Is it possible to measure the alternator current in the positive line with a victron smart shunt. It seems impossible to put the shunt between the alternator housing and the engine block to interrupt the ground. Or are there other options?
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Measure the alternator current with a Victron SmartShunt ?
Our single 4 cell 300Ah LiFePO4 battery both starts the truck and powers the motorhome behind.
As mentioned the SmartShunt must be placed in the negative wiring. That is an easy task being the only connection to the battery negative terminal. All chassis connections are on the other side of the shunt.
Measuring the alternator current is an easy maths calculation.
An example of our setup a few minutes ago. Victron solar controller turned off.
Ambient battery current draw. Ignition on. vs current a minute or so after engine startup.
Not too bad. Initial c95A from a Mitsubishi Fuso 3.9l TD 100A rated alternator. No smoke yet after 8 years fulltime travelling despite all the doomsayers.
I have a Victron 500A SmartShunt and Junctek 400A shunt in series installed when they were first introduced.
Engine starting is typically a one second operation so current measuring is very brief.
Both have displayed peaks of about 740A on those rare occasions that I managed to capture readings.
Perhaps thousands of engine starts over the last 8 years. Both shunts still look pristine.
The SmartShunt must be installed in the negative cable, all the electronics expect the shunt to be 0V and the fly lead the battery voltage.
It is possible to use a SmartShunt for alternator current if you have a system where all negatives have their own wiring and do not use the hull / chassis like most boats. However, if you have an RV or similar where all the negatives go through the chassis with a single ground/ negative cable to the battery then you will not be able to separate out the alternator current.
Sorry, but I just want to measure the total current of the alternator, not only the current that goes in and out of the starter battery. My camper has also a dc/dc convertor for charging the leisure battery en a straight 12V line to feed the absorption fridge. This will not be measured with a shunt on the starter battery ...
