Car adapter for GL-X750-Ext 4G LTE Smart Router

blinkiz · 2019-02-23T11:27:36.117Z

Hello
I would like to use GL-X750-Ext 4G LTE Smart Router in a car. The car has 12 volt internal and the GL-X750-Ext 4G LTE Smart Router use 12 volt. Does anyone have recommendation how to safely use the GL-X750-Ext without first converting power into 230V?

I know I can buy a cigarette car adapter DC/DC 12V->12V but I do not know the dimension of the power plug. What are the specification of the power plug?

alzhao · 2019-02-24T08:00:39.913Z

cigarette car adapter DC/DC Is OK.

The diameter is 4mm

blinkiz · 2019-03-08T12:15:22.028Z

So the diameter of the required power plug is
12V, 1.5A center positive, 4.0mm OD; 1.7mm ID

Is this correct?

alzhao · 2019-03-09T14:52:08.373Z

I cannot confirm 100% before I can hold the power adapter in hand next week.

tve · 2019-03-10T18:58:56.487Z

blinkiz:

So the diameter of the required power plug is
12V, 1.5A center positive, 4.0mm OD; 1.7mm ID

I can’t tell you the exact 1/10th mm, however, you need one of the yellow-tipped plugs that is approx 4mm OD.

Update: I have a power plug that “fits”, except that it’s not long enough due to the router housing. The tip of the plug on the A/C adapter is 11.5mm long while the tip on my yellow plug is 9.5mm long and the missing 2mm prevent a connection to ground when the PCB is in the housing. Grrrr!

tve · 2019-03-10T21:49:48.518Z

As an FYI, the GL-X750 requires 9.6V minimum to turn on, once on it will stay on down to 8.2V but switch off at 8.1V.

rnd42 · 2020-07-26T19:54:24.820Z

Did somebody try it with more then the 12,2V DC which the original 230V AC delivers? Usually car, caravan and boat batteries output rather between 13V-14V DC. Still wondering if the Spitz has voltage regulators that would cope with up the 2V more?

Johnex · 2020-07-26T20:44:16.991Z

Actually in my car when its running, the alternator pushes the voltage up to 14.7V. You can open your x750 and check the specs of the voltage regulator, but since the cigarette plug of the car is connected directly to the battery, you will get a lot of spikes from the motor.

The best thing you can do is get something like this Polulu 12V buck/boost converter:

pololu.com

Pololu 12V Step-Up/Step-Down Voltage Regulator S18V20F12

This powerful step-up/step-down regulator efficiently produces a fixed 12 V output from input voltages between 3 V and 30 V while allowing a typical output current of up to 2 A when the input voltage is close to the output voltage...

tve · 2020-07-26T21:05:26.747Z

I highly recommend getting a voltage regulator that is designed for car use. Cars in particular have quite high voltage spikes due to ignition, starter motor and other fun stuff. Typically you’d use a voltage regulator that accepts up to 40V input, or at least one that allows for transient spikes above 40V.
If you’re designing for a caravan then you may be OK with something that is rated for around 20V, but you do have to account for the fact that flooded lead acid batteries should be equalized every now and then to somewhere between 15V and 16V.