Minimal electrical needs and solar panels

[highseas]

625 amp hrs. of battery capacity translates into 312 useable amps,between complete recharges.Barely enough for full time liveaboard.In Mexico right now sun is low angle is so my solar isn't doing much(about 8-9 amps midday),and wind is inconsistant so windgen doesn't either.Running the fridge day after day at anchor is the biggest draw,then the laptop with it's attachments.Most lights are LED.I have 5 brand new 12v lead acid group 27's.(600ah) ,240 watts of solar(on the flat) and a Rutland windgen.Makes running a Honda gen. a couple of hrs. every 2-3 days neccesary to keep the fridge going.Another month or 2 and that won't be needed.Hot water is made from propane.

[denverd0n]

Originally Posted by Jimbo485

That old rule of thumb was from another era when panels were costly.

Actually, the "old" rule of thumb was $1 spent reducing consumption was worth $10 increasing generation. The 1:5 rule is new, and takes into account the lowering cost of solar panels.

Having said that, however, I will conceded that LED lights may not fit that particular rule of thumb. Mainly because they are still relatively new and not yet very widely used. As such, their expense is still quite high (though less if you also take into account that they last 20-30 times as long as incandescent bulbs, which I'm guessing you didn't).

For most other sorts of energy users, though, I think the 1:5 rule of thumb is pretty close to accurate.

[sailorboy1]

solar is pretty cheap now

I can get a 285W panel for $.098/W and my current mental battle is whether to get 1 or 2.

[carstenb]

Originally Posted by TacomaSailor

Live aboard in Mexico - full time for 3 years and over 950 nights at anchor. At one point we spent 450 consecutive days anchored out. We commonly went for 35 - 40 days with no re-provisioning and no visit to any kind of store or tienda.

Additionally I spent about 90 days a year on the hook when not cruising full time - a lot was in the winter in Puget Sound.

There is a huge difference in what electrical power you need for the occasional one week cruise in US waters and what you need for full time on the hook live aboard in the tropics.

When we were planning the full time cruise to Mexico there were two things my wife said she would not tolerate hearing:

"We don't have enough electrical power for...."

"You can not take a shower 'cause we don't have enough water"

Amp hours / day
refrigerator - 35 ( cold beer, ice cubes & frozen meat)
water maker - 25 ( can never have enough fresh water)
computer - 25 ( I am a real computer geek and addicted )
TV/DVD - 10 (when it's your full time home you need the amenities)
anchor light - 8
other lights - 24
SSB/HAM - 6 ( e-mail and I was a controller on 3 nets much of the time)
microwave - 15 (too hot to use propane much of the time)

About 150 amp hours / day on the hook

Underway the radar used 5 amps / hour and the autopilot uses 3 per hour

winter time Puget Sound cruising (7 hours of daylight and 35 - 45 degree air and water) I used an Ardic diesel heater that consumed 20 - 40 amp hours per day.

I have four 125 watt panels and 625 amp hours of battery capacity and have never regretted the solar panels I installed 13 years ago.

My panels are rigidly mounted on an arch over the rear of the cockpit. I consistently saw over 25 amps at 14V for over 4 hours a day in the Mexican winter and 31 amps at 14.4V during the Mexican summer. Our batteries were always full recharged by 2 PM at which time we started the water maker running and forced the refrigerator to run full time to hard freeze the expansion plate. We could usually run both the water maker and reefer for two hours while still trickle charging the batteries.

Thank you for the exact numbers. Always makes it easier to figure own usage

[Sumner]

Originally Posted by highseas

625 amp hrs. of battery capacity translates into 312 useable amps,between complete recharges.Barely enough for full time liveaboard......

With his 150 daily load he could go 2 days without any sun, but then of course would have to recharge plus provide for the daily need.

Originally Posted by highseas

..I have 5 brand new 12v lead acid group 27's.(600ah) ,240 watts of solar(on the flat) and a Rutland windgen.Makes running a Honda gen. a couple of hrs. every 2-3 days neccesary to keep the fridge going..

Just wondering why you chose to go with the five 12 volt batteries vs. say 4 of the deep cycle 6 volt and possibly one 12 volt? The 12v 27's I've seen are rated at about 90 to 105 amp/hrs on a 20 hour rate (450 to 525 amp/hrs).

