Challenges with Solar on boats

[GrowleyMonster]

Originally Posted by lifemiles

I have 24 Solar panels running through 12 MPPT controllers each capabable of 100v max. This way, when the sun starts shining early on, the two panels conjoined deliver enough voltage to start charging a already (24v Batterybank)
The batterybank consists out of 24 x 2volt Gel battery's, 1500 Ah each, so I have 2 x 24v banks parallel delivering 3000 Ah. enough to run everything on my 130' yacht (lights all LED) including a professional sized fridge and freezer cell

Thats one incredible system. I am asbolutely gabberflasted.

[jheldatksuedu]

I understand about MPPT (Maximum Power Point Tracking) controllers, that's what we want, but do they do anything when the panel voltage is less than the battery?

My real question is many of the devices called solar panel charge controllers don't say anything about MPPT, should I assume that basically they are in fact that, but just don't use that terminology.

Have people bought controllers they are unhappy with for some reason?

[newhaul]

Originally Posted by jheldatksuedu

I understand about MPPT (Maximum Power Point Tracking) controllers, that's what we want, but do they do anything when the panel voltage is less than the battery?

My real question is many of the devices called solar panel charge controllers don't say anything about MPPT, should I assume that basically they are in fact that, but just don't use that terminology.

Have people bought controllers they are unhappy with for some reason?

To answer your questions. First no a charge controller does nothing when panel voltage is below battery voltage.
Secondly. If a charge controller doesn't say that it is mppt it definitely is not mppt. Also many cheaper controllers that say they are mppt actually aren't mppt. They are just pwm controllers with the mppt label placed on them . you have to do a bit of research on controllers.
(Do your due dilligance )

[john61ct]

Originally Posted by jheldatksuedu

I understand about MPPT (Maximum Power Point Tracking) controllers, that's what we want, but do they do anything when the panel voltage is less than the battery?

My real question is many of the devices called solar panel charge controllers don't say anything about MPPT, should I assume that basically they are in fact that, but just don't use that terminology.

Have people bought controllers they are unhappy with for some reason?

Any true MPPT would say so, and panel voltage needs to be well above charging V, to optimize MPPT I'd say at least 30-40V.

There are **hundreds** of absolute cr^p cheap generic "brands" made in China at the low end, I don't think **any** are actually MPPT, just fraudulently labeled.

Quality vendors are Morningstar, Blue Sky, Outback, Midnight Solar, Victron, Genasun, maybe a few others.

If you have low power requirements, the Victron MPPT 75/15 for under $100 is excellent value.

[mitiempo]

Originally Posted by newhaul

To answer your questions. First no a charge controller does nothing when panel voltage is below battery voltage.

Depends on the controller. Some are boost controllers such as this Genasun:
https://genasun.com/all-products/sol...st-controller/

[mrlee]

Hi all...I am by far no expert on any of this stuff but in my experience I have found the all the calculations to "dial in" your panels to your needs with the correct charge controllers etc. is a lot of hassle to a novice. I went with the overkill method. I have a meager 250Ah battery bank and I use hardly none of it as I don't have a fridge etc...so with that said, I installed 500 W of solar with a Morningstar controller and all I ever do now is check the water in the batteries once a month and my bank is always at 13.4 volts.
After I start adding things I'll let y'all know the difference but I cannot foresee any major issues. I am also going to go up to a 450 Ah bank in the fall.
They say "less is more"...but here I think it's "more is less" in agrevation.
Any input? Am I missing something here?
Thanks for all the great info everybody...

[mitiempo]

Originally Posted by john61ct

Any true MPPT would say so, and panel voltage needs to be well above charging V, to optimize MPPT I'd say at least 30-40V.
Quality vendors are Morningstar, Blue Sky, Outback, Midnight Solar, Victron, maybe a few others.

If you have low power requirements, the Victron MPPT 75/15 for <$100 is an excellent value.....

A good MPPT controller such as the Victron 75/15 will work with any nominal 12 volt panel (which has a voltage of about 18 or so). Series of these panels work better as long as there is no shading. Two 12 volt panels in series will start charging earlier in the AM and continue later in the PM as long as not shaded.

From what I have seen the only controllers to buy are Victron, Outback, Genasun, Morningstar, Bluesky, or Midnite.

$50 doesn't buy much of a controller generally but a controller like the Victron 75/15 is not much more and offers full adjustment of all parameters.

[newhaul]

Originally Posted by mitiempo

Depends on the controller. Some are boost controllers such as this Genasun:
https://genasun.com/all-products/sol...st-controller/

Paul I stand corrected however I also noticed that these controllers will not work in an install where the solar panel will ever put out a voltage that is higher than the nominal voltage of the battery bank.

[mitiempo]

Originally Posted by newhaul

Paul I stand corrected however I also noticed that these controllers will not work in an install where the solar panel will ever put out a voltage that is higher than the nominal voltage of the battery bank.

