Does this solar system sound OK for my needs and setup?

[tartansail]

Agree with Noelex that this is a reasonable system, but don't skimp on the controller. It's relatively short money. We are also on a mooring or at anchor. We have had 2X125 watt Solbians wired in parallel to Genasun GV10 MPPT controllers for the past four years. We have a very similar battery setup -- 4X6V DuraCells from Sam's Club giving 460Ah. We find that we can leave the AB fridge on its lowest setting when we're off the boat to keep the beer cold on return. The biggest gripe I get from my wife is that we don't run the engine enough to make hot water. I can live with that.

[john61ct]

Solar hot water's not rocket science.

(see what I did there? 8-)

[basssears]

+1 for Victron controller, with Bluetooth dongle. -- Bass

[Tessellate]

Good plan, and you're doing much the same thing I'm currently doing. Only differences are I went with the GoPower 2x100w panels on Amazon and a Victron 75/15 with Bluetooth dongle.

Those panels are amazingly cheap compared to the GoPowers. I'm a bit jealous I missed noticing those. Cheaper flexible panels sometimes have quality issues and die earlier, but at that price point it almost doesn't even matter because you could consider them a replaceable element. And the warranty is pretty good (95% power/5 years, 90% power/10 years, 80% power/25 years), so it's just a matter of whether the company is still around + will honor it.

Also get a backing board for the panels on the bimini mount. The manufacturers recommend it, and panels I've seen on boats that didn't use backing boards on a bimini mount got heavy crazing / cracking after 2 years or so. There are other CF threads about this.

Your current electrical usage is very low, so that'll be plenty of power for now. The fridge is pretty much our only power consumer, so as an all-LED boat without fridge we'd only need a tiny panel as a battery topper. 200W is plenty for a fridge in non-tropical areas. 5.6A*2 = 11.2A. Our fridge only draws 8A, for 2-4 hours per day. Even at only 50% solar output (5.6A) for a few hours that'd be enough. Maybe if people run their fridge super cold to freeze ice and stuff then it's a different story. Or in the winter. But in winter the fridge only needs 2 hours (16A) or so per day.

[Elie]

I had about the same setup: Flexible solar pannels on bimini, and a pseudo MPPT controller. It became obvious that the annonced capacity of the pannels was never reached: In fact in the best situation I never got mote than 6.5 amps, and the comtroller died after 1 year. Repaired(sent at my cost to China) under waranty.
I added a large rigid pannel(270 watts) then the controller died after 3 months. The total power was good enough for my 2 fridges, but the poor controller was unable to dissipate the generated head, and was delcared definitivly dead...I'm in the process of buying a new controller. No a cheap Chinese thing!

So in my opinion, 200 watts is not enough and the annonced power has nothing to do with the reality. A cheap pseudo MPPT is a waste of money. Morningstar make serious MPPT controllers. other too I presume.

[john61ct]

Along with Victron Midnight and Bogart Trimetric integrate with shunt-based battery monitoring, logging etc.

Blue Sky, Outback, Votronic also good quality.

If you need customizable setpoints, may require an add-on remote.

Not sure about marine-robustness though other than Victron's.

[BobLoucks]

Hi
I just set up with 6x6 golf cart batteries in 3 pairs use gen 2 panel 265watts, intelligent PVM controller and a Cobra 2565 inverter
My mooring is also without power
Northern latitude avg 5.5 hours sunlight
Panel rated to produce 1100 watts per day
Running a 560 watt per day energy efficient bar fridge
Has been running 2 weeks without starting the engine in the am voltage drops to 12.2 by noon up to 12.4
Also switched all lights to LED
So far so good

[john61ct]

Originally Posted by BobLoucks

Running a 560 watt per day energy efficient bar fridge

Sorry but I can't tell what that means.

Watts (and amps) are instantaneous, power / flow rate respectively.

Watt-hours - usually amp-hours at 12V - is quantity stored or used over time.

How many AH used per day is the usual way to compare apples to apples.

