MyFishFinder Forum
MFF US Northeast => Massachusetts => Topic started by: Baitbucket on Aug 17, 2020, 07:26 PM
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480x 18650 3200mAh cells. Building a 6kwh battery backup for the house that will charge off my 8.5kwh solar system.
24v pack may be next for the boat. For those wondering, a 110ah 24v battery is about 25 lbs.
(https://i.postimg.cc/TpbqQhjP/IMG-20200817-195944.jpg) (https://postimg.cc/TpbqQhjP)
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Very cool!
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What will you be able to run off that battery and for how long?
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It's amazing what you can do with 18650 cells. If you make a 24v for the boat, what are the advantages of building one over buying a pre-made lithium deep cycle? Cheaper?
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I am sure he will say cost...
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Following. I was looking at power walls to be charged by my 16kwh Generac so it doesn't need to run constantly in an outage like the one we just had.
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Following. I was looking at power walls to be charged by my 16kwh Generac so it doesn't need to run constantly in an outage like the one we just had.
Yeah, those must not be cheap.
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What will you be able to run off that battery and for how long?
My solar array generates 50kWh daily on average. So during the day, this battery wouldnt drain at all. I could run my whole house off it theoretically during the day. At night, i would limit it to my critical loads, IE: Fridge, freezer, hall lights, and some outlets. Those would run for roughly 15-20hrs off the battery, which should easily get me through the night. Winters would be tougher, but the best part about this is its all modular and scalable. Need more power? Add more batteries.
It's amazing what you can do with 18650 cells. If you make a 24v for the boat, what are the advantages of building one over buying a pre-made lithium deep cycle? Cheaper?
PRICE PRICE PRICE! For enough cells, you are looking at about 340$ shipped to build 1x 16.8v 4s battery and 1x 12.6v 3s battery for a total of 29.4v. You could do 2x 16.8v batteries, just make sure your trolling motor can handle 33.6v. Then pick up 2 60amp BMS's for about 15$ ea, some shrink wrap, a case to put it in, wires to handle 60amps, and you can probably build both for under 500$ total. Best part is, you can charge it with any 30-35v charger, as the BMS will balance the cells and cut off the voltage.
Conversely, if u were to just buy a 12v 105+ah battery, you are looking at 800-1000$ each. So figure 1500-2000$.
4X The price and not nearly as fun lol
Following. I was looking at power walls to be charged by my 16kwh Generac so it doesn't need to run constantly in an outage like the one we just had.
Powerwalls are so stupidly over priced. You are looking at close to 12-15k installed.
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My solar array generates 50kWh daily on average. So during the day, this battery wouldnt drain at all. I could run my whole house off it theoretically during the day. At night, i would limit it to my critical loads, IE: Fridge, freezer, hall lights, and some outlets. Those would run for roughly 15-20hrs off the battery, which should easily get me through the night. Winters would be tougher, but the best part about this is its all modular and scalable. Need more power? Add more batteries.
PRICE PRICE PRICE! For enough cells, you are looking at about 340$ shipped to build 1x 16.8v 4s battery and 1x 12.6v 3s battery for a total of 29.4v. You could do 2x 16.8v batteries, just make sure your trolling motor can handle 33.6v. Then pick up 2 60amp BMS's for about 15$ ea, some shrink wrap, and a case to put it in, wires to handle 60amps, and you can probably build both for under 500$ total. Best part is, you can charge it with any 30-35v charger, as the BMS will balance the cells and cut off the voltage.
Conversely, if u were to just buy a 12v 105+ah battery, you are looking at 800-1000$ each. So figure 1500-2000$.
4X The price and not nearly as fun lol
Powerwalls are so stupidly over priced. You are looking at close to 12-15k installed.
Yes they are money. Don't look at the price for that generac installed! They don't give them away at that size but I can run everything! That said it worked its arse off for 7 days after that tropical storm and I realized I need storage....probably solar at some point as well.
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Yes they are money. Don't look at the price for that generac installed! They don't give them away at that size but I can run everything! That said it worked its arse off for 7 days after that tropical storm and I realized I need storage....probably solar at some point as well.
I got my solar a couple years ago right before all the rebates and srec programs ended. My array cost $30k, but i only ended up paying $12k after the rebates. The remaining 12k was put on Massachusetts solar loan at 1.4% for 10 years. Every Megawatt of power I generate equates to 1 SREC which sells back to the Ele company for 250-300$. I generate 10 megawatts a year for 2500-3000 in SREC income. My loan is 200$ a mo. Do the math lol.. My SRECs pay my loan and i make another 300-500, plus no electric bill (200-250/mo). It sounded to good to be true and i was waiting for the "oh by the way" that made it all not worth it. But it never came. Ive been trying to talk people into solar since. But that 20-30k loan looks scary to alot of people.
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It would delay my next boat purchase but I have the cash for that and I am highly interested in discussing this more with you.
