Solar Panel Wiring Choices

[accrete]

Originally Posted by Thomas G.

Other opinions...
The RV Battery Charging Puzzle « HandyBob's Blog

Thanks for posting that link. I'd forgotten how much i enjoyed reading his blog! Solid info on the topic, & his updated info is fresh.

[chse]

<-- I hope the experts are done with their discussion which cable to put first.

I have an unrelated question - Solar Blvd lists the weight of these panels at 20lbs each, is this true? Seems a bit heavy.

Originally Posted by Ken in Philly

First and foremost, thanks to this wonderful community, 90 watts of solar (2x45W) panels just arrived from solar blvd.
Thanks for this new obsession!

[Thomas G.]

Originally Posted by chse

<-- I hope the experts are done with their discussion which cable to put first.

I have an unrelated question - Solar Blvd lists the weight of these panels at 20lbs each, is this true? Seems a bet heavy.

I looked at three different 90 watt panels on eBay and they were about 18# each.

[chse]

Originally Posted by Thomas G.

I looked at three different 90 watt panels on eBay and they were about 18# each.

So 20 lb. for one 45 watt is indeed a bit heavy. They have a 40 watt panel that is 10 lb. but a bit more expensive. I wrote them an email lets see what they say.

[chse]

Originally Posted by accrete

Thanks for posting that link. I'd forgotten how much i enjoyed reading his blog! Solid info on the topic, & his updated info is fresh.

Not sure, I think he is a total d*rk. Why is he constantly yelling at his reader and telling me what an idiot I am (I feel guilty, though I don't even own a generator!). The info is good- but is it worth the suffering?

[KevinPete]

Never weighed my 85W panels, but I'm sure they're heavier than the newest technology. Still not bad, my son has no problem adjusting or moving them. As soon as it stops raining, I might grab one and weigh it. They originally were for temporary traffic lights and signs, 3 of them run an LED light very well, 24/7.

I checked that site out, he definitely doesn't mind sharing his opinions! Some good information, but nothing groundbreaking. I will agree that some of the people selling and installing solar systems have no real idea what they're doing, but that's true in any business. DIY folks need to educate themselves, but the information is all out there, free if you look for it.

Sorry for clogging up the thread with the wire stuff, but it's nonsensical to spend hundreds or thousands to buy a system, then cheap out on the wire and have a choke point that limits your system, even a small bit. Copper is expensive, the difference between 100' of 14-gauge wire and 100' of 4/0 is huge, but so is the performance and capacity. I'm a big believer in the "cry once" theory, buy the best you can afford, and cry only once, instead of every time you have to deal with a sub-standard system.

[Thomas G.]

Originally Posted by KevinPete

........Copper is expensive........

And I'll once again mention that my local metal recycler has rolls and rolls of new copper wire being scrapped daily that can be purchased for a tiny percentage of new prices at a retail store. Every metal recycler is different and some don't like to resell, but generally it is a cash into pocket with a wink deal. So, if one place turns you down, ask at another. Ditto with aluminum and stainless steel.

[Thomas G.]

Originally Posted by chse

Not sure, I think he is a total d*rk. Why is he constantly yelling at his reader and telling me what an idiot I am (I feel guilty, though I don't even own a generator!). The info is good- but is it worth the suffering?

I agree that the guy is rude, but I've found that his basic guidance to be on target. My theory is that some people think that if they provide good information it entitles them to titillate themselves by abusing others. Every forum has one or two.

[Byron Kinnaman]

Originally Posted by KevinPete

Never weighed my 85W panels, but I'm sure they're heavier than the newest technology. Still not bad, my son has no problem adjusting or moving them. As soon as it stops raining, I might grab one and weigh it. They originally were for temporary traffic lights and signs, 3 of them run an LED light very well, 24/7.

I checked that site out, he definitely doesn't mind sharing his opinions! Some good information, but nothing groundbreaking. I will agree that some of the people selling and installing solar systems have no real idea what they're doing, but that's true in any business. DIY folks need to educate themselves, but the information is all out there, free if you look for it.

