KevinC_63559
New Member
Hi all. I've been tracking solar power since my dad brought home a few cells in my teenage years. I'm 65 now, so awhile... I love seeing things like the newer Hybrid inverters which seem to be pulling a lot of "wouldn't it be nice if..." things together (peak shaving, off-prime charging, etc.). I live on a 121 acre farm, described by one visitor as "Officially the backside of nowhere!" (actually in NE Missouri, USA - but its 15 miles to the nearest gas station). We recently experienced the longest power outage since we bought the place in 2008 - over 37 hours. Compliments of gas generators, we didn't lose any food storage, but it was tough getting out for gas to run those. Had to share that generator between my house and my office/workshop (about 500 feet away). The incident has pushed me into finally "doing something" with solar. Oh, handy enough around basic power electronics that I built my own 2000 amp data center and wired it back to the pair of transformers the electric company dropped on pads for me (yeah, (10) 200amp panels all maxed with 20amp 240V breakers - that was not a typo).
So here is the plan - I would appreciate feedback. A main goal is to be able to bootstrap up a full system without having any significant parts left over at the end.
1) Try and spend roughly $300/month and build up a basic system that might be usable for something, like charging cell phones (minimum) and running a freezer or refrigerator a few hours a day (goal). To that end, I've bought my first LiFePO4 12V 100amp battery, a small 4amp charger (which will double for charging some 12V9A gell cells), and a 500W (1000W surge) full sine wave inverter. Charged up the battery, played with the bluetooth BMS via my iPhone, and hooked up a 12V USB charger (also purchased). Meet month 1st budget and have a few things to play with.
2) Found DIY Solar for U and this forum. Figured it was better to ask first and buy later. Love the diysolarforu (?DSFU?) Sol Boost Buck 20amp MPPT charger - the only MPPT charger I found so far that is USA made and sourced, and that features great FCC Class B stats. Figure if they are focused on making a unit that comes in 19db below FCC requirements, they likely have the big things down pat.
3) Sketching out in my head a potential sequence of events:
Month 1: Buy one of the above charge controllers.
Month 2: Buy a bundle of 10 solar panels (for best price - but blowing the budget this month, but that is what tax returns are for).
Month 3: Mount (1) pane generating 12V @ 350W (STC) to max input into the charge controller. Likely do this on a temporary wooden fixed frame.
Month 4: Buy an eco-worthy tracker to get more hours out of the array, removing the temporary wooden fixed frame.
Month 4b - rig a 12V system to power the eco-tracker, perhaps (1) extra panel on the eco-worth feeding a basic 12V battery system.
Month 5: Another battery - another 3 panels on the tracker, convert to 24Vx700W
Month 6: Another battery for a standalone 12V for the long term supply to the tracker.
Month 7: Check on the specs of the latest Sol Buck Boost - hoping for 24V/48V variant. Depending on results, things get a bit fuzzy, but:
Either another charge controller for the standalone 12V battery, or a new 24V/48V one repurposing the original for the standalone system
Month 8: Another tracker, using up 4 more panels (1 spare at this point - maybe parallel that one into the 12V standalone system)
Month 9-13: Learn LEARN Learn. Maybe expand batteries monthly. See where Hybrid inverters are.
Month 14: <maybe> Convert to hybrid inverter using tax refund.
There are a bunch of questions associated with the above, and I suspect more to follow:
A) Understand battery pricing better. My current 12V100A LiFePO4 was sourced from Amazon, and sold for $180 shipped. Came with a Bluetooth BMS and sounded decent, but what do I know?!? Obviously Chinese with the brand-of-the-month being "Fiunie" which I've never heard of before. Cheap, maybe usable for the 12V standalone system later, if not will be considered an educational expense. When I web surf most solar battery sites, I typically see 12V100A in the $800-$900 range and don't understand the 4X price. DSFU sells what I suspect is the best BMS system for $80, so the difference between my $180 unit and a $800 unit can't be the quality of the BMS. Should I instead me buying (4) packs of individual cells from https://ezealco.com/ and adding a DSFU BMS? Total cost would be around $245 - a small premium over the $180 I spent. Of course doing that would lead me to a System's Data Master for $240, but that is a one-time charge, so maybe a month 9-13 thing.
B) The DSFU charge controller advertised a max STC 12V350W input, or 24V700W input. Using the Sunwatts reference site, that's going to be tricky. I remember when panels were 100W each, but apparently modern ones start at 360W. Is that 10W difference really going to break things, or is it within the margin of error, especially since its STC not PTC or NOCT?
C) What can the Eco-worthy tracker actually handle in panels? They sell 100W and 190W ones, but modern ones are a lot cheaper per watt (like almost half).
D) If I eventually end up with a hybrid inverter, what would I use my DSFU controllers for? One for the 12V standalone system, that's cool. Most (if not all), of the hybrid inverters have their own MPPT charge controllers, with loser, if any, FCC Class B ratings. I dabble in listen-only HAM radio, so interference is a concern.
