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Old 31-01-2013, 04:13   #1
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Need a little help designing my solar system & new bank

Need a little help designing my solar system & new bank

Ive read=
MY Total Amp Hrs used on average day is 200 amp hrs- I have read if I - multiply by 3 and will have a fairly accurate indicator of required battery bank size. If 200 amp hours per day will need a battery bank of 600 amp hours at the 20 hr .rate. This size to consumption ratio will discharge your batteries to about 66% of capacity. Although you can discharge the bank to 50%, your battery longevity will increase dramatically if you design for the lower discharge target and the extra money spent at the outset will more than return in battery life. If you have an ongoing charging source such as solar panels or a wind generator you can factor in their contribution and subtract that number from your daily usage. Its recommend, however, that you size the bank as described and the charge source contribution will decrease depth of discharge and further lengthen your battery life--


I have been reading as much as I can - but would like a little help on what would be ideal-

• I’m using about 200 - amp hrs a 24 hour day average- - with 3-5 hours sailing- - more if I’m on a longer passage- -

• I found -280 watt-36 volt- 7.66A- amp solar panels -14.5% eff- at $.89 a watt (Jedion)- I have room for 3 on my arch & could put 1 more on the Bimini if needed-

• MPPT or PWM , how big should the battery bank be-would 550 amps work well with the solar charging most of the time?

• how many panels would be enough-

• what kind of Amps would be expected a summer day in the Mediterranean- any idea with these pannels?

• MPPT or PWC- what is the best brand?

• What will happen if the solar panels produce more amps than I use & what to do about that if anything?
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Old 31-01-2013, 08:34   #2
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Re: Need a little help designing my solar system & new bank

You cat guys are so lucky having room for all those solar panels.

3panels will give you plenty of power.
Summer in the med you should be averaging over 350AHrs.
Not many people stay winter in the med, but if you do you will only be producing about 100AHrs in the worst months. However most of year you will exceed your 200AHrs comfortably.

Battery bank size is more dependent on the variation from day to day than anything else. The med in summer is very consistent so you can get away with a smallish battery bank. Nevertheless (assuming LA) 600Ahrs is small for this amount of solar and 200AHr consumption. For summer in Med I would thinking of 600-800AHrs and for general use 800-1000AHrs.

With the higher voltage panels you need an MPPT controler. At this level you are in the big league. The best controlers of this size are Outback and Midnite. Get one that will cope with some expansion in case you put some more panels in the future.
I would buy an Outback 80 which will go up to 1250w at 12v

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• What will happen if the solar panels produce more amps than I use & what to do about that if anything?
The boat will burst into flames
No nothing will happen the controllers will reduce the output from the solar panels.
More panels are great. It's also helps reduce the need for a large battery bank. If you can easily install more panels do it. Solar is now cheap and believe me you will find ways to use the power.
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Old 07-04-2013, 15:51   #3
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Re: Need a little help designing my solar system & new bank

I am new into thi, but very interesting, I need to have extra energy only in summer when I go with the family and I donīt want to bother neighbors at anchoring. My boat is a 40 feet elan Sailer kind of regatta .cruiser. I do regattas during the winter...so I need my pannels to be essaly removed....at the end of the vacation time. My main concern is the refrigerator.....about 6 amps/hour maybe less. Then lights etc...

So what kind of cellular/ panel you sugest .....or where can I look, ?

Thanks
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Old 07-04-2013, 15:58   #4
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Re: Need a little help designing my solar system & new bank

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Originally Posted by 4fish View Post
I am new into thi, but very interesting, I need to have extra energy only in summer when I go with the family and I donīt want to bother neighbors at anchoring. My boat is a 40 feet elan Sailer kind of regatta .cruiser. I do regattas during the winter...so I need my pannels to be essaly removed....at the end of the vacation time. My main concern is the refrigerator.....about 6 amps/hour maybe less. Then lights etc...

So what kind of cellular/ panel you sugest .....or where can I look, ?

