Solar

[MrBill_FLL]

-FWIW,
the AP has various settings for how often it reacts per minute.

I find downwind to be the most demanding, in 3'+ seas, I'll either hand steer, or need to bump up the refresh rate... and that will probably be at least double the amps used.

 

[Doug J]

Great info you guys! Needless to say I have much to learn about this stuff, but reading the exchange of ideas is fantastic!

About 6 volt golf cart batteries;
What's the deal? Are they really better? Doesn't a golf cart battery have 3 cells, 2 volts each? A 12 volt battery has 6 cells 2 volts each. Are golf cart batteries deemed to be better because the cells are made of more led or some other material, so they draw down at a slower rate?

Is it true in the old days, before deep cycle 12 volt batteries, 6 volt golf cart batteries was the only way to be able to recharge over and over, so the belief two 6 volt batteries connected together to produce a 12 volt system is better, carries on to this day? Now days we have 12 volt deep cycle batteries. Seems like two of those vs two 6 volt batteries would be better. As I say, I have much to learn about this.

About the A/B/BOTH switch, using two 12 volt deep cycle batteries. Isn't there some advantage to say, using one battery during the day sail, powering the AH etc., and saving the other battery fully charged for night?

 

[Mike B1026]

I think there is a bit of confusion there. That controller can be set several different ways. You can set it so both batteries charge, when one is full it will then send all the power to the second one. Or you can set either battery as the priority one, then the other one gets the full charge. Many times the retailer doesn't give all the info. You can go to MorningStar's site and download the owners manual.

The thing is Walt according to their literature in the link I posted the second battery doesn't receive a charge until the first is fully charged. From the sales literature...

I agree that it shouldn't work that way, but they say it does. I think that actually they just have a combiner circuit in the charger that is like...

http://www.defender.com/product.jsp?path=-1|328|51495|299265&id=750182

...the combiner we bought for the Endeavour like in the link above. Their charger is meant to work with a starter and house battery. I don't see it being a good charger for Doug's application,

Sum

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[Doug J]

-FWIW,
the AP has various settings for how often it reacts per minute.

I find downwind to be the most demanding, in 3'+ seas, I'll either hand steer, or need to bump up the refresh rate... and that will probably be at least double the amps used.

Okay, so the idea is to tweak my AH to use less power. All about power management. My handheld GPS of course can run on internal batteries, but won't last all day. I guess I could let it run on internal batteries until they run down, it starts to alarm when the batteries get low, then I could plug in to house power. That would help too!

 

[Stu Jackson]

G

About the A/B/BOTH switch, using two 12 volt deep cycle batteries. Isn't there some advantage to say, using one battery during the day sail, powering the AH etc., and saving the other battery fully charged for night?

IS IT BETTER TO HAVE ONE OR TWO BATTERY BANKS FOR HOUSE USE?
(By Nigel Calder - I DIDN’T write this!!!)

The popular arrangement of having two house banks alternated in use needs scrutiny before I go any further.

LIFE CYCLES: As we have seen, the life expectancy of a battery in cycling service is directly related to the depth to which it is discharged at each cycle - the greater the depth of discharge, the shorter the battery’s life.

This relationship between depth of discharge and battery life is NOT linear. As the depth of discharge increases, a battery’s life expectancy is disproportionately shortened. A given battery may cycle through 10% of its capacity 2,000 times, 50% of its capacity 300 times and 100% of its capacity around 100 times.

Let’s say, for arguments sake, that a boat has two 200-ah battery banks, alternated from day to day, with a daily load of 80 Ah. Each bank will be discharged by 40% (80 Ah of one of the two 200 Ah banks) of its capacity before being recharged. The batteries will fail after 380 cycles, which is 760 days (since each is used every other day). If the two banks had been wired in parallel, to make a single 400 Ah battery bank, this bank would have been discharged by 20% of capacity every day, with a life expectancy of 800 days, a 5% increase in life expectancy using exactly the same batteries!

But now let’s double the capacity of the batteries, so that the boat has either two 400 Ah banks, or a single 800 Ah bank, but with the same 80 Ah daily load. The two separate banks will be cycling through 20% of capacity every other day, resulting in a total life expectancy of 1,600 days. Doubling the size of the battery banks in relation to the load has produced a 210% increase in life expectancy. The single 800 Ah bank will be cycling through 10% of capacity every day, resulting in a life expectancy of 2,000 days - a 25% increase in life expectancy over the two (400 Ah) banks, and a 250% increase in life expectancy over the single 400 Ah battery bank!

