Solar and alternator charging on passage observations and questions

[ka4wja]

(please forgive any bluntness, and please NOBODY take any offense to any of my comments/observations here....everyone is different, and I mean no offense to anyone!!!)

Monte,
{Edit:
I just saw Maine Sail's posting....and wish to emphasize his excellent words of wisdom....and while, I've already written all of the below and will go ahead and post it...}

Sounds like you had a great time, but used a LOT of electricity...
Some of the answers to your questions will depend on exactly what is installed on-board and how it is programmed....so, before I get to that, perhaps I can give you (and others) some info that will be helpful!!!

Originally Posted by monte

We recently made our first multi week passage from the canaries to Martinique. Our power budget was around 280Ah/ day for passage making and around 150Ah at anchor.
Actual power usage was closer to a consistent 18Ah continuous, so more like 420A/day. This was with the AP, plotter, 2 fridges, computer, radar on all the time.

1) First off, I know that "cruising isn't camping" and that everyone deserves their creature comforts (especially on a long passage), and good food, good drink, entertainment, good hygiene, plenty of sleep, etc. are all important....so, I'm not going to give some rude comments about sailing/cruising in comfort ('cause I like my comforts as well)!!
But...
But, 420 A/H per day? Wow!!

2) I understand the AP and fridges, but why a "plotter", "computer", and "radar", running "all the time"???


3) Regarding radar:
You were on a long trade wind passage where fog is extremely rare, and while it can be hazy at times, and squalls can pop up from late season tropical waves, etc.but visibility is usually good....so, unless you were in the middle of a Tropical Storm, I don't get the radar running at all, let alone 24/7!!
And what commercial shipping there is, is easy to spot / steer clear of, so radar is unnecessary....


4) Regarding computer:
Some may use this for entertainment, but certainly not 24/7? So, I'm not sure what this was used for....certainly not for navigation, as your compass and a paper chart works well for that on a long passage.....and turning on a GPS a few times a day, and plotting your fix on the chart is all that is necessary...


5) Regarding plotter:
Like the computer, not needed on an ocean passage....there's nothing on the chart but water, until you get close to landfall...
And if AIS were the reason, there still is no reason to run a plotter 24/7...
Some feel AIS is a necessity (yes, I have it on-board and do use it 24/7 when at sea), there are MUCH MUCH better ways to use it...such as Vesper Watchmate!!



So...


6) So, if you were to simply switch off these 3 devices, I think your energy consumption when on passage will significantly decrease!

And FYI, just so you don't think I'm somehow "anti-hi-tech" (I'm NOT), here are a few pics of my Nav Station...


AIS Transponder





Nav Station


Nav Station




7) And, while I'm not familiar with cruising cat sail trim (I'm a longtime monohull sailor), sailtrim affects AP power consumption....
I know the temptation is to "get there", but many times reducing sail, and/or not sailing so aggressively, is much better for everything and everyone....and...
And on monohulls, this reduces steering effort and hence AP energy consumption!!!



8) Regarding the fridges....
(I have a 5 cu ft freezer and 5 cu ft spill-over fridge....which I can keep at 5*-8*F and 34*-38*F, in 90*+ F summertime, without running all the time....actually just a little more than half the time, using 40 - 75 A/H per day)
In order to reduce refrigeration energy consumption, it is ALL about INSULATION!!!!
Okay, maybe not "all" insulation, but 95% - 98% insulation, and of course learning how to minimize cold loss by limiting the amount of openings per day, as well as not using the "front door", etc...
(but assuming you're using Danfoss-based units, as almost everybody is nowadays, the "brand" or "controller" is almost irrelevant...it is the insulation that makes the difference!!)

Every hour spent improving your fridge insulation is worth months / years of pleasure and enjoyment on-board...not to mention all the energy savings!!!

