Loading Batteries with sunlight

[Portuguese]

Gents
I am looking into the possibility of not installing a genset in my boat. I am presently designing the letrical capacity based on two battery banks:
1 x 4 x 220 amps house bank
1 x 3 x 150 amps engine, bilge pumps, windlass and BT.- Having in mind that I will have the engine on when I use the windlass and the BT.
To charge these two banks I am thinking about installing up on the roof a 4 or 6 solar panels with appropriated hardware. Can anyone advise on the size and number of the panels?
Thanks
Portuguese

 

[FlyWright]

I have a friend with similar banks on his sailboat in Mexico. He has 440W of solar panels to feed his batteries. He supplements with a small Honda eu2000i generator hooked up to a 6 gal gas tank when his demands exceed his recharging capacity.

 

[bobofthenorth]

Without knowing how much electricity you use its impossible to say how much panel acreage you need. We have roughly 200 watts on our converted bus and that's not much more than decorative. With really careful management we can survive without the generator but its not a lifestyle most would choose. Limited TV, limited computer use, effectively no microwave/coffee maker use, absolutely no chance of electric water heating. To my way of thinking 400 watts on the boat is a bare minimum to have any semblance of our "normal" lifestyle and with 400 watts we will still need to run the genset for cooking (we're all electric) and water heating. With a propane range and a propane water heater maybe 400 watts would be possible with no genset but it would be a serious lifestyle alteration for most people. I do know a guy who lives in a 5th wheel with 400 watts of solar and no genset but he has adjusted his lifestyle to match his power consumption. He can't even reliably read a book after dark because he needs to adjust his light bulb consumption to match his batteries' state of charge. I'm currently in the middle of a davit upgrade. When that's done I will mount 600 watts of panels on the davits and at that point I still expect to run the genset 1 or 2 hours per day.

(edit)

You also need to consider angle of incidence.* Your buddy in Mexico will have close to 90 degree incident sunlight all the time.* Up here in the PNW the best we can expect is around 60 degrees which makes a huge difference to panel output.* My new panels will be on an MPPT controller to take maximum advantage of early and late day sunlight.*


-- Edited by bobofthenorth on Sunday 12th of February 2012 07:29:37 PM

 

[FF]

Solar is PERFECT for keeping up a battery bank that is not providing energy.

IF you wish long term storage , Solar is the best.

But if you will be attempting refrigeration , solar has a very hard time.

NO matter what you do a SOC meter should be the FIRST purchase., so you wont destroy those nice new batts.

 

[Larry M]

I would suggest the genset. We anchor out 9-10 months a year.* We have a 6 cubic ft refrigerator*and a 3 cubic foot freezer, both have 4 inches of insulation and their own DC compressors.* We use between 150-175 amps per day excluding travel days.* When we run the generator, less 2 hours per day,*we charge the batteries, make water, heat hot water and vacuum.* We have a 2800 watt inverter for when the generator isn't on for TV, power tools and microwave.* If we went with solar, our daily usage would have to increase by 25-30 amps/day for now we would need a DC water maker.* We would be hard pressed to generate that amount of power consistently from solar panels.***

 

[psneeld]

The cheapest, easiest way to keep batteries topped off is a great battery charger and a 1000W or 2000W Honda generator.* It can run tools, microwave, etc...etc on or off the boat.* they are very quiet...more quiet than most wind generators (they can be sound enclosed better for sure).

The only advantage of solar that I can see is that it keeps the batteries topped when you aren't there.

 

[marinetrader]

I have a 195 watt solar panel that I am very pleased with; it is sized to my electrical usage aboard. If I were to do it all over again, I would install as many panels as I could fit in; the way ise it, you can't have to many.

 

[Codger2]

psneeld wrote:
The cheapest, easiest way to keep batteries topped off is a great battery charger and a 1000W or 2000W Honda generator.

The only advantage of solar that I can see is that it keeps the batteries topped when you aren't there.

******* I agree! Don't get me wrong...a diesel generator is by far the best, safest, etc. but for most boaters that I know, the Honda 2000EU is an economical fix for those anchoring out for a weekend or two /year. They don't have another diesel to maintain or the expense of buying one and given a thimble's worth of common sense, can operate & store it quite safely.

