The “Myth” of 100% by Midday

[Kenomac]

Originally Posted by Simi 60

So get a better freezer.
We have a 5 draw cheapy from Kmart, cost around $100.
Keeps meat and icecream , if so inclined, solid on lowest settings allowing us several months at a time away from the dirt people.

There’s nothing wrong with our huge Frigoboat double compressor freezer, we just choose not to use it, we have a freezer incorporated into our upright fridge which serves our needs.

After a cloudy morning, its now 4pm and we find ourselves at 99%, so I turned on the watermaker and there’s still 3Ah going into the house bank over and above what’s being used by the watermaker and fridge. 34 gallons of fresh water will be produced over the next 2 hours and the house bank will be back up to 100% by 6pm.

No generator use today, getting plenty of juice out of these Solbian flex solar panels.

[rha9]

I've read the posts to this thread with interest. My situation isn't really comparable, a part time cruiser at most. All of the posters have very high power requirements compared to mine, so I understand power generation would be critical. Still, the physical size of these solar arrays seems immense. One writer said his was 2200 Watts? I have a single 100 Watt panel and it measures about 1/2 square meter. How do you get 22 of these on a boat with all the associated wiring without interfering with the sailing function? Perhaps I have misunderstood something?

[a64pilot]

Originally Posted by rha9

I've read the posts to this thread with interest. My situation isn't really comparable, a part time cruiser at most. All of the posters have very high power requirements compared to mine, so I understand power generation would be critical. Still, the physical size of these solar arrays seems immense. One writer said his was 2200 Watts? I have a single 100 Watt panel and it measures about 1/2 square meter. How do you get 22 of these on a boat with all the associated wiring without interfering with the sailing function? Perhaps I have misunderstood something?

I believe he is a large power boat, and then many of the larger systems are Cats, that are very beamy and have more room.
I’m the average 40’ cruising boat and can fit four 250W hard house panels.
Three are on the davits over the dinghy, dinghy is 10’6” long without the motor so the panels are slightly smaller than the dinghy, the fourth is on the Bimini, so they aren’t really taking up room that isn’t already taken up, just put over existing “things”
However of course it depends on how much power you use, if you use less, then you need to generate less.

I struck out with a better half that wasn’t real enthused with this cruising thing, this was my idea, her idea of camping was in our 36’ fifth wheel for example.
So right from the beginning I was trying as much as possible for unlimited power and water as I knew that if so were chasing her around fussing another how much water she used to wash her face etc, it would negatively impact us cruising.
But others needs of course vary

[noelex 77]

Originally Posted by rha9

I have a single 100 Watt panel and it measures about 1/2 square meter.

On our first yacht we fitted a 46w solar panel. This was in the days when such a panel was very expensive. Several years later we updated to 75w panel. Luxury . Later I added a single 10w panel that charged a small battery to power our anchor light. No LED lights in those days, so the anchor light was a significant electrical draw. There was no other form of power generation.

Despite the limited power we cruised for a couple of months at a time on this boat, almost always at anchor.

It is simply a matter of matching your power consumption with the power output. Our battery SOC was not fundamentally any different to our results today. Battery voltages were the same. On this boat we had a single Sonnenschein 75 AHr Gel battery. This battery lasted 16 years so we must have been doing something right.

There were no solar regulators, or at least none we could afford. Turning on loads (such as lights) was our PWM to reduce the solar output. I built a simple volt and ammeter display that was our battery monitor and needed watching like a hawk when the batteries were at a high SOC.

So you don’t need a large solar array to enjoy cruising, nor does the solar or battery bank size effect the correct settings or management. The lessons from the solar threads still apply, but don’t install a 3000w inverter .

[a64pilot]

Originally Posted by denverd0n

Often stated? I don't think I've ever seen anyone say that.


It's all going to depend on how much solar capacity you have, and how much needs to be put back into the batteries. That should be obvious to anyone who thinks about it a little bit.

