Just getting started.....

[JoeD.]

........ and I know just enough to be dangerous! This is a great forum to read! My first post.

 Let me tell you what I have, and ask you what would be ideal to make a working system.

  I have been given a supply of GNB Absolyte 2 volt cells. Non spillable. The style printed on the label says GNB 1-50A13 320a.h.  Here is a link to a page which shows them. They are the ones listed under the word "Signal"

 http://www.google.com/url?sa=t&source=web&cd=6&ved=0CDoQFjAF&url=http%3A%2F%2Fwww.tpscrail.com%2FProducts%2FGNB%2Fgnb.htm&ei=S6BJTJP6GYKC8ga8_bT2Dg&usg=AFQjCNG6ppWkZSy_udLNLEXaBiPA-nK1kg&sig2=5emC4NFJWgbv8VhHfiMTKw
 
  I've got 24 of them right now. 48 volts' worth, and these I have here at home are  320 amp-hour (each), some are even more than that.  They are out of railroad signal department use, and the railroad changes them out every so often due to Federal requirements.  I've topped them off with distilled water and put them on the railroad supplied charger and got them back up to 2.25 volts each. Well, 18 of them- 6 of them are being stubborn and don't want to come up. Maybe I need to jolt them with more voltage to get them back to top condition (if possible)  So, I have 36 volts of battery.

 They came with all the connecting cables and etc.  Right now, I use them to power a 2 way radio I use as a police scanner for lack of anything else to do with them!

  What I want to do is rig up a system I can use at the house to use these batteries as power for my home computer (and maybe other things I can decide on later.)  Let the sun keep the batteries charged up and let the computer be a stand alone system. I let the cdomputer run all the time, so what better way to take advantage of R.E.

  Right now I have one of the Harbor Freight 45 watt solar panel kits. They are on sale at a local HF place for $139. I think I'll buy 3 more sets while they are on sale.

  I have read nothing bad about the HF panels, so am I missing something? Are they a good beginners way to get my feet wet.? I think I need to buy one of the MPPT style charge controllers.. I haven't decided on how big a unit to get.

  Another question on panels in general. Would it be any help to place a sheet of Lexan (plexiglass) in front of the panels when they are mounted to protect them from being struck by hail?  Maybe mount them an inch or so above the panel surface. I have quite a few sheets of 4'x8' sheets of 1/8th inch Lexan I could make shields with.

  So, to summarize, I think I have the expensive part covered with a free supply of batteries, I just want some guidance on what sort of system to set up to keep them charged.
 

[ghurd]

"I have read nothing bad about the HF panels"
Then you have not read long enough!
They are good to get your feet wet.

The HF panels tend not to last very long.
I would not consider them suitable for series use on a MPPT because it generally doesn't take long before the outputs of the panels varies wildly.

I would suggest using a more standard controller at this time.
Save your MPPT money until you get the system a little more figured out.
Maybe spend the MPPT money on better panels.  That would be wiser, long term economically speaking.

Do not put anything in front of the panels.  The output will drop drastically.
Even cheap panels will take quite a beating without damage.
Not the hail capitol of the world here, but I never heard of any panel around here being damaged by hail.
G-

[SparWeb]

I tend to a small flock of GNB 90A's myself, and there are a few laggards in the bunch here too.  Like you I got them "used".

Nothing beats a constant float charge for a very long time (months) with the occasional blip of higher voltage (not too high!).

You can download the user's manual from the Exide website:   http://industrialenergy.exide.com/sub_navig.asp?main_description_en=Absolyte&lng=en&cl=Brands

There are ways of improving the life of these batteries (I haven't tried them but you might) such as    http://www.batteryresearch.com/

To maintain my 440 Ah stack at 24V at float charge, it takes a 2-3 amp trickle.  I bought 260W of solar panels specifically for this last year.  If you get another HF panel, you will have just enough for several hours of float charge every day.  Unless, that is, you USE the batteries.  Then the picture changes.

Using the computer 24/7 requires an equivalent supply of solar energy, times a safety factor for cloudy days and to overcome inefficiencies in the system.  Your computer's constant demand for 300 Watts becomes a requirement for 1200 Watts of solar panels to keep up and survive.  If it's a laptop or something parsimonious like that, then you won't need nearly as much solar panel and/or can last longer without sun.

