Getting Started on Solar

So I want to put some solar panels on the boat. I have read the blog post about solar and need to start with the basic issue - "How much power do I use?"

I have no clue. I do know I can go over night and the engine will start if I set the battery switch on both. So really I have no information to start with.

I read I should put in an instrument to measure my State of Charge. I have a Link 10 on my instrument panel that is not hooked up to anything (no wires coming out the back) I also have a used Freedom Basic Remote Monitor sitting in a box that I assume would hook up to my Freedom 10 Inverter/charger.

What is my best bet to install so I can monitor SOC? Is there an easier to install magic bullet?

John

You can calculate the amp hours used if you know what they draw. Add up each device and then multiply it by the hours the device is used. You won’t pick up small parasitic loads, but you will get in the ballpark. You don’t want to draw your house batteries down below 50%. If you know the capacity of your battery bank you can figure how much you can use and not go below the 50% number. Keep in mind it takes a really long time to get above 85% SOC, so you are really working with about 35 to 40% of the house bank capacity.

A variation on what Comodave said: Another option is to switch off all the devices on the boat and then switch them on, one at a time, to see how many amps they draw on your Link 10. The fridge and freeze will draw the most. Multiply each by what you estimate their duty cycle to be (by device), then multiply by 24 hours to determine total draw. Sum that and it should approximately equal what you use each day while on the hook.

Ideal to have the right wattage of panels that will accommodate that. The reality will be somewhat different.

Jim

Lots of very knowledgable folks here on electrical stuff. FWIW, I’m not one of them.

I strongly recommend going to TF member CMS’s website and read this article.
https://marinehowto.com/installing-a-battery-monitor/

It will give you a basic idea of how your battery monitor would work and how it should be installed.

Then I would read this article.

https://marinehowto.com/smart-gauge-battery-monitoring-unit/

I have a Ah/Coulomb counter on my boat. I will be adding (when i get around to it) a Balmar Smart Gauge. FWIW, you can order the Balmar Smart Gauge from Compass Marine Services which is what I will do when that round tuit comes my way.

The Link 10 will give you total amphours used. Read the CMS article and download the Xantrex installation instructions. Daily amphours used, amphour capacity of your house batteries and how long you generally plan to hang out at anchor are the three parameters you need to know to size a solar panel system.

David

He says the Link is not hooked up to anything. This is a fine instrument to tell you what you need to know, but first it needs to be installed. It's an easy install for an electrician, the only hard part for a amateur is that a shunt will need to be installed in the battery cable to measure current. The Link 10 draws it's measurements from that.

Do you know if that instrument was ever installed? If so, the shunt may already be present, and the Link 10 wired which is quite simple.

A working SOC meter is required , the rest is a guess.


The install will pay for itself in battery sets not ruined.

Ok, so if the Link 10 doesn’t provide that information, use a DC clamp meter on the battery cable to determine the same statistics.

So I believe the Link 10 was installed as it looks like it's been around the block, and it's in my instrument panel.

I have new wiring between the batteries and the switches, did not see a shunt, so that is a consideration.

The Xantrex monitor was sitting in a box, looks used, the wires are not connected to a plug at one end, but I can't find anywhere it was mounted.

Reading the posts (thanks guys) it looks like the latest technology is the Balmar unit. Gives the best readings, don't have to calibrate, and easiest to install - also most expensive.

Reading up,on the calibration of SOC meters makes me lean to the Balmer.

As to storage battery capacity, not really an issue as I have two new T-105's and could add more. Just want to go overnight and then some if the day is cloudy and rainy. The limiting factor in the solar panel selection is the available space on the roof.

FF said:

A working SOC meter is required , the rest is a guess.


The install will pay for itself in battery sets not ruined.

Click to expand...

^^^^
This... I have a Magnum inverter with the battery monitor connected to the remote. Without it, it's all SWAG.

Why buy a new Balmar? The Link is a fine unit. Look for the shunt between the negative post on the battery and the neg buss. You can buy a new one for $20 if necessary.

It takes only 3 small wires to finish connecting the Link.

For 1-2 days on the hook, you probably dont need solar,another pair of GCs maybe.

David

I believe the Balmar unit is a State Of Charge meter, rather than an amp-hour counter. The proponents of the Balmar suggest it is better as it is easily set up to be fairly accurate, whereas the Link or similar can be set up in ways that are inaccurate.

