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How did this happen?

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SunCatcher

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Dec 24, 2021
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A friend called up and wanted to know if I could help his friend out of a situation. He has no money and is living in a cabin off grid. So I foolishly said why not. His family helped put together a system and then things went bad and he fried the charge controller. So found a new one for under a $100.00 And so now the real problem begins. The system is not sized correctly and now I need ideas to see how to find a way to put something together that might work. Here is what he has

4 - AGM centennial CB12-115 which are 12v 115 AHr
4- Mighty Max 100 watt 18.2 VMP 5.49 Imp solar panels
4- Newpowa NPA 120S-24H 120 wattVamp 33,54 V 3.75 amp solar panels
- Powmr 60A mppt charge controler
- Vevor pure sine wave inverter 3000watt 24 volt Inverter

From what I can tell he daisy chained (put in series) all the panels together which would have exceeded the PV input as per attatchment specs for 24 volt charge controller. Where do we go from here? those panels a nowhere near enough to run a 3000 watt inverter and the miss matched panels are far from ideal.

I am looking around for new and or used solar panels and the best
deal I have found is $120.00 ea. for some 250 watt units. But not sure where that money would come from. Any thoughts? Ideas??? would sure be appreaciated. I dont mind doing the work if we can find something that would work on a very limited budget. Those parts are easily Googled if you need more info.

Thank you in advance

Suncatcher
 

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So another friend of a friend type situation. . .

From what I see that unit has 160voc, from Amazon. It was also 85$, which is a decent deal if those specs are right and it last more that a few months.

Who says a 3k inverter running a 10w light bulb doesn’t have enough PV with 400w to charge those AGM to float each day.

It’s not the size of the inverter but the loads he’s driving.

He have a fridge and electric hot water running off that or very minimal loads?
 

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740GLE said:
Who says a 3k inverter running a 10w light bulb doesn’t have enough PV with 400w to charge those AGM to float each day
Click to expand...
Right, 2kW charging in good sun. Nevertheless the battery bank is a little small if a refrigerator or furnace is running overnight. Sortof how I ran a few years: just barely getting by. Usually.
 
I haven't talked to the guy about what load he has... but he is in a tough place in life and so it is what it is at least for now. I was thinking it would be nice to add a few more panels but then we would have three different brands and sizes. I will call him this morning and try and see what kind of load he expects... he might even have a propane fridge. He heats with wood so that helps.

I have looked at articles on how to size Inverter/PV panels and from what I am seeing they want you to have slightly more PV than the Inverter and give a strong impression that what we have here will not begin to operate a 3000 watt inverter.

Will update on what he is trying to power up. So far if this would run the Inverter then we could charge his cell phone and laptop ;)
 
Here is the update. His basic needs are a small "dorm" type fridge one year old and energy efficient. A small box freezer also a year old and energy efficient. A few lights and a computer.

His plan is to unhook the load during the day and run a few small power tools such as sander and wood lathe.

Suncatcher
 
SunCatcher said:
Here is the update. His basic needs are a small "dorm" type fridge one year old and energy efficient.
Click to expand...
60W running, maybe 80
SunCatcher said:
A small box freezer also a year old and energy efficient.
Click to expand...
Another 80W
SunCatcher said:
A few lights
Click to expand...
What kind?
SunCatcher said:
and a computer.
Click to expand...
125-300W but need specifics
SunCatcher said:
His plan is to unhook the load during the day and run a few small power tools such as sander
Click to expand...
~700W
SunCatcher said:
and wood lathe
Click to expand...
Need to know HP - Assume ~800-1000W

I ‘think’ the 3000W inverter will do that but lathe startup might be sketchy
 
THANK you for the replies. Right now he has 880 watts of panel and even on a good day that will produce maybe 4000 watts of electricity??? I have been scouring the net looking for solar panels and found that I could get around 3000 watts of new panels for around $1200.00 but that is a lot of money just to fall out of the sky. However there are times when the windows of heaven seem to open up and I found new slightly damaged panels for $85.00 Here is the add and so I called the guy...

" New 48 volt 144 cell Bi facial 450Watt Solar panels. These have cosmetic damage only. They have full function as factory specs call for. Will test all panels before you take. You just need to You tube resealing the cracks from bad handling on pallets or pre installation. These are incredible panels for a great price and I only have 50 left maybe a few less. You will not be disappointed. Selling for 85$ each you would spend over 400 each panels plus to buy these and ship them. PM me for details. "

I know my friend would help with this and I know a couple other people and so if this were divided 3 or 4 ways it just may be possible. Anyone have experience with these kind of panels? Would 6 be enough or just go for 7?
 
New panel with "cracks" meaning shattered tempered glass?
Some people here received a broken panel when they ordered a pallet, sealed them with something.
I would not buy a broken panel.

What else could be "cracked"? If something to do with frames, not glass or cells, then should be OK.

Look at what SanTan Solar carries, including new/used/bad backsheets. Then check Craigslist and eBay for local sellers to pick up from rather than shipping.

Solar Panels | SanTan Solar

www.santansolar.com www.santansolar.com


1669390281318.png
 
75w Frig
75w Freezer
50w Inverter
100w All other loads

300wh x 24 hours = 7200wh/day

PowMr CC 85% effecient
Inverter 85% effecient
AGM batteries 85% effecient
Winter solar output 75%

A minimum system to barely meet his expectations during only good conditions:
5 to 7.5 kWh of batteries
2kW of PV panels

Cheap panels and batteries do come up...
Hopefully someone will read this and donate their old system when upgrading!
 
