Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 25-05-2016, 15:55   #61
Senior Cruiser
 
StuM's Avatar

Cruisers Forum Supporter

Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43
Posts: 6,713
Re: Wattage Usage on a 30' sailboat

Quote:
Originally Posted by Pete7 View Post
Really? like tablets using 10AH and depth sounders 7AH
A tablet can easily use 10Ah and a depth sounder 7Ah.

A normal tablet charger runs at 2 Amps @ 5V or about 0.83 Amps @ 12 V. So about 12 hours of charging tablets would by 10Ah.

A depth sounder with an LCD display can run around 1 Amp @ 12V, so it will use 7 Ah for every 7 hours it is used. If you go for a fancy colour one, then you could be looking at around 3 Amps so 7 Ah for a bit over 2 hours usage.

Did you perhaps confuse Amp hours with Amps?

Maybe you should look at the link I posted earlier.
__________________

__________________
StuM is online now   Reply With Quote
Old 25-05-2016, 18:13   #62
Registered User

Join Date: Mar 2008
Location: Akron, Ohio
Boat: Bristol 29(1967)
Posts: 598
Re: Wattage Usage on a 30' sailboat

Quote:
Originally Posted by mitiempo View Post
Most people like to learn.

I guess some don't.

Yep ... that's about where I'm at.

After learning and relearning almost everything many times over, I am sick & tired of learning ... I just want to do ... and do, simple.

I really just want to fit in a niche that I'm sure exists among all sorts of sailors in 30 feet sailboats ... Kinda like golf, when you ball winds up a foot inside someone else, and that someone else "schools", you by going over the ground you need to follow ... just observe and mimic ... that's kinda what I want to do ... I don't want to learn Windows 8, don't ever want to touch Windows 10. I've learned to hate computers and now I've accidently hit a key pair that has diminished my screen text #@&(^#$#%%^&*(& ANOTHER thing to learn now.

So, forgive me for improper labeling ... cause I know how it bothers "some" people.

Besides, even with proper labeling, the whole thing's kinda of crap-shoot anyway, what, with the sun, latitude, flying white carp and rainy days.

After all is said and little is really exact in the real world...

BTW ... I kinda like the smaller letters after all ... where in the &%$$*&^*%#^ did I put those glasses?
__________________

__________________
SURV69 is offline   Reply With Quote
Old 25-05-2016, 18:28   #63
Registered User

Join Date: Feb 2009
Posts: 1,848
Re: Wattage Usage on a 30' sailboat

Stu
we are all very impressed with your knowledge seeing how you know the difference between amp hours and just plain amps and possibly watts. But it seems everybody else here knows what the open saying except for you. so I will be continue to be impressed by your knowledgebut even as dumb as I am I understand what we are talking about here
__________________
motion30 is offline   Reply With Quote
Old 25-05-2016, 18:30   #64
Registered User

Join Date: Mar 2008
Location: Akron, Ohio
Boat: Bristol 29(1967)
Posts: 598
Re: Wattage Usage on a 30' sailboat

Cap Bill Des:

Very useful ... not exact for sure, but very useful for what I'm thinking.

The 4,12 volt, 30 watt panels are only my initial foray into solar and I'll be adding more power as I go along.

Basically, my panels will not be near as efficient up north, but I run a fridge very intermittently, a small laptop for a few hours and after that LED lights, a very small MP3 player and the VHF radio(the 6 AA batteries last, seemingly forever,

I also have dedicated interior lights with their own little solar panels ... backup

Ericson boats have always looked roomy...


John
__________________
SURV69 is offline   Reply With Quote
Old 25-05-2016, 18:37   #65
Registered User

Join Date: Jul 2012
Posts: 280
Re: Wattage Usage on a 30' sailboat

I'm not sure why the OP is so afraid of mounting his panels. dealing with 4, 30 watt panels is a pain and will take much more effort than making a mount. 3 pieces of straight tube, 2 elbows and 2 rail mounts for your arch, then a pair of tubes on a slide hinge and another pair of rail mounts for support and you're done. I just built one today... then you can put a 140W or 200W panel up there and be done... AND it gives you shade.

