positive ground update

sam c

installed a flexmate 80, what a difference!. batts at float by 1pm, going to add more batts.
I now have 3 panels that are not being used (sunpower 48v 215 watts) the ground problem ( +) if I understand what i have read, is not going to be a problem at this voltage,?, 48 to 12,
I have been playing with the 3 extra panels by cutting them in and out of the circuit to keep the 80 at 75 amps output, early am, cloudy days,
is there a device to do this automatically
thank all of you for the help, SAM

DirtLife

Ahh interesting. Having enough panels to peak the Felx even on poor days. Have you reached out to Outback about just leaving the three on and over powering the guy? Perhaps it will accept the extra 15 to 18 amps and just waste it on good days? Maybe you could set up a strong excess use: water heater, air pump/ water pump storage up hill?
I see this was ten years ago. You still with us Sam? 

Also I’d like to hear how your life is going with that positive ground system. I’m knowingly walking into one now. 

Tecnodave

There is an issue with overpowering MPPT controllers. I am doing that with my MidNite controllers. I many stormey days in a row and when foul weather drops down on me I switch in extra banks for added power. This works well but the problem arises when you would be expecting total cloud cover, then cloud cover dissipates to full sun. The controller will not be able to use the extra power and will not operate the panels at MPP, the input voltage rises dramatically causing extra heating in the controller. My Classic's fans run continuously , Kid's are running noticeably hotter. Heat is the arch enemy of electronics. I normally run the Classis at 2400 watts out of the rated 2700 watt capacity , but switch in an extra 1200 watts /panels for cloud cover. My Kid's are rated about 800 watts at 24 volts but I am running 1200 watts /panels in in foul weather.  I am very hands on my solar system and am a amateur weather forecaster, logging into national weather service several times a day to see the satellite data,storm patterns.

I would not recommend doing this if you can't keep an eye on things all the time. If I have to leave for any reason I assume that I will get full sun and switch out the extra banks.

david

mcgivor

Tecnodave said:

There is an issue with overpowering MPPT controllers. I am doing that with my MidNite controllers. I many stormey days in a row and when foul weather drops down on me I switch in extra banks for added power. This works well but the problem arises when you would be expecting total cloud cover, then cloud cover dissipates to full sun. The controller will not be able to use the extra power and will not operate the panels at MPP, the input voltage rises dramatically causing extra heating in the controller. My Classic's fans run continuously , Kid's are running noticeably hotter. Heat is the arch enemy of electronics. I normally run the Classis at 2400 watts out of the rated 2700 watt capacity , but switch in an extra 1200 watts /panels for cloud cover. My Kid's are rated about 800 watts at 24 volts but I am running 1200 watts /panels in in foul weather.  I am very hands on my solar system and am a amateur weather forecaster, logging into national weather service several times a day to see the satellite data,storm patterns.

I would not recommend doing this if you can't keep an eye on things all the time. If I have to leave for any reason I assume that I will get full sun and switch out the extra banks.

david

Weather forecasting is something I've abandoned, it seems I can manipulate weather, water the plants it rains, run the generator the clouds disappear, wash the clothes clouds move in, it's uncanny how that works.

jonr

Most MPPT controllers are designed to self-limit their input power to a level that they are designed to handle.    Electronics can run pretty hot without damage.