E) Confused about matching solar panel max voltage to the specification for the DSFU charge controller. The text on the charge controller page indicates a maximum working voltage of 54V. A typical solar panel per Sunwatts shows a max open circuit voltage of 49.8V, and (connected?) max voltage of 33.9V. Not a problem for a 12V system but would be way out of range if two panels were run in series to make a nominal 24V system. Amperage is a tad high too, at 10.8 amps X 2 for a 2x2 array yielding a max of 21.6 amps of input into a 20 amp controller. Really REALLY don't want to burn up controllers.
Would appreciate and welcome all comments and clarifications!
Kevin
So here is the plan - I would appreciate feedback. A main goal is to be able to bootstrap up a full system without having any significant parts left over at the end.
1) Try and spend roughly $300/month and build up a basic system that might be usable for something, like charging cell phones (minimum) and running a freezer or refrigerator a few hours a day (goal). To that end, I've bought my first LiFePO4 12V 100amp battery, a small 4amp charger (which will double for charging some 12V9A gell cells), and a 500W (1000W surge) full sine wave inverter. Charged up the battery, played with the bluetooth BMS via my iPhone, and hooked up a 12V USB charger (also purchased). Meet month 1st budget and have a few things to play with.
2) Found DIY Solar for U and this forum. Figured it was better to ask first and buy later. Love the diysolarforu (?DSFU?) Sol Boost Buck 20amp MPPT charger - the only MPPT charger I found so far that is USA made and sourced, and that features great FCC Class B stats. Figure if they are focused on making a unit that comes in 19db below FCC requirements, they likely have the big things down pat.
3) Sketching out in my head a potential sequence of events:
Month 1: Buy one of the above charge controllers.
Month 2: Buy a bundle of 10 solar panels (for best price - but blowing the budget this month, but that is what tax returns are for).
Month 3: Mount (1) pane generating 12V @ 350W (STC) to max input into the charge controller. Likely do this on a temporary wooden fixed frame.
Month 4: Buy an eco-worthy tracker to get more hours out of the array, removing the temporary wooden fixed frame.
Month 4b - rig a 12V system to power the eco-tracker, perhaps (1) extra panel on the eco-worth feeding a basic 12V battery system.
Month 5: Another battery - another 3 panels on the tracker, convert to 24Vx700W
Month 6: Another battery for a standalone 12V for the long term supply to the tracker.
Month 7: Check on the specs of the latest Sol Buck Boost - hoping for 24V/48V variant. Depending on results, things get a bit fuzzy, but:
Either another charge controller for the standalone 12V battery, or a new 24V/48V one repurposing the original for the standalone system
Month 8: Another tracker, using up 4 more panels (1 spare at this point - maybe parallel that one into the 12V standalone system)
Month 9-13: Learn LEARN Learn. Maybe expand batteries monthly. See where Hybrid inverters are.
Month 14: <maybe> Convert to hybrid inverter using tax refund.
There are a bunch of questions associated with the above, and I suspect more to follow:
A) Understand battery pricing better. My current 12V100A LiFePO4 was sourced from Amazon, and sold for $180 shipped. Came with a Bluetooth BMS and sounded decent, but what do I know?!? Obviously Chinese with the brand-of-the-month being "Fiunie" which I've never heard of before. Cheap, maybe usable for the 12V standalone system later, if not will be considered an educational expense. When I web surf most solar battery sites, I typically see 12V100A in the $800-$900 range and don't understand the 4X price. DSFU sells what I suspect is the best BMS system for $80, so the difference between my $180 unit and a $800 unit can't be the quality of the BMS. Should I instead me buying (4) packs of individual cells from https://ezealco.com/ and adding a DSFU BMS? Total cost would be around $245 - a small premium over the $180 I spent. Of course doing that would lead me to a System's Data Master for $240, but that is a one-time charge, so maybe a month 9-13 thing.
B) The DSFU charge controller advertised a max STC 12V350W input, or 24V700W input. Using the Sunwatts reference site, that's going to be tricky. I remember when panels were 100W each, but apparently modern ones start at 360W. Is that 10W difference really going to break things, or is it within the margin of error, especially since its STC not PTC or NOCT?
C) What can the Eco-worthy tracker actually handle in panels? They sell 100W and 190W ones, but modern ones are a lot cheaper per watt (like almost half).
D) If I eventually end up with a hybrid inverter, what would I use my DSFU controllers for? One for the 12V standalone system, that's cool. Most (if not all), of the hybrid inverters have their own MPPT charge controllers, with loser, if any, FCC Class B ratings. I dabble in listen-only HAM radio, so interference is a concern.
E) Confused about matching solar panel max voltage to the specification for the DSFU charge controller. The text on the charge controller page indicates a maximum working voltage of 54V. A typical solar panel per Sunwatts shows a max open circuit voltage of 49.8V, and (connected?) max voltage of 33.9V. Not a problem for a 12V system but would be way out of range if two panels were run in series to make a nominal 24V system. Amperage is a tad high too, at 10.8 amps X 2 for a 2x2 array yielding a max of 21.6 amps of input into a 20 amp controller. Really REALLY don't want to burn up controllers.
Would appreciate and welcome all comments and clarifications!
Kevin