Here's an article and (photos), I wrote about improving my refrigeration insulation....
Frig/Freezer






9) As for your charging and storage..

a) Your 1200 watts of solar sounds okay, but your output seems lacking a bit....
Assuming MPPT controllers, should have 85 amps, or so, out in full sun in summertime....and about 70 - 75 amps or so, in wintertime....
But, yes cloudy skies do reduce outputs...
And, yes shading KILLS the output!!!


b) Battery bank sounds adequate....but did you ever check the Specific Gravity of the cells???
Or did you just go by voltage and a battery monitor???
And, did you ever test their capacity, not just "state-of-charge"???


c) And, the standard Yanmar alt, seems to be doing what it is supposed to do....standard internally regulated alt...
(an ext. regulated alt, with a better charge profile, where it will hld in "Bulk" mode until the batteries have come up to a specified voltage for a specified amount of time, before throttling back the charge current in "acceptance" mode....would be an improvement!!!)

Originally Posted by monte

So a couple of questions I have are,
I know 12V is much lower than 60%, but assumed this was low due to the constant power draw and if they were at rest for an hour the true voltage would have been quite a bit higher. Is this assumption correct?
Yes, this seems correct to me....(but again, I wasn't there, and I can only give general answers...)



I know that battery monitors aren't always accurate with SOC %
For most "battery monitors", this is an understatement!!!

but this is really all we had to go on, and I know they can get quite a bit out over time. Ours did seem fairly consistent with it's readout though.
That's good!!


When we started the engine to charge, I found 1200RPM in neutral was enough to put in around 80 amps and any more revs didn't increase the input, but after 30 minutes the input would drop to 40 amps, even though the batteries were still only 60%. Is this because the voltage went up to 13V and the alternator has a regulator to cut back the input?
Yes and No...
Both voltage and temperature cut-back...

And, in the future, also remember that the charge acceptance rate of flooded cell batteries is low compared to gels or AGM's....(but 840 A/H bank, that is down to 50% - 60% charge, should accept more than 40 amps...)

But, why "neutral", why not in fwd gear??
Perhaps you had planty of wind, and were already at hull speed??
(I know with my Autoprop, even idle speed in gear gives me a good push when motorsailing...)


This was a bit frustrating as 80amps continuously would have charged the batteries much faster and meant half the engine running time
Yes, frustrating, but understand that when alt get hot (which can be just 10 - 15 minutes of run time) their output does fall off, and sometimes significantly!!
And now you see why so many recommend an ext regulated alt, and especially a heavy-duty, hi-output, ext regulated alt, so that it will still output its rated ("hot rated") output, after hours....

Hopefully these observations will assist anyone else and also hopefully someone can explain the alternator output question.

Sorry, gotta go....
Hopefully my observations, comments, and answers, will also be helpful!!!


Fair winds...

John
s/v Annie Laurie

[Maine Sail]

Originally Posted by sailorboy1

Well these don't seem right to me. I have 460AH batteries and a 290W of solar and I can get 60AH charge a day in the Northeast, even on most partly cloudy days.

I think what he meant was 60A (amps) of output on a 1200W array, not 60Ah's (ampere hours) per day. A 60A output on 1200W is well within the range of correct. He's getting way more than 60Ah's per day out of the solar array but also consuming over 420Ah's per day when at sea which can still leave a deficit.....

[cwyckham]

Originally Posted by sailorboy1

Well these don't seem right to me. I have 460AH batteries and a 290W of solar and I can get 60AH charge a day in the Northeast, even on most partly cloudy days.

And this is why people really have to wrap their heads around the difference between A and Ah. Monte's using them interchangeably and confusing us.

Rate of flow: A
This is the amount going into or out of a battery or being consumed by a light bulb or whatever. (this is like gallons per hour)

Amount of electricity in the battery (as in how full is the bucket) or the amount of electricity that is used by a light bulb in a day. (this is like gallons)

I realize it's confusing because we're used to having a per hour measure like gallons per hour for rate and this is sort of backwards from that. It is, however, worth getting it right.

[monte]

Thanks john for the detailed reply. Yes 420 is a lot. For some reason I was expecting a lot less and maybe we should have conserved more energy. I guess we are used to our shorter passage making style and may need to adjust for the 24/7, remembering that advice like the computer might use around 3Ah, so over a day thats 75Amps. The reason we had it running was because we use if at the nav desk with opencpn and for AIS target info. We could have managed without it easily enough. Also the iPad had a workout as we were viewing the plotter wirelessly on it, so in effect we had 3 plotters running 24/7
Radar was mainly for squalls. Normally I would have it on a 15min scan cycle with guard zones set to show shops, but this was useless as the guard zone alarm was going off continuously with passing squalls. We did turn it off at times during the day when we could track squalls visually.
To give you an idea, this was a pretty typical night with the waypoints showing squalls we were tracking, or had tracked in the past hour or so

Also regarding the plotter and AIS, this pic is from pretty much mid Atlantic. 3 ships all within 20M of us and all heading different directions. I wouldn't want to shut down safety systems to conserve energy. I doubt the plotter uses that much, maybe as much as the computer...

