Assorted solar panels 20w to 110w

[rossny]

Hello, I own 6 solar panels: Max Power 20w 1.22A 16.5v, 60w 3.6A 16.7v, 64w 3.88A 16.5v, 80w 4.63A 17.3v, 85w 4.83A 17.6v, 110w 6.43A 17.1v. Can these be used together? My battery bank is 6 #27 12v gels from WM, I think they are about 100A each. My boat will be at a mooring with a refrigerator running.
How would you ( in simple terms) wire this into my grid? Do I need a separate controller for each or one large for all. Will one shaded one limit all the rest?
Thanks for all advise and opinions.

[newhaul]

All to a common rail and then to the controller ( all positives together and all negatives together then to the controller) and partial shading will limit the output of the shaded panel

[nimblemotors]

If you want to maximize the amount of power you get from them,
then I suggest one of the miniMPPT converters for each one connected in parallel into one battery charger. The chargers that do DC-DC are MPPT battery chargers.

[newhaul]

Originally Posted by nimblemotors

If you want to maximize the amount of power you get from them,
then I suggest one of the miniMPPT converters for each one connected in parallel into one battery charger. The chargers that do DC-DC are MPPT battery chargers.

Are these mini units available for purchase today and if so what is the price?
Also then you would need to add the cost of a 40 amp mppt main controller

[nimblemotors]

Originally Posted by newhaul

Are these mini units available for purchase today and if so what is the price?
Also then you would need to add the cost of a 40 amp mppt main controller

The link in my signature is to the kickstarter, where they are available for $25, assuming we get to qty 100.

With 350 watts of solar, a 40 amp charger is a good idea, a 'pwm' one will not do, it must downconvert the '24v' to '12v'.

[newhaul]

However a cheap pwm will get the system operational until the micro unit hit the market. How much will it cost to get in on the ground floor for your micro mppt units

[rossny]

WM has a mastervolt 40a solar charger, is this MPPT?

Sent from my VK810 4G using Cruisers Sailing Forum mobile app

[newhaul]

Originally Posted by rossny

WM has a mastervolt 40a solar charger, is this MPPT?

Sent from my VK810 4G using Cruisers Sailing Forum mobile app

As far as I can find from master volt no it is a pwm controller
SCM40 | Mastervolt Marine
Here is a reasonably good unit at a reasonable price from an american company
Amazon.com: Renogy® Tracer 4210 40 Amp MPPT Charge Controller 12/24V 100VDC Input: Patio, Lawn & Garden

[Bill_E]

I am far from expert in solar technology but I'll add my $0.02. Check out MainSail's article on installing solar. Compass Marine How To Articles Photo Gallery by Compass Marine How To at pbase.com Also, there is a lot of discussion (that I don't quite understand) about the effect of shading when you have several panels wired together. (I'd love to find a good tutorial.) Also, MainSail regularly comments on this board and has a column on another sailing board where there are comments about the differences between MPPT controllers. I wish I had read all of that before I purchased and installed mine. I get a lot of noise on the VHF from the MPPT controller. Right now I'm trying to figure out if I can eliminate it with shields, grounds, and ferrites. If not, I'm probably going to have to buy another MPPT because the noise is really unacceptable.

I am of the belief that you really have to be able to program all battery chargers to match the type of battery or you'll shorten the battery life significantly.

Bill

[GrahamHO]

My understanding is that you should only wire 2 panels in parallel with one controller for each pair of panels. So 6 panels should have 3 controllers. If you have say 6 panels with one controller, the 5 in the sun can damage the one in the shade. That from a solar company web site. It's also the way I've wired my boat. My 2 Optima AGM house batteries are still going strong after 12 years. The Optima starting battery lasted 10.
2 or more controllers can connect to one battery if you want.

[noelex 77]

Originally Posted by newhaul

All to a common rail and then to the controller ( all positives together and all negatives together then to the controller)

+1

That is a diverse range of panels.

In parallel everything will be OK. A single controller is fine. There is little point going for a single MPPT controller with such a large spread of Vmp's so a simple non MPPT (ie PWM controller) is the most cost effective option.

[newhaul]

Originally Posted by GrahamHO

My understanding is that you should only wire 2 panels in parallel with one controller for each pair of panels. So 6 panels should have 3 controllers. If you have say 6 panels with one controller, the 5 in the sun can damage the one in the shade. That from a solar company web site. It's also the way I've wired my boat. My 2 Optima AGM house batteries are still going strong after 12 years. The Optima starting battery lasted 10.
2 or more controllers can connect to one battery if you want.

Could you please show the link to the information you quoted. I am willing to bet that the company that recommended only 2 panels to a controller also recommends their own controller personally I have seen systems with up to 24 panels in the 200 watt range on house systems on a single charge controller here is the link to an 800 watt off grid kit using 8x 100 watt panels and a single controller
Premium Solar Kit 800W | Renogy Store
Here is a 400 watt 12 volt kit with a pwm controller
Mono Starter Kit 400W | Renogy Store
Funny thing is both have more than 2 panels on a single controller.

[newhaul]

Also shade on a panel would not be an issue the panels would be in parrell not in series so you would just loose the output of the shaded panel

[nimblemotors]

You might want to read my thread on Electric Boat Forum

Panels put in parallel is dramatically better when there is shading.
When they are put in parallel, they are forced to have the same voltage.
A panel that is shaded will be forced to have the same output voltage as those not shaded, so it can't contribute much, it has to drop its current very low to get the voltage the same as the others. The way to get the most is to have each panel output the same voltage regardless of shade or type of cells.
That is what this miniMPPT controller board does that I created.

Nobody makes these boards because generally shade is never a problem for a solar installation, if it was, they wouldn't install solar!
Whereas on a sailboat shade is pretty much going to happen if you have a mast or rigging or antenna.

[socaldmax]

This is what I would do. I would sell that random collection of solar panel on CL for $1.50 per watt, price in a little haggle room so they knocked off a few bucks but you end up at $1.50 per watt per panel. That will net me about $625.

I'd buy 2 x 300 watt panels and mount them on an arch on the stern, away from any shade.I've been buying new panels for as low as 60 cents/watt lately, but let's assume you end up paying 75 cents/watt, so the 2 panels cost you $450, plus tax. Then I'd buy 2 20 amp MPPT controllers for $100 ea and connect each panel to it's own controller. After $625 from the solar panels and about $680 spent on new panels and controllers (plus whatever for cabling, which you'll save a ton on not stringing a bunch of random panels together) you'll be way ahead for just a few $$.

You'll get double the output (very close to 40 amps under ideal conditions), no shading, and it won't look like a hodge podge of "stuff" on your boat, which will help with resale value in the end.