Author Topic: Bit the bullet  (Read 13104 times)

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Offline philb

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Re: Bit the bullet
« Reply #15 on: April 26, 2012, 07:14:03 pm »
Great job on the ammeter box bj. With a little gray spray paint, it will look like you started out with a UL listed (expensive) electrical box.
I've made round holes with a torch and later with jig saw prior to using a manual hole punch. I won't go back. A hydraulic hole punch?   I'm green with envy!  :)

The LG solar laminates I bought had the cells on top of the glass. That is, from the sun side, EVA-cell-EVA-glass-white tyvek(?). I thought the glass was supposed to be on the sun side.  :o So, I have to wonder why the glass couldn't be some other material? It must deal with expansion and contraction on the cells.

It does take a lot of time on the 'other items'. Much more time than I would have imagined. This weekend is strictly devoted to the 'other' items.

Thanks for posting bj. It's definitely worth the read. I'm looking forward to more. Inquiring minds...

Offline oztules

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Re: Bit the bullet
« Reply #16 on: April 26, 2012, 08:17:45 pm »
"
The LG solar laminates I bought had the cells on top of the glass. That is, from the sun side, EVA-cell-EVA-glass-white tyvek(?). "

This is weird... Surely not EVA on top.... it gets messy too easily.... everything sticks to it. I suspect some other film on top of the EVA that does not attract dirt like a magnet. It would make the vacuum impossible also.

Usually tedlar backing. Tyvek was not as good as normal plastic sheet for backing. Tedlar is good stuff, but expensive.

Do you have any pics of the LG panels of which you speak... I'm amazed to put it bluntly... :o


.............oztules
Flinders Island...... Australia

Offline bj

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Re: Bit the bullet
« Reply #17 on: April 26, 2012, 08:23:05 pm »
  Thanks Oz, Phil.  Oz: 6x6  supposedly tested,"A" grade, but not tabbed.   Did a quick dirty test on a box, 1000W light source. All equal, but, that's a very
rough test.  Pic tomorrow,  raining cats and dogs, and the camera is 100m away.
   Phil: I would have thought glass on the outside too.  You are bang on about the other stuff, but I've been at it for a while, as I knew I was going to do
this, one way or another.  (back to tabbing)
"Even a blind squirrel will find an acorn once in a while"
bj

Offline Wolvenar

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Re: Bit the bullet
« Reply #18 on: April 26, 2012, 09:53:21 pm »
My Sharp seem to have the EVA on the top ( sun side) also and yes it is rather sticky.
Pine needles will stick there in wind, and they are always dusty looking after rain.
So they seems to require extra work to keep clear
Trying to make power from alternative energy any which way I can.
Just to abuse what I make. (and run this site)

Offline bj

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Re: Bit the bullet
« Reply #19 on: April 27, 2012, 06:42:02 am »
  For OZ----still tabbing
"Even a blind squirrel will find an acorn once in a while"
bj

Offline bj

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Re: Bit the bullet
« Reply #20 on: May 09, 2012, 01:06:25 pm »
  For a break from tabbing, I more or less finished the cabinet for the panels.  All that's left basically is wiring, and the Volt meter. (on order)
  And, just to prove that I have been doing some tabbing.    The pic is of finished ones.  One thing I have found out, is that iron temp is critical
to making good time.  I started out maxing it, but had to go back sometimes, and remelt.  Lowering the iron temp
to just above melt (50-75 deg) made for one pass, good spread etc.
"Even a blind squirrel will find an acorn once in a while"
bj

Offline oztules

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Re: Bit the bullet
« Reply #21 on: May 09, 2012, 01:51:01 pm »
Now that brings back memories...... chin up, it's nearly winter now, and partly cloudy.... 19000 wh today.... tabbing tabbing.....

I liked hot iron and fast movement. But whatever works is good.

.....oztules
Flinders Island...... Australia

Offline Dave B.

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Re: Bit the bullet
« Reply #22 on: May 09, 2012, 02:47:23 pm »
BJ,

  Looks nice. How did you isolate your buss bars from each other and the metal cabinet ?  Dave B.

Offline Dave

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Re: Bit the bullet
« Reply #23 on: May 09, 2012, 02:55:32 pm »

That's a sweet looking panel box, well done getting things lined up soo nice :D

...something of an awkward comment here....um..Have you tried stringing any of those cells together yet? Afraid it looks like you are tabbing the backs and plan on stringing them together on the fronts?

The few cells I worked with, were very difficult to get the series string connections as straight as the tabbing connections..the ribbon seems to walk more during the stringing than during the tabbing and doing the fronts first (the important side to be straight) and then string the backs seemed to be the goods..

