question

dominique-martin avatar image
dominique-martin asked

Temperature compensation on MPPT bluesolar

last week I prepared a bluesolar MPPT150-60-Tr charge controller.

I used the BT dungle with my smartphone. I was surprised to find that the temperature compensation did not have a direct effect on the battery charge voltage. So I set the coefficient to -60mV / ° C for a battery in 24V and I did not see any change in the absorption and floating voltage, while the temperature of the technical room was 5 ° C.


Can you explain to me the reason?

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klim8skeptic avatar image
klim8skeptic answered ·

Hi DM,

If you are using the mppt inbuilt temp compensation, it will take the temperature at the start of the day (when the panels get sun) and use that temp for the rest of the day. How cold was the mppt?

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dominique-martin avatar image dominique-martin commented ·

Hi Klim,

For the test, the temperature case was about 0°C. So indeed, I have to experiment the controller , first without PV (DC supply) and after a night, I will connect the DC supply... If I had your mail, I could send you photos of my process.

I have not seen your explanation in the Victron manual...Are you from Victron team or are you an installer ?

It's the first time that I post on the community.

Thanks for your help !

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klim8skeptic avatar image klim8skeptic ♦ dominique-martin commented ·

Hi Dom,

I am an end user, like most of the people who post here.

It is probably best that you change the temp compensation back to -32mV/C for your 24v batteries (or your batt manufactures recommendation) until your confident things are working right. At worst the batts might be a little undercharged, vs overcharged.

Adding photos is easy, click on the mountain with dot symbol and search your phone/computer for photo.

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ dominique-martin commented ·

Hi @Dominique Martin,

There is a description of the behaviour that @klim8skeptic describes here by Victron Energy team:

https://community.victronenergy.com/questions/1643/how-the-internal-temperature-compensation-feature.html

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