There are two immediate conclusions to be drawn from these figures:

1. For a given total battery capacity, wiring the (house) batteries into a single high capacity bank, rather than having them divided into two alternating banks, will result in a longer overall life expectancy for the batteries.

2. All other things being equal, any increase in the overall capacity of a battery bank will produce a disproportionate increase in its life expectancy (through reducing the depth of discharge at each cycle).

FOR BATTERY LONGEVITY, A SINGLE LARGE (HOUSE) BANK, THE LARGER THE BETTER, IS PREFERABLE TO DIVIDED (HOUSE) BANKS.

 

[Mike B1026]

I'm sorry you consider our pricing outrageous. I think you are comparing apples and oranges however.

The panels that we sell come with the mounts and wiring installed. You simply remove the panel from the box and install on your railing. Takes less than a minute. The wiring is Ancor safety cable and includes a weather tight connection which makes removing the panel quite simple. We even include water tight plugs for those connectors when they are disconnected. The brackets are made from anodized aluminum for corrosion resistance. The stainless fasteners are isolated from the aluminum for added corrosion resistance. We also use Ultra Tuf-Gel for all the stainless steel fasteners and other areas prone for corrosion.

The site you linked to has very good products I assume. But I don't see any panels under 85 watts and I see no mounts for mounting on marine applications. We aren't trying to compete with the large solar applications.

There are many sailors that only need panels from 20w - 80w and they want the convenience of being able to take a panel out of the box and attaching it to their boat, without the hassle of fabricating clamps and mounts.

They also don't have the access to anodized materials or marine quality wiring and connectors. Not everyone wants to spend a weekend rounding up parts and manufacturing a kit to mount a solar panel they purchased on the Internet nor do they have the ability to do it properly.

I respect your thoughts on pricing but but at least lets compare apples to apples.

I am sorry but solar Panels should not cost more than four - five dollars a watt all premium panels have a excellent guaranty usually ten - twenty year replacement. Frankly one look at the prices and I would never do business with coastal solar sales contact these guys for a quote http://www.sunelec.com/ tell them EXACTLY your application and a engineer will shoot you a price much more reasonable. I know these guys I live two blocks from the ocean (I live in salt Air) the Hail resistant Panels are the strongest made and I would bet they save you some serious Money!!! over eight dollars a watt is outrageous.

 

[walt]

If you need the capacity of two batteries (about 200 amp hours - 100 available to use if you want to keep low stress), I like two six volt batteries in series simply because I had trouble with two 12 volt batteries kept in parallel. With the parallel setup, I would always have one battery that used a lot of water, one that didn’t (identical batteries bought at the same time). My six volt setup has not had this issue at all. I think if I had maintained the water a lot better than I do, I would not have had a problem with the 12 volt batteries. This water issue is pretty much gone with the two six volt batteries.

Also, the cycle is generally smaller when two batteries are used at the same time. For example, if you have 200 amp hours of battery total in two batteries and used 50 amp hours a day, your daily cycle would be 25% of capacity. However, if you used one battery at a time, your daily cycle would be 50% of capacity. Of course with the single battery, your only doing the 50% cycle every other day but I believe this is still harder on the battery. I would bet that one of the habits of people who make batteries last a long time is that they in general have lower discharge cycles on the battery.

The charge monitor is not necessary, I did not have one for years and you can watch voltage and current patterns and have a pretty good idea of battery state. But the charge monitor integrated amp hour feature sure is nice to have especially on a longer trip and the one for $150 only has a single current shunt – ie, it only does a good job of monitoring the amp hour use of a single battery. The system also gets a lot simpler with just the charging and monitoring on one single battery (however its configured). Not everyone will agree and have some good points but I sure don’t miss having a 1-2 battery switch and have never had any issue from not having one.

 

[Mike B1026]

I agree with Stu's post but keep in mind, the batteries should be identical. Even different age batteries will have an affect much less types (flooded-gel-AGM) or capacities. Having a "a-b switch" will give you the option of using your batteries either way.

IS IT BETTER TO HAVE ONE OR TWO BATTERY BANKS FOR HOUSE USE?
(By Nigel Calder - I DIDN’T write this!!!)

The popular arrangement of having two house banks alternated in use needs scrutiny before I go any further.

LIFE CYCLES: As we have seen, the life expectancy of a battery in cycling service is directly related to the depth to which it is discharged at each cycle - the greater the depth of discharge, the shorter the battery’s life.

