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Just Clever Things

How to monitor your battery in a vehicle

Is everything turned off?

Do you ever have the need to make sure every switch is turned off so nothing is draining your battery?

12V Shunt

Just take a look at the display and make sure it says zero current

If you want to meassure your appliences just turn them on and read the display

Shunt display

There are many different brands and models to chose from, the thing to look for is how many amps it can take. The amps has to match your battery or battery bank. The way it monitors is also different, some of them have a display attached to it, mine has a wireless monitor and there is bluetooth versions as well

The one I’m using is a Juntek with a wireless connection and it is great when I’m troubleshooting some electric connections or switches. I just connect power to the monitor  with a battery bank and bring it with me. Or just plug it in the nearest 12v outlet. 

This is something you can install yourself and I have listed some tools for this on the Juntek post. If you want to change the way it present current going out or into the battery then you can do it when you install the shunt. I have mine connected so it shows – minus current when something is withdrawing power and + plus when it is charging. Just reverse the connecting points on the shunt in your preferred way

I couldn’t find my version on Amazon right now but it is there sometimes

If you already have invested in Victron products then I recommend the shunt from them, it can be monitored in the Victron Connect app and talk to your other products as the solar regulator here

This is a great way to charge your leisure battery and want a controlled charging function. Use this and take good care of your new lithium battery and don’t go directly from your alternator. Take a look at this 12 to 12 charger. It is important to check if your alternator can charge your LiFePO4 battery, they are often called smart alternator. But just to make sure use a DC to DC charger, like this one

Victron has a good YouTube channel, check it out here

If you are going to use this on the same battery as the start battery make sure it can take the current. It all depends on the size of the engine and also whether it is diesel or petrol engine. It can vary from about 50 A to around 250 A.

Diesels in general require higher starting current. 


A shunt is a device that is used to measure the current flowing through a circuit. In a 12V circuit with a shunt, the shunt is placed in series with the load (the component that consumes power), and a voltage drop is generated across the shunt. The magnitude of this voltage drop is proportional to the current flowing through the circuit.

To measure the current, a voltmeter is connected across the shunt. The voltmeter measures the voltage drop across the shunt, and using Ohm’s law (V = IR), the current flowing through the circuit can be calculated.

Do you need a new Leisure battery, take a look at this

Do you need to measure individual cables then take a look at these portable clamp meters, just make sure it can measure DC current

OBS Make sure it is the DC Current if you want to measure current in a vehicle

Questions? use the chat and I'll get back to you 🙂

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