niel wrote: »
i chose solar because i'm a bit nuts compared to the average person by their definitions of what is nuts or normal. i'm normal in my mind.)
Most off grid systems don't produce as much energy as it takes to create the system and recycle the batteries.
northerner wrote: »
Photowit, just wondering what source you got that from? My understanding is that the solar panels alone have less than a 2 year pay back in energy return. In an off grid system, the batteries would undoubtedly have the worst energy return (from a standpoint of the entire system). Lead acid batteries have a large recycling infrastructure already in place, and the lead, acid, and other components can easily be reused. But I would think there still would be a pay back.
Photowhit wrote: »
For the most effiecently built panels (which I have a few of Evergreen) the return of energy based on grid tied system is 16-18 months(I think they were claiming 12 months at the end), but with an off grid system you must have 4x the number of panels for the same amount of energy availability, then add in the batteries and balance of system... I think if I ran the numbers, since I'm using in essence a 1 day storage during the summer (my major usage to run an A/C, but our heat comes with sun) I might be a little on the plus side, but then again I have too much array as well.
northerner wrote: »
Efficiency of a battery system is about 70 %.
Muskoka wrote: »
Were not nuts living off grid, we were nuts living on the grid.;)
When my sister comes to visit from the city, she shakes her head and smiles.
I take that as a compliment, she's always said I was the smartest in the family, and I have the least from a financial standpoint. I also don't have any debt, none.
So, in the end, who's really nuts. I wake up every morning with a smile on my face, can't be too bad.
You simply can not get to even 70% even in a DC only system.
Edwardo wrote: »
I'm getting discouraged...As much as my wife and I would like solar power i'm wondering if its worth all the headache.We do have a choice..Why did you choose to go with solar and are you glad you did?
BB. wrote: »
Measuring power output from the Charge controller can be miss-leading...
Most solar charge controllers (especially for solar panels) are "series controllers"... They only let through the amount of energy to "recharge" the battery and supply "daytime loads".
If the battery is full, and the there are no other loads--The series charge controller (typical MPPT and PWM solar type) will simply turn off the current from the solar panel. And, at that point, the charge controller will stop "logging" AH/WH "generated".
This is a question that comes up on occasion... Could not a "smart" MPPT charge controller, for example, just sample Vmp/Imp once every 5 minutes and use this information to "estimate" the amount of available energy (Watts*Time) vs the actual charging energy (used to float the battery bank and run any daytime loads).
If you have a dump load--That is another issue... The charge controller (in theory) is always outputting its maximum energy (solar, wind, etc.) and any excess is diverted to the shunt load(s). So, in that case, you have the actual amount of energy collected and used (depending on how the logging is setup and such--Many people do not log the output of their direct connected wind turbines--So there are still some unknowns).
Photowhit wrote: »
I think Bill already answered your reply. You aren't measuring what the panel could produce, but rather what the batteries needed. I might even suggest your system is unhealthy from what you've reported, since much of the time when your batteries are near full top 90% or so, Your charge controller will tapper the charging current back, though perhaps you had a sunny month and managed to top off your batteries regularly.
But as Bill stated your just measuring the charging not the available energy which would pass through to the grid in a grid tied system. Off grid systems need to waste energy to remain healthy.
The newer charge controllers do help utilize the extra energy, with their ability to start opportunity loads like water heating. I'm looking forward to figuring out how to get my washer to run as an oportunity load, perhaps starting the cycle then switching curcuits so my Midnite Classic will turn the power back on when it reaches float...