Incorrect. Read the manual, the max panel open circuit is 63 volts.

https://genasun.com/all-products/sol...st-controller/

[john61ct]

IOW buck **or** boost, very nice feature, thanks for pointing to those!

[CaptJamesCook]

Originally Posted by lifemiles

I have 24 Solar panels running through 12 MPPT controllers each capabable of 100v max. This way, when the sun starts shining early on, the two panels conjoined deliver enough voltage to start charging a already (24v Batterybank)
The batterybank consists out of 24 x 2volt Gel battery's, 1500 Ah each, so I have 2 x 24v banks parallel delivering 3000 Ah. enough to run everything on my 130' yacht (lights all LED) including a professional sized fridge and freezer cell

So cool Lifesmiles. Will you leave your boat to me in your will?

For a 40' if I divide your system by 3 I would not have enough room for the panels..

[Stu Jackson]

Originally Posted by mrlee

Hi all...I am by far no expert on any of this stuff but in my experience I have found the all the calculations to "dial in" your panels to your needs with the correct charge controllers etc. is a lot of hassle to a novice. I went with the overkill method. I have a meager 250Ah battery bank and I use hardly none of it as I don't have a fridge etc...so with that said, I installed 500 W of solar with a Morningstar controller and all I ever do now is check the water in the batteries once a month and my bank is always at 13.4 volts.
After I start adding things I'll let y'all know the difference but I cannot foresee any major issues. I am also going to go up to a 450 Ah bank in the fall.
They say "less is more"...but here I think it's "more is less" in agrevation.
Any input? Am I missing something here?
Thanks for all the great info everybody...

Good for you. Know, however, that not everyone can throw money at something because they decide not to spend the time to do their due diligence (i.e., homework, research). There have been many posts here, and I'm sure in the solar vendors' websites, that says X watts ~= ah input per day.

And for your future "maybe I'll get a fridge" idea, it would be prudent to do an energy budget to figure out if your system will support it, and, if so (it should) wouldn't it be interesting to know how many nights on the hook you can spend without recharging, i.e., starting your engine? Maybe some people aren't curious as to how systems are designed and balanced.

None of us was born an electrician, but a little study and some math shortcuts like the one above, can make it easy and, well, interesting.

But heck, if you don't care, then keep throwing $$ at it. However, another way to look at it is: "Gee, if I carefully designed and balanced my electrical support system instead of just throwing $$ at it, maybe I could buy that fridge sooner!"

Your boat, your choice.

[jheldatksuedu]

After seeing the word boost on here I looked up this on eBay

24/36/48/60/72V 10A DC-DC Boost LCD MPPT Solar Regulator Charge Controller 7210A

$37 plus free shipping, I'll definitely look much closer and probably give one a try.

24/36/48/60/72V 10A DC-DC Boost LCD MPPT Solar Regulator Charge Controller 7210A | eBay

also check

$35
seems to be same thing, but doesn't say boost

http://www.ebay.com/itm/LCD-10A-MPPT...3D302223606709

[mitiempo]

Originally Posted by jheldatksuedu

After seeing the word boost on here I looked up this on eBay

24/36/48/60/72V 10A DC-DC Boost LCD MPPT Solar Regulator Charge Controller 7210A

$37 plus free shipping, I'll definitely look much closer and probably give one a try.

24/36/48/60/72V 10A DC-DC Boost LCD MPPT Solar Regulator Charge Controller 7210A | eBay

also check

$35
seems to be same thing, but doesn't say boost

LCD 10A MPPT Solar Panel Battery Regulator Charge Controller 24/36/48/72V T7Y2 | eBay

Those are the kind of controllers I replace wit Victron after they fail.

Why would you buy an unknown brand controller and trust your battery bank to it to save a few dollars?

See post #67

[jheldatksuedu]

Everything I do is about saving a few dollars, I bought my boat for $5000 on eBay and a few years of enjoyable work, Actually I could sail it in about a month of work, now I'm just changing things to get it ready for 2nd circumnavigation. I bought the 100 watt panels on eBay for $67 each, new. I need to do things such as rebuild the bargain bought watermaker and 4KW Fisher Panda that I've got 3 of for parts, work on my folding bike wheel, install my washer drier and replace a head with a walk in tub. Install the composting toilet that I modified to fit the boat. I built the hard cockpit cabin and dodger from parts salvaged from a power boat scrap yard, windshield and fiberglass panels re-shaped to look good and fit the boat. Modified and built the nesting fiberglass sailing dinghy. Built homemade lockable steel doors to replace the companionway sliders. the list goes on and on, I'm enjoying it and everything has to do with saving a dollar here and there. I retired 10 years early and haven't had a pay check for all that time, now that I'm finally getting social security, I now have no worries about money, but I still try to save a dollar. It's in my blood. I just wish I could find a mate, that's when I'll need all this money I've been saving.....

If the controller fails there is a very good chance I could fix it, and with equipment and tools I'll have with me on the boat.

Go to my website for pictures of most of this stuff.