Solar - 400 watts

[Submariner]

I've finally completed our solar panel upgrade on Channel Surfing.
400 watts, we now have our energy independence during boating season.
I have seen as high as 27 amps going to the house bank from solar.

I wasn't a believer in solar before. I am now. We just finished a 4 day cruise in the San Juan's for Puget Sound Spot Prawns fish'n season. I never connected to shore power. We are seeing over 2,000 watts a day (about 150 amps, daily). Our normal daily consumption is around 1,200 watts. We did have FANTASTIC weather this past week, but even in previous weeks looking at cloudy/overcast skies we still saw over 1200 watts a day.

After 4 days of no shore power our battery bank was down to 42% (-200 ah). Note, our Firefly G31's house battery bank, I will run them down to 20% regularly if need be. With Solar putting back in what we used, 42% state of charge after 4 days of use, I was quite happy with those results.

It's also important to note that we are heavy heavy users of electrical. I work from the boat. Charge my laptop, run the WIFI/LTE router all day, inverter runs all day. I'm on zoom meetings most of the day. Meanwhile, we put 160 Spot Prawns in the freezer each day to freeze our daily catch. We don't conserve electrical, we use what we want. We do, however, turn things off we aren't using.

Solar Upgrade
I removed the factory 160 watt polycrystalline panel.
I installed a pair of Sunpower 200 watt 23.7% efficient mono crystalline marine grade solar panels.
(They are the same width as the factory panel, and about 3 inches shorter!)
I ran NO new wires for this upgrade.
I upgraded the factory PWM solar controller to a Victron MPPT SmartSolar 100/30 controller.
The 12volt red/black pair that went from the solar controller to the engine battery are no longer used so I pulled the fuse on them.
I connected the port and starboard solar panels in series (not parallel). I have no shading problem up top, and I wanted the amps to remain low, and the voltage to go high (around 70 volts DC).

I've updated our photo gallery with current pictures of the complete set up as well as instrumentation showing real-world stat's.
http://www.tugnuts.com/gallery2.php?g2_itemId=79431

We also published a video on our YouTube channel about this upgrade. ("Let's Go Channel Surfing")
https://youtu.be/M_BzO5R1AD8

As an added bonus... the clamp on stainless brackets I used (Gemini Products) look great and hold the panels up off the roof rack about 2 inches higher. This provides more clearance for opening the aft hatches. And the solar panels cover the aft hatches entirely so if it's raining out, we can still open those two hatches without water running in.

The big con to this upgrade, I have little room up on the roof rack for a kayak or anything else to store. Having enough power was more important to us.

If you're looking to upgrade your house battery bank, consider solar as well. Maybe even consider upgrading solar first.

 

[scross]

I agree!
Adding or enhancing solar production capacity is a great way to get to energy independence. After a week of upgrading from my original installed 180 watt panel to a 315 watt solar panel I am seeing 80-90 Amp Hours a day. With the new portable freezer I am using 110-120 Amp Hours a day. Worst case I have 3 days off shore power in one place without drawing down my 4 flooded 115 Amp Hour house batteries. Move the boat for an hour every other day and I am 100% self sufficient.
And adding solar is a less expensive upgrade than going to fancy tech batteries!
And, even with the larger 315 watt panel installed, I still have plenty of room on the sports rack for either a kayak or two or a good sized cargo box. I’m now thinking of a bigger cargo box to hold our two inflatable SUPs since I now know a larger cargo box will fit up there!

Edit: Added photo taken today at 7PM in Shallow Bay in Sucia with new panel installed. Partial panel shading from Yakima cargo box but that only happens very early or late in the day. Received 98.3 Amp Hours from panel as of 8:10 PM today!

gallery2.php?g2_itemId=80065

 

[Craigmconrad]

Nice!

 

[Nwdiver]

How much did you run your engine during the 4 days? Am curious how much that added to the battery charging

 

[Submariner]

How much did you run your engine during the 4 days? Am curious how much that added to the battery charging

Less than 60 amps a day from the engine. We were 4 miles from the fishing grounds. Never went above 6 knots and were done fishing in an hour.

I also ran the hot water tank each day and showered on the boat. -65 ah draw. I was experimenting to see what I could do, how far I could go with electrical.

 

[Nwdiver]

Nice, I think I will hold off on updating my new c-288 to lithium until I get a little experience with the stock batteries and solar.

 

[Submariner]

Rule of thumb for sizing a solar array in the Pacific Northwest and BC... Take the wattage, divide by 4 and that's how many amps you can expect to see, on average.

400 watts / 4 = 100 Amp-hours (average).
315 watts / 4 = 79 Amp-hours (average).

On really sunny days in June, we've seen a division of 2.3 instead of 4. Cloudy days also actually put out quite a bit of solar too. We've all reached for our sunglasses on an overcast day before. It doesn't have to be clear blue skies for the panels to output decent power levels. The grey/black clouds when it's raining are the days to rely on engine charging, shore power, and a larger battery bank to get you to the next day.

