Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 09-06-2012, 07:27   #1
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 19,726
Electrical Musings

Ive been living for a couple of weeks, off and on, on my mooring with no working generator. This has given me some insights into my electrical household on board, and raised a number of questions.

I have a Rutland 914i which does not seem to be working properly, producing 8 amp/hours of power (at 24v) in 40 hours of windy weather, according to its own control panel. The wind generator is a huge disappointment and has no measureable effect on my electrical budget.

I have just spend about $2500 on a professional electrician who installed the Rutland and rewired my system to consolidate the negative bus, so that the shunt for the Victron battery monitor works correctly, and so that I have a master fuse in the system to protect against a fire. This expensive work does not seem to have had the desired effect. The shunt does not seem to be measuring amps in and out correctly. On shore power with dead batteries, the Victron Multiplus charger puts 30 amps or so into the batteries according to the battery monitor. The charger is supposed to put out 70 amps.

And 50 or 60 amp hours of power consumption according to the battery monitor bring my batteries down from a full charge to 50% - 60% (measured according to light load voltage, not a true open circuit voltage test). I have a 420 amp hour bank so this does not seem right. I killed my batteries once, so I accept that their capacity might be reduced, but surely I can expect to get at least 120 amp hours of power out of them from a full charge to 50%. So I guess the battery monitor is showing me 50% of the amps going in and going out not all the power is going through the shunt.

For all that, electrical life on board is perfectly fine, and so I think that ALL my problems must be in my measurements. I run my main engine for just an hour or an hour and a half, approximately once a day (in reality, maybe once every 20 hours). The main engine charges with a big 110 amp schoolbus alternator, regulated by an Adverc. In just an hour and a half, say, I get what looks like a full charge light load voltage up to 25.4 volts or so, which it holds for a couple of hours under this light load, then starts to slowly decline, reaching 24.3 volts or so what looks to me like 50% -- 55% charge after a day of normal domestic use including plenty of inverter use (coffee maker, microwave, toaster, charging computers and phones, etc., etc.), cabin lighting, refrigeration (separate large fridge and large freezer), water pump, 3 hours of central heat for making hot water and drying out the after heads after my shower, etc. I am not making much of an effort to conserve power.

There is no way that 420 amp/hours of batteries can be brought from 50% to 100% charge in one hour, or even in an hour and a half, by a 110 amp alternator, so clearly there is something wrong with my measurements.

I am guessing that I am consuming not 50 or 60, but 100 to 120 amp/hours of power in my typical day. I am guessing that I am not using my batteries from 100% to 50%, but probably from 80% to 50% or 90% to 60%. I am perplexed that I am not able to measure this.

I realize from these weeks that my 6.5kW generator (presently broken) is not really the best power source to support this kind of life on board. It is incredibly inefficient at charging my batteries using the 70 amp Victron charger. The acceptance rate falls to 10 amps or less (according to my battery monitor probably its really getting double that) very quickly, and so it takes hours to accomplish what my main engine with its bigger alternator and more aggressive Adverc regulation does in an hour or so.

That WhisperGen Stirling engine gadget no longer made would be perfect for this lifestyle on board producing heat and 900 watts of power with no noise and 0.8 liters an hour of diesel consumption. I reckon five or six hours running that would cover 100% of my daily electrical needs, plus heat and hot water, for a gallon or so of diesel fuel. Cool! Downside, however, is (was) staggering cost, and not very compact, weighing 90kg.

Alternatively, it will sound strange coming from the owner of a heavy-duty diesel genset, but a Honda E100i would be efficient I would get no heat from it, but three or four hours should cover all my electrical power needs. My Victron charger/inverter can limit the power it takes from an AC power source, and has an appropriate setting for a 900 watt generator. I guess this would be the cheapest, simplest, fastest option.

The point is that 6.5kW of power cant be used efficiently for battery charging. The battery acceptance rate is simply too low. And all of my AC power requirements ALL of them, since I dont have air conditioning are perfectly fulfilled by my inverter. I just dont need 6.5kW of AC power at one time, ever, unless I am washing clothes (and even that can be done from the inverter).

