Solar package review for Houseboat- feedback and suggestions please

[Houseboat Dave]

How did your set ups work out on the houseboats? I am also adding solar to my Houseboat and looking for a solar package that is simular to these.

[SteveCA]

Steve, Can you share your info with me on what system you purchased and did you do your own install or did you use someone here at Lake Shasta? Local installers are trying to steer me away from higher voltage panels due to issues they have had in the past. I sounds like they work great if installed and maintained properly.

Check your email for information that cannot be shared here.

[russ]

Steve, Can you share your info with me on what system you purchased and did you do your own install or did you use someone here at Lake Shasta? Local installers are trying to steer me away from higher voltage panels due to issues they have had in the past. I sounds like they work great if installed and maintained properly.

If Steve wants to PM you with the vendor's name OK but don't put it on the site.

[rzelred1]

Houseboat Solar at Shasta Lake

Steve, Can you share your info with me on what system you purchased and did you do your own install or did you use someone here at Lake Shasta? Local installers are trying to steer me away from higher voltage panels due to issues they have had in the past. I sounds like they work great if installed and maintained properly.

[SteveCA]

Hi Steve, Can you tell me what you finally did for a solar system. I also have a houseboat on Shasta Lake. I just put it in dry dock and plant to install solar panels. i keep hearing about issues with 36 volt panels on a 12 volt system causing problems. We have 4 6 volt batteries and want to add 6 110 watt 38volt panels. I'm trying to find someone who can look at our system and tell us if what i want to do will work.
Thanks Ray Zeller

mod - Deleted direct email link. Please enter email into your profile, do not post it in a post.

We installed the system and it works just fine despite all the doubts. As you know. Shasta has full sun and virtually no clouds on 90% of the summer days. 80 percent of our heavy battery use occurs while there is full sun so the theoretical issues with "insufficient batteries" just doesn't show up in real life usage. Keep in mind that we monitor the system and the batteries so that we never have a problem. If we have a cloudy day, we just go lighter on the battery usage and use the generator if needed. In reality, I would say that is less than 10% of the days during the summer. We don't use the boat much during the winter so I am not concerned about multiple days with little to no sun putting a major strain on the batteries.

We are using 36 volt panels with no issue. Just be sure to use a good MPPT charge controller. These controllers will convert the 36 volts to 12 volts (14.4 Volts in reality ) with very little loss. That is why the MPPT controllers cost several times as much as the PWM controllers (which will convert to 12 volts, but lose 2/3 of the solar power in the process).

[rzelred1]

Houseboat solar at Shasta Lake

Hi Steve, Can you tell me what you finally did for a solar system. I also have a houseboat on Shasta Lake. I just put it in dry dock and plant to install solar panels. i keep hearing about issues with 36 volt panels on a 12 volt system causing problems. We have 4 6 volt batteries and want to add 6 110 watt 38volt panels. I'm trying to find someone who can look at our system and tell us if what i want to do will work.
Thanks Ray Zeller

mod - Deleted direct email link. Please enter email into your profile, do not post it in a post.

[SteveCA]

Here is a photo of how the Houseboat is used. Basically is is used like a house. I may move once every 3-4 days at most. As you can see, there is a lot of unobstructed space on the roof for panels. Lake Shasta sunny on 95% of the summer days. the only issue is heat. It can get quite hot with temps in the high 90's and occasionally over 105. BTW, this is not the boat we are installing the system on. Our boat has no rails on the top deck.

Constellation 01.jpg

[SteveCA]

OK this makes it a full time system being in the boat for a full week.

You have two issues but workable.

The big one in my opinion is the batteries. They are undersized and wrong type for the application. If you intend to use 3 Kwh/day, then the batteries need to have 15 Kwh capacity. At 12 volts 15,000 wh / 12 volts = 1250 AH. Using 225 wh 6 volt batteries in parallel is not the way to go and asking for failures and a maintenance nightmare. Instead you want to use 1250 AH cells like a Roll S2-1275AGM 2 volt 1200 AH battery if the batteries will be used for engine cranking, or if no engine cranking then a Rolls S-1590 2 volt 1200 AH Flooded battery.

For the panels is not a huge issue because you do have the generator, but will need a good battery charger. The problem with the panel is on paper you have enough wattage to generate 3 Kwh/day you desire, bu tin practice will fall short because the calculations assume perfect orientation and tilt angles on a fixed system like a house. On a boat you cannot have that and orientation and tilt is dynamic changing every second with your direction, pitch, and roll. On a boat you will likely have to mount them flat on top of a deck, then you might have shade issues casting shadows from mast and sails if it is a sail boat. You will never be able to achieve full production.

Sunking,

Thanks for your feedback. I intend to wire the 6 volt batteries in series, in sets of two, and then parallel wire for the three sets to get 12 volts. I prefer to wire 4 6V batteries in series to get to 24V (for the inverter), but the boat systems all run on 12V. I understand your suggestion on the batteries and it looks like your design calls for 20% discharge which I understand is best for longevity. We will have to consider the cost benefit of using a lot more batteries versus shorter life. for us, the boat is used at most 40 days a year so I wouldn't be upset with 200 cycles of life under higher discharge percentages. that should give us 5 years which I understand is the likely useful life of the batteries.