The factory panel we had was 160 watts. 160/4 = 40 amp-hours (average) a day.

Winter time, this math doesn't work regardless of the panel. November/December/January, the angle of the sun is too low on the horizon. We would see at most, 40 watts out of our 160 watt panel. Once March/April came around it changed drastically and we would frequently see that 160 watt panel put out 120-150 watts.

 

[scross]

Martin,
For planning purposes I was using the watt rating of my panel divided by 4 to get how many amp hours a day I would yield. For the past week, not counting the day on shore power, I am averaging 1.22kWh a day from the 315 watt LG panel. At 14.6 volts that averages 83.6 Amp Hours per day. Today’s 98+ Amp Hours was exceptional.
I’m averaging not the rule of thumb 25% Amp Hours yield from the 315 watts but a slightly better 26.5% yield. A small difference to be sure but I’ll take it! As the panel ages over the next few years I’ll probably get closer to the 25% rule of thumb yield.

 

[Submariner]

Martin,
For planning purposes I was using the watt rating of my panel divided by 4 to get how many amp hours a day I would yield. For the past week, not counting the day on shore power, I am averaging 1.22kWh a day from the 315 watt LG panel. At 14.6 volts that averages 83.6 Amp Hours per day. Today’s 98+ Amp Hours was exceptional.
I’m averaging not the rule of thumb 25% Amp Hours yield from the 315 watts but a slightly better 26.5% yield. A small difference to be sure but I’ll take it! As the panel ages over the next few years I’ll probably get closer to the 25% rule of thumb yield.

Jeff Cote at Pacific Yacht Systems talks of this formula all the time. I've researched the math the conventional way. You find a chart on the Internet that talks about what the average sun per day is in a particular region.

Here's an example:
http://www.bigfrogmountain.com/SunHoursPerDay.html

Seattle is 4.83 hours a day as a high, 3.57 hours a day as an average, and 1.6 hours a day for a low.
400 watts * 3.57 hours a day = 1,428 watts /day. Divide that by 14.6 volts (charge voltage) = 97 amps.
Hence, the 400 watts / 4 = 100amps a day easy formula.

This past week I was seeing between 2,090 and 2,680watts/day.
2,680 watts / 14.6 = 183 amp-hours.

I also noted that some of my solar stat's got skewed as it would enter into the absorption and float charging phase. There were times when I saw solar at 0 watts with gorgeous sunshine because the batteries were at full charge. By day two, I made sure I ran enough electrical to get below 80% SOC so solar always had a place to put those electrons in the bulk charging phase. (I wanted to measure actual effectiveness of solar).

In this picture, the stat's showing 4 days ago.. the two light shades of blue indicate absorption and float phase. The white indicates bulk charging phase.
http://www.tugnuts.com/gallery2.php?g2_itemId=80056

 

[knotflying]

I’m curious. If I understood you correctly, after four days you were at 42% state of charge and have run your batteries down as low as 20% state of charge? Are they AGM? AGM can take that abuse, but they will still not last if you do that to often. You may want to add a battery or two and consider a little power management.

 

[CruisingElvinRay]

Submariner is the king of power management. If memory serves, he has firefly batteries.


Sent from my iPhone using Tapatalk

 

[Submariner]

I’m curious. If I understood you correctly, after four days you were at 42% state of charge and have run your batteries down as low as 20% state of charge? Are they AGM? AGM can take that abuse, but they will still not last if you do that to often. You may want to add a battery or two and consider a little power management.

I upgraded my house battery bank to three Firefly Oasis G31 batteries. 348Ah total, at 225Ah usable. Firefly batteries are an AGM battery which makes them an easy drop-in replacement to the factory OEM batteries. They use carbon foam that resists corrosion and sulfation (there's very little lead actually in them). The manufacture states that you may run them to zero percent for about 600 cycles, but for best life expectancy, it's recommended to run them down no more than 20% state of charge for about 1000-1300 cycles. So far, the lowest I've taken them is 42% (-200Ah). Firefly Oasis batteries are about as close to lithium batteries one can get, without going lithium and staying within the normal AGM charging profile. I've read to expect at least 10 years of life, maybe more, out of these batteries.

The other nice thing about Firefly's, they don't need to be recharged immediately like a typical AGM. You can run a Firefly battery down to say 40% SOC, leave it sit for 6 months, then recharge it without issues. Because of this, technically Firefly batteries don't need the float phase of battery charging.

To maintain the health and longevity of Firefly's, they do require a minimum of 20% charge rate, which is double the norm of AGM batteries. I started with 2 Firefly's and had added a second 25Amp battery charger. When I added the third Firefly I had to upgrade the 25amp battery charger to a Victron Skylla 70 amp battery charger (70 amps being 20% of 348ah). I also kept the 20amp battery charger that came with the boat and can run both chargers at the same time to get a 90 amp-hour charge rate. (Firefly's will take up to a .5C charge rate, which for 348ah would be about 170amps).

We published the following videos about our battery upgrade.