Thanks
You might look at the Solbian panels. Very light and easy to remove if you have a good place to mount them. Much more expensive than the hard frame mounted panels. Solar Power Solutions- High Output & Lightweight Panels
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Old 08-04-2013, 05:11   #5
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Re: Need a little help designing my solar system & new bank

Ram:

So start with the basics: 200 amp hours of load in 24 hours.

Solar panels will put out about 1/3 * the wattage in amphours on a sunny day. So to replace that 200 amphours you need 600 watts. But you will need more to cover cloudy days, so go for 800 watts.

Your batteries need to be sized to cover night time and at least one cloudy day. So figure you need to draw down a day and a half of daily consumption from your batteries occaisionally. So that is 300 amphours. Drawing down to 50% is ok, so that gives you 600 amphours of battery capacity. More would be ok and would let you cover more cloudy days without starting your engine or genset.

Your 800 watts of solar panels will be made up of 3-4 200+ watt panels. These are always about 34V at peak power output. So to charge a 12 V battery bank, you need a MPPT controller to balance the solar panels voltage output with the voltage input needs of the batteries. A PWM controller will waste more than half your solar output. When the batteries are full, the controller just shuts off. Solar panels are fine if left unloaded unlike a wind generator.

Blue Sky, Outback are good brands of MPPT controllers. Make sure that it is rated to accept the VOC (voltage open circuit- typically about 40 V) and the maximum current that the panels can produce.

David
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Old 08-04-2013, 06:52   #6
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Re: Need a little help designing my solar system & new bank

My battery bank is 330 Amp plus a 70 Amp for the engine, so thatīs starting to short.....But will be difficult to increase it. At least are gelled.
My idea is place then on top of the bimini, so looking at the space I think will be difficult to get more than 250 W. I AM LOOKING AT THE SOLBIAN PANELS. Do they make any sense...? That will really help ....?
I am interested in an easy way to place them and just use them during the summer when I do the cruissing, latter on I remove the bimini...
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Old 08-04-2013, 07:11   #7
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Re: Need a little help designing my solar system & new bank

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Originally Posted by 4fish View Post
I am new into thi, but very interesting, I need to have extra energy only in summer when I go with the family and I donīt want to bother neighbors at anchoring. My boat is a 40 feet elan Sailer kind of regatta .cruiser. I do regattas during the winter...so I need my pannels to be essaly removed....at the end of the vacation time. My main concern is the refrigerator.....about 6 amps/hour maybe less. Then lights etc...

So what kind of cellular/ panel you sugest .....or where can I look, ?

Thanks
I used my existing dodger frame and added an arch from Sailrite to make a solar bimini on my 30 foot sailboat. I connected the two with aluminum flat bar to which the solar panels are mounted. They are easily removed but, so far they have survived brushes with three Hurricanes including 95 MPH winds during Hurricane Sandy:
THE BIANKA LOG BLOG: SOLAR BIMINI PART SEVEN: PANELS INSTALLED
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Old 08-04-2013, 14:50   #8
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Re: Need a little help designing my solar system & new bank

That looks very strong, nice set up, but I need something even simpler, the question is if it will resist ?
Whatīs the total amount that youīre getting ?
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Old 08-04-2013, 15:27   #9
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Re: Need a little help designing my solar system & new bank

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Originally Posted by djmarchand View Post
Ram:

So start with the basics: 200 amp hours of load in 24 hours.

Solar panels will put out about 1/3 * the wattage in amphours on a sunny day. So to replace that 200 amphours you need 600 watts. But you will need more to cover cloudy days, so go for 800 watts.

Your batteries need to be sized to cover night time and at least one cloudy day. So figure you need to draw down a day and a half of daily consumption from your batteries occaisionally. So that is 300 amphours. Drawing down to 50% is ok, so that gives you 600 amphours of battery capacity. More would be ok and would let you cover more cloudy days without starting your engine or genset.

