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Small Cabin Forum / Off-Grid Living / MPPT voltage question answered
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groingo
Member
# Posted: 18 Sep 2016 11:33
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After over a weeks waite I finally got an email reply from Andy at Tracer and Midnite Solar who both say that their CC's up to 40 amp models only allow 18.50 volts maximum power input from PV panels with no further explanations.
Would be interesting to see how different CC's handle their input power and daily KWh production numbers to see how the lower power effect daily power production.

MtnDon
Member
# Posted: 18 Sep 2016 12:15 - Edited by: MtnDon
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There is something wrong with that statement; something misunderstood somewhere along the line.

One of the big reasons people buy MPPT controllers is to be able to series connect panels because they want to raise the voltage and keep the amps down in order to use smaller gauge wire in long runs.

I regularly see 80 to 90 volts going into my Midnite The Kid (a 30 amp maximum rating MPPT charge controller). The Kid specs clearly state the maximum input is 150 VDC, and it will handle up to 162 VDC although after 150 VDC it will shut down, but won't be damaged unless the voltage exceeds 162.

My Brat, also a Midnite product, but a PWM controller, is rated to 60 VDC input. Midnite makes no other 30 amp or less controllers. Hence I am at a total loss as to what their rep told you. maybe there was a misunderstanding in the question? Every time I have talked to someone at Midnite I have come away with feelings of confidence. I have never has any reason to contact Tracer so have no idea about them.

A search for Tracer controllers comes up with info on 20 & 40 amp models with a max input of 100 VDC.

So something is weird / strange with the info you were given.

dunnie
Member
# Posted: 19 Sep 2016 21:15 - Edited by: dunnie
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Not sure if this is what your looking for but this is right from the Renogy website on the Renogy 40 Amp MPPT Solar Charge Controller. Max. Solar Input Voltage: 100VDC

groingo
Member
# Posted: 19 Sep 2016 22:20
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What I would like to see is what PV Input readings people are actually getting because the manuals and specs and reality are very different things.

MtnDon
Member
# Posted: 19 Sep 2016 23:05
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My sunny normal runs up to 90+ volts around solar noon time. That's three series connected panels with a Vmp around 28 or 29 VDC, feeding into a MPPT Kid. That is actually higher than the Vmp rating, which is likely due to the high altitude. Less atmosphere = more sun. More skin cancer too.

Specs and reality are very close there. The reality is also that the Kid does accept higher voltages that have spiked to a highest ever recorded maximum of 141 VDC.

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