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Current draw with Smart Shunt using battery cutoff


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battery switch.pdfI am planning to install a Blue Sea  battery cutoff switch. I am also installing a Victron Smart Shunt.  I don't have solar or lithium but do plan to add them down the road. 

If I install the cutoff on the  (+) lead as indicated in the attached sketch, will the two small wires that serve as the temperature probe allow any current flow while the cutoff switch is open? (in the battery cutoff position)?

Thanks, 

Steve #512

,battery switch.pdf

 

 

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That would be a good question for Victron to verify.  But their spec sheet says that the shunt draws less than 1 mA, so even if that's continuous even with battery power cut off, that would be less than 9 Ah a year, if my math is correct.

Snowball • 256 • 2018 Ford Raptor

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Posted (edited)

I'm not familiar enough with lead acid batteries to know how long they can be left without a charge.  They'll lose charge on their own over time even without a draw, and how quickly they do so depends on the battery type, temperature, and probably other things as well.  But I don't think that the draw from the shunt would be much of a factor.  Trojan says that the best practice for their batteries is to not allow them to go below 70% while stored, so I think if you don't have a battery maintainer on them that you'd probably want to check them every few weeks regardless.

Edited by Overland

Snowball • 256 • 2018 Ford Raptor

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I agree with Overland on this and I do have the Trojan T-105's (lead acid batteries).  During storage I check mine every 6 to 8 weeks.  Normally all I do is add water - they don't take much but since I'm at the storage yard I do it anyway.

Bill

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The Victron temp probe should be just like the Zamp solar one, it is just a variable resistor. With power removed from the system, it won’t do anything at all in terms of current. You could actually move the small red power wire for the SS to the other (switched) side of your cutoff switch. Then the SS will be powered off entirely. But leaving it attached as drawn, you should be able to connect with the app and read battery state, even with the battery bank disconnected. I think.....

John Davies
Spokane  WA

Edited by John E Davies
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