BTW... MPPT is not that beneficial for 12V panels, as I assume your 30W ones are. PWM is fine for that. When you go to higher volt panels, MPPT becomes much more efficient.
__________________
zstine is offline   Reply With Quote
Old 25-05-2016, 19:13   #66
Registered User

Join Date: Jul 2012
Posts: 280
Re: Wattage Usage on a 30' sailboat

FWIW, attached is my power budget for a family of 4, a 20 yr old AB refer, water maker, planning to go to the Caribbean. 'old boat' refers to advice/examples in Don Casey's 'this old boat'... hope that helps. I'm building my arch now and am going to put a pair of 60 cell panels up for something around 550W.
Attached Thumbnails
Click image for larger version

Name:	pwr budget.jpg
Views:	53
Size:	123.1 KB
ID:	124891  
__________________
zstine is offline   Reply With Quote
Old 25-05-2016, 19:30   #67
Registered User

Join Date: Mar 2008
Location: Akron, Ohio
Boat: Bristol 29(1967)
Posts: 598
Re: Wattage Usage on a 30' sailboat

zstine:

The bracket I'm making will be large enough for larger panels. The last 3+ feet of the Bristol 29 is storage, but the backstay begins it's trip to the mast head and the boom is only 2 feet in front of that. So, shade from the panels is not really a benefit(except for my cats who like the rear deck).

If I could, I found some 300 W, 30 volt panels in Canal Fulton, Ohio for about $211, which can be had for $175 each(I think), if one(or more), were willing to buy a skid of panels.

Anyway, my constrains are about 4.5 feet by 3 feet, if I want the panels completely within the footprint of the boat(vertically). If I'm willing to stretch the panels(log ways), I could actually go, maybe 6 feet, but the 3 feet is just about required.

If I get larger panels, the idea is to replace the lifeline with stainless tubing
between the stanchions and place two panels, each, on each side of the cabin.

Obviously, the more the better, but I like the 30 watt units ... lighweight and can be placed inside the boat if a hail-storm approaches.

I looked at your spreadsheet ... what ... no Air Conditioning?
__________________
SURV69 is offline   Reply With Quote
Old 25-05-2016, 20:46   #68
Marine Service Provider

Join Date: Sep 2008
Location: Victoria B.C.
Boat: CS27
Posts: 1,729
Re: Wattage Usage on a 30' sailboat

Quote:
Originally Posted by zstine View Post

BTW... MPPT is not that beneficial for 12V panels, as I assume your 30W ones are. PWM is fine for that. When you go to higher volt panels, MPPT becomes much more efficient.
22% more efficient in this accurate test.
MPPT vs. PWM Controllers Photo Gallery by Compass Marine How To at pbase.com
__________________
mitiempo is online now   Reply With Quote
Old 25-05-2016, 23:40   #69
Senior Cruiser
 
StuM's Avatar

Cruisers Forum Supporter

Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43
Posts: 6,713
Re: Wattage Usage on a 30' sailboat

Quote:
Originally Posted by mitiempo View Post

With LifePO4. As the author says, you don't get as much gain with LA.
__________________
StuM is online now   Reply With Quote
Old 26-05-2016, 08:02   #70
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
Re: Wattage Usage on a 30' sailboat

This is like those British scientists who invented the greenhouse effect ;-)

What I want to point at is that you will find anything as COMPLEX as you make it.

Real life example here, sub-30' boat with 150W solar, 110Ah lead-acid car grade battery as house, and a PWM controller.

An average crossing day consumption: 15Ah.
An average anchored day consumption: 25Ah.

Engine started to make juice: 2 times x 1 hour (on the crossing).

Stuff absent (or not used) onboard:
- fridge,
- TV,
- AP,
- radar,
- anchor winch,
- watermaker ;-(

Stuff present onboard:
- AIS/VHF,
- LEDs,
- tablets,
- ssb receiver.

Only twice in 8 months of sailing and cruising we were unable to recharge our house bank to '100%' full. We sailed from the Canaries to the West Indies and back.

Consume less, produce heaps. Modify ... your behaviour first, then your equipment choices!

Cheers,
b.
__________________
barnakiel is offline   Reply With Quote
Old 26-05-2016, 08:09   #71
Marine Service Provider

Join Date: Sep 2008
Location: Victoria B.C.
Boat: CS27
Posts: 1,729
Re: Wattage Usage on a 30' sailboat

Quote:
Originally Posted by StuM View Post
With LifePO4. As the author says, you don't get as much gain with LA.
True, but there is still a worthwhile gain. With solar you will be in bulk charge mode in most cases until the bank is at approximately 95% SOC. This is in contrast to Mainesail's 99.5% SOC with LiFePo4. This assumes a reasonable size bank - say 4 golf carts in series/parallel for 440+ AH. I do have one customer that gets over 100 amps from his array but he is the exception. Most solar arrays will output less than 20 amps which is only 4 - 5% of bank size.

As for cost of PWM vs MPPT there is little difference when features are taken into account. Sure you can buy an inexpensive PWM controller but they are not very adjustable if at all. A PWM controller that is set at 14.4 is not the best for a bank that requires 14.8 volts.

