Tools For DIY Solar Projects

[Muhendis]

27 minutes ago, Crossy said:

If you are making up your own battery packs I would also invest in some Uni-Seal jointing compound.

 

A quick rub over with emery on the terminals followed by a smear (you really don't need much) of this stuff will ensure a good and long-lasting contact. Use it on all your high-current joints.

 

It's definitely not cheap, but one tube will last you a lifetime, shake well before use.

 

https://www.lazada.co.th/products/i2156648662-s7185722295.html

 

I use Vaseline on my terminals and bus bars. keeps the copper shiny and bright for ever.

[Crossy]

7 minutes ago, Muhendis said:

I use Vaseline on my terminals and bus bars. keeps the copper shiny and bright fort ever.

 

The issue is the battery terminals themselves; the differing metals (aluminium terminals vs copper busbars) can cause corrosion.

 

Vaseline will definitely help by keeping the damp out but for a "proper job" use the real stuff. It's loaded with Al dust to fill any minor gaps (even the scratches from the emery) with conductive goop. For a few 10s of Amps, no major issue but when you get into "real" power every milli-ohm matters ???? 

[Muhendis]

23 minutes ago, Crossy said:

Vaseline will definitely help by keeping the damp out but for a "proper job" use the real stuff. It's loaded with Al dust to fill any minor gaps (even the scratches from the emery) with conductive goop. For a few 10s of Amps, no major issue but when you get into "real" power every milli-ohm matters

I didn't know damp was a problem. I have always thought oxygen was the nasty one. I can understand the electrolysis caused by different metals but that is usually in a solution of dirty water. 

I once tried lubricating grease but that didn't help at all. Copper oxidised quite nicely after a few weeks.

[Crossy]

Yeah, oxidation needs oxygen and moisture (didn't you do the iron nail in water experiment in high school?), but differential metals will corrode with just a little damp.

 

 

[Pink7]

42 minutes ago, Crossy said:

Yeah, oxidation needs oxygen and moisture (didn't you do the iron nail in water experiment in high school?), but differential metals will corrode with just a little damp.

 

 

Thanks for sharing. Imagine having batteries still in top shape after some years running, but suffer from rust on terminals and bars...????

 

Pink 

[thaibeachlovers]

On 12/29/2022 at 11:48 PM, Crossy said:

Yeah, oxidation needs oxygen and moisture (didn't you do the iron nail in water experiment in high school?), but differential metals will corrode with just a little damp.

 

 

My "chemistry" lessons consisted of writing equations in an exercise book. No explanation given about them. Never had any experiments.

Worst chemistry teacher on the planet. LOL.

He was so bad I still remember him when most of the other teachers have faded into obscurity.

[Crossy]

29 minutes ago, thaibeachlovers said:

My "chemistry" lessons consisted of writing equations in an exercise book. No explanation given about them. Never had any experiments.

Worst chemistry teacher on the planet. LOL.

He was so bad I still remember him when most of the other teachers have faded into obscurity.

 

We had a supply (replacement) Chemmy teacher like that, boring as flip! He looked like Alf Garnet and so that was always his name "Alf", still don't remember his real name. Incredibly I still passed Chemistry O-Level.

 

Of course, he had zero control over a class of rowdy teens, so high jinks were order of the day. A Bunsen-burner on the water tap projects a stream a long way! Connecting the gas tap to the water tap (using the rubber pipe off the bunsen) fills the gas pipe with water (there was a lot of trouble over that one, apparently it damaged the gas supply).

[TimeMachine]

Anybody know where to buy cheap solar panels? Seems they are more expensive in Thailand than in Australia after having to travel all the way from China. Does the Government tax these heavily?

[couchpotato]

16 minutes ago, TimeMachine said:

Anybody know where to buy cheap solar panels? Seems they are more expensive in Thailand than in Australia after having to travel all the way from China. Does the Government tax these heavily?

Thai watsadu had many for sale yesterday...don't know prices...size looked to be about 2m x 1m.

[Pink7]

45 minutes ago, TimeMachine said:

Anybody know where to buy cheap solar panels? Seems they are more expensive in Thailand than in Australia after having to travel all the way from China. Does the Government tax these heavily?