As far as the panels and shade issues, we are quite fortunate because the boats tends to spend the entire day docked in an Idylic cove with no pitch or roll because the front end pontoons are beached and the boat is tied off to shore. The panels will be mounted flat on the top roof where there is no shade whatsoever. As I understand it, the ideal tilt during the summer months is around 12 degrees facing south. We will be at 0 degrees facing south with 12 hours of sunlight. i know they are not all full sunlight hours but in the summer, at least 5 of those hours are close to full sun.

I would like to know what you think of using Sharp 235W B panels. Are they reliable? the warranty is only 90 days.

[inetdog]

The problem with the panel is on paper you have enough wattage to generate 3 Kwh/day you desire, bu tin practice will fall short because the calculations assume perfect orientation and tilt angles on a fixed system like a house. On a boat you cannot have that and orientation and tilt is dynamic changing every second with your direction, pitch, and roll. On a boat you will likely have to mount them flat on top of a deck, then you might have shade issues casting shadows from mast and sails if it is a sail boat. You will never be able to achieve full production.

For a general case boat, these are all important, and in addition will include concerns about running the main engine or a separate generator, etc.
But the OP has a houseboat.
The tilt and fine orientation while moored are going to be issues, and flexibility to re-aim the system if the boat is moved may be issues, but not on a day-to-day or hour-by-hour basis.

[Sunking]

I should also add that the usage on this houseboat is not daily. It is a weekender to one week max usage several times a summer.

OK this makes it a full time system being in the boat for a full week.

You have two issues but workable.

The big one in my opinion is the batteries. They are undersized and wrong type for the application. If you intend to use 3 Kwh/day, then the batteries need to have 15 Kwh capacity. At 12 volts 15,000 wh / 12 volts = 1250 AH. Using 225 wh 6 volt batteries in parallel is not the way to go and asking for failures and a maintenance nightmare. Instead you want to use 1250 AH cells like a Roll S2-1275AGM 2 volt 1200 AH battery if the batteries will be used for engine cranking, or if no engine cranking then a Rolls S-1590 2 volt 1200 AH Flooded battery.

For the panels is not a huge issue because you do have the generator, but will need a good battery charger. The problem with the panel is on paper you have enough wattage to generate 3 Kwh/day you desire, bu tin practice will fall short because the calculations assume perfect orientation and tilt angles on a fixed system like a house. On a boat you cannot have that and orientation and tilt is dynamic changing every second with your direction, pitch, and roll. On a boat you will likely have to mount them flat on top of a deck, then you might have shade issues casting shadows from mast and sails if it is a sail boat. You will never be able to achieve full production.

[SunEagle]

BTW, Here is a link to a pre-packaged system for 2940 watt hours per day:

http://www.wholesalesolar.com/products.folder/systems-folder/REMOTETELECOM.html

It uses 3 ET 245's so I am 30 watts shy of their packaged system.

Careful. That item delivers 2940 watts per day not watt hours. It will give you about 735 watts for only 4 hours each day. The watt output goes down before those 4 peak hours and after those peak hours even with the sun shining.

It doesn't give you the size of your battery system which is what you really need to know to handle any loads when the sun isn't providing peak power.

It is a nice system but may be much smaller than what you are looking for.

[russ]

BTW, Here is a link to a pre-packaged system for 2940 watt hours per day:

http://www.wholesalesolar.com/products.folder/systems-folder/REMOTETELECOM.html

It uses 3 ET 245's so I am 30 watts shy of their packaged system.

A very different application - you are wanting instantaneous draw of high current - hang loose as one of the guys will be along to help you.

[SteveCA]

BTW, Here is a link to a pre-packaged system for 2940 watt hours per day:

http://www.wholesalesolar.com/products.folder/systems-folder/REMOTETELECOM.html

It uses 3 ET 245's so I am 30 watts shy of their packaged system.

[SteveCA]

I should also add that the usage on this houseboat is not daily. It is a weekender to one week max usage several times a summer. I understand that the proposed sizing may be on the light side, but keep in mind the light occasional usage, all of which is in the summer, with a 10 KW westerbek generator for any serious loads or microwave heavy days. We are mainly trying to avoid running the generator first thing in the AM for a cup of coffee or a 40 second microwave blast for some bacon. The proposed solar installation is by no means a stand alone system for the houseboat.

[SteveCA]

It's not the solar panels that are holding you back it is the battery system that needs to be real big to handle your needs at night.

Even on sunny days if you had a 3kw system you would only get that much output for a few hours tops. The rest of the daylight would only yield a portion of the total system wattage. To get your 3kw all day long would require a system many times the size of the 3kw. Your house boat will not be big enough to mount them all.

Okay, I'm trying to understand the math so tell me where I went astray/mis-represented my needs. I believe I may have misrepresented my needs. I don't need a constant 3KW. I need 3000 watt hours total per day:

The 3 X 235 watt panels, assuming 6 hours of full sun per day, theoretically put out 4230 watt hours. Assuming 70% efficiency in the charge controller and inverter (for microwave and coffee pot use), the daily supply should be about 3000 watt hours. 6 golf cart batteries with a total of 600 amp hours at 12 volts discharged to 50% yields 3600 watt hours per day. In reality, the lionshare of the use will be during the daylight hours, not at night so I assume that the batteries will rarely discharge to 50% on sunny days. If we have cloudy days, which is fairly rare, we will curtail use and run the generator for all AC usage. this is the math behind my proposed design. What have I missed?