But yes I agree we could have and probably should have reduced our consumption to stay within our budgeted use. Several times en route I looked at the BM drawing 18amps and switched off some items and thought...hmm that's only 2amps, and switched it back on, but it's the total of the 2 and 3 amp draws that add up to the 18-20amp constant draw.

Regarding trim and the AP use, we do always try to trim for balance and to ease the load on the AP. We also try to reduce the AP sensitivity down to 3 where possible but at times it needs to be set higher to handle wind and wave conditions.

The fridges, well we left them on but should have turned off the cockpit fridge after the first week as it was just for cold drinks which we could have easily put in and out of the galley fridge as needed, so yes we definitely wasted some energy we didn't have there.

I didn't check the specific gravity while underway, again I would assume it inaccurate due to the constant current draw. I've never done a test on the batteries, maybe when main sail comes on board

Thanks again for the feedback and comments.


Monte

[Dockhead]

Originally Posted by monte

Thanks john for the detailed reply. Yes 420 is a lot. For some reason I was expecting a lot less and maybe we should have conserved more energy. I guess we are used to our shorter passage making style and may need to adjust for the 24/7, remembering that advice like the computer might use around 3Ah, so over a day thats 75Amps. The reason we had it running was because we use if at the nav desk with opencpn and for AIS target info. We could have managed without it easily enough. Also the iPad had a workout as we were viewing the plotter wirelessly on it, so in effect we had 3 plotters running 24/7
Radar was mainly for squalls. Normally I would have it on a 15min scan cycle with guard zones set to show shops, but this was useless as the guard zone alarm was going off continuously with passing squalls. We did turn it off at times during the day when we could track squalls visually.
To give you an idea, this was a pretty typical night with the waypoints showing squalls we were tracking, or had tracked in the past hour or so
Attachment 94209
Also regarding the plotter and AIS, this pic is from pretty much mid Atlantic. 3 ships all within 20M of us and all heading different directions. I wouldn't want to shut down safety systems to conserve energy. I doubt the plotter uses that much, maybe as much as the computer...
Attachment 94210
But yes I agree we could have and probably should have reduced our consumption to stay within our budgeted use. Several times en route I looked at the BM drawing 18amps and switched off some items and thought...hmm that's only 2amps, and switched it back on, but it's the total of the 2 and 3 amp draws that add up to the 18-20amp constant draw.

Regarding trim and the AP use, we do always try to trim for balance and to ease the load on the AP. We also try to reduce the AP sensitivity down to 3 where possible but at times it needs to be set higher to handle wind and wave conditions.

The fridges, well we left them on but should have turned off the cockpit fridge after the first week as it was just for cold drinks which we could have easily put in and out of the galley fridge as needed, so yes we definitely wasted some energy we didn't have there.

I didn't check the specific gravity while underway, again I would assume it inaccurate due to the constant current draw. I've never done a test on the batteries, maybe when main sail comes on board

Thanks again for the feedback and comments.


Monte

I'm going to take a somewhat different point of view and say you should be using as much power as you want, as long as you're not wasting it.

Crossing an ocean is a peak life experience -- why should you waste your nerves on saving a couple of watts here and there?

You only have one problem here, in my view, and a very solveable one -- you don't have a proper mechanical means of generating power. Car-type alternators are not designed or made to produce bulk power, and forcing them into that role is guaranteed to end in tears. And without even external regulation, then it's just hopeless.

All you need is a decent school bus alternator on one (better both) engine. With a proper external regulator. A large frame alternator (requiring double belts) and at least 200 amps.

Then you can happily produce bulk power while motor sailing, get your batts up to 90%, and let the solar do the rest. 200 amps nominal will probably get you 160 realistic amps at moderate engine speed -- that's your whole power budget in 3 hours or so a day, not counting the solar. Woohoo.

