question

erik-forslund avatar image

SmartShunt configuration on starter battery

My Fairline boat will be installed with a SmartShunt, but I am a bit confused on how to connect the negative wire from the starter battery. The question is whether connect to "system side" or "battery side". I have seen 3 different pictures. Two of the pictures are from different versions of SmartShunt Manual and the 3rd one is from Solarquip web site where I bought my SmartShunt.

https://www.solarquip.se/produkt/victron-energy-smartshunt-500a-50mv-bluetooth/

For me it makes more sense to connect to the "battery side".

One of the pictures in the manual also shows connection to the start-engine and alternator. That makes sense with one engine, but I have two.

My config is a bit odd (Fairline), where I have 3 batteries connected to "consumtion bank" but also serves as starter/charger for engine no1. And the "starter battery" is connected to starter/charger for engine no 2. I just want to monitor the "starter battery" in SmartShunt, but I think I should not bother about the "system side" of the wiring. I probable need to write down the schema, but hope that someone can explain the negative wiring from the starter battery. The rest I hope I know. Yes, the setup is odd, and later I will reconfigure my system a bit. But as today I have two different banks which are non-connected and no VSR either. And I do have 2 separate chargers.

pic3-alternator.jpgpic2-solarquip.jpgpic1-manual.jpg


smartshunt
pic1-manual.jpg (45.9 KiB)
pic2-solarquip.jpg (25.0 KiB)
pic3-alternator.jpg (56.1 KiB)
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3 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

The 2nd picture is wrong.

Only the main battery is connected to the battery side of the shunt, all other negative have to be on the "system" side of the shunt.

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Thanks for the answer, and yes, this seems to be the recommendation, but I still don't understand WHY. Since my 2nd battery (Starter) will never ever be exposed to the "main battery bank", and therefor any use of 2nd battery will not affect the measuring parts of the SmartShunt. I just want to understand and it is also related to wiring and distances. Can you convince me even more?

Do you want to charge the main battery from the alternator?

If yes you couldn't measure that current if the negative of the starter battery is connected to the battery side of the shunt.

If not it shouldn't matter at which point you connect the negative of the starter battery, but just in case you should do it right and connect it to the system side of the shunt.

erik-forslund avatar image
erik-forslund answered ·

OK, thanks. I am not talking about a generator or a charger. I am only talking about the negative wiring to the 2nd battery. I tried to write down my configuration (attached picture) if it helps.schema.jpg


schema.jpg (81.8 KiB)
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ALL negative have to be connected to the "system" side of the shunt, ONLY the main battery negative is connected to the"battery only" side of the shunt.


In your picture the SmartShunt can not measure the charging from the 50A charger or the two alternators.

27988-schema.jpg

27988-schema.jpg (107.0 KiB)
erik-forslund avatar image
erik-forslund answered ·

Yes you are of course right. The picture is not complete, but the two negative wires (one from charger and from port engine). But still I think the negative cable from 2nd battery and the negative from the port engine are still an issue. I don't see a reason for them being connected to the system side. But maybe it is smart to do so anyway but I don't see a reason. Charging the 2nd battery is still not of the scope for measuring in SmartShunt. Thanks for the discussion - I learn new things every day. Maybe I will buy a Victron MultiPlus soon, so I need to prepare.

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