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I got my solar a couple years ago right before all the rebates and srec programs ended. My array cost $30k, but i only ended up paying $12k after the rebates. The remaining 12k was put on Massachusetts solar loan at 1.4% for 10 years. Every Megawatt of power I generate equates to 1 SREC which sells back to the Ele company for 250-300$. I generate 10 megawatts a year for 2500-3000 in SREC income. My loan is 200$ a mo. Do the math lol.. My SRECs pay my loan and i make another 300-500, plus no electric bill (200-250/mo). It sounded to good to be true and i was waiting for the "oh by the way" that made it all not worth it. But it never came. Ive been trying to talk people into solar since. But that 20-30k loan looks scary to alot of people.
You say "array", I assume you did not put this on the roof of your house? Stand alone array? And what is the life expectancy of the panels? I mean if you pay off the loan in 10 years, do the panels last another 10? Doesn't seem like a down side to this at all.
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You say "array", I assume you did not put this on the roof of your house? Stand alone array? And what is the life expectancy of the panels? I mean if you pay off the loan in 10 years, do the panels last another 10? Doesn't seem like a down side to this at all.
Array can apply to both roof and ground. Mine are on my roof. As for life expectancy, i believe they degrade as fractions of a percent (i want to say .25) per year, but i think type plays into this. So you are looking at 2.5% degradation over 10 years. They also have a 10 year warranty.
This is my 4th year with them and haven't noticed any drop off. In fact, May of this year was my best month ever.
The largest system you can have in Mass is 10,000 without some special permit needed. I always tell people to put up as many panels as they can fit on their roof. Worst case you have a nice credit from the ele company, and you generate more srecs. I literally covered every inch of my southern facing roof.
It would delay my next boat purchase but I have the cash for that and I am highly interested in discussing this more with you.
Im happy to help, but so much has changed as far as rebates and SRECs since i got my panels.
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Battery processing has begun.
This consists of charging each cell to full, then fully discharging it to get its full capacity in mAh and its internal resistance, I number each battery and write both of these down. Then you charge it back up to full and stick them in a box for 2-3 weeks. After that you check voltage on each to ensure they are able to hold a charge.
(https://i.postimg.cc/Wdm13kJQ/batteries.png) (https://postimg.cc/Wdm13kJQ)
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Very cool Will. I don't care about rebates at all. I dont want to rely on the grid or my generator in an emergency so this highly interests me.
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Very cool Will. I don't care about rebates at all. I dont want to rely on the grid or my generator in an emergency so this highly interests me.
I think the federal rebate is 26%. So whatever you end up paying, you get 26% back when you file your taxes over 3 years.
Does your house face south and have good exposure? Sunnumber.com is a pretty good site to get a quick guesstimate on how well your house would do with solar.
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Most of my house is shadded but I have a large yard that gets tons of exposure all day where an array could be placed.
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Most of my house is shadded but I have a large yard that gets tons of exposure all day where an array could be placed.
Ground array about triples the price due to hardware and having the run the cable underground to your house.
It was way cheaper for me to remove a few rows of trees to improve my sun exposure. I got to keep the tress they cut down to split into fire wood, essentially paying for the cost to have the trees removed.
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Isn't that the way it goes. These trees here will stay...couple of birch, oak and a willow. Shade all day immediately around the house is tremendous. I guess I'll have to spend more money if I go solar.
Meantime I need to get the panel for the generac re-wired. They wired a majority of the breakers to baseboard heat. No need for that with the pellet stove.
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Meantime I need to get the panel for the generac re-wired. They wired a majority of the breakers to baseboard heat. No need for that with the pellet stove.
I assume the Genrac has its own panel with breakers? If so, just leave the baseboard heat breakers off. Having the option to flip them on (should the pellet stove die) is a nice backup option.
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^^^^^^^^^^^^
What he said.
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It does. The issue Will, is that there's lights in the house that are not wired to the breaker, like bathrooms. So yes I agree leaving maybe one or two wired makes sense but not every room.
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It does. The issue Will, is that there's lights in the house that are not wired to the breaker, like bathrooms. So yes I agree leaving maybe one or two wired makes sense but not every room.
Light are important as well lol
If you need one of the breakers that the heat is on to add lights, that sound like a good swap. If u have space for more breakers, i would just have them add more for the lights.
I read and article and watched a couple videos on wiring those critical loads panels, its stupid easy..
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I'll check some of those videos out and see what I can learn.
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WOW :tipup: :tipup: :tipup: :tipup: :tipup:
Will, I am very impressed! I have been looking into this for awhile and you have posted some of the best information I have seen yet.
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WOW :tipup: :tipup: :tipup: :tipup: :tipup:
Will, I am very impressed! I have been looking into this for awhile and you have posted some of the best information I have seen yet.
Many thanks man. If you have any questions please feel free to ask.
I havent posted an update in a bit on this. I decided to not use the 18650 batteries. While they are great for battery back up, they arent the easiest to get setup. Ive decided to switch over to Lifepo4 cells instead. They strap together with bus bars and are safer for in home use. They also are much easier to add on additional batteries. I have them on order and will update when I get them in. On the plus side, i sold the 18650 cells i had for $250 more than i paid.
Now i just need to find an electrician that can AC couple my existing converter to a hybrid inverter to hook the batteries to. Im confident I could do it myself, but having someone who has done it before would be beneficial.