I said motor sailing, because it seems ridiculous to me to run an engine while sailing and not having it in gear. Why waste the drive? And your engine doesn't like having little load. Here the school bus alternator is already better for the engine's health, too, and not just your power budget.

[socaldmax]

From my point of view, I wouldn't fault you for using the amount of power that you used. You were there, none of us were, so if you felt it necessary or you felt safer with the radar and chartplotter on, then that was the right decision.

It sounds to me like the only real upgrade left is a couple of externally regulated large frame alternators like everyone else has mentioned and your next trip will be even easier!

I've seen preview ads for a high output DC generator from China. It's fairly small, like the size of a 2000w generator, but instead of putting out AC it puts out DC power. I have no idea how well it works or if it's a pile of junk, but DC charging caught my eye as being a little more efficient than an AC gen powering a battery charger.

[roland stockham]

Originally Posted by monte

Thankyou and Thankyou, Roland, the battery bank is 840Ah. Yes we can reduce consumption. We didn't use much water and the watermaker just draws 24Ah for 65l. We probably ran it for an hour/ day. I'm not sure about the 3 stage regulator, I don't really understand how the factory alternators work or are wired. Maybe that's an option though..
Sailorboy, 85Ah is 85 amps per hour. We were probably averaging 50Ah for 6 hrs on a good day due to cloudy conditions, so putting in 300Ah with a shortfall of 130Ah.

That may be the problem. A smart 2 stage regulator replaces the alternator regulator and gives a different charge profile. The problem with all standard alternators, marine or otherwise, is that they are set to maintain a fully charged battery and provide power for any other services running. This works fine in a car or motor boat where the engine runs all the time but not on a sail boat with heavy batteries.
The problem is that to recharge the batteries in any reasonable time you need a hight charging voltage of 14.6 - 14.8v in order to get a decent charge rate. That is fine when recharging but once the battery is charged if you keep supplying power at that voltage you will overcharge it, loose battery water and eventually wreck the battery. Standard alternators avoid this by setting the charge rate at 14.2v. This will charge a battery but very slowly once you reach about 60% charged. That is why you see charge rate drop so much.
The smart regulators have a first step (bulk charge) which is current limited to protect the battery and alternator from overeating. this should be either at the max rate the battery will ecept charge or the alternators max output, whichever is lower - charges to about 80%. Once it reaches 14.8v it switches to step 2, voltage limited and usually on a timer, this completes the charge at 14.8v but with a steadily reducing current. Generally full charge is reckoned to be when the current drops to 5% of the batteries capacity. The regulator then switches to the third step (float charge) with a voltage of 13.8v and will maintain the batty without overcharging.
This is exactly the same way that your shore power charger works but by controlling the alternator.
Good solar regulators work the same way with 3 step regulation. The best ones also convert excess voltage from the panel into additional current, cheaper ones wast it and run hotter. (solar panel can produce more than 20v)

This type of setup will generally more than halve your charging time. Equally importantly it fully charges the batteries which standard regulators don't. Unless you regularly hook up to shore power you will get a much shorter life from you battery bank without a smart regulator.

A point to watch on installation is that often the factory wiring will be designed for a standard alternator charging system. For a smart regulator you need to check that all the wiring and switches are capable of continuously taking the maximum output from the alternator or things will burn out.

I use a Sterling Power regulator which has worked fine for 10 years but there are several others. Hope this helps (and that I am not telling you stuff you already know!)

[monte]

Thanks Roland, that clarifies things a lot. I had hoped to avoid having to charge using engines, hence the large solar array and battery bank. Maybe I'll try be more conservative with consumption on longer passages or look into the alternator upgrade and regulator.
Regarding running the engines in neutral, well yes we were doing 7K with folding props and I figured having them turn at 1200RPM was more likely to create drag than propulsion. Also the only time we needed to charge was a couple of hours from midnight to get us through till the sun was up. At 1200 RPM they use about 1 litre/ hr
Also my batteries seem to require quite high charging which I guess doesn't fit the standard alternator profile
From exide
Bulk/absorption 14.8-15V
Float 13.5-13.8V
It also states that 12.44v is 50%, 12.52 is 60%, 12.6 is 70% and 12,77 is 90%
These figures are higher than I am used to with standard flooded cell batteries and one of the onboard BMs doesn't like to see the battery voltage over 14.6 and starts an alarm every day when the solar pushes them up to 14.8 which us what I set the solar controller to. So I'm guessing the alternator is cutting out even lower than recommended the float charge