For example I sell a basic PWM 10 amp controller for $64 Cdn, not adjustable. I sell a Victron MPPT 15 amp controller for $169 - totally adjustable in every setting. Unless the budget is very tight most buy the MPPT. Sales run about 30 MPPT to 1 PWM controller.

With the limited number of panels that can be placed on most sailboats it makes sense to get as much output from the panels as possible - even if the gain is less than the 22% shown by Mainesail.

I estimate the gain to be 15% or more with MPPT. It makes no sense to leave that on the table. It can mean the difference between running the engine for extra charging or existing totally on solar. I know what I would prefer.
__________________
mitiempo is online now   Reply With Quote
Old 26-05-2016, 08:10   #72
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
Re: Wattage Usage on a 30' sailboat

Quote:
Originally Posted by SURV69 View Post

(...)

If I get larger panels, the idea is to replace the lifeline with stainless tubing
between the stanchions and place two panels, each, on each side of the cabin.
OK at anchor but not under way in a 29' Bristol.

You can have snap connectors and an alternative 'sailing' placement for the panels - think of the backstays and or cabin top.

PS If you go the snap way, make sure your caps are 100% watertight.

b.
__________________
barnakiel is offline   Reply With Quote
Old 26-05-2016, 08:56   #73
Moderator
 
Pete7's Avatar

Cruisers Forum Supporter

Join Date: Aug 2009
Location: Solent, England
Boat: Moody 31
Posts: 8,561
Images: 14
Re: Wattage Usage on a 30' sailboat

Quote:
Originally Posted by StuM View Post
With LifePO4. As the author says, you don't get as much gain with LA.
Do you really think the OP has money for LifePO4? You criticised me for using amps instead of amp hours, and then post this in a thread when someone looking is looking for advice on solar for a 29ft yacht.

Thankfully barnakiel and I posted some real life experiences with solar set ups.

Peter
__________________
Moody 31 - April Lass
Pete7 is offline   Reply With Quote
Old 26-05-2016, 09:05   #74
Moderator
 
Pete7's Avatar

Cruisers Forum Supporter

Join Date: Aug 2009
Location: Solent, England
Boat: Moody 31
Posts: 8,561
Images: 14
Re: Wattage Usage on a 30' sailboat

Quote:
Originally Posted by SURV69 View Post
Basically, my panels will not be near as efficient up north, but I run a fridge very intermittently, a small laptop for a few hours and after that LED lights, a very small MP3 player and the VHF radio(the 6 AA batteries last, seemingly forever,
Au contraire Your northern lattitude can actually work in your favour. What time is sun up in Ohio in June? and what time does it set? Okay you pay for it in December and January when the panel won't even light a bicycle light but who is sailing then? Also solar panels reduce efficiency as they get hotter. Is Northern US colder than the carib?

So real life experience; I am at 50'N and whilst I don't have a hug amount of amps being generated at 6am the panels do work and continue to do so into the evening which is how they charge to 100%, slowly over many hours. This also means the batteries don't off gas as they used to do with a mains charger or the engine, so don't loose as much electrolyte.

Pete
__________________
Moody 31 - April Lass
Pete7 is offline   Reply With Quote
Old 26-05-2016, 09:08   #75
Senior Cruiser
 
newhaul's Avatar

Cruisers Forum Supporter

Join Date: Sep 2014
Location: puget sound washington
Boat: 1968 Islander bahama 24 hull 182, 1963 columbia 29 defender. hull # 60
Posts: 3,994
Re: Wattage Usage on a 30' sailboat

Using a pwm vs an mppt
Personally here is what I tell customers : it depends if you have a large array and a all house bank say in the neighborhood of 1.5 watts per ah of usable battery bank pwm is fine.
Small array less than a watt per usable ah then an mppt is a good idea.
I can get programmable 30 amp pwm controllers for under 50 bucks.
With that in mind I usually suggest getting an additional panel if there is room to mount it.
__________________

__________________
Non illigitamus carborundum
newhaul is online now   Reply With Quote
Reply

Tags
sail, sailboat

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
ISO high wattage panels skipgundlach Electrical: Batteries, Generators & Solar 0 17-01-2016 06:37
Is there interest in bi-facial high wattage panels? jbpatents Electrical: Batteries, Generators & Solar 69 13-10-2015 17:05
double the inverter double the wattage? drousy88 Electrical: Batteries, Generators & Solar 21 27-03-2013 09:26
Inverter Draw is it relative to the appliance using it or the wattage of the inverter felixqld66 Electrical: Batteries, Generators & Solar 5 06-06-2011 06:50
Series Wiring of Different-Wattage Solar Panels? Beausoleil Electrical: Batteries, Generators & Solar 8 24-11-2009 06:51



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 15:11.


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.