Solar Panels for Marine Use

[a64pilot]

Assuming your 20 amp controller is rated at 17.49 volts like your panels are, then yes, it's enough.
But, and I have absolutely no idea about this, if your 20 amp controller is rated at say 14V volts then it's not enough
20 amps X 12 volts = 240 watts.

Do you have the specs handy of the controller your looking at?

I'm far from being a Solar expert, heck I don't even have Solar myself yet, so do not take anything I say on face value. trust, but verify

[hellosailor]

"Im happy with purchasing the Nasa"

Am I the only one who suspects that it might be an ignorant weasel that would take the name of the world's foremost space and technology agency and use it for their own corporation?

I mean, if the guy was just looking for short names at random, there's only, what some 456,976 ways to make a 4-letter name in modern English. 614,656 if you use a couple of the forgotten letters like eth and thorne.

NASA? Really?

[Rustic Charm]

Originally Posted by hellosailor

"Im happy with purchasing the Nasa"

Am I the only one who suspects that it might be an ignorant weasel that would take the name of the world's foremost space and technology agency and use it for their own corporation?

I mean, if the guy was just looking for short names at random, there's only, what some 456,976 ways to make a 4-letter name in modern English. 614,656 if you use a couple of the forgotten letters like eth and thorne.

NASA? Really?

Really! That's your contribution?

[Rustic Charm]

Originally Posted by a64pilot

Assuming your 20 amp controller is rated at 17.49 volts like your panels are, then yes, it's enough.
But, and I have absolutely no idea about this, if your 20 amp controller is rated at say 14V volts then it's not enough
20 amps X 12 volts = 240 watts.

Do you have the specs handy of the controller your looking at?

I'm far from being a Solar expert, heck I don't even have Solar myself yet, so do not take anything I say on face value. trust, but verify

Okay, so it's as simple as muliplying the max amps of the controller by the volts to work it out. That's what I wanted to know.

Although, if it was 14v, then 20 x 14 = 280 watts, which means i would be able to increase the size of the panels to 140 watts each. At the max 16 v, then 20 x 16 = 320, which then gives me a max of 160 watt panels?


Supply voltage 8 - 16 Volts DC
Supply current 1.5 milliamps
Battery capacities 5 - 999 AMP Hour
Load current 199 AMPS Maximum
Charge current 199 AMPS Maximum
Shunt Standard 50 millivolt @ 200 AMP


SpecificationsSupply voltage8 - 16 Volts DCSupply current1.5 milliampsBattery capacities5 - 999 AMP HourLoad current199 AMPS MaximumCharge current199 AMPS MaximumShuntStandard 50 millivolt @ 200 AMPSpecificationsSupply voltage8 - 16 Volts DCSupply current1.5 milliampsBattery capacities5 - 999 AMP HourLoad current199 AMPS MaximumCharge current199 AMPS MaximumShuntStandard 50 millivolt @ 200 AMPSpecificationsSupply voltage8 - 16 Volts DCSupply current1.5 milliampsBattery capacities5 - 999 AMP HourLoad current199 AMPS MaximumCharge current199 AMPS MaximumShuntStandard 50 millivolt @ 200 AMP

[a64pilot]

It is simple math, but I would leave considerable margin as sometimes there are other vairables, like it may have been rated in a cool environment, and you may be mounting it in a hot environment with little airflow.
I have no way of proving this, but it seems in my experience anything whether mechanical or not just seems to last longer and perform better if it's not used to close to 100% of it's capacity the majority of the time. I feel sure you would be OK with a 20 amp controller as I assume it will be rare that you actually get close to rated power out of your panels, but with a 30 amp, you have plenty of "cushion"

[Rustic Charm]

Originally Posted by a64pilot

It is simple math, but I would leave considerable margin as sometimes there are other vairables, like it may have been rated in a cool environment, and you may be mounting it in a hot environment with little airflow.
I have no way of proving this, but it seems in my experience anything whether mechanical or not just seems to last longer and perform better if it's not used to close to 100% of it's capacity the majority of the time. I feel sure you would be OK with a 20 amp controller as I assume it will be rare that you actually get close to rated power out of your panels, but with a 30 amp, you have plenty of "cushion"

Yes, I believe it probably IS simple maths, but for something so simple I'm having a devil of a job getting simple confirmation of what this simple equation is. Is it the max amp size of the controller muliplied by the max volts? Or is it the max amp output of the panels muliplied by the number of panels?

