diy solar

diy solar

looking to buy used solar panels, need thoughts.

kpreuss77

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Jun 27, 2021
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I'm thinking of purchasing 6 of these because they wont be running at peak efficiency.

I have a 24v 280ah Lifepo4 battery.
I have a 24v 10a charger on its way
I also have a 1500w 24v inverter on its way.

now i would like to add 1000w or more solar cells, mppt controller, and any wiring / switches.

im starting with the solar cells because i got a renogy 40a mppt with bluetooth for $50 off of a friend. still in box. but i dont think that is the controller i want.

so first,

these cells even used, and in southeast Michigan, should produce 1000w during summertime, maybe 250w during winter?

what controller should I pair with these used solar cells? or just use the renogy?

Kevin
 
ok.

but these panels should give me 1kw output during summerdays? 250w during winter?

i thought i remember someone saying that during winter, you only get 20%-25% of output from panels.

ultimately im looking for 2kw per day during winter in southeast Michigan. sunrise to sundown. charging a 24v 280ah battery. the battery will have a 2kw load per day. roughly.

i was told to also have battery for 3 days here. because solar cells aren't efficient during winter. but i also have a generator and 24v charger. so i was thinking

(6) 250w used cells should do the trick until i get more money to throw at this next summer.

Kevin
 
It's not so much the efficiency of the panel, being winter the cold will boost your VoC a bit and actually give you more voltage for the MPPT to play with. The issue is that the sun isn't directly hitting the panels very often unless you're out there constantly adjusting the angle all day. You'll probably want to think about simple ways to make your panels adjustable if you can. There are various threads here about how people have made their ground mounts adjustable involving pipe and 4x4's.

The best thing I think you can do is to split your strings. Since you're looking at 6 panels, check your VoC and see if the MPPT will handle a 3-panel series string. The math would be (VoC x 3 panels x 1.2 cold boost) and if that number is lower than the Max PV Input on the MPPT you're golden. Then face 1 string of panels a bit to the SE and the other to the SW and that will maximize the hours that sunlight is hitting your panels.

If you get the facing better and the angle right, your panels should perform quite well. Granted with 6 panels you're only going to get a max of 1500w, but if you can get the angles and duration dialed in there's no reason you shouldn't be able to exceed the 2Kwh/day.
 
Are you only looking at Santan because you are close and can pick them up?

Have you checked Craigslist in your area? It’s often easy to find panels for $.50 per watt or better for new panels.

If you reveal your city or zip, maybe someone can point you to deals near you,
 
Go secondhand
Here in Australia I have been buying 270w Jinkos with 9.5 years of the 10 year warranty remaining for $60 delivered.
 

I'm thinking of purchasing 6 of these because they wont be running at peak efficiency. ...

Kevin
I've been looking to set up something small and fairly cheap for the hunting cabin, and was looking at some of their $40 panels. For me, shipping a pallet of panels is $300 regardless the number of panels on the pallet. It seems to make more sense to order a full twenty panels. Besides, the extra panels gives me something to experiment with.
 

I'm thinking of purchasing 6 of these because they wont be running at peak efficiency.

I have a 24v 280ah Lifepo4 battery.
I have a 24v 10a charger on its way
I also have a 1500w 24v inverter on its way.

now i would like to add 1000w or more solar cells, mppt controller, and any wiring / switches.

im starting with the solar cells because i got a renogy 40a mppt with bluetooth for $50 off of a friend. still in box. but i dont think that is the controller i want.

so first,

these cells even used, and in southeast Michigan, should produce 1000w during summertime, maybe 250w during winter?

what controller should I pair with these used solar cells? or just use the renogy?

Kevin
I have these panels (I paid $576 for 12 of them shipped, so they price has gone up since then). I wouldn't count on them being too far off rated capacity. The best number I have seen so far on mine is 86% on a string of three (641w out of the rated 750w) and that was laying on the ground. I routinely get 1750w out of the nine (2250w) on my garage roof pointed southeast (more east) at a crappy 10% angle (almost flat). They are used, but they are solid quality Trina panels.

