diy solar

diy solar

Planning off-grid workshop/home in northern Wisconsin

Wow, 7600 starting bid. And I'm literally about an hour away from there right now. Hmmmmm. I've priced all that's included at about $18k(new). It would save me a lot of time and trouble to be able to just roll that thing onto my property and start working. I even plan on buying a flatbed trailer at some point. If you guys had to start from scratch building a system, knowing what you know now, would you buy this, and for what price? Why so cheap, is used solar gear just not worth much?
 
And the 10k/obo unit is in my home town of minneapolis MN, very close to my land. The internet gods are telling me to buy one. So does anyone here have one of these? are some of them lemons? why are they everywhere at %50 off retail? The inverters are obviously top quality, but the panels are relatively cheap, and I don't know much about the batteries other than that there is a decent chance that they are neglected junk. You guys need to talk me into it, or talk me out of it, I just don't know that much at this point.
 
Wow, 7600 starting bid. And I'm literally about an hour away from there right now. Hmmmmm. I've priced all that's included at about $18k(new). It would save me a lot of time and trouble to be able to just roll that thing onto my property and start working. I even plan on buying a flatbed trailer at some point. If you guys had to start from scratch building a system, knowing what you know now, would you buy this, and for what price? Why so cheap, is used solar gear just not worth much?

Because Warren Buffet got taken for a cool 1/3 of a billion dollars. All told, DC Solar took in $1B. They had a dream, but couldn't lease them out very fast. Story is they built many and scattered GPS trackers around while the trailers piled up in their yard.

Lots of stuff got liquidated, from new in the box components to complete trailers.
I think prices have ranged from $0.10 on the dollar for some original bankruptcy auctions, to $0.25 on the dollar I paid for a pallet, to the $0.40 or $0.50 prices you're seeing.

I would pass on the trailer with bad battery, pay $600 more for trailer with one good battery if he lets it go near starting bid. Or, communicate with the guy who has one with two batteries, see how low he will go.

You will see threads with a couple members who bought them. They may have some indication of battery condition.
If not abused, the batteries should be good for at least another decade, and then they have the scrap value of a ton of lead.

Even though I bought a pallet of SI 6048, when I saw a metal enclosure with them and a Midnight (but not the rest of the trailer) for $3500 I was quite tempted.

If just using the components, it's a toss-up. But if you have room to place the trailer and put it to use, those prices seem attractive.
Later you could hang the box on your wall, freeing up the trailer.
And as I said earlier, to expand PV I'd add panels elsewhere and AC couple with a Sunny Boy, plus add a load-shed relay between this unit and the utility panel in your building.
 
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I had seen one eBay lot of 35 SI-6048. Had to remind myself I wasn't really going to scare up a bunch of contract jobs and go install them all.

Here's a related thread.

 
I got a hold of the seller. I'm gonna go take a look today. There are more up coming auctions as well, looks like the units with the kubotas and light towers are now going for 14-15k at these auctions. If I don't end up getting a whole trailer, I think I will at least pick up a couple Sunny Island inverters and a midnite 250 since the market seems to be flooded with cheap used units and they are high quality components. That would be a great starting point for my system.
 
Consider a 3rd Sunny Island, if you might want to do 120/208Y (17 kW continuous)
3-phase breaker panels will cost more, but you can use 208 (and split-phase panels) for most household heating, A/C, and motor loads.
The 3-phase might be nice for shop tools and pumps.

But of course, 120/240 split phase works well too.
Probably you'll never need more than 11,500W continuous from battery. If you do, in split phase you could have 2s2p SI 6048 for double the output.
But just with 2s1p, while the sun shines you get the AC output of Sunny Boy in addition. Sunny Island will handle a few seconds of surge when you first start a load and then ramp up Sunny Boy's output to 100% if needed.

Once you get your Sunny Islands you can watch for suitable Sunny Boys on eBay. Sometimes there are used or new old stock for cheap. SMA has a list on their website showing which models are compatible.

Which auctions are you seeing with the diesel generators? More DC Solar bankruptcy auctions, or resellers on eBay and the like?
 
Those are pretty cool, and the generator would be nice, although I think I'd almost prefer a cheaper gas generator for its ability to run on wood gas in the future. it would be great to have a stand alone system while I'm building the barn. my plan was to temporarily install my system on a 20ft container until my building is done and I can re-install inside. 25k is high though. those inverters are 3400 each, and who knows what you are getting when you buy 5 year old used lead acid batts.

I'd really love to see some detailed schematics of systems in this size range. I'm curious about you combine outputs from several different inverters. Is it as simple as running all the outputs to the same breaker box? How about combining power from your solar system and a generator for heavy loads? How about charging dis-similar batteries if you've cobbled your bank together over time? Individual chargers for that? I personally learn visually, a picture is worth a thousand words, ya know?