Hedges said:
New panel with "cracks" meaning shattered tempered glass?
Some people here received a broken panel when they ordered a pallet, sealed them with something.
I would not buy a broken panel.

What else could be "cracked"? If something to do with frames, not glass or cells, then should be OK.

Look at what SanTan Solar carries, including new/used/bad backsheets. Then check Craigslist and eBay for local sellers to pick up from rather than shipping.

Solar Panels | SanTan Solar

www.santansolar.com www.santansolar.com


View attachment 121762
Click to expand...
I wouldnt want to work with anything like what is pictured that is for sure. Hopefully I can look at the panels soon.
 
Pete@SolarBatteryBarn said:
75w Frig
75w Freezer
50w Inverter
100w All other loads

300wh x 24 hours = 7200wh/day

PowMr CC 85% effecient
Inverter 85% effecient
AGM batteries 85% effecient
Winter solar output 75%

A minimum system to barely meet his expectations during only good conditions:
5 to 7.5 kWh of batteries
2kW of PV panels

Cheap panels and batteries do come up...
Hopefully someone will read this and donate their old system when upgrading!
Click to expand...
that would sure be wonderful
 
SunCatcher said:
" New 48 volt 144 cell Bi facial 450Watt Solar panels. These have cosmetic damage only. They have full function as factory specs call for. Will test all panels before you take. You just need to You tube resealing the cracks from bad handling on pallets or pre installation. These are incredible panels for a great price and I only have 50 left maybe a few less. You will not be disappointed. Selling for 85$ each you would spend over 400 each panels plus to buy these and ship them. PM me for details. "
Click to expand...
Talk about sugar coating a turd......
 
Is this your inverter?
1669400455552.png
The background consumption is not that bad.

My personal experience with frigs and freezers running in the winter is that they cycle on and off a bit less in my rather cool cabin. The frig in the kitchen is ~ the farthest place from the woodstove, and I'm finding it consumes only at 800W in January as compared to July at 1200W.

Here are the numbers I would estimate.....
Winter (assume 2.5sunhours per day)
inverter: 360Wh
frig: 600Wh
freezer:500Wh
lights/TV: 600Wh
total: 2060Wh
The panels might make 880W X 2.5sh = 2200Wh of power.

Summer (assume 5.0 sunhours per day)
inverter:360
frig: 800Wh
freezer:600Wh
lights/TV 500Wh
total: 2260Wh
The panels might make 880W X 5.0sh = 4400Wh of power

So, winter is the killer here. One day of cloudy/rainy weather and the system dies.

Yes, more panels is the best option. Where are you physically located? Have you checked Craigslist in your area for deals?

Here's one option for your friend to cut overnight consumption. Fill extra milk jugs or 2L soda bottles with brine solution, such that they will solidly freeze during the daylight hours, then shut of the frig or freezer overnight to coast with the doors solidly shut. Let your "brine units" carry you through the night without stuff thawing.

Another option is, is there any way you can build your friend an array frame that rotates so it can track the sun? I made single-pole rotating arrays that can be rotated left to right, and I've found that a 1000W array has made as much as 5100Wh during Febuary, close to the shortest day of the year. You'll be able to almost double your sunhours to carry you through the darkest winter months.
 

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MichaelK said:
Is this your inverter?
View attachment 121773
The background consumption is not that bad.

My personal experience with frigs and freezers running in the winter is that they cycle on and off a bit less in my rather cool cabin. The frig in the kitchen is ~ the farthest place from the woodstove, and I'm finding it consumes only at 800W in January as compared to July at 1200W.

Here are the numbers I would estimate.....
Winter (assume 2.5sunhours per day)
inverter: 360Wh
frig: 600Wh
freezer:500Wh
lights/TV: 600Wh
total: 2060Wh
The panels might make 880W X 2.5sh = 2200Wh of power.

Summer (assume 5.0 sunhours per day)
inverter:360
frig: 800Wh
freezer:600Wh
lights/TV 500Wh
total: 2260Wh
The panels might make 880W X 5.0sh = 4400Wh of power

So, winter is the killer here. One day of cloudy/rainy weather and the system dies.

Yes, more panels is the best option. Where are you physically located? Have you checked Craigslist in your area for deals?

Here's one option for your friend to cut overnight consumption. Fill extra milk jugs or 2L soda bottles with brine solution, such that they will solidly freeze during the daylight hours, then shut of the frig or freezer overnight to coast with the doors solidly shut. Let your "brine units" carry you through the night without stuff thawing.

Another option is, is there any way you can build your friend an array frame that rotates so it can track the sun? I made single-pole rotating arrays that can be rotated left to right, and I've found that a 1000W array has made as much as 5100Wh during Febuary, close to the shortest day of the year. You'll be able to almost double your sunhours to carry you through the darkest winter months.
Click to expand...
What a well put together post. Thank you.
 
Other than properly wiring the panels to the new controller, the easiest way to make that system better is to teach him how not to kill it with consumption.

When i first went off grid i had an inverter and battery situation not all that different, but what WAS different was that i had 5kw of panels hooked up on day 1. I would prioritize expanding the solar even more so than expanding the batteries. I wouldn’t even think about upgrading the inverter until both the others have been majorly improved because he already has enough invertert that if he loaded to max it would be a countdown minutes to ‘dead’ in the low 2 digits, like 10-15mins. ?
 
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