Not sure if you can return the other items you bought, but it sounds like you are a perfect candidate for a all in one (MPP Solar or Growatt).
 
Are you only looking at Santan because you are close and can pick them up?

Have you checked Craigslist in your area? It’s often easy to find panels for $.50 per watt or better for new panels.

If you reveal your city or zip, maybe someone can point you to deals near you,
live in Berkley Mi. 48072.

looking to move in the next couple of months and get a much larger yard.

first showing of our house yesterday. didnt think of Craigslist or similar .

i would need to have Santan ship them btw.

plus these panels are soo cheap, i have another problem. mppt controller. a single one or multiple? getting the panels first. then mppt controller by Christmas hopefully, if supply chain holds up
 
live in Berkley Mi. 48072.
 
If the OP is going to grid tie the $50 panels ... what about the 'white labeling'? Will the utility allow them to be hooked to the grid?
 
If the OP is going to grid tie the $50 panels ... what about the 'white labeling'? Will the utility allow them to be hooked to the grid?
No. These will not pass inspection, There is absolutely nothing wrong with the Santan panels (mine are Trina), but without the mfg labels they will not pass inspection unless the inspector is not paying attention.
 
I bought 10 of the Santan (Trina) panels last May and they all worked just fine, yielding close to rated power on the best days. Typical in September-October at mid day seems to be around 1700W for 2250W nominal (my array is 3x3). Shipping was expensive though and when I looked recently is now even worse.
 
Any other recommendations from the forum for sources of used panels, preferably on the East coast? I know Santan is opening also in Savannah, I'm also looking at panels from Signature Solar.
 
Just checked on shipping for one pallet of panels from SanTan to 63841. It's $300. Ouch! They lowered the price to $30 on their 'cracked vinyl' panels, which would be perfect for pop's hunting cabin. Hard to justify spending as much on shipping as on the actual product. Thought about ordering a full pallet but pop's hunting cabin will need at most six, and not sure what to do with the remaining fourteen as they cannot be tied to the grid.
And no, I see no one selling panels near my location.
Hate to say it, but searching fleabay for 'solar panels pallet lot' garners quite a number of hits, some with free shipping (of course nothing is free). Bonus, some retain their manufacturer's label making them grid-tie 'able.
 
EPEVER MPPT Solar Charge Controller 40A 150V PV Solar Panel Controller Negative Ground W/ MT50 Remote Meter + Temperature Sensor PC Monitoring Cable[Tracer4215BN] https://www.amazon.com/dp/B07429RK4...abc_S1Z1VWMDBF8XWD9J8DXY?_encoding=UTF8&psc=1


what about this mppt controller then. birthday in a few weeks. maybe i buy something new(mppt) vs looking for deals and waiting

My favourite "go-to" SCC for inexpensive jobs ... never has let me down ....and I think I have done about 30+ of them
 
Just checked on shipping for one pallet of panels from SanTan to 63841. It's $300. Ouch! They lowered the price to $30 on their 'cracked vinyl' panels, which would be perfect for pop's hunting cabin. Hard to justify spending as much on shipping as on the actual product. Thought about ordering a full pallet but pop's hunting cabin will need at most six, and not sure what to do with the remaining fourteen as they cannot be tied to the grid.
And no, I see no one selling panels near my location.
Hate to say it, but searching fleabay for 'solar panels pallet lot' garners quite a number of hits, some with free shipping (of course nothing is free). Bonus, some retain their manufacturer's label making them grid-tie 'able.

try FaceBook Marketplace ... and Craigslist ....

Ebay has never been my go-to place for panels ....
 
try FaceBook Marketplace ... and Craigslist ....

Ebay has never been my go-to place for panels ....
Don't do FB but had a friend look. Nothing but the harbor freight variety of panels around here. Craigslist is a huge no. They are pros and cons about living in the middle of cornfield county USA.
@SolarSteve some of the ebay sellers are located on the east coast. Clr_solutions_llc , gogreenmansolar are a couple.
 
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