Your 800 watts of solar panels will be made up of 3-4 200+ watt panels. These are always about 34V at peak power output. So to charge a 12 V battery bank, you need a MPPT controller to balance the solar panels voltage output with the voltage input needs of the batteries. A PWM controller will waste more than half your solar output. When the batteries are full, the controller just shuts off. Solar panels are fine if left unloaded unlike a wind generator.

Blue Sky, Outback are good brands of MPPT controllers. Make sure that it is rated to accept the VOC (voltage open circuit- typically about 40 V) and the maximum current that the panels can produce.

David
You presented a dream for me....So not only space limits solar panels, the other big issue is battery capacity, As I said I have only 330 Amp. and very difficult to increase. So if I need to keep the batteries to a minimum of 50%, I have to count that I have for use 165 Amps , which I need to cover from an energy source. If I can place only 250wats panels....I just be able to get about 83 amps a day....on a sunny day, thatīs not much....but at this moment I am not staying more than 5 days at anchor in the same place so, most likely I will move and run my engine at least a bit. I probably need to run it to get hot water...

So my question comes again, does it makes sense to get the solar as I presented..??,
Will it shorten a lot the time of engine charging when necessary?
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Old 08-04-2013, 15:47   #10
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Re: Need a little help designing my solar system & new bank

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Originally Posted by 4fish View Post
You presented a dream for me....So not only space limits solar panels, the other big issue is battery capacity, As I said I have only 330 Amp. and very difficult to increase. So if I need to keep the batteries to a minimum of 50%, I have to count that I have for use 165 Amps , which I need to cover from an energy source. If I can place only 250wats panels....I just be able to get about 83 amps a day....on a sunny day, thatīs not much....but at this moment I am not staying more than 5 days at anchor in the same place so, most likely I will move and rum my engine at least a bit.

So my question comes again, does it makes sense to get the solar as I presented..??, will it shorten a lot the time of engine charging when necessary?
I will mesure more exactly
If you plan to exist 5 days without recharging your batteries 330 AHrs only gives you 33 AHrs a day before the batteries get below 50%. Even this is optimistic it assumes the batteries the batteries start at 100% and have their original capacity.
You need to add an alternative charging source that will make up the difference .

If using engine charging more than 80% is difficult to achieve, even with a long run, so you will have about 100AHrs before the batteries reach 50%
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Old 09-04-2013, 02:01   #11
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Re: Need a little help designing my solar system & new bank

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If you plan to exist 5 days without recharging your batteries 330 AHrs only gives you 33 AHrs a day before the batteries get below 50%. Even this is optimistic it assumes the batteries the batteries start at 100% and have their original capacity.
You need to add an alternative charging source that will make up the difference .

If using engine charging more than 80% is difficult to achieve, even with a long run, so you will have about 100AHrs before the batteries reach 50%
Until now I have been using the engine charging, I do have installed an ADVERC , battery management system

Quote from maker " NOTE: ADVERC is a controller not a booster. There is no forced feeding of the batteries. ADVERC simply creates the correct voltage climate at the batteries, which then takes what they want in terms of charging current. Heavily discharged batteries can expect and obtain a high alternator output, whilst well charged batteries will take much less.Battery and alternator life are considerable improved but the main benefit comes from having more available battery capacity at one's disposal, two to three times, without having to install extra batteries and bigger alternators."

And it works pretty well, but I do have to run the engine, of course, So as you said I need an alternative charging source, to minimize engine charging, I tried a portable generator, but is to noisy even the Honda or Yamaha , and need to make a set up for it, then gasoline etc....So If not really need it I will try to avoid.