And with all the cheap lithium batts coming out of china and other places, is that starting to be a more cost efficient option than lead acid? how about safety? I build and fly racing drones that use 5 and 6s lipos, and those things literally turn into a F-ing blowtorch when they have a thermal runaway. I've seen some people build some massive 18650 packs, and those can get pretty nasty when they fail too...
the lithium iron phosphate battery chemistry is not like your drone batterys at all.. Im a 5th scale rc nut and have had plenty of lipo packs torch up, its not the same tech...
 
LiFePO4 does look like its safety, cost, and performance is pretty good. But I have the impression 3rd-party BMS aren't ideal yet. From what I've read I don't think they do an optimum job of managing high charge rates over a range of temperatures and SoC. Although, the durability of the batteries may be sufficient to tolerate the charge rates they see and give acceptable life.

Even if starting from scratch today I'd prefer to get a deal on a healthy FLA included with one of these trailers instead of starting out with LiFePO4. In the future, BMS could be more ideal and switch to lithium.

Using LiFePO4 today could still be reasonable. If I did that and batteries had the possibility of charging at lower than room temperature, I would set maximum charge rate very low, maybe around 0.1C. Because I use oversized PV, I could expect to maintain that charge rate all day long even under fairly overcast conditions. (It is only with high charge rates available like 0.5C that I'm concerned BMS doesn't throttle current down as temperatures approach freezing.)
 
Which auctions are you seeing with the diesel generators? More DC Solar bankruptcy auctions, or resellers on eBay and the like?


It looks like a bunch just ended. Or maybe these auctions aren't legit? I know there are many online auction scams.
 

It looks like a bunch just ended. Or maybe these auctions aren't legit? I know there are many online auction scams.

I think those are legit, the "wholesale" liquidation of DC Solar's inventory, from which all the resellers get inventory we're seeing marked up elsewhere.
More auctions coming, yet to be scheduled.
It is possible earlier auctions had even lower prices, from what some forum comments suggested.
They do show results of closed sales, e.g. $11k to $12k with diesel generator:


Somebody who bought at those auctions and hasn't managed to sell yet, is considering parting out a trailer, might be a way to buy at small markup. (remember they had to pay 15% buyer's premium)
 
if the batteries did not get charge and no water over 3-5 years i would give it a good 50:50 chance to revitalize them.
would defenetly not reccomend buying them "blind" without proper testing.
Very good chance out of a block a few cells will be dead...
for SUPER price could consider buy 3 to buily 2 working ones, but we talking almost scrap level price then
 
We built a small off-grid place with a garage and all the utilities and then built a larger home. The original house has a Schneider SW4848 with nine 300 watt panels and lead-acid batteries so the most it will ever produce is 2800 watts or so. We also have a propane generator that we thought we would have to use for all the building of the new house but it turns out the solar system works much better. There was none of the dip you get with a generator and most of these pieces of equipment (saws, compressors, etc.) are on for a very short time so you can't even see the change in the battery level. We ended up never using the generator. Don't know about a welder but the other stuff works great. The system gives it what it needs immediately so it's better for your tools.
 
So I've looked at a few private party seller trailers, as well as the display model at the Bid Industrial HQ in phoenix. There are a bunch of auctions set to end in the coming days. I also saw an ad on FB for the 230w panels @ $75 a piece and a slew of other ads for bits and pieces. Anyone looking for solar right now who is in the SW or willing to travel there will be a kid in a candy store. With 20k you could piece together the most badass setup with 3 phase, 10kw of PV, kabota genny, etc.

Gotta look out for neglected, dead FLA batts tho. One I looked at was completely dry, they have all been sitting for years is seems. Whats the the best method for testing the condition of the batteries? Can dry, dead batteries be brought back to life?

I think I am going to buy a unit with a genny and towers off a pp seller in TX rather than deal with the auctions. I used to be a car dealer, and I just don't like auctions. This is kinda funny; the guy in charge at bid industrial was un able to talk or give me any useful information because he was "on the phone with his attorney". he looked very stressed so I didn't press him. haha
 
:) I prefer auctions to used car dealers. No pressure or questionable tactics (other than shill bidding), just me deciding if I want to up my bid. :)

For cars, I prefer estate auctions. No one ever sold a car because it ran too well, but estate cars are often low mileage and it is the owner who stopped working.
Got our '97 sable in 2001 that way. 4000 miles on it. Rear brake shoes were shot.

Dry is bad for batteries, unless they are brand new and never got filled.
If they have plates covered in all cells and voltage reflects good SoC, these should be OK. But unless you check all cells of all trailers you might bid on, hard to know.

Note the significant weight of a trailer with two forklift batteries, make sure you have a suitable tow vehicle.
 
:) I prefer auctions to used car dealers. No pressure or questionable tactics (other than shill bidding), just me deciding if I want to up my bid. :)

For cars, I prefer estate auctions. No one ever sold a car because it ran too well, but estate cars are often low mileage and it is the owner who stopped working.
Got our '97 sable in 2001 that way. 4000 miles on it. Rear brake shoes were shot.