Sorry for clogging up the thread with the wire stuff, but it's nonsensical to spend hundreds or thousands to buy a system, then cheap out on the wire and have a choke point that limits your system, even a small bit. Copper is expensive, the difference between 100' of 14-gauge wire and 100' of 4/0 is huge, but so is the performance and capacity. I'm a big believer in the "cry once" theory, buy the best you can afford, and cry only once, instead of every time you have to deal with a sub-standard system.

You have to gain enough knowledge to be able to know what is misinformation, pure nonsense and valid information. Example of nonsense "the difference between 100' of 14-gauge wire and 100' of 4/0 is huge, but so is the performance and capacity." There is a difference, but there's a point of diminishing returns, which 4/0 gauge far exceeds.

[Thomas G.]

Originally Posted by Byron Kinnaman

....... There is a difference, but there's a point of diminishing returns, which 4/0 gauge far exceeds.

Yea, bigger wire is generally better, but there is a reasonable limit to everything.

[Byron Kinnaman]

Originally Posted by Thomas G.

Yea, bigger wire is generally better, but there is a reasonable limit to everything.

Yup, and a bigger bolt is generally better. Right?

The truth is components (wire or bolts) need to be the sized to do the job, nothing, nothing smaller.

I built a lot of electronic control circuits using 30 awg wire or 32 awg. That happened to be the best size for what I was doing. Sometimes I used a larger wire for higher voltage circuits because of the thicker insulation.

Do you water your lawn with a 6" diameter hose? If not, why not, bigger is better isn't it?

[Thomas G.]

Originally Posted by Byron Kinnaman

Yup, and a bigger bolt is generally better. Right?

The truth is components (wire or bolts) need to be the sized to do the job, nothing, nothing smaller.

I built a lot of electronic control circuits using 30 awg wire or 32 awg. That happened to be the best size for what I was doing. Sometimes I used a larger wire for higher voltage circuits because of the thicker insulation.

Do you water your lawn with a 6" diameter hose? If not, why not, bigger is better isn't it?

[Byron Kinnaman]

Originally Posted by Thomas G.

How many times are you going to edit your post, Tom?

[Thomas G.]

Originally Posted by Byron Kinnaman

How many times are you going to edit your post, Tom?

Until I stop laughing.

[KevinPete]

Originally Posted by Byron Kinnaman

Example of nonsense...

Why is this "nonsense", Byron? Did I say 4/0 would be necessary, or even appropriate, for a small PV system? What I said many posts earlier was that I would go with a 12-3 cord and keep it under 25' for a small RV system. Is that nonsense too? Don't really care if you "designed" circuits with spiderwebs and rainbows, that has no bearing here. Perhaps you'd be comfortable with a cost comparison between 28-gauge wire and 12-gauge? 14 and 8? Whatever.

Originally Posted by Thomas G.

Yea, bigger wire is generally better, but there is a reasonable limit to everything.

Yes, there is, which is why I said I would go with #12 wire, which is actually under what is specified in the NEC, but still probably good enough for what we're using it for. If I was putting PV panels on my house roof, and the batteries in the basement, I would absolutely use 4/0 copper. I know this because I talked to a licensed and experienced electrician who actually installs standalone and grid-tie PV systems. I wasn't just pulling numbers out of the air to be ridiculous, which brings us to-

Originally Posted by Byron Kinnaman

Do you water your lawn with a 6" diameter hose? If not, why not, bigger is better isn't it?

Really? You have to rely on a fallacious comparison to prove a point that was never contested in the first place? Perhaps you could throw another ad hominem attack in for good measure? Again, whatever.

[alan H]

Hey guys isn't this getting a bit childish

[Thomas G.]

Originally Posted by alan H

Hey guys isn't this getting a bit childish

Mom, he's looking at me funny.

[rabbit]

Is the 12awg from panel to controller? Last goround on this the consensus seemed to me to be that, in the average one or two-panel RV hookup, 18 gauge was adequate for 25-50' there and maybe #6 or 4 for a short run controller to battery.

jack

[KevinPete]

Originally Posted by Thomas G.

Mom, he's looking at me funny.

Now that's funny. I'm just funny-looking.

Rabbit, whatever you feel comfortable with, from speaker wire to welding cable. Now I'm gonna head down to the fire station and get my "big red watering can". It's parked right next to the whaaaaaambulance.

[Mike Magee]

Gives new meaning to the phrase, "getting hosed"....