This relationship between depth of discharge and battery life is NOT linear. As the depth of discharge increases, a battery’s life expectancy is disproportionately shortened. A given battery may cycle through 10% of its capacity 2,000 times, 50% of its capacity 300 times and 100% of its capacity around 100 times.

Let’s say, for arguments sake, that a boat has two 200-ah battery banks, alternated from day to day, with a daily load of 80 Ah. Each bank will be discharged by 40% (80 Ah of one of the two 200 Ah banks) of its capacity before being recharged. The batteries will fail after 380 cycles, which is 760 days (since each is used every other day). If the two banks had been wired in parallel, to make a single 400 Ah battery bank, this bank would have been discharged by 20% of capacity every day, with a life expectancy of 800 days, a 5% increase in life expectancy using exactly the same batteries!

But now let’s double the capacity of the batteries, so that the boat has either two 400 Ah banks, or a single 800 Ah bank, but with the same 80 Ah daily load. The two separate banks will be cycling through 20% of capacity every other day, resulting in a total life expectancy of 1,600 days. Doubling the size of the battery banks in relation to the load has produced a 210% increase in life expectancy. The single 800 Ah bank will be cycling through 10% of capacity every day, resulting in a life expectancy of 2,000 days - a 25% increase in life expectancy over the two (400 Ah) banks, and a 250% increase in life expectancy over the single 400 Ah battery bank!

There are two immediate conclusions to be drawn from these figures:

1. For a given total battery capacity, wiring the (house) batteries into a single high capacity bank, rather than having them divided into two alternating banks, will result in a longer overall life expectancy for the batteries.

2. All other things being equal, any increase in the overall capacity of a battery bank will produce a disproportionate increase in its life expectancy (through reducing the depth of discharge at each cycle).

FOR BATTERY LONGEVITY, A SINGLE LARGE (HOUSE) BANK, THE LARGER THE BETTER, IS PREFERABLE TO DIVIDED (HOUSE) BANKS.

 

[Ormonddude]

I'm sorry you consider our pricing outrageous. I think you are comparing apples and oranges however.

The panels that we sell come with the mounts and wiring installed. You simply remove the panel from the box and install on your railing. Takes less than a minute. The wiring is Ancor safety cable and includes a weather tight connection which makes removing the panel quite simple. We even include water tight plugs for those connectors when they are disconnected. The brackets are made from anodized aluminum for corrosion resistance. The stainless fasteners are isolated from the aluminum for added corrosion resistance. We also use Ultra Tuf-Gel for all the stainless steel fasteners and other areas prone for corrosion.

The site you linked to has very good products I assume. But I don't see any panels under 85 watts and I see no mounts for mounting on marine applications. We aren't trying to compete with the large solar applications.

There are many sailors that only need panels from 20w - 80w and they want the convenience of being able to take a panel out of the box and attaching it to their boat, without the hassle of fabricating clamps and mounts.

They also don't have the access to anodized materials or marine quality wiring and connectors. Not everyone wants to spend a weekend rounding up parts and manufacturing a kit to mount a solar panel they purchased on the Internet nor do they have the ability to do it properly.

I respect your thoughts on pricing but but at least lets compare apples to apples.

They have all sizes and can custom make them to suit any need from laminants as far as Apple and Oranges - Power is Power and this is where I see the most smoke and mirrors first of all I went to school for electrical engineering second they will tell you where the cells came from how its made send you any specs you want and custom design the set up for free and they have the charge controllers you recommended starting at fifty dollars a shot. All I am really saying and suggesting is get two Quotes after you see the apples are apples and the oranges are in fact oranges and that those prices are almost in considerably HIGH then make your Choice. A lot of business people see Boat or Yacht and go into over charge mode and I cant help but feel this is the case. I could speak more on the subject but I Think I can be most helpful waiting till the smoke clears.

 

[Mike B1026]

No smoke that I can see. I appreciate your thoughts.

They have all sizes and can custom make them to suit any need from laminants as far as Apple and Oranges - Power is Power and this is where I see the most smoke and mirrors first of all I went to school for electrical engineering second they will tell you where the cells came from how its made send you any specs you want and custom design the set up for free and they have the charge controllers you recommended starting at fifty dollars a shot. All I am really saying and suggesting is get two Quotes after you see the apples are apples and the oranges are in fact oranges and that those prices are almost in considerably HIGH then make your Choice. A lot of business people see Boat or Yacht and go into over charge mode and I cant help but feel this is the case. I could speak more on the subject but I Think I can be most helpful waiting till the smoke clears.