What I really need is a micro diesel generator, ultra quiet, which produces 1kW or 1.5kW of power. It would be key for it to be ultra quiet so that it could be left running for long periods of time. As far as I know, such a thing does not exist. If it were really silent, it could be 500W or 600W and could be left running most of the time.

Or a big solar array, I guess. How much solar would I need to produce 100 amp/hours of power a day at this latitude? Thats 2.5 kilowatt/hours, approximately. Im afraid it would be huge and that there would no place to put it on board. If you can get four hours of rated capacity per day, I would need 600 watts of panels ridiculous, I guess. But maybe 50 amp/hours a day would do it that would stretch my time between other charging to two days (or maybe get me to one day if Im using more power than now like at anchor (anchor light and electronics) or in cold weather (central heat running). And maybe that amount of solar would allow me to use my 6.5kW generator more efficiently run the genset in the morning but only just as long as the batteries are taking a bulk charge, then shut it off and let the solar system do the absorption charge.

Hmmm.
__________________

__________________
Dockhead is online now   Reply With Quote
Old 09-06-2012, 07:52   #2
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29 49.16 N 82 25.82 W
Boat: Pearson 422
Posts: 12,368
Re: Electrical Musings

Well you seem to be doing a lot of musing. Lot of time on your hands lately?

A few ideas off the top of my head.

The battery monitor.

1. Are all grounds on the opposite side of the shunt from the battery? If the wind gen doesn't seem to be charging is it grounded in the correct location?

2. Did you calibrate or zero out the monitor? You need to set the initial programming so the monitor knows the state of charge of the batteries when it starts the measurement. So charge the batteries to 100% and set the monitor. Otherwise it might measure charge in and out but won't know the % charge in the batteries. Also make sure it is programmed with the correct amp hour capacity of your system.

The Victron charger

1. 70 amps is not overly large for your system.

2. If, as you suspect, your batteries are at a high state of charge, the amps from the charger will taper off and you won't see anything close to 70 amps. What does it show when the battery voltage is way down?

Overall

1. When the wind gen is running do you see a higher voltage at the batteries? If not, can you go back up the system point by point checking voltage to see if you are getting good output at the wind gen?

2. Same general question about other charging sources.

Diesel Gen.

I have had the same thought. Would love to find a diesel equivalent of the Honda EU2000. Of course it would have to be a lot heavier than the gas engine but could still be a lot smaller and lighter than the typical marine gen set.

I have looked at a couple of smaller units, around 3.5 KW which I'm considering but they were all pretty expensive.
__________________

__________________
The water is always bluer on the other side of the ocean.
skipmac is offline   Reply With Quote
Old 09-06-2012, 08:27   #3
Registered User

Join Date: Feb 2009
Posts: 1,848
Re: Electrical Musings

I have found that agm batteries work well for fast charging as they have a higher acceptance rate
__________________
motion30 is offline   Reply With Quote
Old 09-06-2012, 08:43   #4
Moderator
 
nigel1's Avatar

Cruisers Forum Supporter

Join Date: Oct 2009
Location: Manchester, UK
Boat: Beneteau 473
Posts: 5,179
Re: Electrical Musings

With my D400 wind geny, the battery monitor registers about 14.8V in big gusts with the batteries at close to full capacity.
Might be a PITA, but can you do a sort of calculation based on what is running on the boat, and for how long, its rated consumption, and come up with a theoritical total daily amp consumption. Would be a rough comparison against what the monitor says your using.
__________________
Nigel
Beneteau 473
Manchester, UK
nigel1 is offline   Reply With Quote
Old 09-06-2012, 08:49   #5
Senior Cruiser
 
DeepFrz's Avatar

Cruisers Forum Supporter

Join Date: Mar 2006
Location: Winnipeg
Boat: None at this time
Posts: 7,930
Re: Electrical Musings

1 1/2 hrs. on the alternator will not bring your batteries from 50% state to a full state of charge. It will take 4 or 5 hrs. at least. At most I would say you are getting to 85% soc and down to 50% so you really are only using 35% of your battery capacity, instead of 50%. That is a conservative estimate, you may actually be getting much less than that.

