question

ripper avatar image
ripper asked

Temperature output of Mppt 100/20 erratic, no derating visible

Hi,

I am logging my MPPT 100/20 and get above image on a good day when the rated amps are drawn for extended periods.

Red is temperature, green the charge state, light blue pv voltage, blue the Amps, yellow battery voltage and green actual watts made.

At 65 degree the temperature , when presumably further rising, reads erratic values. Is the MPPT giving out false values?

Also, when reading this

https://community.victronenergy.com/questions/1845/mppt-internal-temperature-and-throttling-informati.html


And looking at my graph or following my BMV "by hand" it does not or has ever derated. When charging my scooter it has to bring the rated power for hours and does. I wonder whether everything is alright, I am not complaining as it does exactly what I want it to. Not that it has much of a chance to do otherwise as it is factor 4 overlayed with over 2kWp.



MPPT Controllers
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1 Answer
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi Ripper,

The inbuilt temperature probe for the MPPT is used once each day on startup (before production) to set the temperature compensation.

It is not used again for calculating battery voltage because the internal heat created by the MPPT would give a false reading. From then on it is used instead to protect against device over temperature.

If you want a more precise temperature compensation for your batteries, We recommend enabling Bluetooth (by installing the Bluetooth Smart dongle if necessary) and the Smart Battery Sense option, or BMV-712 with external temperature probe that you can place on the batteries themselves. This is called a VE.Smart network - https://www.victronenergy.com/live/victronconnect:ve-smart-networking

You could also use a MultiPlus external temperature probe and share the temperature sense with the MPPT via a GX device.

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joeoffgrid avatar image joeoffgrid commented ·
Hi Guy,

I am wondering if and how the controller communicates device over temperature protection is active?

I am dealing with mystery issues on my cooling box and now suspect the blue solar 75/10 may be the actual cause.

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