No, he’s right, I and others have often said that, often, but the reason was to try to get people to really look at what their SOC is and not just trust the Solar controller to do the right thing right out of the box and or to not believe the battery monitor, cause they too can and will lie to you, especially if taken right out of the box and only bank size input and not reset often etc.
Charge needs to be verified by ending charge current if AGM or by specific gravity if flooded, or ending charge current.
It was meant as a warning statement, although still I believe most don’t get to 100% by Noon, If at all on average.
I’ve not gotten years of cruising behind me yet, but just hanging around Georgetown last year waiting to renew our Visa, I heard over and over boats with three year old or newer banks that were having real problems, I mean so bad that things were shutting down at night bad, that’s likely around 10 to 11 V at night. It seemed to be the number one problem on the morning net.
I even considered taking another Honda next time to loan out, cause most had stock alternators and Lord knows how long it would take a stock alt to charge a dead bank?
Not everyone of course, but I was astonished at the complete lack of understanding of a battery and Solar. They had no idea really, they though for example that 12V was fully charged, it’s a 12V battery isn’t it?

These statements are meant to be taken as an average and don’t take into account the middle of Summer when insolation is the highest it’s going to get.

However it’s like I said earlier, it’s very similar to saying that hull speed is a limiting speed, most of the time it is, but there are times when you can blow right by hull speed, even in an overweight non high performance boat like mine.

[a64pilot]

Originally Posted by noelex 77

Your concerns are reasonable. It is certainly not a perfect system. However, it is not just a simple timer as you suggest. If you watch your Outback controller the absorption time will frequently pause and even reset itself back to zero on occasions. It does not work like a simple egg timer. The controller looks at the voltage and this determines if the timer is counting down, paused, or reset back to zero.

The idea is that even with different solar conditions the smart absorption timer will only reach zero and terminate the absorption phase when the batteries are fully charged. As I indicated above it is not perfect, but if the settings are correct (and unfortunately they rarley are) the controller will do an acceptable job in terminating the charge at the correct point even in different conditions (within reason).



Your Outback will do exactly this (although many cheaper controllers will not). A shunt and associated control box is available for the unit (unfortunately it is an optional accessory) and this will terminate the absorption phase at the perfect end amps every time.

This automatic control is also a great way to see the correct absorption time. The absorption time still measured and displayed even though the shunt is now controlling the termination of the absorption phase. My previous yacht had this system and the average absorption time was around 20 mins. Your larger 1000w solar array (although also with a larger battery bank) will likely have a longer typical absorption time than 20 mins, but it is very unusual (but not impossible) for this this to be longer than the two hours which is the default setting for the Outback.

Do you have a name of this option, or a link? I’ve never heard of it but would like to have one as I’m currently AGM and need to get to full, but don’t like overcharging either, I’ll eventually go to Gel and assume especially then that overcharging is even worse on Gel.
I already have the Mate external display

[noelex 77]

Our system on our previous yacht was the Flexmax 60 controller, Mate (the old original version), Flexnet DC and shunt.

From memory all these components were needed (although you already have the most expensive parts).

The above system as well as adding end amps termination also works as a battery monitor.

Edit:
A64 sent me a PM that Outback indicated that a “hub” was also needed. This is correct. On our previous yacht I installed this behind a cupboard and so had forgotten about its existence until the reminder.

[a64pilot]

What I can find is that yes the Flexnet DC is the needed toy, it requires a 50mv 500 amp shunt.
I already have a 50mv 500 amp shunt for my Magnum BMK which seems to perform the same features as the Flexnet, for the Magnum of course.
Assume I can connect both devices to one shunt as I don’t want to series connect shunts if I can avoid it.
Need to call Outback I guess.
Thing isn’t cheap though, about $300 it seems at a quick look.

[sailorboy1]

Originally Posted by noelex 77

Our system on our previous yacht was the Flexmax 60 controller

I have a Flexmax 50 and it was more than my panels back when I installed it. But it is worth it as you can program and set EVERYTHING from voltages to time at to tail amps.

