question

steveinglis avatar image

Absorption voltage not reached

Hi, I just installed a Smart Solar 100/30 and a 385W AmeriSolar panel on my boat.

So far very happy but a little confused about 2 things.

1) The absorption voltage is set in the MPTT at 14.71v (for my Trojan FLA batteries) however I never see (in Victron Connect History) a voltage higher than 14.5v on the batteries

Also

2) I never see a PMax anything like my panels theoretical maximum of 385W. My actual maximum PMax today was 170W. This even on a very sunny June day in Greece at midday

Today VC reported that we were Bulk charging for 3h 35 and then absorption for 1h

Do I have a problem with my setup or is this all normal

Thanks for help


mppt smart solar
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2 Answers
steveinglis avatar image
steveinglis answered ·

tozz

thanks for responding.

My settings are pretty standard I think

Voltage 12v
Current 30A
ChargerEnabled
Preset Trojan (My Custom)
Expert OFF
Absorption V 14.70V
Float 13.50V
Equ 16.20V
Auto Equ Disabled
V compensation -16.82mV/deg C
Battery temp is proba around 25deg C
Low temp cutoff disabled

Load Output always ON

Point taken about power output.

Is PMax restricted by SOC of battery ? ie if the battery is already pretty full when charging commences will PMax be retsricted ?

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tozz avatar image
tozz answered ·

1) We need some details about your settings.

2) That doesn't sound too bad. The 385W is it's STD value. STD stands for standard test conditions. So it'll only reach that when all criteria is met. eg. 25C cell temperature (not the air temperature), solar irradiance, mass of air, etc, etc.

So in practice you'll never reach that 385W. On a very sunny day in Greece the panel was probably way more than 25 degrees C.

I usually get the highest peak output somewhere in february, when the sun is shining but it's still cold outside. In a day like today where it was around 23 degrees C, I get about 30% less.

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