my first attempt at home made panel

[RifRaf]

its funny, you guys have to believe that it gets under the cells by itself, its hard to believe till you pour it around the cracks then come back 15 minutes later and look, sure there is a few pockets to work out from a few cells, but you have the time on your side. personally though i still thin it out a bit more because i am trying to cover a larger area with the 6x6 cells, the fronts still are sealled fine, and can add more later on the backs to fill up the gaps between some cells due to the capillary action

[designer43]

Soldering

Probably everybody knows this, but just in case...

Most of the videos don't tell the whole story of how to solder. Most say you don't want solder peaks, but don't tell you how to avoid them.

One tip is, don't finish a joint by lifting the iron straight up. Slide the tip off horizontally. Most of the solder will stay on the tip.

Work quickly, the longer the joint is hot, the more the molten solder/flux will break down and loose surface tension. This also helps keep cells from turning into 'potato chips'.

Always use 63/37 tin/lead solder because it has the fastest transition to solid. This will cut down on cold solder joints that open or corrode easier over time. A little lead never hurt anybody

Keep your sponge wet. Your iron tins much easier. Tin the tip sparingly. Don't start with a blob.

[martinjsto]

Thanks designer43, I think most people think they know how to solder but its enlightning to actualy be informed of the correct proceedure for perfect joints, so your saying there is a big diff between 60/40 which i have a lot of, and 63/37? or are they close enough to not warrent sourcing 63/37.
I have purchased a 58w variable temp soldering station and have found a huge difference being able to set a temp to solder, i find it takes me a few cells of adjusting the temp for the process to become seemless and to achieve a smooth join.
i also find the temp setting for the back (pos) side needs to lower else the silver starts to lifts off if i use the same temp setting as the front (neg). not sure if its my iron or do you also experience this. Im using 6x6 cells.
RifRaf you mentioned about thinning the sylgard, something we discussed earlier, do you still only use 1 tub when thinned for the 60 cell sliding door panel you are making or do you need 2 tubs? also do you notice any extra shrinkage due to thinning?

I have been talking to a silicon manafacturer that has a distributer in NSW.

http://www.wacker.com/cms/en/products-markets/products/product.jsp?product=10728

they produce a product for the solar industry its called solar 3210 A/B a two part flowable silicon, and from my convesation with the distributer I was informed it has been specifically made as a encapsulant for solar cells, I have informed them of the excessive cost of Sylgard and that there is a lot of DIY that would be interested if they could get in small quantities at a better price than the Sylgard is sold.
im now waiting a reply.

[designer43]

[QUOTE=martinjsto;16352]Thanks designer43, I think most people think they know how to solder but its enlightning to actualy be informed of the correct proceedure for perfect joints, so your saying there is a big diff between 60/40 which i have a lot of, and 63/37? or are they close enough to not warrent sourcing 63/37.

<snip>
I'd rather switch than fight. Every little bit helps.
This may be more than anybody needs to know about the Eutectic Properties of solder:

http://www.chemguide.co.uk/physical/phaseeqia/snpb.html

(scroll down to the Phase Diagram)

[RifRaf]

the 60/40 rolls of solder that we find over in AU are just fine, i too would avoid lead free, never liked the stuff. having the right temp and a decent iron and tip, and lots of practice is required. most of the videos i have seen of people soldering cells use many incorrect techniques, though they still succeeded,

for a 60 cells 6x6 panel using 2 tubs of sylgard, doing half then the other half with 1 tub each, thinning out the bigger part 3:1 before use, a 20 cell 6x6 panel would be fine to do unthinned, i'd still like to be able to afford 3 or 4 tubs per 60 cell panel and have a think unthinned encapsulant, though can always add more to the back later and even a backing panel once all has been tested for months. it does shrink i guess but you don't really see it, it must mostly be just flatting the whole panel as it cures slowly rather than sucking in at the edges like normal silicone that gets a hard outside fast and shrinks heaps. the tiny bubbles i had (because i didn't have a vacuum sealer, picked one up that should do the job for next panels) on the face of the cells in places did get a little bigger

as for sylgard alternatives if its a 2 part silicone that says it for solar panels and cheaper please try it, am sure it will work in the same manner. did try and source sylgard in australia from Dow outlet but with the current exchange rate its still 25% cheaper to get it on ebay even after postage

[solarrules]

hot gun

Just wanted to throw in that I used a 100/140 Watt soldering gun. It worked really well - no warpage and I was able to work really quickly. $30 for the whole kit, including carry case, at local home improvement store.