 

[Phil Fill]

For your size boat and purpose I would forget solar and install a small 3 to 5 KW second gen set.* So are you still looking at a cruise generator?** Solar is for small boats with no/little creature comforts.**

They do make small protable DIESEL gen sets.* I would go with diesel before gas as we have a hundred of gallons of diesel storage alread on our boat.*

*

 

[Bendit]

Our system is 24V but for simplicity, I'll talk 12V equivalents.*
It all depends on the weather...
Our house bank is 420ah*and we have 2 x 80W solar panels. With a reasonable amount of sunlight or light overcast, these panels will keep 2 x DC fridges and a DC freezer going while still topping up the batteries.
Hot water is not possible but limited use of the inverter for a hairdryer or vacuum cleaner is OK. Obviously, the batteries discharge somewhat during the night, but since the fridges are not being opened and*the ambient temp is lower, the discharge is only to about 75%.
However, after a week of rain on our summer cruise, I was thankful for our little DC genset which we ran for about an hour a day. This has never happened before, and*we usually only run the genset once or twice in the whole cruise simply to give it a run.
In hindsight, I would put 4 panels on the roof and delete the genset, saving both money and weight. The bad weather we had this time around is so*unusual that I would simply run the main engine when necessary to top up.

I should point out that, like most Kiwis, we anchor out every night. A night in a marina is very rare.


-- Edited by Bendit on Monday 13th of February 2012 04:17:24 PM

 

[Rebel]

We have finished our project of 3x130w panels on the Bimini and am pleased to say that despite a lot of wet weather this summer in Sydney, the days we were staying on the boat after we had finished kept our 440ah topped up with the refrigerator running 24/7 radio, tv, and lights when needed without the batteries discharging below 80%. Even in light rain or cloud there was some power going to the batteries. I will be back on the boat for 8 days in April so that will be a good test to see how they go. After that I hope to jettison our genset and use the space for something more useful like tools to fix other parts of the boat Admittedly we are not able to use the panels to heat water but the heat exchanger on the engines connected to our hot water system lasts for 2 days with the 2 of us aboard for showers and other hot water comes from boiling the kettle for dishes etc. Some may consider this camping but my wife who is NOT a camper is very happy with this compromise as the one thing she hates more than camping is the noise of the genset and the money I keep spending to keep it going. Im all for keeping my SO happy!! We too are on a swing mooring or anchor out and hardly go near a marina.

 

[psneeld]

Rebel wrote:
We have finished our project of 3x130w panels on the Bimini and am pleased to say that despite a lot of wet weather this summer in Sydney, the days we were staying on the boat after we had finished kept our 440ah topped up with the refrigerator running 24/7 radio, tv, and lights when needed without the batteries discharging below 80%. Even in light rain or cloud there was some power going to the batteries. I will be back on the boat for 8 days in April so that will be a good test to see how they go. After that I hope to jettison our genset and use the space for something more useful like tools to fix other parts of the boat Admittedly we are not able to use the panels to heat water but the heat exchanger on the engines connected to our hot water system lasts for 2 days with the 2 of us aboard for showers and other hot water comes from boiling the kettle for dishes etc. Some may consider this camping but my wife who is NOT a camper is very happy with this compromise as the one thing she hates more than camping is the noise of the genset and the money I keep spending to keep it going. Im all for keeping my SO happy!! We too are on a swing mooring or anchor out and hardly go near a marina.

*May I ask what kind of hot water heater you have that lasts 2 persons 2 days?

wow...that's great as I don't think I've seen a house water heater that could do that

 

[FF]

"When we run the generator, less 2 hours per day, we charge the batteries"

Even AGM which have a large acceptance rate will not get fully charged in 2 hours a day.

Not even a 300A bus alt with smart charger will do it.

You can cycle between 50% and 85% , but charged (100%), sadly,probably not.

 

[Larry M]

FF wrote:
..."When we run the generator, less 2 hours per day, we charge the batteries"....

You can cycle between 50% and 85% , but charged (100%), sadly,probably not.

FF:* Your right again FF,**

* we can't*top*our batteries off on less 2 hours per day of generator run time alone.