As has been stated on this forum many times, battery voltage is a poor way to estimate battery capacity.
__________________
DeepFrz is offline   Reply With Quote
Old 09-06-2012, 09:21   #6
Moderator Emeritus
 
hummingway's Avatar

Cruisers Forum Supporter

Join Date: Jan 2010
Location: Gabriola Island & Victoria, British Columbia
Boat: Cooper 416 Honeysuckle
Posts: 6,933
Images: 5
Re: Electrical Musings

I don't know if I'm as far north as you Dockhead but I'm pretty sure the weather isn't exactly solar friendly but I've been pretty happy with my solar setup. 350 watts from two Sharp 175's gives me 20 amps at 12 volts during peak production hours when they're unshaded. Mine aren't ideally located. I don't use as much power as you it sounds like but I mostly run my e2000i if it's cloudy and I want to run the watermaker. The panels and the controller weren't cheap but it's been money well spent. Even on a cloudy day they will still put a decent amount in. Of course in winter when our days so awful short and the angle of the sun poor the number of amp hours become greatly reduced but even in those months it keeps the batteries happy.
__________________
We are the universe contemplating itself - Carl Sagan

hummingway is offline   Reply With Quote
Old 09-06-2012, 09:43   #7
Do or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
Re: Electrical Musings

Regardless everything else, the first step would be to spend a little more money and buy a clamp-on multimeter that can measure DC amps. MOST CAN ONLY MEASURE AC AMPS so make sure to get the right one. I just bought a second meter and found it at Radio Shack, their own brand.

Just clamp it on the negative cable from the battery bank and compare with your monitor. Move it to right next the shunt and compare notes again. You'll quickly find where the error is.

The Rutland and all other low output windgens are imho worthless Why keep up with cost, maintenance and complicated mechanical things with bearings and such when they don't make a positive impact to life aboard?! I never got that but assume it's the idea that turning blades makes one a better cruiser

There are some quiet high output windgens around with the D400 and Superwind leading the pack and I might be convinced to get one when I would not have room for the 0-maintenance solar panels

cheers,
Nick.
__________________
s/v Jedi is offline   Reply With Quote
Old 09-06-2012, 10:50   #8
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 19,726
Re: Electrical Musings

Quote:
Originally Posted by s/v Jedi View Post
Regardless everything else, the first step would be to spend a little more money and buy a clamp-on multimeter that can measure DC amps. MOST CAN ONLY MEASURE AC AMPS so make sure to get the right one. I just bought a second meter and found it at Radio Shack, their own brand.

Just clamp it on the negative cable from the battery bank and compare with your monitor. Move it to right next the shunt and compare notes again. You'll quickly find where the error is.

The Rutland and all other low output windgens are imho worthless Why keep up with cost, maintenance and complicated mechanical things with bearings and such when they don't make a positive impact to life aboard?! I never got that but assume it's the idea that turning blades makes one a better cruiser

There are some quiet high output windgens around with the D400 and Superwind leading the pack and I might be convinced to get one when I would not have room for the 0-maintenance solar panels

cheers,
Nick.
Yes, I regret that I ignored good advice to go solar. The Rutland is a big disappointment. If it had made 2 or 3 amps average during windy weather, as it should accoring to the maker's propaganda, it would be fine -- would not perhaps cover that much consumption but would at least keep the batteries topped up when I'm not on board -- the original purpose in buying it.

Good advice about using the clamp meter -- I will do that. I do have a decent DC clamp meter. It's a bit of a pain to get to my batteries, but I'm due to check the electrolyte levels anyway, so I'll get on that tomorrow. That should clear up the mystery about what's really being consumed, at least -- removing one variable.