For the purpose of determining your amp use, and solar requirements, the Link type amp-hour counter is preferable in my opinion. This tells you how much power you are using, and how much needs to be replaced each day. The Balmar tells you when you need to charge your batteries, but little else.

Newer amp-hour counters than the Link have more features and nicer displays, but add little to what the Link will tell you.

The remote for the Freedom is a very course measurement, not a replacement for the Link (though nice to control the Freedom). If it were my boat, I'd power up the Link to see if it is alive, if so I'd find the shunt or buy another, and hook it up. You will have all the information you need, cheaply. If the Link 10 is dead, I'd buy another amp-hour counter, there are many on the market. If you know you are going solar, you might consider buying one of the controllers that includes this function (for example the Blue Sky offerings work well). That will track the charge in and out of the battery from whatever source, as well as control the charge from the solar panels.

The off grid home owners and RV folks are not very interested in playing with electronics.

They just want to make their batt set not die , and last as long as it can.

These are cheap, and fit the bill.

https://www.offthegridrvs.com/Trime...MI3pWn1dPu2wIVC77ACh0RuQnPEAQYBSABEgIlOPD_BwE

Hi guys, I checked, there is no shunt. I looked into the Trimetric unit, I liked it, but since I have no shunt, I have to add the shunt price, the wiring kit, and a new battery cable into the mix. Makes the Balmar unit more price competitive.

I have a space on the cabintop for two 3'x5' panels.

PMF1984 said:

Hi guys, I checked, there is no shunt. I looked into the Trimetric unit, I liked it, but since I have no shunt, I have to add the shunt price, the wiring kit, and a new battery cable into the mix. Makes the Balmar unit more price competitive.

I have a space on the cabintop for two 3'x5' panels.

Click to expand...

Keep in mind that your initial question was about solar and how much you might need. Folks like me skewed the discussion somewhat. The Balmar Smart Gauge really only tells you one thing, your battery bank SOC. This is important for ensuring the long life and health of your battery bank. However, it won’t tell you what your current Ah use is to help you decide how much solar you want to install.

FWIW, I knew that I could only reasonably mount one panel. Since I knew that wouldn’t meet all my power needs, I just decided to try and get as much power out of it as I could with the hope that it would bring the batteries up to full charge while on the hook after using the genset to do bulk charging. So far, it is working pretty well. I will admit that when the temps hit 90 degrees, it has a hard time keeping up with both my interior fridge/freezer as well as the 12v freezer sitting in the cockpit.

If I was you and had space for 2 panels, I’d use two of the panels that I went with. Very expensive, but it is rated at 365W and I’ve seen mine actually produce over 400W on occasion.

Thanks Dave,

So it was actually very easy for me to pick out some panels. I wanted mono-crystalline panel and I just picked the largest ones that would fit in the available space 2 160W panels. There is room for one more, but I'm not sure if I'll need it....

PMF1984 said:

Thanks Dave,

So it was actually very easy for me to pick out some panels. I wanted mono-crystalline panel and I just picked the largest ones that would fit in the available space 2 160W panels. There is room for one more, but I'm not sure if I'll need it....

Click to expand...

I have solar. My advice is to get the third panel, if you have the space. Faster recharge of the batteries and less time sitting at just below 100% SOC. Remember the battery recharge is competing with the daytime loads for the available output for the panels and those daytime loads win that battle. Wish I had the space for another panel.

Jim

PMF1984 said:

Thanks Dave,

So it was actually very easy for me to pick out some panels. I wanted mono-crystalline panel and I just picked the largest ones that would fit in the available space 2 160W panels. There is room for one more, but I'm not sure if I'll need it....

Click to expand...

Well, I have one 365W panel and I’d love to have another. I’m happy with my panel but it would be much better if I could double that capacity. When the sun is shining, it is nice to put as much energy back in the bank as possible. Up here, we have lots of days with overcast or broken clouds. I’ve see my panel jump between 300+ watts to 80 watts as the clouds go by. Being able to put out 600 watts of power between clouds would help get the batteries topped off.


2 x 160W panels will give you 320W. If you have the room, I’d likely add that third panel while you are at it. You won’t regret having the extra capacity and it is lot easier to do the third panel while you installing the other two. The 320W will help a lot keep your batteries up, but 480W certainly won’t be more than you could use.