 

[Sumner]

If you’re going by this

Two Battery Charging Solar charge current is shared between the two batteries based on a user selectable priority. When one battery is fully
charged, all of the charge current flows to the other battery.

I’m not sure how you interpret that to mean that the second battery does not receive any charge until the first one is full. It just says that once one battery is full, all the charge goes to the second battery. It does not say the second battery won’t receive any charge until the first one is full. Maybe I’m missing something?.

I probably just misunderstood what they were saying,

Sum

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Our Endeavour 37

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[Cruiser1]

If you want to only start with 40 watts now I'd go with something like this...

http://www.solarblvd.com/Charge-Con...,-12V-Pwm-Charge-Controller/product_info.html

Sunsaver for $25 and then rethink things if you start adding more panels. We used that with a 40 watt panel and it worked fine....

http://purplesagetradingpost.com/sumner/macgregor/outside-22.html

Hi Sumner,
I have been checking out the specs on the Morningstar Sunguard SG-4 - bit dearer out this way than over your way but still cheap compared to other alternatives for a simple system. I currently have a `10W panel but will end up installing a 40W panel. Do you know if these SG-4 panel controllers are suited to both GEL and sealed wet cell batteries?

I currently have a 60ah Sealed Wet Cell and a 110ah GEL battery and will be using either one on the boat until the other one dies - not sure what way I will go eventually, although I note your recommendation of using 2 x 6V golf cart batteries and will probalby eventually go that way.

 

[Mike B1026]

The SG-4 is a "basic controler" with 4 wires coming out of it, nothing else. It has no adjustments or settings for type of battery etc. After reading the manual, I see no mention of a 4-stage algorithm meaning it doesn't have a "boost" stage. Doesn't appear to have a bypass in case of "PWM noise". It's much better than a "shunt" type controller but not in the same league as the SunSaver (Gen3) and higher controllers by Morningstar.

Hi Sumner,
I have been checking out the specs on the Morningstar Sunguard SG-4 - bit dearer out this way than over your way but still cheap compared to other alternatives for a simple system. I currently have a `10W panel but will end up installing a 40W panel. Do you know if these SG-4 panel controllers are suited to both GEL and sealed wet cell batteries?

I currently have a 60ah Sealed Wet Cell and a 110ah GEL battery and will be using either one on the boat until the other one dies - not sure what way I will go eventually, although I note your recommendation of using 2 x 6V golf cart batteries and will probalby eventually go that way.

 

[Sumner]

The SG-4 is a "basic controler" with 4 wires coming out of it, nothing else....

I'm only recommending that controller if someone is not sure how much solar they want to end up with and just wants a controller for a 20-40 watt panel for now and wants to save for a better controller and more solar later. Worked well for us,

Sum

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Our Endeavour 37

Our MacGregor 26-S Pages

Our Trips to Utah, Idaho, Canada, Florida

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[Cruiser1]

The SG-4 is a "basic controler" with 4 wires coming out of it, nothing else. It has no adjustments or settings for type of battery etc. After reading the manual, I see no mention of a 4-stage algorithm meaning it doesn't have a "boost" stage. Doesn't appear to have a bypass in case of "PWM noise". It's much better than a "shunt" type controller but not in the same league as the SunSaver (Gen3) and higher controllers by Morningstar.

Not sure what all the technical terms mean Mike, but are you saying the SG-4 is only suited to wet cell batteries?

My understanding is that solar panels can put out very high voltages (up around 20V) and this needs to be reduced down for any battery types. The Gels and the AGMs cannot take as high a voltage as the Wet Cell batteries. They often say a 10W panel does not need a controller on the assumption that with the battery mostly down a bit in charge, most of the time, the voltage will never get high enough to damage the battery. On the other hand I guess if the battery had been fully charged up on a battery charger then the 10W panel could do some damage - is that correct?

 

[Cruiser1]

I'm only recommending that controller if someone is not sure how much solar they want to end up with and just wants a controller for a 20-40 watt panel for now and wants to save for a better controller and more solar later. Worked well for us,

Yes Sumner, thats exactly where I am at. I like to keep my boat as uncomplicated as possible, at this stage, and understand exactly what you are saying.

Would just be nice to have a controller that would be OK on either of the batteries I currently have. I 'think' my 60ah sealed wet cell may have a limited life. A friend gave me the 110ah Gel battery and although it has not been used for some time I have had it tested on full charge and discharge and it still seems to be in good condition - only drawback is the weight and at 33kg is not that easy to move around!

