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Shunt and Battery Monitor

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#21 Dirt Rider

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Posted 19 August 2019 - 04:03 PM

If I can ask a stupid question, I am going to add a second battery in parallel, how do I add a shunt for each battery, and how will it know which battery it is seeing if both are connected?


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#22 buckland

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Posted 19 August 2019 - 04:36 PM

Well what I know wouldn’t fill a shot glass but if you are making one big battery outta two.... why would you need two shunts? They are performing as one battery unit.
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#23 Dirt Rider

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Posted 19 August 2019 - 05:04 PM

So I know the charge on each battery individually 


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#24 buckland

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Posted 19 August 2019 - 05:53 PM

Shouldn’t the charge be the same if they are in parallel ?
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#25 Dirt Rider

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Posted 19 August 2019 - 07:15 PM

Thats the problem, cannot get a real sense of each battery, idealy they should be the same, but if not how would I know?


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#26 buckland

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Posted 19 August 2019 - 08:21 PM

All I would do is disconnect occasionally and put an ohm volt meter on each post to test each battery separately. Would only take a second or two. Otherwise if they are the same type battery attached in parallel they should wear the same. Not a good idea to attach two batteries that are different ages.
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2016 Duramax 2.8 Diesel long bed Colorado 4WD with 2011 Eagle

Lordwoodcraft  instagram        Rob
The only people who ever get anyplace interesting are the people who get lost.
Henry David Thoreau
"Work to achieve not to acquire"

 


#27 Vic Harder

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Posted 19 August 2019 - 09:06 PM

This is a great question.  The BMV has an option for "mid point" voltage testing, but that only works for series connections. 

 

As Buckland suggests, the two batteries should be identical in makup/brand/age.  To use the shunt as intended, I would suggest using a buss connection for both batteries to ground to, and from there go to the shunt.  You will NOT be able to see individual SOC for each though


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#28 PaulT

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Posted 19 August 2019 - 09:40 PM

I’ve wondered when someone would ask this question. :)

For a short time, it bothered me that this info was unavailable, but the cost of obtaining it is well past the point of diminishing returns, IMHO.

If it is a concern, attach the positive lead from solar & load on one battery, and place the negative lead from the shunt on the other battery, swallow hard & enjoy your camping. Life keeps getting shorter.

Paul
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I thought getting old would take longer.





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