I didn't go solar then because I didn't have a good place to put any panels. Now I'm willing to go a little further. I could mount them on my davits -- there is a space there which would do for one panel 1600 to 1800mm long and 800 wide, approximately. The problem is that I am 24 volts, so I need two Two Eopply 190 watt panels would be 1580 x 808 each, so would need a space 1600 x 1600 roughly -- won't really fit, too wide

If only there were a controller which would let me charge a 24v bank with a single panel, then one of this might do well. Unfortunately, this does not exist as far as I know . . .
__________________
Dockhead is online now   Reply With Quote
Old 10-06-2012, 06:08   #9
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 19,726
Re: Electrical Musings

So, it seems that some of these panels might work for a 24v system.

There panels: Sanyo: Sanyo HIT-250 - HD

http://midsummerenergy.co.uk/pdfs/Sa..._datasheet.pdf

produce 40 volts open circuit voltage, and produce maximum power at 32.8 volts. Surely with a decent MPPT regulator one of these would be fine for a 24v system? 250 watts -- the dealer claims that they will produce 52 amp/hours of power on an average UK summer day (at 24v), and 10 amp/hours on an average UK winter day. The summer output -- if this is not a wild exaggeration like the Rutland performance numbers -- would cover at least half of my average daily power budget and would really cut generator runs, and would clearly keep my batteries up when I'm not on board. That panel is expensive -- more than $1000.

This one: Eoplly: Eoplly 190W moncrystalline

is only about $400, and produces 190 watts, claimed. Open circuit voltage is 37v, max power at 30 v -- probably still enough to charge a 24v system through an MPPT controller?

Both of them will fit comfortably on my davits. Didn't want to put a solar panel there, but my thinking is evolving.
__________________
Dockhead is online now   Reply With Quote
Old 10-06-2012, 13:45   #10
Moderator
 
noelex 77's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: Living on dirt waiting for our new yacht to be built.
Boat: Half built Bestevaer.
Posts: 10,618
Re: Electrical Musings

Quote:
Originally Posted by Dockhead View Post
Yes, I regret that I ignored good advice to go solar. The Rutland is a big disappointment. If it had made 2 or 3 amps average during windy weather, as it should accoring to the maker's propaganda, it would be fine -- would not perhaps cover that much consumption but would at least keep the batteries topped up when I'm not on board -- the original purpose in buying it.

Good advice about using the clamp meter -- I will do that. I do have a decent DC clamp meter. It's a bit of a pain to get to my batteries, but I'm due to check the electrolyte levels anyway, so I'll get on that tomorrow. That should clear up the mystery about what's really being consumed, at least -- removing one variable.

I didn't go solar then because I didn't have a good place to put any panels. Now I'm willing to go a little further. I could mount them on my davits -- there is a space there which would do for one panel 1600 to 1800mm long and 800 wide, approximately. The problem is that I am 24 volts, so I need two Two Eopply 190 watt panels would be 1580 x 808 each, so would need a space 1600 x 1600 roughly -- won't really fit, too wide

If only there were a controller which would let me charge a 24v bank with a single panel, then one of this might do well. Unfortunately, this does not exist as far as I know . . .
There are a couple of solar regulators that will boost voltage. With these you can use a( nominally) 12v solar panel on a 24v system, but generally you are better getting a higher voltage solar panel. High voltage is OK most MPPT regulators will reduce the voltage without problems.
__________________
noelex 77 is offline   Reply With Quote
Old 10-06-2012, 13:50   #11
Moderator
 
noelex 77's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: Living on dirt waiting for our new yacht to be built.
Boat: Half built Bestevaer.
Posts: 10,618
Re: Electrical Musings

Quote:
Originally Posted by Dockhead View Post

is only about $400, and produces 190 watts, claimed. Open circuit voltage is 37v, max power at 30 v -- probably still enough to charge a 24v system through an MPPT controller?
Those voltages are a bit too low for a 24 v system. The panel will work, but a higher voltage will work better.
__________________
noelex 77 is offline   Reply With Quote
Old 10-06-2012, 14:21   #12
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 19,726
Re: Electrical Musings

Quote:
Originally Posted by noelex 77 View Post
Those voltages are a bit too low for a 24 v system. The panel will work, but a higher voltage will work better.
Thanks -- and this one? http://midsummerenergy.co.uk/pdfs/Sa..._datasheet.pdf

Open circuit voltage is 43, and max power voltage is about 35. 'Spensive! But a good bit more power from the same size panel, and a good brand name (for whatever that is worth).