[roland stockham]

The fig for batter volatage on charging stages look normal to me, are the same min & max I use but I have a cut out at 14.9 to protect electronics.
The voltages for % charge only apply if the battery has stood with no input or output for at least 3hr so never happens at sea. Voltages at those levels will be lower. I use engine to recharge if the voltages goes below 12v and consider it urgent if it gets down to 11.5, I think that is generally about 50% and 70% discharged but it depends on the current draw at the time. Of course there is the old fashioned way of doing it - when the electric lights go dim light the oil lamps!
Good sailing

[HKTim]

I just noticed on the yanmar site that the standard alternator on the 4JH5CE 54 HP engine is now 125 A. I recall it used to be 60 or 80 A. Does anyone know if other changes have been made (belts?) and what brand of alternator they are now using? I was in the middle of planning an upgrade to a balmar or mastervolt alpha alternator. But have stopped to get more details on this first.

[leftbrainstuff]

You'll never get an accurate battery volt reading while you're using them everyday. But watching the trend is the important bit.

As others have said you need a decent marine house battery rated alternator. Those wimpy automotive types only give you a surface charge.

You should also be able to knock that 420 Ahr / day draw down. Think half with a little magic and hard work.

We find lots of shading of solar on a yacht. Especially in the marina. We're in the process of miving them to the arch and making them directional. This has improved our power generation by a third. They are useless on a dodger.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[millhouse_44]

Hello all;

I've been following this post sequence trying to figure out my problems with my system. I have a Leopard 40 Cat with 600 Ah battery bank of sealed AGM batteries. Standard alternator fit-out not three stage external which I will get sorted based on these posts thank you!

I recently fitted 540 Watts of Solar panels (3x180W panels) with an MPPT charge controller (3-stage). I have been cruising in Thailand since install, about a month and I've been monitoring the performance of the solar. I have not been impressed so far with what I'm getting and I have some theories on why it is not working as advertised. I was expecting to get about 150 Ah of power from the panels and we are consuming about 240 Ah per day, so I knew there would still be a deficiency but since we are on the move regularly and have an onboard Genset I was not worried about having to top up once in awhile (OK, about every 2-3 days).

My problem is that my panels are not pushing out enough voltage. Actually, the MPPT controller is not 'letting' them - the voltage into the controller is coming in at 19 V but the 'out' voltage is only about 12.8. This is in 'bulk' and 'boost' mode. I've seen as high as 13.2 to boost mode and in float it is about 13.2 as well. The controller is set for closed-cell batteries (which I have) but this reduces the voltage for charging down about 0.7 V from what it would be with regular flooded lead-acid (according to the MPPT specifications see attached).

My theory is that the problem is with temperature. It is very hot here and sunny every day. The temperature rises rapidly in the morning and during the heat of the day is 36-40 degrees C. The solar system is tested at 25 degrees C and from what I'm reading online there is a loss of 10-25% in power output from the panels as temperatures rise. The issue though is that I'm still seeing 19V coming into the charge controller and only 12.85 out (on average). I'm wondering if the charge controller is overheating and therefore reducing the efficiency? The controller does not feel warm to the touch and I don't even hear the internal fan running most of the time on it.

The other thing is, I am wondering about changing the MPPT controller setting back to the 'standard' (non-closed cell) setting to up the voltage output. I read that using this setting can damage closed-cell batteries but I presume that is only if the voltage is too high. Does anyone know whether this 'trick' to up the voltage would work or have any negative consequences for the batteries over the long term? (the output should be 14.8 for non-closed cell and 14.2 for closed cell during bulk charging and 13.8V and 13.2 during boost according to the specifications of the charge controller).

Lastly, the MPPT charge controller has a temperature compensator input on it that is not currently connected. Obviously some form of thermostat can be installed on this that will help the unit compensate for the higher temperatures. I have asked the installers about the fitting needed and ordering one. Does anyone have any experience with this? Will this help solve the 'voltage out deficiency' problem I'm experiencing?

Thank you for the assistance!!