Check Global, I got quite a good deal on mine. Check my post

 

Pink

[Crossy]

1 hour ago, TimeMachine said:

Anybody know where to buy cheap solar panels? Seems they are more expensive in Thailand than in Australia after having to travel all the way from China. Does the Government tax these heavily?

 

If you are in BKK the big Amorn branch in the Old Siam Plaza (Ban-Moh) sometimes have good deals that don't appear on their website.  GPS 13.745733798113017, 100.50018885896024

 

Panels are zero rated for duty, just 7% VAT to add. 

 

[Crossy]

Not in stock at our local branch but available for delivery.

 

https://globalhouse.co.th/product/detail/2014234503503

 

[Muhendis]

3 hours ago, TimeMachine said:

Anybody know where to buy cheap solar panels? Seems they are more expensive in Thailand than in Australia after having to travel all the way from China. Does the Government tax these heavily?

If you are anywhere near Buriram, Ruangsangthai have some 350W (I think) for 3,250 each.

[Muhendis]

3 hours ago, Crossy said:

He looked like Alf Garnet and so that was always his name "Alf",

My old chemistry teacher looked like that too but this was pre Alf Garnet. Ours got the name "Bilko" as in the cartoon character Sergeant Bilko.

[TronxII]

On 12/29/2022 at 10:45 AM, Crossy said:

I would also invest in some Uni-Seal jointing compound.

Can you elaborate how you use this? I fear, you put it between the conductors which carry the high current.

Like we did in the old days with the blue stuff on car battery poles?

 

@Pink, The DIY approach is ok, but with electricity, the first failure might be the last. I would avoid voltages over 24V for my first installation, also on the solar panel side. Also these batteries are beasts, if it's your first time, I'd go with a ready made battery and not DIY.

Read about DC arcing and have a look at these pictures.

These guys explain it well.

[Crossy]

2 minutes ago, TronxII said:

Can you elaborate how you use this? I fear, you put it between the conductors which carry the high current.

 

Yup, you clean the terminals first, apply the goop, then assemble.

 

The goop has aluminium dust which fills any microscopic gaps with a conductive material whilst the greasy carrier keeps out the damp and air. You really only need a smear, one tube should last a lifetime.

 

So, you have to use it during the assembly process or if you strip your pack to re-configure or add cells etc.

[TronxII]

50 minutes ago, Crossy said:

The goop has aluminium dust which fills any microscopic gaps with a conductive material whilst the greasy carrier keeps out the damp and air.

Yes, but there where you should have copper on copper atoms touching of the two conductors, or Cu and Al (which is actually not so nice), at this point, you add another layer of something. And this something is less conductive than Cu, even if it is silver dust.

The other badly prepared parts, where no metals touch, get now some paste with a resistance of 1Ohm. Which is great, but does not add much to the correctly touching metal connection of far under 1mOhm.

So basically, adding this paste, increases your contact resistance. And 1 mOhm at 100A is 10W of loss at this point. Edit:  0.1miliOhm is 1W of loss.

Do you have equipment to measure the resistance of your connections with and without the paste?  I dont have the paste, so i cannot prove my point by evidence.

[Crossy]

1 hour ago, TronxII said:

Yes, but there where you should have copper on copper atoms touching of the two conductors, or Cu and Al (which is actually not so nice), at this point, you add another layer of something. And this something is less conductive than Cu, even if it is silver dust.

The other badly prepared parts, where no metals touch, get now some paste with a resistance of 1Ohm. Which is great, but does not add much to the correctly touching metal connection of far under 1mOhm.

So basically, adding this paste, increases your contact resistance. And 1 mOhm at 100A is 1W of loss at this point.

Do you have equipment to measure the resistance of your connections with and without the paste?  I dont have the paste, so i cannot prove my point by evidence.

 

My understanding is that most of it gets squeezed out where there is going to be metal-to metal contact anyway, but it's entirely up to you if you use it or not.

 

It's recommended by many (but not all) in the wider battery community where you have dissimilar metals (aluminium battery terminals and copper bus bars).