[mitiempo]

Originally Posted by a64pilot

20 amps X 12 volts = 240 watts.

12 volts doesn't charge a battery - 14.4 volts does.

A 15 amp controller would work but would be marginal. A 20 amp controller would be a better choice. Even larger - 30 amps - would leave room for more panels in the future.

Controllers are usually rated for amps of solar input, not output.

[Bagelista]

Deleted

[Rustic Charm]

Well, my NASA arrived today. Looks good quality, so as long as it performs as good.

[a64pilot]

Originally Posted by mitiempo

Controllers are usually rated for amps of solar input, not output.

Yes, but panels vary quite a lot in their output voltage, do they not? Plus if you wire them in series or parallel, that changes the voltage greatly, vary the voltage and you vary the amperage, so what voltage was used to rate the controller.
Point was to derive at amperage, voltage must be known, and if a marketing dept wants a high amp number, they may well quote it at a low voltage.
My intent was to show that possibly, depending on how liberal the marketing guys are, that how much power a 20 amp controller can accept may not be as much as you would like, and that at least in my opinion he would be better off with a 30 amp.

[HG02]

I looked around for a while and got totally confused I ended up buying a LG neon X 300 watt 33 volts it had a good feed back on houses its around 1 meter wide and 1.600 meters long I wanted some thing on my cabin roof to add shade when I'm in a warm climate Shading also worried me from boom and masts so I also fitted a MPPT controller only a mid price one but it will convert 60 volts down to 12 volts heres a couple of photos I place a old seat cover over half the panel to represent mast boom shading to see what the voltage drop would be 14.4 was with out the old seat cushion cover thrown over the panel the 13.8 was with the cover on the panel it was an overcast day with rain

[HG02]

heres a photo of the weather out side

[u4ea32]

Originally Posted by hellosailor

"Im happy with purchasing the Nasa"

Am I the only one who suspects that it might be an ignorant weasel that would take the name of the world's foremost space and technology agency and use it for their own corporation?

I mean, if the guy was just looking for short names at random, there's only, what some 456,976 ways to make a 4-letter name in modern English. 614,656 if you use a couple of the forgotten letters like eth and thorne.

NASA? Really?

I have always had the same nagging feeling about that name. Its just a nagging feeling, but...

I have not yet started laying down the stack of money to buy stuff yet, but its coming soon (hence I am lurking on all these solar threads).

I have been thinking about a more DIY approach using the newly emerging "internet of things"

There are now lots of little cheap computers, costing tens of dollars, with lots of little cheap interfaces for monitoring and controlling electrical stuff, communicating over various wired and wireless networks, that can provide the info and controls via the web and your smart phone of whatever you have.

I dunno, but it sure seems a lot more cost effective than what is out there made with ancient technology. To say nothing of being free from some specific companies repair issues when you should be out sailing and having fun.

Anyone besides Capt Coullion doing it the old DIY way?

[a64pilot]

How do you DIY a Solar panel?

[Scot McPherson]

Originally Posted by a64pilot

How do you DIY a Solar panel?

Buy the individual cells and assemble them yourself. It's the only way if you want to cover say a pilot house. But they are very delicate, and you WILL break a few. Solar panels are just the solar cells assembled and packaged into a rigid working panel for you.

If you want to assemble them in shapes, like the top of the pilot house, you can make it flush. But you'll still need to find a way to cover and protect them with plexi or something like that.


Scot McPherson
Sent from my iPhone using Tapatalk - now Free