WE KILLED OUR HOUSE BATTERIES on our Ranger Tug R27 OB/ and you want to replace them with firefly's?
https://youtu.be/AehPUYetDzU

ADDING A 3RD FIREFLY BATTERY TO OUR HOUSE BANK/In our Ranger Tug R27OB
https://youtu.be/HJu3UsbGMq8

We're still putting together the video on the 70amp battery charger installation and will publish it here shortly.

 

[Irish Mist]

Thanks for sharing very helpful

 

[Submariner]

And adding solar is a less expensive upgrade than going to fancy tech batteries!

This is so true!

When I started down this path of evaluating the electrical system on my boat, I looked into lithium. It's not just a battery drop-in replacement. All charging sources must be adapted to support lithium. (Solar charger, automatic charge relays, shore power battery charger. The engine alternator can't directly output to lithium and needs a DC to DC charger of sorts added). And then there needs to be a BMS (battery management system, which is different than a battery monitor) added as well. The battery charger must be increased in size as well.

Our first step was to install the Victron battery monitor (BMV-712) which let me know what everything consumes on the boat. Then I was able to evaluate our requirements. I put together a comprehensive power management spreadsheet and would play with the numbers. Once I knew our requirements were around 1,200 watts a day I sought to size everything accordingly. But batteries are only 1/2 of the equation. They are a bucket that holds electrons. Eventually that bucket will run empty. This is where solar comes in, to replenish that bucket and fill it back up. If not sized appropriate, it'd be like filling up a swimming pool with a garden hose.

I'll need to re-evaluate our electrical requirements, as with me working from the boat more often, those work days are well above the 1200 watts/day. A non-work day for me on the boat is around 1,200 watts/day.

I've read a lot of your past posts about solar, as well as others, and was seeing that once folks went above 300 watts of solar, they universally said the same thing: "We are energy independent and use what we want". Which was precisely the goal I was after.

 

[Nwdiver]

When you were investigating your solar panels, did you look at the flexible type? I’m thinking that the shade over the cockpit might be an option.

 

[scross]

Thanks for all the info Martin. For those of us like me, who are just trying to get our boats capability set to match our cruising needs in the easiest and most economical manor, it’s great to have someone well versed in a subject to turn to.
If you ever buy a portable freezer, throw out all your past power consumption data. These things are great for extended cruising but they are real power hogs! Add about 800 watt hours per day (55 AmpHrs) for your consumption.
Now, if I could just find a way to squeeze 50 gallons of fresh water into my 30 gallon fresh water tank I’d be all set!

 

[Submariner]

When you were investigating your solar panels, did you look at the flexible type? I’m thinking that the shade over the cockpit might be an option.

I did look at that option. Rigid panels are the least expensive, flexible panels are more expensive for the same amount of watts. It's a decent gap in price between the two styles. Since I had the roof rack already I went with the least expensive and easiest option to go big on solar (rigid solar panels).

However, my wheels were turning a bit when I found those Gemini Products stainless clamps, when I saw this picture on their web site.
http://www.tugnuts.com/gallery2.php?g2_itemId=80074

This could be used to easily build a roof rack over the bimini to move the rigid solar panels to, which would free up the roof rack for kayaks and other storage; or to provide more mounting space for more solar panels.

The other option would be to pay a canvas shop to stitch the flexible panels into the top of the bimini canvas.

 

[Submariner]

Additional information about the Firefly Oasis AGM batteries that you can take down to 20% state of charge (80% depth of discharge). As close to lithium batteries as one can get while staying within AGM. More power, less space and weight, longer lifespan.

Recommended - Firefly Oasis Carbon Foam Battery Perfect for a Boat
https://youtu.be/vi6czCNSqp8 (3 minutes)

Comparison: Firefly AGM vs. AGM vs. Flooded Lead Acid Batteries
https://youtu.be/SIVS0WD7Xq8 (5 minutes)

 

[knotflying]

Great video on the conversion. Excellent workmanship also.

 

[cmwahl]

We have several flexible panels. The main reason was we wanted one on top of our Yakima storage pod. The flexible panels are only so flexible. Any flexing on a routine basis and the electrical connections between the cells break. And the flexible panel also will overheat because of the heat generation of the panel with no airspace underneath. So we placed our panel on top of the plastic board, flexed it one time then, then mounted it on the top of our pod. It is a sun power 110 watt panel. We also have two sun power 50 watt panels forward of the solar panels. Mounted on the thin plastic. We then added one very narrow zamp panel, 90 watts, to our rack next to the factory panel, which we kept. All added panels are close in specs to the factory panel, not exact, but close enough. Altogether we have 440 watts. We keep the Morningstar duo controller and have a Balmer battery monitor system from the previous owner. We are still considering changing to a Victron controller, but that’s another years project. I think you could add the flexible panels to the Bimini, if you can control the flexing of the panel, they have a limited amount of flex. We do not carry kayaks. Oh and we also replaced our AGM batteries with the Firefly Oasis, but only 2.