We have a 1100 amp hour house bank of 10-6 volt golf cart batteries and try to run between 60 and 80% full when at anchor.* Once every few days to a week or two are travel days*which bring*the batteries up.* If we aren't moving every week to*10 days, we run the generator for ~5-6 hours*once a*week or so*to bring the batteries to full charge.* We still get partial sulfation and*diminished capacity over time but we can live with that vs running the generator more hours.* We had*a previous set of batteries that lasted*almost 5 years maintaining them as we do now.* The current batteries on Hobo we*installed in October of 2007 and will be changed out this summer.*


-- Edited by Larry M on Tuesday 14th of February 2012 06:59:42 AM

 

[Peter B]

Scott, I recently fitted an Isotherm 42 litre tank which, (once I cleaned the accumulated gunge out the hot water pipes from and to the engine thru the tank), heats quickly, and stays hot long enough for dish-washing and showers for nearly 2 days on the pick not motoring.

Rebel, I am totally with you on avoiding running a genny, and we don't have one, so it you ever find the panels not quite up to it, like in Winter or very cloudy days, and you like to spend plenty of time on the pick, an AirBreeze wind genny will deal with the rest of the demand very well, and the newer ones are quite quiet when charging. Certainly a lot cheaper than a diesel genny, and even money with say a Honda 4-stroke petrol one, and quieter and safer. You can see where I mounted mine in my avatar pic.

 

[Portuguese]

...About gensets, I am thinking about fitting a small Chinese 4kva air cooled diesel genset. They cost $1200. Even if they last only 2-3 years, they become cheap at the end of a 10 years run.

 

[Portuguese]

...something like this

 

[psneeld]

Portuguese wrote:

...About gensets, I am thinking about fitting a small Chinese 4kva air cooled diesel genset. They cost $1200. Even if they last only 2-3 years, they become cheap at the end of a 10 years run.

*not really unless your boat is big enough it can be tucked away so you don't see, smell, or hear it....your boat isn't.

if JUST charging batts is the issue...can't beat a honda 1000.* Otherwise...a Phasor 3kw or so will do the basics in style...and will probably outlast 3 of those $1200 ones for about the same.* Whatever you do...lay your boat out so that a 3-5KW diesel generator can be fitted at some time in the future...otherwise...I think you will be sorry.

 

[Larry M]

psneeld wrote:...if JUST charging batts is the issue...can't beat a honda 1000...

We see alot of second hand Honda 1000's for sale because they are typically to small from what the owners (cruisers) tell us.** The Honda 1000's*output is rated at 120V (8.3A) with 1000W max. and*900W rated (7.5A).* That won't power much of a battery charger.***

 

[psneeld]

Larry M wrote:psneeld wrote:...if JUST charging batts is the issue...can't beat a honda 1000...

We see alot of second hand Honda 1000's for sale because they are typically to small from what the owners (cruisers) tell us.** The Honda 1000's*output is rated at 120V (8.3A) with 1000W max. and*900W rated (7.5A).* That won't power much of a battery charger.***

*Those are the 120 V outputs...the DC output is 10 times that less any loss by the charger..

Here's a typical 3 Bank 40 amp charger's 120 V input requirement
Input: 105-130 VAC, 50-60 Hz, 650 Watts
Dimensions: 10.9"L x 7.8"W x 4.2"H
Weight: 5.9 LBS.
Well within the 1000's capability...most cruisers are pissed it won't run their microwave or margarita blender..


-- Edited by psneeld on Tuesday 14th of February 2012 03:43:18 PM

 

[Phil Fill]

Portuguese wrote:
...something like this

That is what I am looking at.* Take the wheels off, bolt on a*white metal enclosurer.* *****

 

[bobofthenorth]

Stay clear of the CCC (cheapo chinese crap) gensets.* I tried to talk myself into buying one for the bus but fortunately didn't succomb to the lure of the low price.* Last week we had an extension cord strung across the float to a fellow cruiser who bought a CCC set less than a year ago.* He said it made about 6 hours.* That pretty well matches what I learned when I was considering one of them.* Most telling for me was the retail places I found that used to sell the units but no longer carry them.* If you watch there's old Onans out there but you have to move quick because they don't stay on the market long.* I ended up finding a 6.5 Onan J series for the bus.* I also briefly considered the quiet Hondas but by the time you pay the price for one of them or better yet one of the Yamahas you might as well buy a real used diesel.

"The bitter taste of low quality lingers long after the sweetness of a low price has faded."

 

[BruceK]

First up, panels extend battery life by keeping them well charged, saving you money longterm. When you walk onto the boat your batteries should be always full. Charged batteries seem to accept charge more easily.These advantages alone makes them worthwhile.