So thinking that if I need to run my engine just one hour a day or sometimes less I will be happy....
So my plan should work with only 250 wats of solar panels ? Remenber, Only for summer in the Mediterranean sea.
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Old 09-04-2013, 02:30   #12
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Re: Need a little help designing my solar system & new bank

The Med in summer has very good and consistent insolation. 250w of solar will allow you to average about 100AHrs per day from solar.
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Old 09-04-2013, 04:30   #13
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Re: Need a little help designing my solar system & new bank

last year we put 540w of solar, a tristar MMPT controler and 700Ah of batteries in Sephina. The system works well for us.
Heres our power budget,

power budget

BUDGET 1 - Passagemaking
ITEM Amps/h hours/d Ah/day
fridge 5 10 50
freezer 2.5 5 12.5
water pump 2.5 0.5 1.25
shower pump 5 0.1 0.5
appliance 10 1 10
VHF 1.5 2 3
GPS/plotter 2 24 48
Radar 4 5 20
Autopilot 3 24 72
running lights 0.2 12 2.4
cabin lights 1 6 6
CD/radio 4 4 16
computer 3 6 18
watermaker 2 1 2

total (approx 11amps/hr) 261.65

BUDGET 2 - at anchor
ITEM Amps/h hours/d Ah/day
fridge 5 10 50
freezer 2.5 5 12.5
water pump 2.5 0.5 1.25
shower pump 5 0.1 0.5
appliance 10 1 10
VHF 1.5 2 3
GPS/plotter 2 0 0
Radar 4 0 0
Autopilot 3 0 0
running lights 0.2 12 2.4
cabin lights 1 6 6
CD/radio 4 4 16
computer 3 6 18
watermaker 2 1 2

121.65

CHARGING BUDGET
Solar (600W ) 36 6 216
Wind Generator 2.5 24 60

276

Battery Bank 4/140Ah total 560Ah - total usable 280Ah to 50% capacity
on passage expect full charge at 4pm, using 180amps overnigth till 8am
at anchor solar should easily cover daily needs.
On passage charge can be suplimented using alternators from 50%-80%
should take (30%x560Ah) approx 3 hrs one engine to supply (3 x 40A) 120Ah
options going forward include additional solar panels
additional wind gen
larger alternator
honda petrol gen

As you can see the solar is ample for when at anchor and we have found that some motoring when sailing makes up for any shortfall underwway. We havent done any long passages yet but I think it would be fine as well.
Price for installation in Les Sables was Furniture and installation : Solar panels 3 x 180w 24v with stainless steel frame on davits + regulator MPPT Tristar 45a : 3700€HT
Check out Lagoon4us's post in the lagoon forum for some details on a Greece panel supplier and pics of his installation as well.
PS the wind gen didnt do much for us in the Med last year but solar is definitely the go
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Old 09-04-2013, 05:24   #14
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Re: Need a little help designing my solar system & new bank

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The Med in summer has very good and consistent insolation. 250w of solar will allow you to average about 100AHrs per day from solar.
That sounds Ok, I may survive with it, for starting point should be fine.
For what I understand if I cannot get more storage for the energy (batteries) it doesnīt make much sense to get more solar energy

Latter when I donīt have kids around the deck (monohull) I may be able to get some more panels. and find the placement of bigger battery bank. That will be difficult.
Thank you

Dante thanks for all the information it looks very good, I will try to make my own table at this moment my real needs will be at anchor so I will use your table as a reference, no freezer no water maker.
If I can get does 100 Ahrs per day from the 250 w panel I will be really happy
Thank you !
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Old 09-04-2013, 05:47   #15
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Re: Need a little help designing my solar system & new bank

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That sounds Ok, I may survive with it, for starting point should be fine.
For what I understand if I cannot get more storage for the energy (batteries) it doesnīt make much sense to get more solar energy
For solar, the amount of energy you have to use is dependent on how much you can produce. Batteries only even out the good/bad days and of course night and day. If the majority of your energy is from solar The isolation in the med in summer is very consistent so only a small battery bank is fine.

Unless you go for a ridiculously small bank your energy from solar will be far more dependent on the array size and little to do with the battery bank size at least in areas of consistent weather.
Production from the engine is far more dependent on battery bank size, so if this is a significant proportion of your power production a larger battery bank is needed.
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