Watts reading low

[Fauxlimey]

Hi,
I'm a newbie, and I finally got around to installing my Classic 150SL (I've had it for 3 years, but was getting by with a smaller CC and one 315W panel). It seems to be working beautifully. I have a 360 Ah AGM battery bank at 12V. I'm in an off-grid cabin in upstate New York, and my panels are on an east facing roof (I know... not so clever, but it suits me for the moment). Now I have four 315W panels (2x2), which put out a max of 90V. I don't use much power, probably 100W max for short periods of time. I hit float by 11 in the morning on a sunny day, and I can use lots of power without affecting the SOC when the sun is shining.

My question: Why is the watts reading on the Classic so low? It's typically under 100W, often in the teens, although I have seen it top 700W in bulk charge mode in direct sunlight. Surely the reading should be higher??

[mike90045]

my 5kw of pv, slowly ramps up from dawn, till about 10am, when the sun is full on, and then I'm only pushing 3kw. And if the batteries are full, they pull much less from the solar

[ClassicCrazy]

Hi,
I'm a newbie, and I finally got around to installing my Classic 150SL (I've had it for 3 years, but was getting by with a smaller CC and one 315W panel). It seems to be working beautifully. I have a 360 Ah AGM battery bank at 12V. I'm in an off-grid cabin in upstate New York, and my panels are on an east facing roof (I know... not so clever, but it suits me for the moment). Now I have four 315W panels (2x2), which put out a max of 90V. I don't use much power, probably 100W max for short periods of time. I hit float by 11 in the morning on a sunny day, and I can use lots of power without affecting the SOC when the sun is shining.

My question: Why is the watts reading on the Classic so low? It's typically under 100W, often in the teens, although I have seen it top 700W in bulk charge mode in direct sunlight. Surely the reading should be higher??

In Bulk the controller will charge with all available PV power.  When it gets to Absorb it will  hold the absorb setpoint voltage by lowering the current as the batteries charge . Like Mike said batteries will take less current as they charge. If the controller wasn't there and let all available power in then the voltage would keep rising , the batteries bubbling and potentially getting hot and ruined.  If you have a Whizbang installed and want to see the true potential power when the Classic is in absorb, then turn on a bunch of loads until you see the system amps start to go negative - then you can see what the PV is capable of putting out at that particular time.

Larry

[Fauxlimey]

Thanks for the replies. That makes total sense. I bought my PVs on Craigslist, hence my worry lol. Larry, thanks for the suggestion. I do have a Whizbang Jr. so I'll give that a shot, next time the sun shines. Today is terribly dull and rainy (still getting 65V, though). I'm loving the Classic so far   

[boB]

Watch for the display saying Absorb or Float which means the watts is throttling in order to regulate voltage.  That would be normal.

When in MPPT and the sun is shining good on your panels, (no clouds), then you can expect higher power output.