diy solar

diy solar

SMA Sunny Boy capabilities

From what I know, the Signature Solar batteries BMS will not work with the SI. No communication. Or it is hit and miss. SOK BMS works with SI, but they also cost more. That is why I've been on the fence as to what LI battery to get.
 
From what I know, the Signature Solar batteries BMS will not work with the SI. No communication. Or it is hit and miss. SOK BMS works with SI, but they also cost more. That is why I've been on the fence as to what LI battery to get.
Seems to be a common issue with BMS and inverters "failing to communicate ". One reason this forum is so valuable is to point these issues out, and post work arounds that aren't worse than the issues they "solve".
 
My first solar system was built for low voltage stuff like led lights, the computer, phones, and such. Stuff that really can be replaced with flashlights and emergency radios.

When the power is off for days, what matters is having hot and cold running water, keeping the pipes from freezing and the frozen food from thawing. That's mostly high voltage stuff as the off grid crowd knows, and if you take that stuff off grid, you really don't need the grid anymore for anything.
 
One of the good things is that there are a lot more options available now. Power storage is the next thing. On the fence until I can figure out a good LI battery storage system (one that won't break the bank) that will work with the SI's. PV panels and inverters are super cheap now (compared to what they were 20 years ago) so making power during the day is no problem. It is storing it for night time use that is still a bit of a challenge.
 
Indeed. Both inverters and batteries are far from catching up with panels, but both are changing fast. Ten years ago it took 2 Sunny Boys to do what a single mid level one does today, and then there's Lithium...
 
I stared out with 2 x 2500 watt Sunny Boys that cost $2,500 each. Now you can get 1 x 7.7 for around $1,700. Price went from $1/watt to $0.22/watt. Almost 80% less. Will be nice if batteries go the same way (price wise that is). Panels were 12% efficient. Now they are 22%? That is really good also. Never planned that they would be obsolete before the 25 year warranty ran out. The panels cost $4.50/watt and now they are in the area of $0.68/watt. So basically prices went from $5.50/watt to $1/watt now. Plus rebates.
 
I stared out with 2 x 2500 watt Sunny Boys that cost $2,500 each. Now you can get 1 x 7.7 for around $1,700. Price went from $1/watt to $0.22/watt. Almost 80% less. Will be nice if batteries go the same way (price wise that is). Panels were 12% efficient. Now they are 22%? That is really good also. Never planned that they would be obsolete before the 25 year warranty ran out. The panels cost $4.50/watt and now they are in the area of $0.68/watt. So basically prices went from $5.50/watt to $1/watt now. Plus rebates.
Exactly so. I also started with 2 sunny boys (3200w ?) and two 3500w rooftop arrays. But 4k was a big system ... And we while all expected batteries to be consumables, todays batteries can go thousands of cycles with good power left. From very rare and ridiculously expensive to just plain expensive.
Progress.
 
Ha. Great. Right. Started with dry cell or alkaline batteries in MAG lights. Replaced all the time, but got a charger that supposedly recharged alkaline batteries. Worked ok. Then on to NiCD rechargeable memory batteries, then NiMH batteries and now lithium. Have a head light that uses 2 x 18650 batteries that I got 7+ years ago that I use all the time and never replaced that batteries yet. Just regchage them at night. Never bought a Duracell again. When I think of that 4D cell MAG light in comparison to today's LED's.... 10x the power, more light, better beam and batteries that last basically "forever."

If only SMA did a bit more on the software side of the SI's...No ethernet, no wifi (unless you can write your own code)....and more support for DIY lithium batteries. REC BMS I know, but those are expensive, especially if you want 40 or 60 or 80 or 100+ KWH of storage.
 
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Frankly after the last ten years, I was glad to find SMA was still a respected brand. The whole appeal of online logging and troubleshooting is lost on me. A dinosaur, I am.
 
Yes, they are still built with good quality parts and have a good warranty. Very reliable and long lasting. The surge capabilities of SI is impressive.
 
Well I'm searching for a NOS SI. @Hedges metioned seeing some on fleabay, and there are lots of sbs available barely used to handle the grid side of things.
 
Well I'm searching for a NOS SI. @Hedges metioned seeing some on fleabay, and there are lots of sbs available barely used to handle the grid side of things.

Google search with site:craigslist.org as well.

