Welcome to this page on how to build your own GSM or Sounder battery charged Notification devise.


Now if you would like to see the Circuit working then visit my You Tube page here.


1). I designed this simple set up to let you know when your car battery or deep cycle battery, Ni-Cad, Ni-MH or ,Cell phone battery or any type of rechargeable battery has been fully charged by making a simple circuit like this you can be notified when the charge has turned off on the battery charger.

2). Every thing in this simple design is off the shelf components that can be got from any where, The problem with charging vehicle battery's you may have an older charger that are well known for over charging them.

3). This simple design can be built at low cost it allows you to have your vehicle battery, Ni-Cad, NI-MH or any type of rechargeable battery charging for the right amount of time then cut off the power to the charger.

4).In the photo below you can see every type of Rechargeable battery charger has the charging time on it this is a guide as not all rechargeable battery's will have the same mAh, On them you need to work this out Using the charge on the Charger in mAh and on the rechargeable Batteries they have on them in mAh.

5). Now as soon as the battery is fully charged this will switch a simple relay circuit off as well this is connected to a Cell Phone it will use the one touch/speed dial on the phone to phone you to let you know your battery has finished charging.

6). This Cell Phone signal would be best sent to a Cell phone and have the name show up as Battery full, What is nice about this you won't over charge your battery and when it is finished you will get the call just look on your Mobile Phone and see what name shows up, Then you just disconnect the call and it cost nothing to get the signal.

7). Now how it all works is very simple, First connect a timer switch to your battery charger work out the amps hour/mAh from the battery and on the Charger.

8). Now input the charging time into the timer switch so it starts and stops automatically and get hold of a 12 volt adapter this is to power the relay circuit see Schematic below.

9). Why we are on about Batteries a very good devise to have for testing the condition of your Lead Acid Battery is a Hydrometer to see the condition of your battery  Click here. 

10). Now if you find your battery is not in a good condition you can get a battery Desulphator  Click here.

11). You may also like to get a Battery Load tester Click Here.


Or you can build it with a Sounder on it see Schematic Diagram below.

Now in the Schematic above you can see the devise working fine if you would like to see my You Tube video then click here



Now in the Schematic Diagram above I have designed this to Switch a Siren on and activate the one touch Dial in a Cell Phone to Call me, If you would like to see the devise Working then Visit My You Tube Page Here.

11). When you have built your circuit connect the battery charger to your timer switch and connect the battery leads to your battery, Then using a extension lead connect your 12 volt adapter to the input of your circuit.

12). You can use any type of Cell phone as long as it can work with speed dial or one touch dial, How to modify a old cell phone see my link below.


How to modify any one touch/speed dial cell phone.

Now you have all the things you need to modify your cell phone first we will need to load the mobile number in to the phone make sure you have the ringer set to silent all so one touch answer turned off and one touch dial or speed dial turned on.

It would be best to send the signal to a back-up mobile phone when activated as they have caller display on them.

Now say if you put your own mobile phone number into number 5 and connected the wire's coming from the relay to number five this number locked into the phone will be called as soon as the relay closes within 2 or 3 Seconds.

Now I will open my own cell phone after you have opened yours and taken out the screws you may see some thing like this as you can see from the photo below all phones have copper pads this is where we will solder our two wires from the relay if you have loaded your own mobile number in all from 2 to 9 then any one pads will allow you two connect the wire from number 2,3,4,5,6,7,8,9 pads.

You can buy a Cell phone opening kit of sites like Ebay cheap.


In the photo above you can see the phone with case off and how to solder the two wires.

In the photo above you can see I have soldered the two wires to the in & out side pads of the modified phone in the photo above I used my Nokia phone.

You may also want to add a little bit of hot melt glue to the bottom of the wires to take some of the stress from the solder contacts see photo below.

Now connect the end of the wire to the end of the Circuits relay.


Why we are on about Batteries a very good devise to have for testing the condition of your Lead Acid Battery is a Hydrometer to see the condition of your battery Click here.


Please note if you have any problems please do e-mail me: anthony@anthony-dacko.net I am all ways more than happy to help.