Most Danfoss-type fridges are reported to use 20-40 AH per 24 hours, depending on size, insulation, ventilation and desired internal temp vs outside weather.

[BobLoucks]

First off it is a Danby Enerstar rated 4.4 cu ft bar fridge w/freezer NOT a Danfoss compressor
Also the charge controller is an intelligent PWM
Regarding the power consumption it draws 0.8 Amps at 115v
The Enerstar rating attached rates the power consumption at 226KWhr which equals about 560 Whr per day versus watts to your point,

Hopefully this clarifies things

[StuM]

Originally Posted by BobLoucks

Hi
I just set up with 6x6 golf cart batteries in 3 pairs use gen 2 panel 265watts, intelligent PVM controller and a Cobra 2565 inverter
My mooring is also without power
Northern latitude avg 5.5 hours sunlight
Panel rated to produce 1100 watts per day

Panels can't be rated to produce "watts per day".
1. A Watt is an instantaneous measure. 1 second or 1 hour with the same irradiation, a panel will produce the same number of Watts.
2. Daily output from panels is dependent on weather, solar angle, shading, latitude among other factors. There is no way a panel can be rated on daily output.

Based on your 5.5 hours and "1100 Watts", presumably, your panels are rated to produce 200 Watts under test conditions and you are assuming that you will get 1100 Watt hours per day out of them. In "Northern latitudes", that is an ambitious figure, especially if you only have "5.5 hours of sunlight" and not "5.5 hours of equivalent full insolation sunlight".


Yet you say 265 Watts earlier. Do you have 200 or 265 rated Watts of solar?

Running a 560 watt per day energy efficient bar fridge

Same comment about re Watts per day. Presumably you mean that the fridge consumes 560 Watt hours per day.

Has been running 2 weeks without starting the engine in the am voltage drops to 12.2 by noon up to 12.4
Also switched all lights to LED
So far so good

Is that 12.4V with solar charging happening or an "at rest voltage" measurement after the batteries have sat for a while with no charge or load on them. You should be reading a lot more than 12.4V at noon with solar charging connected.

What is the maximum voltage your batteries actually get to in the early evening once you lose any solar input ? If you are reaching 12.4V maximum, you are only getting back up to about 75% SOC and are killing your batteries.

[EmeraldCoastSailor]

What material do you use for backing a flexible solar panel?

[StuM]

Originally Posted by BobLoucks

First off it is a Danby Enerstar rated 4.4 cu ft bar fridge w/freezer NOT a Danfoss compressor
Also the charge controller is an intelligent PWM
Regarding the power consumption it draws 0.8 Amps at 115v
The Enerstar rating attached rates the power consumption at 226KWhr which equals about 560 Whr per day versus watts to your point,

Hopefully this clarifies things

.8A @ 115V is roughly 7.5A for a nominal 12V system. So your fridge will be using about 7.5A or 95W when running. If continuous, that would be 160Ah per day.

The Enerstar rating of 226KWhr p.a. = 620 Wh per day, not 560.
Which is about 50Ah per day.

So it looks as though your fridge is rated on the basis of it running approximately 20 minutes per hour on average.

Anyhoo, you are looking at replacing about 50Ah per day with your 200W (?) of solar panels in "northern latitudes". That will be OK in decent weather, but you'd better hope that you don't see several days of heavy overcast/rain.

[BobLoucks]

It is rated at 265 watts
It ran for 2 weeks in crappy weather.

Last time I contribute to a discussion

[john61ct]

Hey this is how we all learn, you need a little thicker skin for some of the best teachers. Accurate common terminology is important too.

And it's very common for us to overestimate input from solar until actually measuring SoC with an accurate monitor.

[john61ct]

Originally Posted by EmeraldCoastSailor

What material do you use for backing a flexible solar panel?

Aluminum, usually supplied as an add-on from the vendor.

Critical the panels aren't subjected to flex once installed, even a slightly curved mounting surface is meant to be fixed.

And best case the still don't last nearly as long as framed rigid ones.