[martinjsto]

Hi all,
been a busy month building my seccond pannel, I used the method of pouring silgard over the 3 sides of the cells and allowing it to seap under and encapsulate. i still ended up with lots of bubbles, it seems the silgard went off quite quickly as it set in 4 hrs and the silgard hadnot completly seaped under the cells, it was a 32 degree day so i asume this was the issue. i left for a further 5 days without disturbing and the silgard did move a fraction but hardly any difference to the bubbles. output is good at 21.6v 6.75 amps midday reading. i am happy with the results we will just have to see if the air caused any issues later. i will try the vacuum set up next time and pick a cooler day.
i have been building a solar tracker for the two pannel i have made to pump water on my block.
see:

http://solartracker.greenwatts.info/solar_tracker_LM339_pcb.htm

the circuit was quite easy to construct and the tracker frame is nearly finnished. i am using a power antenna off a car as the reduction, a 3.6v screwdriver as the motor and gearbox. still got to connect the circuit and motor to the assembly and pick up some bicycle sprockets for the final drive. all going well should give about 20% better output.
I will post some pics soon along with results.
Martin

[bidaw]

This gives me sooo many ideas...

Thanks!

[martinjsto]

hi all

hi everyone, i have been busy paving and building retainer walls for the last few months so not much to report at the moment, the original two pannels are working well and i am happy to take them down to my property to use to pump water. starting my 3rd and 4th pannels soon just waiting on cells, tracker is finnished but the circuit i built had issues with the power draw and blew the chips, although there is a new board design that utilises relays to run larger motors off the same circuit, worth a shot. as an alternative circuit i have ordered one of the red rock trackers in feb and am waiting the delivery. my next tracker will use 12v actuators instead of cogs and chains. a lot less to go wrong.
I am now confident that I can make 140 to 160 watt pannels that will last 20 plus yrs for around $2.20 per watt, thats with a bit of profit. and around 1/3 the price of purchased cheap china pannels. yes there is no warrentee except that i can either fix any problem that may arise or make a new one anyway. i believe this is the advantage you get by making your own stuff over just buying it if you have the time, you get to understand the principles and methods to make something therefor you can always fix or replace it.
I will post some new pics soon of the new pannels soon, hopefully these will be my best looking ones after learning some tricks from Rifraf and other forum members.

Martin

[russ]

Hi Martin,

You have been one busy lad! Looking forward to your update.

Russ

[rollandelliott]

elastosil

Did you ever get to try the elastosil encapsulant? I'm going to call up the USA branch and see if I can get a sample. Sounds like a neat product.

[martinjsto]

thanks Russ, yes the day never seems long enough. Rollandelliott, i did get a reply but they wanted me to purchase in quantities, i asked for a small sample to test on a single cell but didnt recieve a reply, i think i will stick to the Sylgard for the meanwhile anyway.
I calculated out the cost to build two 130 to 140 wIatt pannels (used 135 watt for calcs):
Sylgard worked out to $71.65 each, i purchased 2 lots, delivered express. the cells work out to $211.90 delivered. glass and aluminium framing from salvage yard cost $20 add $25 for sillicon and tabbing wire and solder. $60 for two junction boxes and diodes. total of $460.30.
the pannels do actually put out 21.6v at 8amps but i dont see that too often usualy see 21.3v at around 6.5 to 7 amps so i am working on 135 amp pannels adverage.
$460 /270 is $1.70 per watt. not too bad and a great power source for the shed or pumps.
I think I have stated this before but i cannot stress the importance of using correctly rated components and that i only use my pannels on off grid pumping stations or shed power, not for the home. no saving is worth your families life.
Martin

[rsiedl]

Great info

thanks for sharing