Dry is bad for batteries, unless they are brand new and never got filled.
If they have plates covered in all cells and voltage reflects good SoC, these should be OK. But unless you check all cells of all trailers you might bid on, hard to know.

Note the significant weight of a trailer with two forklift batteries, make sure you have a suitable tow vehicle.
Can you explain to me in more detail, or provide me with a link, how to check the condition of dry FLA batteries, and properly refill? I am going to look at another trailer tomorrow and I'm almost positive that the batts will be dry. All of the 2014-2016 units have had dry batts. I've been told by a few people who have purchased them, that they were dry but came back to life when filled. How much life do you think will be left in them in this case? And what are they worth used, in working condition?(If I come across more I can buy)
 
In the past I've had new "dry charged" batteries, which were charged once when manufactured, then electrolyte drained, then dried out.
For those, we purchase acid electrolyte, fill, let settle so bubbles come out, top off, then put into use.

Other than that, I've had batteries that got dried out one way or another, like some cells cooked. Maybe that happens with some cells bad. I fill with distilled water (people say above the plates but below the indicator ring) and do an equalizing charge. They started my cars for a while, but I don't know how much capacity remains.

Lead-acid batteries are worth something as scrap. I haven't checked out the prices because I just have a couple old car batteries, took them to O'Reily's for $10 store credit.

Maybe somebody else here knows if those batteries were bought dry, never filled? Or got dried out? You'll have to ask them.
 
Most of the cells filled, some half, some maybe dry. The midnite 250 was on and showing 50v. I am unable to get the slave inverter to power on, which is a little concerning, master starts up. Any advice for troubleshooting?
 
Most of the cells filled, some half, some maybe dry. The midnite 250 was on and showing 50v. I am unable to get the slave inverter to power on, which is a little concerning, master starts up. Any advice for troubleshooting?
I got it figured out. 15 mins before you can restart. put some diesel in the genny and that fired up too.
 
Thanks for the replies.

Offgridenclave, I agree with your approach, I'm not huge into planning (or over planning) to be honest, haha. I suppose my plan is to build biggest/best system that I can afford, and then adjust/supplement my power consumption to conform to what that system is capable of. I do however want to verify that the more power hungry tools will not overwhelm the system, but its not always easy to find the start up amps especially if I don't even own the tool yet.

The possibility of having to get a diesel welder generator IF my system can't cope with welding is fine, so the system doesn't necessarily have to support welding. if it does, cool, bonus.

It looks like I can afford a pretty decent 5000w-ish inverter charger which would have around a 10000w peak rating. As for panels, I can probably afford 4-6kw. I haven't really gotten an idea of what size battery bank is going to be appropriate. Do you guys think that an inverter that size would handle starting up a large 240v air compressor? And what's this I hear about modifying electric motored tool to "soft start"I '

Thanks for the replies.

Offgridenclave, I agree with your approach, I'm not huge into planning (or over planning) to be honest, haha. I suppose my plan is to build biggest/best system that I can afford, and then adjust/supplement my power consumption to conform to what that system is capable of. I do however want to verify that the more power hungry tools will not overwhelm the system, but its not always easy to find the start up amps especially if I don't even own the tool yet.

The possibility of having to get a diesel welder generator IF my system can't cope with welding is fine, so the system doesn't necessarily have to support welding. if it does, cool, bonus.

It looks like I can afford a pretty decent 5000w-ish inverter charger which would have around a 10000w peak rating. As for panels, I can probably afford 4-6kw. I haven't really gotten an idea of what size battery bank is going to be appropriate. Do you guys think that an inverter that size would handle starting up a large 240v air compressor? And what's this I hear about modifying electric motored tool to "soft start"?

I really do not have extreme experience with solar, and none with 240v.. I have how ever done a lot of data gathering with what I have.I started out with an off-grid 500w 5-100w 12v panels. I have a 40A MPPT CC and a 3000rw PSW inverter. The system has been expanded to 2 racks of 6 panels and a second 40w MPPT CC.. The battery bank has been expanded to 800Ah LA Deep cycle RV batteries.. That powers all the lights in the 3300sqft home all day... , 3 huge fridge/freezerss, a 1000w microwave, a 1500w hot water pot occasionally. Obviously, not all is on all the tiwme. The system produces more than we use right now, in mid summer. and the batteries are fully charged for night. But in the morning, they are low and need charging. So, that tells me that in winter, I need to not run it down at night.

I have run and electric chainsaw drills, angle grinders, saws all, chop saw, planer, skill saw all day long and not depleted the charge. I also have 2 fans that run in my greenhouse 24/7. I never turn them off.

I think that you will face the same problem that I have here in NW Oregon. North latitude which means short days in fall and winter and spring. That is 3/4 of the year. Also, at our latitude, we have a low angle of sun as it moves across the sky. That said, it severely limits production of power.

My system is mostly for winter backup when power goes out which is often. If heavy snow causes the outage, I will also run out of gas for the generator in about a week.
 
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