Thanks for the input. I was thinking about the third one and the installation as it would be smart to size the wires and the controller for the third one anyway. So really the cost of the third panel doesn’t add much.

Looking at the controllers at emarine, I see that the Morningstar Prostar PS-MPPT-40, the Blue Sky SB3024DiL, or the Victron Blue Solar MPPT Charge Controller 150-45 will suit my needs.

This is for 3 160 watt panels.

I notice that the Blue Sky is over $100 less than the other two units. Any way to make a choice here other than by price?

I've had the Blue Sky on the sailboat for 10 years. It has been flawless. You can get the remote for it (and a shunt) that gives you complete battery monitoring capability. SOC, amp hours, etc., works better than any others I have tried. That can be added later if budget dictates. Blue Sky is now owned by Genasun.

I'd go with the Victron if I had other Victron equipment on board, as they integrate well (and Victron is generally quality stuff).

Wee they were sold out of the Blue Sky but got a comparable Victron CCV0051.

Just had a few questions about sizing the wire to the controller.

Voltage =18.8v (from Data Sheet)
Amps = 3 x 8.8 amp (from Data Sheet)
Distance Question - Do I use the "round trip" distance like I use for the load size?
Allowable line loss?

I have a Blue Sky unit. It works fine. No bells or whistles. I use my Magnum monitor to let me know what is going into the bank. Not as whizzy as Dave’s unit but I know what is going into the bank real time and can add the real-time loads on to calculate the output from the panels.

Jim

So I have installed the Ballard Smartgauge. Also took apart my guest switches and the ground terminal block to clean up the contacts.

Had a good look at the electrical setup. The start battery is wired to the alternator, bow thruster, windlass, Xantrex, and starter. The starter connection is the object of the on/off position on the switch.

To feed the house panel, I can select the house bank, starter bank, or both.

So when I am underway or at anchor wouldn’t I want the xantrex pulling off the house bank?

(Also have a west marine battery equalizer if that makes a difference)

Forgot to add, will attach panel feed to house bank.

It would help me to understand your system configuration if you could draw a simple diagram.

It sounds as if the only time your house bank is being charged is if your 1/2/Both switch is set to feeding the house. Is that correct?

PMF1984 said:

So I have installed the Ballard Smartgauge. Also took apart my guest switches and the ground terminal block to clean up the contacts.

Had a good look at the electrical setup. The start battery is wired to the alternator, bow thruster, windlass, Xantrex, and starter. The starter connection is the object of the on/off position on the switch.

To feed the house panel, I can select the house bank, starter bank, or both.

So when I am underway or at anchor wouldn’t I want the xantrex pulling off the house bank?

(Also have a west marine battery equalizer if that makes a difference)

Click to expand...

I started a reply but it seemed to disappear.

A diagram of your current setup would be really helpful. It sounds as if the only way your house bank gets charged is if the 1/2/Both switch is in the correct position. In other words, your 1/2/Both switch selects which bank gets charged as well as which gets drawn from. I’m not a fan of that type of setup. That is how my sailboat was setup from the factory.

Before setting up an additional charging source, I would suggest that you first have your system setup in the best way for your purpose.

"It would help me to understand your system configuration if you could draw a simple diagram." Yes, I agree. Is there a simple program for this? My hand drawn schematics just confuse me more.

"It sounds as if the only time your house bank is being charged is if your 1/2/Both switch is set to feeding the house. Is that correct?" ITo connect the Alternator and the Xantrax to the house bank, I would either have to set the switch on "Both" or rely on the West Marine Battery Combiner.

The Alternator and Xantrex are on the same pole as the Start Battery. My first switch has 3 terminals, terminal 1 & 2 are connected by a solid copper buss. Terminal 3 is the starter. Gives me the opportunity to turn off power tot he starter, that's it.

The Xantrex says install to power a deep cycle battery. Which it is not doing now.

Do you have a link to the post where you provided a diagram? I remember I liked it.

Here is the diagram.

Don't really envision how I would equalize the house bank with this set up.

Might be as easy as taking the charger off the connection to the Start battery and putting directly on the House battery.

Look into a Victron.....Very affordable and measures everything. Amp Hours , SOC, Instant Watts, Amps, volts etc.. One simple shunt into the Neg Bat terminal, and everything from there on plug and play with harnesses..