 

[Mike B1026]

Anyone that tells you that you don't need a controller for a 10w panel is wrong. (Unless you have a very large battery bank, even then I would want one).

You are right that a gel and a flooded battery should be charged differently. (In an ideal world) The flooded(wet) batteries and AGM's can take a faster/higher charge.

The SG-4 charges at 14.1v. The SunSaver has the ability to select between two settings, 14.1 (gels) and 14.4 (others)

Charts:
http://www.morningstarcorp.com/en/support/library/SunSaverENG_R3_5_12web1.pdf

http://www.morningstarcorp.com/en/support/library/SunGuardENG2_11.pdf

Not sure what all the technical terms mean Mike, but are you saying the SG-4 is only suited to wet cell batteries?

My understanding is that solar panels can put out very high voltages (up around 20V) and this needs to be reduced down for any battery types. The Gels and the AGMs cannot take as high a voltage as the Wet Cell batteries. They often say a 10W panel does not need a controller on the assumption that with the battery mostly down a bit in charge, most of the time, the voltage will never get high enough to damage the battery. On the other hand I guess if the battery had been fully charged up on a battery charger then the 10W panel could do some damage - is that correct?

 

[Cruiser1]

.........You are right that a gel and a flooded battery should be charged differently. (In an ideal world) The flooded(wet) batteries and AGM's can take a faster/higher charge.

The SG-4 charges at 14.1v. The SunSaver has the ability to select between two settings, 14.1 (gels) and 14.4 (others)

Thanks Mike,
Sounds like I am OK using the SG-4 on the Gel battery if the SG-4 is limited to 14.1V. It should also be OK on the Sealed Wet Cell, even if the Wet Cell could take a bit higher voltage. Just want to make minimal investment at this stage, keeping the batteries topped up and avoiding sulfation.

 

[walt]

I have an SG4 that I use for a solar trickle charge on a wet cell battery - works fine and should work fine for you. The only thing I don’t like about it is that it doesn’t have an LED that tells you when it’s charging. For a long time I didnt even know if it was working but eventually verified it with a scope, load etc).

I have a question below - but here is what leads up to it. 3 stage or 4 was mentioned. To put things in perspective for a case like Cruiser 1 has, if you are using 10 watts of solar and your battery is down by 20 amp hour, the current from the panel is about .55 amps when the sun is shining, 0 at night. Assuming that that you get 2.75 amp hours per day from the panel, it takes over seven days to replace the 20 amp hours.

This means that the charging algorithm got interrupted 7 times. I’m guessing that the algorithm resets each time it’s interrupted. Also, if you using the boat at all while its charging and a load causes the voltage to drop to say 12.5 volts, what happens to the algorithm now? I would guess it resets again. So what do all those stages mean when the current is regularly going to zero during the charge cycle and the battery has overnight to "relax"?

It seems to me that a lot of the differences in these controllers (excluding MPPT which is about efficiency) is how fast they put last 5% of charge and if they can put in the last 5%. Maine sail did a test on a particular brand of shunt controller a while ago and showed it was slow but if I remember correctly, the battery started out at 94% charge in the experiment he did. Please correct this if inaccurate but all the slow response only involved putting in the last 6% into the battery.

Now that last 5% might be important to someone for available charge - and of course many ways to deal with that besides a better controller). But the question I have is how important is that last 5% to making a battery last a long time? I haven’t researched this but understand it is best to keep a battery fully charged. But what is difference in lifetime between 95% or 100%? I would guess the main difference is the amount of water that gets boiled off.

The other reason I keep a battery fully charged is that Ive been leaving them outside in a cold climate for years. Fully charged batteries dont freeze. Now does that last 5% make any difference for the freezing case?

 

[Cruiser1]

I have an SG4 that I use for a solar trickle charge on a wet cell battery - works fine and should work fine for you. The only thing I don’t like about it is that it doesn’t have an LED that tells you when it’s charging. For a long time I didnt even know if it was working but eventually verified it with a scope, load etc)...........

Yes that is the toss up for me. The SG4 is about $50 out here but the next step up is a 20A PWM controller with all the bells and whistles for $130. https://www.whitworths.com.au/main_itemdetail.asp?item=80281&search123=80281&intAbsolutePage=1.
Main advantage of the larger 20A controller is that I could always keep using it if I decide to upgrade to much, much larger panels. SG4 and using my multimeter seems like the compromise at this stage.

Sorry I can't contribute to the more technical comments Walt, but I do roughly get your drift.