With out Mac we were out 3 months with 180 watts (Nov/Dec and Mar/Apr) in Florida and the solar provided over 90% of our electrical needs with a portable 12 volt fridge (not as efficient as the one we made for the Endeavour) and a lot of computer time and other minor needs. This was with 2 group 27 batteries that when they are shot will be replaced with two 6 volt deep cycle batteries.

We now have 480 watts on the Endeavour and 4 deep cycle 6 volt and one 12 volt batteries. With the better fridge we have less actual needs for power, but will now probably use some other things like possibly the microwave. I hope to never have to run either the diesel or the Honda,

Sum

[highseas]

I guess I could have switched to 6 volts,but the space for batteries is set for the Gp. 27's.So rather than ripping apart the battery compartment and reconfiguring cables, I replace with same size batteries.Some days there is a cloud cover,further limiting solar charging at this time of year.

[Sumner]

Originally Posted by highseas

I guess I could have switched to 6 volts,but the space for batteries is set for the Gp. 27's.So rather than ripping apart the battery compartment and reconfiguring cables, I replace with same size batteries.

Thanks, that makes sense, especially if they are working for you ,

Sum

[highseas]

I see another 160 watts of solar in my future.My HRSi regulator for my Rutland has the capability to add that to it.

[noelex 77]

Originally Posted by Sumner

With his 150 daily load he could go 2 days without any sun, but then of course would have to recharge plus provide for the daily need.

Even on bad days solar will still produce some power. It is dependent on climate, but even a lousy day in the worst month will see about 40 AHrs most locations from 500w.

It's great to see an energy budget. TacomaSailor obviously has plenty of power, so does not need to economise, but his power demands could be cut fairly substantially without any loss in of function and for reasonably minimal expense.

This would be more sensible than increasing battery capacity if power was ever a problem.

[TacomaSailor]

"TacomaSailor obviously has plenty of power, so does not need to economise, but his power demands could be cut fairly substantially without any loss in of function and for reasonably minimal expense."

Long Term - Full Time cruising is an ongoing series of compromises

My wife and I reached an acceptable accommodation on power/water & cruising - I provide the power and water and she provides the smiling company

Our Caliber 40 has a substantial load carrying capacity so the extra weight and space needed for batteries was no big deal. We had been sailing for quite a few years when we outfitted Mirador from her new boat status. We decided to put everything we needed on board to be really comfortable. For example, the forward shower room has a forced hot air outlet. After three hours on deck in the 45 degree liquid spring sunshine that falls in most of Puget Sound it was a real treat to heat up the shower room and take a really HOT soaking shower.

I enjoy working on boat systems and am pretty good at it so installing and maintaining all the power sources and consumers was fun.

I do know that cruisers on boats with minimal power, ice cubes, fresh water, and amenities, spent most evenings on boats that had all luxuries. I also know that I supplied fresh water to lot's of summer time Sea of Cortez cruisers who didn't want to make a 50 or 75 mile trek to the closest village that might have expensive fresh water for sale.

It would be very easy to cut out power consumption in half but I am very glad we don't have to make that decision.

Installed the panels and Trace C-40 controller in spring 1999 and have never had to do a bit of maintenance on them since then.

Install solar and then forget it is there!

[noelex 77]

My point was there are areas where you cut power consumption for no loss in function and a small cost.
A simple example would be an LED anchor light. This would save about 7AHrs a day, be brighter and not require a trip up the mast to change the bulb.

If you are always producing more than need, such changes are not necessary, but they are worth pointing out for cruisers that might want to visit areas with lower insolation values, who do not have room for as many solar panels, or have other needs that increase their power consumption.

Reducing power does not mean going without, there are many technologies that reduce power consumption, but actually perform better than their power hungry counterparts.

[downunder]

Originally Posted by Don Lucas

solar is pretty cheap now

I can get a 285W panel for $.098/W and my current mental battle is whether to get 1 or 2.

Definitely 2. How could yo ever be sorry, whereas you could if you only go 1.

[noelex 77]

Originally Posted by downunder

Definitely 2. How could yo ever be sorry, whereas you could if you only go 1.

Another vote here for 2. If you have got the room don't even think about only 1. There is no such thing as too much solar.

[dandrews]

Originally Posted by Don Lucas

solar is pretty cheap now

I can get a 285W panel for $.098/W and my current mental battle is whether to get 1 or 2.

Is that .098 or .98?

Don

[Paul L]

These days you can easily spend more on the mounts and copper than on the panels. Price out 10 or 8 awg wire, rail mounts or arches. Plus the controller. They can easily add up to more than the panels.