Rebel`s experience of panel output is what you`d aim for. You should at least be able to run a refrigerator off the panels. Friends with about 300watts of optimally located panels on a 32ft yacht can run 2 Danfoss powered reefers 24/7; so successful are their panels it took them a long time to realise the alternator on the auxiliary engine had failed.

You won`t run an espresso machine or vacuum cleaner but you can do a lot with panels,and you can add more as you need them.

Be sure to use good multi-stage regulators, and install inline fuses just before the battery connections.*

Avoid the cheap Chinese generators. Not reliable and the decibel output can be grossly understated.

BruceK


-- Edited by BruceK on Tuesday 14th of February 2012 06:14:00 PM

 

[Rebel]

I guess what I am seeing in replies, is that we are now talking lifestyle as much as whether we have a genset of some description or SP or a combination. We have a 30lt tank which we have for hot water and while it is not scolding hot by the 2nd day it is more than adeqate for our needs. We also dont stand under the shower and let the water run constantly but rather wet down, switch off, soap up and rinse off. For us this is as much about conserving our water resource that has to be ferried to the boat in the dingy as anything. Again in our neck of the woods marinas are scarce and expensive.
Peter your idea of wind generation is one I have been watching for a while and I believe there are some new carbon fibre blades that cut down the noise. I guess they are no noisier than some gensets I have heard running all night to keep air conditioning and other electrics going and certainly no noisier than a Honda 2000eu on a boat close to us on our mooring that runs almost constantly.

 

[Peter B]

Rebel, mine has the new (hence black) carbon fibre blades, and when putting out ~ 10 amps is say 10 kn of wind, the swishing sound it makes is about the same as say one of those electric weed-eaters - here in Aus they call them whipper-snippers - ie basically an electric edge trimmer for lawns, with a nylon line as a blade. About as loud as that, with a very low level whine from the motor. We have had visitors sleep in the saloon, which is quite close to it as you can see, and on quite windy nights, no trouble at all.

 

[FF]

"I have heard running all night to keep air conditioning and other electrics going and certainly no noisier than a Honda 2000eu on a boat close to us on our mooring that runs almost constantly. "

Marine Air cond is about 15A of 120V , or 150A in 12V.

A wind machine that size would be 30 ft in diameter.

Although there are truck DC air cond that will cool a small cabin.

"Friends with about 300watts of optimally located panels on a 32ft yacht can run 2 Danfoss powered reefers "

Even the best reefers need about 50AH in 24 hours 100AH at 14V is 1400 watt hours , so can be done , BUT the reefers must be small, well insulated and well installed .

With the Home Cheapo house style fridges its closer to 200AH per day with inverter , and a 2800 watt refill needs a solar set that is is HUGE!

14V is required to charge most batt sets/

 

[bobofthenorth]

Rebel wrote:
I guess what I am seeing in replies, is that we are now talking lifestyle as much as whether we have a genset of some description or SP or a combination.

That's absolutely the message I was trying to convey.* You can choose to live a solar lifestyle but it is very difficult to choose to use solar power for your existing lifestyle.* And forget about wind.* Unless you're a lot different than us we choose our anchorages to avoid wind.

 

[Portuguese]

Gents

*

This brain storm has become very interesting. Not the same issue but within the same subject, I am a complete fan of the arrangement in the present pictures. This is made by one of the best professional boatbuilding companies in New Zealand, and it seems to be the perfect world.*The main*DC generator is connected to*the get-home engine. A second DC alternator, smaller, is*connected to the main engine...This is the way, I guess!


-- Edited by Portuguese on Wednesday 15th of February 2012 05:38:59 PM

 

[C lectric]

A friend added three 135W solar panels atop his Bimini and they keep a , fridge, a small freezer and the other assorted DC loads going with full recharge by about 14:00 on a good sunny, summers day. His panels are wired in series for a 36V nominal system supply to the controller. His sytem wasn't cheap but he is happy and it works.

He uses an instant water heater, propane fired for the hot water for showers and sundry.

THis has been posted before although I can no longer find the specific thread, eyes glaze over.

With more room you could add more panels but of course you need the batteries to store the energy.

You need to really look at what you expect to run and for how long.

 

[Tidahapah]

Those photos are from the engine room of one of my favourite displacement cruisers.
Watson Bros 48' a magnificent piece of steel work.