Derek Miller
S/V Small Cat Fun
Phuket, Thailand

[hellosailor]

From the PDF, I see the some of the controllers have a maximum output of 10 amps, which would be some 144 watts at 14.4 volts.

But you're trying to control 540 watts of solar panels, so I'd expect the controller to cut back the output, in order to protect itself, or to behave erratically since it may be damaged. The maximum I see on their PDF is 30A at 12 volts, or 360 watts. Nothing for 540W.

Or am I misreading?

The battery chart I had at hand suggests an optimum bulk charging voltage
of 13.8-13.9 for an AGM battery at 45C, so even taking the heat into consideration, 12.8 volts is too low, but it sounds like that charge controller shouldn't be expected to work in that situation. The numbers don't add up. (But I've been known to get numbers wrong too.)

[BMD21]

well, here's my thoughts, based on cruising, on land and theory. In summary, I feel that Monte's findings are what would be expected with his load and his charging methods. So, one or the other should change. I can comment on charging, but I'll leave the use up to Monty.

First solar panels. I've tried it 2 ways: on a boat going to the South Pacific and Alaska, and feeding our home in SoCal. Everyone appears to understand that solar panels need to be sunlit to produce power. So there's 2 considerations: clouds and shading from the boat's structure. Both have been mentioned above and they can really reduce the daily output. A sailboat has a lot of structure above the usual solar panel mounting, including the sails.

Another factor that seem to be largely ignored is aiming the panels at the sun. If the panel surface is not orthogonal (90 deg.) to the sun, the output is decreased by the cosine of the off angle. For example the cosine of 45 deg is .707, so one only gets 70% of nominal power. I placed the solar panels on the top of the bimini, horizontal. The angle to the sun depended on the boat's heel as well as the sun's inclination. At our house, I installed the solar panels on fixed racks that were inclined to our latitude, which meant that I only got 2/3 of the power that would be produced it the panels were continuously pointed. I've not yet seen a tracking system on a boat. So, (opinion) off-pointing solar panels on a boat causes a significant decrease in the panels output.

So taking all the considerations I've mentioned above, solar panels are not the best for a sailboat whilst traveling. They do add some to the daily electrical output, but not as much as anticipated.

Now for lead acid batteries. I installed a 100 amp Balmar alternator with a 3 phase/step regulator, and a charge monitor, both amps (power, instantaneous) and amp-hrs (energy, work done.) I found that if the charge, into 2 ea 4D batteries, was 80 amps at the start, in 10-20 min it would drop to 40 A, then down to 20 A, along an exponential curve. It took a long time to recharge a lead acid battery,because it's acceptance quickly diminishes. Thats just a characteristic af a lead acid battery. I don't think that the alternator is reducing it's output, but the battery acceptance is decreasing as the battery is recharged.

Since it's expensive to run a main diesel for long periods with low output due to abnormal wear and tear, I got a Honda inverter generator and a hig efficiency battery charger. The Honda output is 120 VAC, so it needs to feed a charger. It'll sustain an output of 20 A DC, (1000i model,) takes little fuel and is cheap compared with overhauling a Yanmer. Yes it takes gas, but it's a good investment. Beware that the Chinese inverter generators don't last. My Honda has run for 10 years with frequent oil changes. The inverter type seems to work best with electronic battery chargers.

One comment on radar. I installed a Navico 3G radar. I'm impressed by the performance up to 16 mi and the thing only uses ~ 1 1/2 amps. Best of both worlds.

Boris

[Ex-Calif]

Millhouse44 - Hello all;

I've been following this post sequence trying to figure out my problems with my system. I have a Leopard 40 Cat with 600 Ah battery bank of sealed AGM batteries. Standard alternator fit-out not three stage external which I will get sorted based on these posts thank you!

I am with HelloSailor - It seems your controller is undersized for the array.

Also it is not strictly a voltage game. The MPPT controller "converts" excess voltage to amps. depending on time of day, shading etc. 12.8 may be acceptable. 13+ is better.

But with the potential to be regulating 45 amps I think you need to get a better controller. There is a discussion going on about "fake" Chinese controllers - I've never heard of Leonics. Also would wonder about the solar panel quality themselves.

PS - Might want to start your own thread rather than hijack Monte's.