10 to 20 watt polycrystalline under $4/watt?

[Titantornado]

So, are there any such deals out there?  I just can't justify paying $7 to $20+ per watt costs for these smaller panels.  I know some folks on here have come across some great deals.  

[willib]

how about the harbour freight ones ( i think they were from there)

45 Watts for ..... how much was it?

 i guess i'm not much of a help

[Titantornado]

Yea, they were under $4/watt, but were thin-film panels.  I might still go that way if I must, but I'd like a good mono or polycrystalline panel to charge the battery for a tracker.  The tracker array will be fitted with 24 volt panels, so tapping off them for the Redrok tracker controller won't work. (22 volt MAX limit)    I could probably bump down to a 5 watt panel to save a few bucks, but was a bit nervous doing so, as we all know how common it is that panels rarely put out advertised power.

[willib]

why not use one of the 12 volt batteries to power the tracker controller  or are you not wanting to drain one battery different than the others?

what voltage is the tracker controller ?

what are you going to power the motors with?

[ghurd]

The 24V battery and 13.8V circuit problem can be solved by adding a 7814. (easy)

It is a voltage regulator that will take the 24V down to 14V.

Only thing I can think of, is to connect the 7814 to the batteries, NOT the panels.  Most 7814's can take 35 or 40V max.  If a series controller goes into regulation, the panel volts can go to open circuit values (over 40V).  Same thing will happen if the batteries are disconnected.

G-

[Titantornado]

Yea, that's a consideration. (and probably the most affordable solution too) I realize I'd have to go to the batteries themselves, as the panels are 44 Voc to start with, and I'm thinking about wiring in banks of two-in-series anyhow.

As for willib questions, I could tap off one of the batteries, as the claimed power useage is supposedly under 2 watts for the tracker.  The controller is intended for a 12v system, with a maximum input voltage of 22v.  I'll probably get an old C band satellite tracker actuator, which gets directly wired to the Redrok controller

[Volvo farmer]

Hehe, I'm going through the exact same predicament. My two harbor freight panels are not keeping up with the demands of the tracker and I have to recharge the batteries with a battery charger about once a week.

However, let me give you some information that might brighten your day. Duane's newest trackers will operate anywhere from 10-44 volts. Mine's wired for 24 right now and it works fine. So even though my batteries are 80 feet from my panels, I decided I'll jerk the wire out of the conduit and add a couple #12 or #10 in there to power the tracker right off my main bank... if I ever get the time :-)

Lastly, when you order your tracker, get the little $5 reverse-inhibiting daughter board. At 24V, my tracker overshoots the sun and reverses the motor every so often. This never happens on my little 12V array though.

[Slingshot]

There's a surplus store in Garland, Texas called "B.G. Microelectronics".  A couple of years ago they had a modest supply of 8-watt polycrystaline panels for $20 each.  A friend and I bought several of these, and they tested good.  The cells were bonded to a fairly thick aluminum plate, which might keep them from overheating so readily as some.  There was a red silcone rubber gasket around the front, and a pattern of holes for an outer frame, but no cover glass.  I was told that these were salvaged from remote oilfield logging equipment.  I don't know if they still get them from time to time, but their phone number is 1-800-276-2206.  They have a catalog, but it's out-of-date as soon as it's printed because they're always getting in new stuff.  You have to call or stop by.  Stopping by is sometimes fun, they had a real cutie working there.

[asheets]

YOu can get the HF ones for around $4/watt when they go on sale and the 20% off coupons are in effect.

[Titantornado]

Ah, this does brighten my day. Good to see he got that voltage limit boosted.  An extra set of wires ran back out to the tracker is the cheap solution, and voltage drop will be of little concern now.