[JoeD.]

Then you have not read long enough!

  You are right there!  I barely got all the original post typed when my ride to go to HF showed up, so I didn't get to see any replies before I left and went and bought three more sets..... Couldn't ask any more questions.

The HF panels tend not to last very long.

  Well, good thing I bought a 2 year warranty. One warranty for 4 panels. Manager said he didn't care- "if they crap out, bring 'em back and change 'em out- I can't tell the difference"!

I would not consider them suitable for series use on a MPPT because it generally doesn't take long before the outputs of the panels varies wildly. I would suggest using a more standard controller at this time.

 OK, fair enough. I was just in a hurry to get SOMETHING going with the batteries while the panels were on sale. I like spending $139 per set versus $249. I can afford to play with these at this price.

  IF there was somewhere close that I could view other solar panel types, I would probably buy something higher quality/higher price/higher output, but these are within an hour drive, so I have something to play with.

  I guess you fellows prebably get tired of the same questions over and over, but there is sooo much to take in, I really didn't know where to start searching on this forum to find out  what I really needed to buy.

  I've looked at the links some have provided on here to places that supply various styles and makes of panels and come away confused with too much information.  What i don't know is what makes these cheap H.F. panels power decay over time, versus a more high dollar unit? What are these made from that makes them inferior?

 

[wooferhound]

It's not as bad as they are saying about the Harbor Freight panels, I have had 6 of them running here for 2 years and while they started out at 1 amp per panel, they are now putting out a little more than half that but have stabilized there and are not going down anymore. I'm getting a steady 4 amps from the 6 panels. Here is my Setup...
http://fieldlines.com/board/index.php/topic,134967.0.html

4 or 5 HF kits could be enough to power your computer 24 hours but it might not be enough for any cloudy days so make sure that you switch it to grid power if your battery voltage falls below about 11.9 volts. I recommend charging 12 volt battery banks with the HF kits.

The cheapest solar panels that I know of can be found here . . .
http://sunelec.com/

[joestue]

btw, these were $1.40/watt yesterday and had over 3000 in stock, they changed the link too http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id=870

[JoeD.]

  So, the link you provided~ I clicked on it and that particular item on the page it brought up shows a cell described as "laminate with adhesive that must be attached to a piece of sheet metal." Is that particular item flexible?

  I deduce from their description that when this arrives at my house that it is not a ready to use item, no frame, mounting apparatus, or wire attached? Just a thin sheet of "solar panel" that I have to get a sheet of metal to attach it to, make a frame/housing/mount to put that into to give it rigidity, then attach wire and junction box?  I really don't understand what I would be getting into.

  I was under the impression that panels in general would all be like what I got at H.F.~ a panel mounted in an aluminum frame, under glass, with a junction box and wire attached- plug and play.

  Am I misguided?  In the world of "real" solar panels, you create your own "frame" to mount the panel in in the quest to save money or for the reason to be "doing it yourself", or is it just that particular item ?
 

  P.S.~ me being in such a rush to JUST DO SOMETHING costs a lot of money= 45 watts X $139.99 = $3.11 per watt. OUCH, but I am sure glad that I didn't pay the $229 price....... Oh, well~ sure beats wasting it on gambling or lottery tickets, which I don't do. At least I have something to show for the money.

  I just got to thinking (a novel concept for me, evidently) that those new sets of panels are still out back in their unopened original boxes- I could take them back to HF and return for money back, buy 2 cells from "sunelec" and have more power for about the same money, That is, after I get the questions I posed above answered.

[joestue]

those are intended to be stuck to a metal roof.
I think you could laminate them to a thick piece of steel flashing (steel for thermal coefficient match, as most metal roofs are steel) and install them on just about anything. (they are 5 meters long though)

if you must mount framed panels on something other than your roof then that's what you will have to get.

[JoeD.]

...to H.F. and got the money refunded, no problemo.....

  Now, I start doing some shopping at Sun Electronics, I guess. I'll need a charge controller and maybe a different inverter if I go with 24 volt system.