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shaneiseminger avatar image
shaneiseminger asked

Two SmartSolar 100/30s, one reads different voltages -- do I need a Smart Battery Sense?

I have a travel trailer with the following:

  1. Solar panels on the roof feeding a SmartSolar 100/30 wired close to the batteries.
  2. A second set of solar panels on a portable rack with a second SmartSolar 100/30, this one mounted behind the panels. There is a 10 AWG, 10m cable that connects these panels to the trailer. This second set of panels can be tilted and turned to keep them gathering the most sunlight possible throughout the day.
  3. A SmartShunt reading charge/load.

Everything is connected via VE.Smart network.

My issue is that the SmartSolar in #2 sometimes reads significantly higher voltage--sometimes in excess of 1v higher--when charging current is higher. That seems to cause both controllers to go into absorption mode sooner than I would expect. I do have a couple of connectors inside the trailer to upgrade that may help this a bit, but I still have a few things I'm not sure about:

  1. Shouldn't the SmartSolars be using the voltage reading from the SmartShunt? VictronConnect shows that they are, but they still go into absorption mode when the voltage at #2 is close to the absorption voltage setting in both SmartSolars. If I bump up the absorption voltage in #2, both go back to bulk mode.
  2. Would a Smart Battery Sense help somehow?
  3. Would it make more sense to put SmartSolar #2 close to the batteries, like SmartSolar #1?


SmartShuntsmart solar set-up helpSmart Battery Sense
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secessus avatar image secessus commented ·

Shouldn't the SmartSolars be using the voltage reading from the SmartShunt?

I would have thought so. Do both controllers in VictronConnect show battery voltage under "this product is configured for VE.Smart network and is receiving..."?

If so, I don't know why one controller is going its own way.

Edited to add: I sometimes see minor discrepancies (like 0.02v) between my Smart Battery Sense and 150|45 controller on the same VE.Smart network. I assume this is due to drift in between voltage data updates. <shrug>


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klim8skeptic avatar image
klim8skeptic answered ·

My issue is that the SmartSolar in #2 sometimes reads significantly higher voltage--sometimes in excess of 1v

This voltage drop is excessive. Out of the range for voltage compensation for SmartNetworking to compensate for.

Use some thicker cable between the mppt and battery.

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shaneiseminger avatar image
shaneiseminger answered ·

I see, good to know. I just redid the voltage drop calculations for the 10/2 cord I'm using now and I think I did them incorrectly the first time, so will try upgrading cabling and connectors throughout.

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Related Resources

Additional resources still need to be added for this topic

SmartShunt Product Page

SmartShunt Installation Manual

SmartShunt Quick Installation Guide

SmartShunt Datasheet

Additional resources still need to be added for this topic

Smart Battery Sense Product Page

Smart Battery Sense Manual