250 watts is good -- the seller promises 50 amp/hours on an average UK summer day -- that's at least 50% of my energy consumption and about 10x what I'm getting out of my wind generator on a windy day . . .
__________________
Dockhead is online now   Reply With Quote
Old 10-06-2012, 14:46   #13
Registered User

Join Date: Apr 2010
Location: Newport News VA
Boat: Egg Harbor sedan cruiser 1970
Posts: 829
Re: Electrical Musings

Quote:
and so it takes hours to accomplish what my main engine with its bigger alternator and more aggressive Adverc regulation does in an hour or
Just a little of my own wondering, what if you had that big alternator running off the generator instead of starting the main engine for charging.

This has me thinking I could rig an alternator to run off my own 6500 watt generator. Right now If my main batteries run down, I can start the generator to power my 12volt DC old Raritan battery 3 bank convertor-charger and it will charge the main batteries. How inefficient this is I have no idea.
__________________
sdowney717 is offline   Reply With Quote
Old 10-06-2012, 14:51   #14
Moderator
 
noelex 77's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: Living on dirt waiting for our new yacht to be built.
Boat: Half built Bestevaer.
Posts: 10,618
Re: Electrical Musings

Quote:
Originally Posted by Dockhead View Post
Thanks -- and this one? http://midsummerenergy.co.uk/pdfs/Sa..._datasheet.pdf

Open circuit voltage is 43, and max power voltage is about 35. 'Spensive! But a good bit more power from the same size panel, and a good brand name (for whatever that is worth).

250 watts is good -- the seller promises 50 amp/hours on an average UK summer day -- that's at least 50% of my energy consumption and about 10x what I'm getting out of my wind generator on a windy day . . .
That panel looks great.

I am not sure of the insolation values in the UK in summer, but 50AHrs @ 24 v from 250 w sounds optimistic,if my my memory of UK summers is accurate. The output on a boat because of the inevitable shadows and difficulty allining the panel is less.Possibly they were referring to 50 A hrs @ 12v, but that sounds a bit low.

I have not sailed in the UK with solar, so others will be able to give you a more accurate estimation of the output, but I think you will struggle to get to get 50AHrs @ 24 v on an average from 250 w on an average UK summers day on a boat.


The most important thing is to fit the maximum wattage that will fit in the space, but that panel is very effecient and it's often worth paying a bit more for this, if it gets you more watts. The extra performance will pay for itself in reduced engine and generator run times.
__________________
noelex 77 is offline   Reply With Quote
Old 10-06-2012, 15:14   #15
Registered User

Join Date: Apr 2010
Location: Newport News VA
Boat: Egg Harbor sedan cruiser 1970
Posts: 829
Re: Electrical Musings

I keep waiting for better solar panels. Might some day get nantenna solar with 90% efficiency and low cost.

MU Develop Solar "Nantennas" that Can Capture 95 Percent of Solar Energy | Inhabitat - Sustainable Design Innovation, Eco Architecture, Green Building

Quote:
Solar efficiencies have increased incrementally over the past years, but they are still hovering around 20% however now an engineer from the University of Missouri claims to have developed a flexible solar sheet that could revolutionize solar power by soaking up over 90% of the suns energy. Patrick Pinhero, an associate professor in the MU Chemical Engineering Department, developed a thin, moldable solar sheet composed of microscopic antennas called nantennas that is able to harvest heat and convert it into usable electricity. Best of all, he says that the technology could be available to the general public within five years.

Read more: MU Develop Solar "Nantennas" that Can Capture 95 Percent of Solar Energy | Inhabitat - Sustainable Design Innovation, Eco Architecture, Green Building
__________________

__________________
sdowney717 is offline   Reply With Quote
Reply

Tags
electrical

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 22:50.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.