui == "" {
+		return res
+	}
+
+	conn := globalPool.Get()
+	defer conn.Close()
+
+	//logit("getDevAlias: Deveui: " + deveui)
+	alias, err := redis.String(conn.Do("HGET", devPrefix+deveui, "alias"))
+	if err == nil {
+		//logit("getDevAlias: alias: " + alias)
+		res = alias
+	} else {
+		log.Print(err)
+	}
+
+	return res
+}
+
+func getActiveUntil(deveui string) string {
+	res := ""
+
+	if deveui == "" {
+		return res
+	}
+
+	conn := globalPool.Get()
+	defer conn.Close()
+
+	//logit("getActiveUntil: Deveui: " + deveui)
+	activeuntil, err := redis.String(conn.Do("HGET", devPrefix+deveui, "active_until"))
+	if err == nil {
+		//logit("getActiveUntil: activeuntil: " + activeuntil)
+		res = activeuntil
+	} else {
+		log.Print(err)
+	}
+
+	return res
+}
+
+type OneMetric struct {
+	Deveui               string
+	Alias                string
+	Timestamp            string
+	BatteryPercent       string
+	ActiveUntil          string
+	DaysUntilDeactivated int // berechneter Wert
+}
+
+func CalcDaysUntil(mydate string) int {
+	var days int
+	layout := "02.01.2006"
+	t, err := time.Parse(layout, mydate)
+
+	if err != nil {
+		days = 0
+	}
+	days = int(t.Sub(time.Now()).Hours() / 24)
+
+	return days
+}
+
+func getLastMetrics(deveui string) OneMetric {
+	var res OneMetric
+
+	url := "http://localhost:9999/api/v2/query?org=beieliorg"
+	data := []byte(fmt.Sprintf(`from(bucket:"beielibucket") 
+                                 |> range(start:-5d) 
+                                 |> filter(fn: (r) => r.deveui == "%s") 
+                                 |> filter(fn: (r) => r._field == "vp") 
+                                 |> last() |> yield(name: "last")`, deveui))
+
+	req, err := http.NewRequest("POST", url, bytes.NewBuffer(data))
+	if err != nil {
+		log.Fatal("Error reading request. ", err)
+	}
+
+	// Set headers
+	req.Header.Set("Authorization", "Token OzSltiHLmm3WCaFPI0DrK0VFAVCiqcORNrGsgHO43jb0qodyVGAumJQ3HRtkaze53BVR3AmHqfkmrwrjq-xTyA==")
+	req.Header.Set("accept", "application/csv")
+	req.Header.Set("content-type", "application/vnd.flux")
+
+	// Set client timeout
+	client := &http.Client{Timeout: time.Second * 10}
+
+	// Send request
+	resp, err := client.Do(req)
+	if err != nil {
+		log.Fatal("Error reading response. ", err)
+	}
+	defer resp.Body.Close()
+
+	//fmt.Println("response Status:", resp.Status)
+	//fmt.Println("response Headers:", resp.Header)
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		log.Fatal("Error reading body. ", err)
+	}
+	//fmt.Println("response Body:", string(body))
+
+	scanner := bufio.NewScanner(strings.NewReader(string(body)))
+	location, err := time.LoadLocation("Europe/Zurich")
+	for scanner.Scan() {
+		s := strings.Split(scanner.Text(), ",")
+		if (len(s) >= 7) && !(strings.HasPrefix(s[5], "_")) {
+			mytime, err := time.Parse(time.RFC3339, s[5])
+			if err != nil {
+				continue
+			}
+			res.Timestamp = mytime.In(location).Format("02.01.2006 15:04")
+			value := s[6]
+			field := s[7]
+			if field == "vp" {
+				res.BatteryPercent = value
+			}
+		}
+	}
+	res.Deveui = deveui
+	res.Alias = getDevAlias(deveui)
+	res.ActiveUntil = getActiveUntil(deveui)
+	res.DaysUntilDeactivated = CalcDaysUntil(res.ActiveUntil)
+	return res
+}
+
+func logit(log_message string) {
+	log.Println(log_message)
+}
+
+func main() {
+	logit("Starting check_battery...")
+	initDB()
+	defer closeDB()
+
+	users := getUsers()
+	for _, u := range users {
+		//fmt.Println(u)
+		u2 := u[5:]
+		my_devs := getMyDevs(u2)
+		for _, d := range my_devs {
+			//fmt.Printf("%s:%s\n", u2, d)
+			if !strings.HasPrefix(d, "@") {
+				last_metric := getLastMetrics(d)
+				// Zuerst der Batteriealarm
+				if last_metric.BatteryPercent != "" {
+					fmt.Printf("%s:%s:%s Percent:%s:%d\n", u2, d, last_metric.BatteryPercent, last_metric.ActiveUntil, last_metric.DaysUntilDeactivated)
+					vp, _ := strconv.Atoi(last_metric.BatteryPercent)
+					if vp < 90 {
+						fmt.Printf("SEND EMAIL %s:%s:%s Percent:%s:%d\n", u2, d, last_metric.BatteryPercent, last_metric.ActiveUntil, last_metric.DaysUntilDeactivated)
+						alias := getDevAlias(d)
+						sendEmailAccu("joerg.lehmann@nbit.ch", alias, d, last_metric.BatteryPercent)
+					}
+				}
+				// Jetzt der Alarm wegen der Abodauer
+				if last_metric.DaysUntilDeactivated < 30 {
+					fmt.Printf("SEND EMAIL %s:%s:%s Percent:%s:%d\n", u2, d, last_metric.BatteryPercent, last_metric.ActiveUntil, last_metric.DaysUntilDeactivated)
+					alias := getDevAlias(d)
+					sendEmailAbo("joerg.lehmann@nbit.ch", alias, d, last_metric.DaysUntilDeactivated)
+				}
+			}
+		}
+	}
+	logit("Done with check_battery...")
+}
diff --git a/persistence.go b/persistence.go
index 889e68b..33c802b 100644
--- a/persistence.go
+++ b/persistence.go
@@ -82,6 +82,24 @@ func closeDB() {
 	globalPool.Close()
 }
 
+func getUsers() []string {
+	res := []string{}
+
+	conn := globalPool.Get()
+	defer conn.Close()
+
+	logit("getUsers")
+	users, err := redis.Strings(conn.Do("KEYS", userPrefix+"*"))
+	if err == nil {
+		logit("getUsers successful!")
+		res = users
+	} else {
+		log.Print(err)
+	}
+
+	return res
+}
+
 func updateScaleSettings(scaleSettings Dev) error {
 	conn := globalPool.Get()
 	defer conn.Close()
@@ -100,7 +118,7 @@ func checkUserAvailable(username string) bool {
 	conn := globalPool.Get()
 	defer conn.Close()
 
-	_, err := redis.String(conn.Do("GET", userPrefix+username))
+        _, err := conn.Do("HGETALL", userPrefix+username)
 	if err == redis.ErrNil {
 		logit("User does not exist and is therefore available:" + username)
 		return true