Great deal or trap?

benthere · February 2009

I stumbled upon someone selling off their old PV system yesterday. The had a Trace 4024 inverter, Trace C-30 charge controller, 24 20-year-old BP 40 watt solar panels, and 4 60 watt panels on a balancing tracker. They were asking $1500 for all of it.

Now, I think I understand that it's a pretty good deal IF a person is okay with modified sine, wants to hook up 24 panels instead of 5, and doesn't live in a place where the wind will blow the tracker off course.

My question, I guess, is; Should I bite? I had planning on installing a ~1KW array and true sine inverter (likely an Outback) for an off-grid-by-necessity cabin. Does the C30 have the ability to bulk, float, and equalize? Would I be better off, even with these panels and inverter, to use a MPPT charger and save on headaches and wire? Will the 4024 power a washing machine and kitchen appliances without tearing them up? Do panels loose their ability to produce as time goes on? Am I a fool for sitting here typing instead of running to pick it all up?

Thanks for helping the noob!

icarus · February 2009

Re: Great deal or trap?

I would consider this deal this way,,,

Consider the value of the panels only. The inverter and charge controller have limited value, IMHO! So it you have 1200 watts of panel for sale for $1500 it works our to $1.25/watt. Not a bad deal,,, but considering the age not really a steal either.

I don't consider the value of the tracker is being very much either.

If you were to sell the panels per each on E-bay they would go for way more than that.

If you want to sell the 60's if you buy them let me know. (quite typing,, go for it and sell me the 60's as my price for advice

Tony

PS The panel output MAY have degraded over time,, but you can test that with a DVM and ammeter, but even if they are only 80% of capacity,, you are getting them for ~1/3 the price of a new panel.

You could part out the pieces that you don't want to reduce your net expense. CC might bring $50, the inverter ?? The tracker, (if you don't want it) a couple of hundred. (just guesses)

I also would go with with the mppt controller regardless. I don't think the charge controller will do eq,,, but I don't remember.

n3qik · February 2009

Re: Great deal or trap?

I would get something a little newer. The panels @ 20 years old are near end of life. Willing to bet some have failed, they just don't know it.

BB. · February 2009

Re: Great deal or trap?

If they are close enough to pickup--it may be worth it...

Good quality solar silicon panels that have not been abused (wires pulled, chipped, etc.) should still be good.

If you can, take a DVM and set it to 10 amps, and each panel, pointed into the sun, measure the short circuit current. And the measure the open circuit voltage (would be great if you have a load--such as a 12 volt lamp or car battery you can connect--with the correct polarity--to check the panel's current under operation).

The inverter--for simple appliances, an MSW inverter should work... The Trace inverters are at end of life--and probably not worth repairing if they fail--so I would not "give" any money for it.

The tracker--will you be able to salvage enough of the mount to make it worth while? Is the base set in in concrete--is it still tracking properly?

The C30 is out of production too... A new C35 is worth $120... The old one, is probably not worth more than a few dollars if it is still working. The manuals for the C30/C30A are available here for download.

In the end, from my humble point of view, the solar panels are probably the only thing worth any money (to me). And I would check them out very closely that most of them work (you should get a good idea of which ones are working and which ones have failed).

24x40w + 4x60w = 1,200 watts

$1,500 / 1,200 watts = $1.25 per watt

Not a steal--but if no shipping, taxes, and all of the panels work... Maybe OK (I am certainly not an expert in the pricing of used solar equipment).

You still have the issue of do you want to figure out how to mount 24 panels--or get 4x brand new 200 watt panels for $3,500 or less...

Everybody is different--I would either avoid the deal or pay less myself. For me, when I set up my solar system--I expect it to last for the next several decades without major issues (batteries and electronics will have to be changed out several times over that period--for sure).

If I need a bunch of smaller panels for other projects--probably not bad... The smaller panels, new, cost closer to $10 per watt (vs $5 per watt or less for the larger panels).

-Bill

Solar Guppy · February 2009

Re: Great deal or trap?

For reference, you can get panels today, non-ul Sun Branded Evergreens for 2.58 watt, 2.98 watt for UL Evergreens, throw in the Fed tax credit and its even less of a difference between the 20 year old panels and new.

The electronics are not worth the cost of shipping, they are all at end-of-life

Ecnerwal · February 2009

Re: Great deal or trap?

Buy it. Use the panels. Sell the rest on eBay - it's not that useful by current standards, but to someone who's wedded to a system and wants spares, if might be worth something. Anything it goes for further reduces your cost per watt, or increases your ability to buy more watts of new to go with it for the same money.

MPPT - actually gets more power out of same panels. Much better than a C30.

MSW .vs. appliances - the only way to know for sure is to sacrifice appliances at the altar (aka, hook them up and see if or how fast they fry, or if they refuse to work). Washing machines are often picky, at least based on my sister's experience.

Assume some degrade, call it $1500 for a kilowatt, be happy with that. Buy another 400 watts with the $1500 you'll have left over from the minimum you'd have to spend to get listed panels, and you'll have 1400-1600 watts, and part of it will be new.

The tracker? Who knows, but if it doesn't make sense in your setup, sell that too. If it does, use it.

<edit - add>
Or you could test the waters selling it all. If Tony will give you enough for 4 60's to buy a new 200/205/210, that's one. And it is true that little panels are much more costly per watt, so a few folks that want a 40 watt panel to run a circulating pump or the like could add up to a few more, and you'd have your new panels. Treating this system as a system makes it a dog - slicing and dicing makes it more of a good deal.

Great deal or trap?

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