Hopefully you have it worked out and the concern is groundless...

Keep at it!
Cheers, Dave

Offline bj

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Re: Bit the bullet
« Reply #24 on: May 09, 2012, 04:55:45 pm »
 ;D  Oz and yes, I was surprised that less heat was better.  No smarts on my part, just started before the iron was hot.  Was
better, then got worse.  Then the light bulb flashed.
Dave B.  Had a long chunk of phenolic bar scavenged from a 600v starter cabinet.  About 1 inch thick, so just made sure screws
from each side only went about half way, and they were staggered as well.
Dave--not an awkward comment at all, I was concerned as well.  Fred sent me darn near a whole box of slightly chipped cells, as extras, so
I experimented.  This way seemed a bit easier for laying them  out, and the front wasn't too bad.  I am being very fussy on the
back, so everything lines up.  (he said with a bit of hope)  If I'm wrong, you'll wake up wondering who is cursing a blue streak.
I also made the tabs a bit long, in case I do have to Z a bit.
thanks to all.  back to   t a b b i n g.
"Even a blind squirrel will find an acorn once in a while"
bj

Offline oztules

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Re: Bit the bullet
« Reply #25 on: May 09, 2012, 05:45:05 pm »
Things I learned with tabbing.

1. It is easier to tab on your tabbing bench.

2. Noting 1, is is easier to tab BOTH sides of the cell on the tabbing bench.

3. This means to within a quarter of an inch of the edges on the back, and an inch overhang on the front.

4. This means that when you string, you only need to hold it all in place for a second or less as you join the 1" overhang to the back of the next cell.

This means two things. First, stringing up your cells is very fast, other wise it is slower than the long tabbing of the front.

And.... you get to concentrate on straight and spaced, rather than how well or poorly the tab went on.

This makes a huge difference to the panel build part of the story. Stringing and spacing becomes a doddle, and you get to do all your tabbing on your favourite work bench..... not hanging over a panel or stringing bench somewhere else where there is room for the full strings (6feet long)

A 2 meter  long right angle straight edge makes for perfectly straight strings, and I used 3/16  square tool steel as the spacer. So getting it perfect is easy, and holding it in place is simple as you are only doing a 1/4 inch of tabbing to join them up.

Whatever works for you is fine for me, but thats how I found to be the easiest way.

Best with it, I almost wish I could do some more........



................oztules
Flinders Island...... Australia

Offline bj

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Re: Bit the bullet
« Reply #26 on: May 09, 2012, 06:34:39 pm »
   The weather here will be nice pretty soon Oz.  Lots of room for you and your better half.
   Had to try  ;D.  Thanks for the tips, I'm sure they will come in handy.
"Even a blind squirrel will find an acorn once in a while"
bj

Offline Dave

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Re: Bit the bullet
« Reply #27 on: May 10, 2012, 06:12:59 pm »

2. Noting 1, is is easier to tab BOTH sides of the cell on the tabbing bench.

And.... you get to concentrate on straight and spaced, rather than how well or poorly the tab went on.

Ding..That clears up any worries. Thanks for that tip for the big cells with the long thin solder stripe on back. I could not see how that would come together, but of course tab both sides and leave longer front solder tabs for series joining ;D

On the small 3"x 6" 4 amp cells, the fronts get/got tabbed and left long enough to hit the large solder pads on the back..At least that's what seemed easy with those.

You're in good hands with the wizard bj.. I"ll be following along from the back corner wearing the pointy hat.

Great fun, Dave


Offline bj

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Re: Bit the bullet
« Reply #28 on: May 11, 2012, 05:51:50 am »
    ;) Dave, just remember I'm only lending you the pointy hat for a little while, I will need it back.
  If Oz hadn't gone through all the heartaches, and then documented it so well, I would not be
doing this.  I, and any one else that tries this, owe him big time.
    Sobering thought---this will be over 2000 feet of soldering. 
"Even a blind squirrel will find an acorn once in a while"
bj

Offline bj

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Re: Bit the bullet
« Reply #29 on: May 11, 2012, 07:41:42 am »
  It occurs to me that I may have confused things a bit, but I think this pic is what Oz
was talking about.  Might be hard to make out, as I tin the entire strip on the front, hopefully easier later.
  Anyway, tab sticking out from the back is longer than required for the next front,  so some adjusting
can be done.
  I suspect this is backwards side wise, from what Oz was mentioning, but the general idea is the same.
"Even a blind squirrel will find an acorn once in a while"
bj