 

Note that the commercial pack manufacturers use laser-welded connections so these issues don't arise.

 

EDIT Apparently the metallic content is actually zinc not aluminium.

[TronxII]

5 hours ago, Crossy said:

It's recommended by many (but not all) in the wider battery community where you have dissimilar metals

Yeah, this "swarm intelligence" and "believes", I know, but we should always question these believes. The same goes with adding compression and charging the cells up to 3.65V just to "balance" them. Where good cells do not need more than 3.4V to be nearly full and no balancing at all. You will see, when your new cells from China arrive????

[Crossy]

@TronxII I think we can agree that the mating surfaces must be clean and oxide-free before making the connection.

 

If one chooses to add anything into the mix to (possibly) ensure the connection stays that way it's entirely up to you.

[TimeMachine]

43 minutes ago, Crossy said:

@TronxII I think we can agree that the mating surfaces must be clean and oxide-free before making the connection.

 

If one chooses to add anything into the mix to (possibly) ensure the connection stays that way it's entirely up to you.

Haha. It is like there's someone out there gonna argue that dirty and oxidised is the way to go. Let's say both ways are right and wrong. That about covers the quarrelling now. Enjoy your newest year all.

 

 

[Crossy]

37 minutes ago, TimeMachine said:

Haha. It is like there's someone out there gonna argue that dirty and oxidised is the way to go. Let's say both ways are right and wrong. That about covers the quarrelling now. Enjoy your newest year all.

 

This is the internet, I never fail to be surprised what some people believe. Some people even think the earth is round

 

[Muhendis]

On 12/29/2022 at 5:33 AM, thaibeachlovers said:

Not wanting to be a wet blanket, but assuming the panels and assorted accessories are expensive, is it false economy to try and DIY if not an experienced handyman?

I learned everything I did by making mistakes the first time, but not normally anything too expensive or not easily fixed.

I learned a lot by observing people that did know what they were doing the first time.

Un-skilled people who join this forum are more advantaged than yer average DIY'ers.

There is stacks of help and core knowledge here so there should be no reason not to jump in and do it yourself so to speak.

Help and support is here if needed.

[Muhendis]

6 hours ago, Crossy said:

 

This is the internet, I never fail to be surprised what some people believe. Some people even think the earth is round

 

The Earth is what!?

[Crossy]

2 minutes ago, Muhendis said:

The Earth is what!?

 

[Muhendis]

3 minutes ago, Crossy said:

 

Phew.

Thanks.

You really had me worried for a moment.

[TronxII]

8 hours ago, Crossy said:

I think we can agree that the mating surfaces must be clean and oxide-free before making the connection.

Yes, and as smooth as possible, like polished, not scratched with coarse sand paper.

So add very fine grained sand paper to the list of tools.

And a milliohm meter would be on my wishlist. Then you could prove these people wrong who say the earth is round. :-), but without it's difficult...

[Pink7]

1 hour ago, Muhendis said:

Un-skilled people who join this forum are more advantaged than yer average DIY'ers.

There is stacks of help and core knowledge here so there should be no reason not to jump in and do it yourself so to speak.

Help and support is here if needed.

If being honest to ourselves what we know and what we don't know, so we are able to research and get knowledge and help on what we don't know  and then also avoid doing more mistakes than needed.

 

Pink

[Muhendis]

1 hour ago, TronxII said:

Yes, and as smooth as possible, like polished, not scratched with coarse sand paper.

So add very fine grained sand paper to the list of tools.

And a milliohm meter would be on my wishlist. Then you could prove these people wrong who say the earth is round. :-), but without it's difficult...

A milliohm meter could be useful, but to check one of these joints properly really calls for high current and a volt meter.

e.g.

Pass 50 Amps through the joint and measure the voltage across it. Application of Ohms law will then give you the real life resistance and power loss

 

[TronxII]

7 hours ago, Muhendis said:

Pass 50 Amps through the joint and measure the voltage across it.

That's what the milliommeter does. Actually, now I know what I can use my bloated 50Ah junk cells for. I was always hesitant to make the opamp circuit for the meter, because no current source that could give 10A or more.

Nice little project coming up ...????