The Sunny Islands out there are mostly from DC Solar fiasco. Prices fluctuate a bit.
I picked up a pallet of them couple years ago. Probably twice the price of bankruptcy auction, but half (or less) than the prices we see now.

Sunny Boys, older models don't do UL-1741-SA/Rule-21. If that isn't required for backfeeding grid, they work great.
I picked up a pallet of them, from a dealer of CHP plants who couldn't get the generator portion anymore.

Sunny Island plus Sunny Boy makes a nice grid-backup or off-grid system. Just check the compatibility list.

https://files.sma.de/downloads/SB-OffGrid-TI-US-en-22.pdf

With only AC coupling, you need a way to shut off loads as battery gets low, so it doesn't discharge to the point SI shuts off. Adding DC coupling is a less elegant solution. I used a "load-shed" relay. If something like AC/heat pump is your only big load, you could control its thermostat wire. Need to ensure there is enough battery to last until Sunny Boy produces again the next day.
 
Google search with site:craigslist.org as well.

The Sunny Islands out there are mostly from DC Solar fiasco. Prices fluctuate a bit.
I picked up a pallet of them couple years ago. Probably twice the price of bankruptcy auction, but half (or less) than the prices we see now.

Sunny Boys, older models don't do UL-1741-SA/Rule-21. If that isn't required for backfeeding grid, they work great.
I picked up a pallet of them, from a dealer of CHP plants who couldn't get the generator portion anymore.

Sunny Island plus Sunny Boy makes a nice grid-backup or off-grid system. Just check the compatibility list.

https://files.sma.de/downloads/SB-OffGrid-TI-US-en-22.pdf

With only AC coupling, you need a way to shut off loads as battery gets low, so it doesn't discharge to the point SI shuts off. Adding DC coupling is a less elegant solution. I used a "load-shed" relay. If something like AC/heat pump is your only big load, you could control its thermostat wire. Need to ensure there is enough battery to last until Sunny Boy produces again the next day.
'Sunny Island plus Sunny Boy makes a nice grid-backup or off-grid system. Just check the compatibility list. ' exactly what I intend to do. There is another thread talking about attaching a SI to the grid and I thiught just buy a sunny boy to talk to the grid.
 
New old stock
Right. Retail price is crazy for SI's. Got mine that way also. Would have had a hard time paying $8K for 2 of them. Hedges made out like a bandit on his deals! They are still worth it at $8k. Superb quality. Some of these others I see will break in a few years and then you throw them away. SMA stuff is made to last.

Little side note - I have 2 Radio Shack 12vdc fans in my inverter cabinet that run off of a 10w solar panel. They turn on in the am and off in the PM every single day for the last 20 years. Still going strong.
 
Google search with site:craigslist.org as well.

The Sunny Islands out there are mostly from DC Solar fiasco. Prices fluctuate a bit.
I picked up a pallet of them couple years ago. Probably twice the price of bankruptcy auction, but half (or less) than the prices we see now.

Sunny Boys, older models don't do UL-1741-SA/Rule-21. If that isn't required for backfeeding grid, they work great.
I picked up a pallet of them, from a dealer of CHP plants who couldn't get the generator portion anymore.

Sunny Island plus Sunny Boy makes a nice grid-backup or off-grid system. Just check the compatibility list.

https://files.sma.de/downloads/SB-OffGrid-TI-US-en-22.pdf

With only AC coupling, you need a way to shut off loads as battery gets low, so it doesn't discharge to the point SI shuts off. Adding DC coupling is a less elegant solution. I used a "load-shed" relay. If something like AC/heat pump is your only big load, you could control its thermostat wire. Need to ensure there is enough battery to last until Sunny Boy produces again the next day.
Right. Don't run the big loads or send power to the grid only at night like a time of use program, especially if net metering isn't an issue ie boondocking, off-grid cabins , or a cabin in a house boat.

All , even a naval galley and shower, take space and electricity at same time but not at night. The battery management, the charger, the grid, and the array all need to talk to each other. Frequently.
My 4 cents ... inflation.
 
An interesting side effect of having a flexible inverter/battery setup:

I can run my enough of my home, including 240v well pump from a 3000 watt 120v inverter generator using an “assist” function of my inverters. Honestly I could likely run the house off the smallest Honda generator because my continuous loads are less than the rated output of these really small generators.

It’s a cost and convenience thing. I use the most fuel efficient generator that is physically small and quiet…relatively.

I have gone 11 days without grid power during an outage last year on a small genie.
 
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