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edwards151 avatar image
edwards151 asked

Which battery temp sensor for MPPT 100/50 and Smart Shunt

I'm putting together my RV solar setup and would like to use a battery temperature sensor, as I understand my Victron MPPT 100/50 charge controller can optimize it's charging of the batteries if it knows their temperature. I currently am using 2 x 6v flooded golf cart batteries, but plan to upgrade to LiFePO4 batteries in the future, so would also like the protection of low temp cutoff. I also have the Victron 500 Amp Smart Shunt. It appears that I can get a temp sensor for the shunt and then the shunt will communicate to the MPPT via bluetooth. I guess I would rather connect the temp sensor directly to the MPPT and not rely on that bluetooth connection if thats possible and recommended.

Which temp sensor should I get and is it connected through the VE.Direct jack on the MPPT or some other way? Are there other good reasons to just connect the temp sensor through the shunt and allow it to talk to the MPPT over bluetooth that I'm not aware of?

Thanks!

MPPT ControllersSmartShuntTemperature Sensor
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1 Answer
JohnC avatar image
JohnC answered ·

Hi @edwards151

The various Victron T sensors are summarized here.. https://www.victronenergy.com/live/temperature_sensors

Firstly, your 100/50 already has internal temp sensing/compensation, but uses it only at sunup to set the day's charge program. That's coarse, but you can compensate to a point by adjusting charge settings for the increase in T your batts regularly experience.

The issue with using the Smartshunt T sensor is that you lose the other V options like (either) midpoint or aux batt monitoring.

The two Smart Sense units are BT only, and mightn't suit an upgraded system, like where you might choose a Multiplus or even add a GX. Wires rule then. And your mppt must be a Smart model for BT to work. VE.Direct should work, but I haven't confirmed that.

And your future Li's may have a bms with T protection anyway.

So it's your choice. And I see no real harm deferring that choice until you decide on those new batts. Or even a Multi and/or GX.. :)


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