[noelex 77]

Originally Posted by a64pilot

What I can find is that yes the Flexnet DC is the needed toy, it requires a 50mv 500 amp shunt.
I already have a 50mv 500 amp shunt for my Magnum BMK which seems to perform the same features as the Flexnet, for the Magnum of course.
Assume I can connect both devices to one shunt as I don’t want to series connect shunts if I can avoid it.
Need to call Outback I guess.
Thing isn’t cheap though, about $300 it seems at a quick look.

The shunt is a simple dumb shunt (the brains are in the Flexnet DC) so I think that should be fine, but I would check with Outback.

Given the total cost of the system, you are adding a lot of features (end amp termination and battery monitor) for a small cost, but it is a rip off. The Flexnet DC is only a few dollars worth of components. Installation will be very simple, although the Flexnet has some LEDs that are vaguely useful although there is no simple way to recess these into a panel for a neat solution.

I made a special flush aluminium bracket for the Flexnet DC on our old yacht, but in the end decided the usufullness of the LEDs did not warrant the trouble of finishing the project. The Flexnet DC was installed under a cupboard. Outback may have improved these anomalies, and the better display of the newer Mate may make these comments outdated.

[noelex 77]

Originally Posted by sailorboy1

I have a Flexmax 50 and it was more than my panels back when I installed it. But it is worth it as you can program and set EVERYTHING from voltages to time at to tail amps.

It is an excellent, very versatile controller. The only slight drawback is a reasonably high self consumption. The Midnite company also have some very similar controllers (the Midnite company was founded by the original designer of the Outback).

[barnakiel]

There are only two things that answer this challenge: one, what you call 100%. Is 99.99% or is 99% = 100%.


The other one is how much you discharged last night vs. how big your array is.


b.

[Q Xopa]

Originally Posted by a64pilot

What I can find is that yes the Flexnet DC is the needed toy, it requires a 50mv 500 amp shunt.
I already have a 50mv 500 amp shunt for my Magnum BMK which seems to perform the same features as the Flexnet, for the Magnum of course.
Assume I can connect both devices to one shunt as I don’t want to series connect shunts if I can avoid it.
Need to call Outback I guess.
Thing isn’t cheap though, about $300 it seems at a quick look.

Midnite Solar charge controllers do this also with their 'Whiz bang junior' Shunt. IMNSHO Midnite solar are better thought out and easier user interface. Not associated at all.

[Kenomac]

Noelex,

Since you rely almost entirely on solar with no generator backup, what do you do on consecutive rainy days? Today we expect rain for most of the day, so I’ll run the generator for an hour, because I don’t expect any solar output. But what do you do during several rainy days without any solar output? Following several rainy days, how do you catch up and get back to 100%?

Ken

[sailinglegend]

Originally Posted by noelex 77

It is often stated on this forum that it is impossible for solar panels to achieve 100% charge by noon using solar alone......

Lets get back to the original point of this thread - it's good to get examples of other systems but your posting doesn't debunk the myth it only confuses it.

You are clearly in the top 10% of those that really understand solar and battery charging and you have helped many on this forum, but this thread has gone off in a different direction. Unfortunately 90% of solar uses think their batteries are fully charged when a little green light comes on, or their voltage drops from 14.4v+++ down to a float voltage of 13.4v+++. Float doesn't always mean the batteries are fully charged should be the message here that needs repeating and reinforcing.

This post from Martkimwat is the worst example of someone thinking their batteries are fully charged.

Originally Posted by Martkimwat

.....I have 260Ahr of house batteries and usually by around 9~10 in the morning, I hear the Merlin Smart Controller relay making as the batteries become fully charged (showing 13.7amps or there about) and the start battery is connected to share the charge......

Originally Posted by noelex 77

The click of the solar controller is probably when it starts charging the second battery bank. This does not necessarily indicate the house battery is full.....

In my experience I believe that the very large number of those who think they are fully charged by lunchtime are wrong - the math tells you that - because with the average small array replacing what was lost overnight this is just not possible for most boats.

We have increased our array by 300 watts to 450w, and now by about 1600hrs we might drop to Float, but we have to reboot our Victron charge controllers to get back to Absorption voltages until return amps tells me there are fully charged.

We lose about 10% of our 630Ah Lifeline capacity overnight.