Gammatronix 12v 24v WITH ALARM battery monitor LED level meter indicator gauge M

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can be shipped within 1 days

Price plus VAT, plus delivery

'M' Monitor Installation Instructions - Download


'M' Monitor Information Leaflet - Download





PROGRAMMABLE LED Battery level indicator / meter


NEVER be left WITHOUT WARNING that your  battery  is going 'Flat'


PROGRAMMABLE Multi Mode, Multi Voltage, Low Power With Fitting Kit


Please note that this 'with alarm' version is not suitable for outdoor use where the unit may become wet. See our 'N' version (without alarm feature) for outdoor use, in our Ebay shop. The coin shown in the image is to indicate unit size and does not come with the unit!



  • Just 40 x 40 x 15mm in size.
  • Good for all Lead Acid, Gel, or AGM (Glass matt) batteries.
  • Works with other battery technologies (Alkaline, NiMh, etc) if the programmable levels suit your application.
  • FOURTEEN levels of indication from 12 LEDs.
  • INDICATES BATTERY OVERCHARGE - protect your vehicle or system from overvoltage caused by ALTERNATOR REGULATOR FAILURE.
  • Voltage : SELECTABLE  12v or24V (Max 30v). Accuracy to better than 1%. Unit will operate down to less than 3.8v.
  • SIX selectable voltage 'maps' to chose from for each of the 12v and 24v ranges. Settings held after power off for 100 Years!!!
  • THREE different display modes (bargraph, Single LED and Blank display).
  • Low Power Consumption : 0.2mA in 'Blank' mode, 2mA in single LED mode,  8mA maximum in multi led mode (all LEDs lit).
  • Just two wires to connect.
  • Internally PTC fused (self resetting) and  Reverse voltage protected.
  • Multiple oversampling - unit takes 10+ readings to obtain greatest accuracy.
  • Display LEDs updated over 300 times a second - each and every second - fast response!
  • Supplied with comprehensive printed instruction sheet


The Details...............


Its annoying when your battery goes flat without warning. This neat little unit can be used wherever you have a 12v, or 24v  based electrical system. Perhaps your bike, car, camper or boat, golf buggy, or that battery you have to power the  DC lighting in your shed can go flat on you without warning, or you would like some idea of how much juice you have left?


This compact gadget will show you by means of twelve 3mm LEDs the voltage level of your battery.


Simple fitment instructions are included with the device. A fitting kit comprising  tie wrap and rear mounted adhesive pads and base is supplied  to allow fitment to any flat or curved surface - fix to dashboard, wall, or any surface you can stick to or loop cable ties around.


The unit has a front panel button to allow selection of display mode AND control of the audible alarm feature.


In single LED mode, the LED will ‘travel’ to the current battery status level. In multi-LED Bargraph mode, all LEDs will light to the current battery status level. In 'Blank'  mode, the display will go dark, drawing an absolute mimimal power from your battery. This is useful where constant illumination may be a nuisance, perhaps in a camper or caravan at night time. The ultra low power consumed in Blank mode is also kind to unmaintained batteries, left uncharged for long periods. Simply press the button to perform a battery test, then switch the unit off again via the button.


In addition to the twelve LEDs, two further indicated levels are provided : The first red LED will fast flash when critical battery level is reached, and the end of scale red and green LED's will 'wink' together to indicate an alternator overcharging condition . This will warn of possible impending damage to your electrical system due to excess voltage from the alternator.




This unit has the ADDITIONAL BENEFIT of an AUDIBLE ALARM SOUNDER providing 85dB of 'warble' alarm to tell you if your PRE SET battery 'low' point has been reached. You decide the alarm point, it is programmable to operate over the first six LED positions on the dial. Should your battery fall below the set point, the alarm will sound for one second every ten seconds until the button is pressed OR the unit will self-reset when the battery voltage rises three LED points above the set alarm level.


Ranges and Programming............


The unit can be easily programmed via the external button by following the comprehensive instructions supplied. You can choose between :

  • 24v and 12v operation.
  • Audible Alarm Setpoint.
  • Choose which of SIX indication ranges you want to use.

AND - during operation, pressing the programming button will cancel the alarm, or cycle between the three display modes (Bargraph, Single LED or 'Blank').


Ranges: Unit can be set to use one of the six voltage 'maps' according to below tables. If the unit is programmed to operate at 24v, the values will be twice those shown in the 12v table below.


The ranges are optimised for  ‘Lead acid’ batteries which  includes Gel and AGM types. Other battery types can be used if a range provided suits your needs.


Units are supplied pre-set to volts map 3 and volts range 1. (standard voltage map ‘curve’ at 12v operation). You can change this using the programming information supplied.



Buy with CONFIDENCE from a UK Limited Company. This product is designed and made in the UK!


Browse this category: Multi LED Voltage Monitors