Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 25-04-2019, 14:51   #1
Registered User
 
Fearnow's Avatar

Join Date: Aug 2011
Location: Annapolis, Maryland
Boat: Lagoon 420
Posts: 260
Solar: Wattage output

I purchased 2-100 watt panels from Renolgy and seeing only 114watts on the best of sunny days. My MPPT controller measures what is coming off the panel along with battery absorption. I assumed I would get close to 200 and have made several calls to the seller but no response. Any ideas?
__________________

Fearnow is offline   Reply With Quote
Old 25-04-2019, 15:07   #2
Moderator
 
sailorchic34's Avatar

Cruisers Forum Supporter

Join Date: Feb 2011
Location: SF Bay Area
Boat: Islander 34
Posts: 5,331
Re: Solar: Wattage output

Panel rated output and actual output, does actually very. Generally 60 65% it's as good as I ever get. The issues of course is panel output drops with temperatures above 68 degrees Fahrenheit and if the angle of the panel isn't correct for the latitude and if there's clouds are Haze in the atmosphere. All reduce the rated output
__________________

sailorchic34 is offline   Reply With Quote
Old 25-04-2019, 15:20   #3
Senior Cruiser
 
StuM's Avatar

Cruisers Forum Supporter

Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43
Posts: 8,357
Re: Solar: Wattage output

Are the panels horizontal (not tilted towards the sun)?
Is this around Annapolis (39 North) over recent months (winter)?.



If so, that's about all you should to expect.
StuM is offline   Reply With Quote
Old 25-04-2019, 15:23   #4
Registered User
 
Fearnow's Avatar

Join Date: Aug 2011
Location: Annapolis, Maryland
Boat: Lagoon 420
Posts: 260
Re: Solar: Wattage output

Ok. For 3 days I have been looking for an answer to what I thought was a simple question. Thanks!
Fearnow is offline   Reply With Quote
Old 25-04-2019, 15:26   #5
Registered User
 
Fearnow's Avatar

Join Date: Aug 2011
Location: Annapolis, Maryland
Boat: Lagoon 420
Posts: 260
Re: Solar: Wattage output

Quote:
Originally Posted by StuM View Post
Are the panels horizontal (not tilted towards the sun)?
Is this around Annapolis (39 North) over recent months (winter)?.



If so, that's about all you should to expect.
Yes, Annapolis and the readings I got were the other day when it was about 70 F
The panels tilt and were facing directly at the sun on a very clear day. Ha, hard to believe a clear day in Maryland lately.
Fearnow is offline   Reply With Quote
Old 25-04-2019, 15:36   #6
Registered User

Join Date: Jan 2017
Posts: 10,454
Re: Solar: Wattage output

The SC only puts out power when a load is pulling it.

As SoC climbs, energy will flow much more slowly until only a fraction of the potential available.

You need a heavy but controlled load to test, and a known good ammeter, don't trust charge source readouts.
john61ct is offline   Reply With Quote
Old 25-04-2019, 15:42   #7
Registered User
 
thomm225's Avatar

Join Date: Aug 2011
Location: Hampton Roads
Boat: 1974 Bristol 27
Posts: 5,047
Re: Solar: Wattage output

Quote:
Originally Posted by Fearnow View Post
Yes, Annapolis and the readings I got were the other day when it was about 70 F
The panels tilt and were facing directly at the sun on a very clear day. Ha, hard to believe a clear day in Maryland lately.
It could be something as simple as your connections.

Sometimes when I have two panels hooked up to the same controller, and I don't see the expected wattage I usually can move the wires with my hand and the watts jumps up to where they are suppose to be which is why now I have my 65 watt panel on my Victron MPPT controller and my 50 watt Renogy panel on my PWM controller .

It's working much better with this setup
thomm225 is offline   Reply With Quote
Old 25-04-2019, 15:56   #8
Registered User

Join Date: Jan 2017
Posts: 10,454
Re: Solar: Wattage output

Unmatched panels should be on separate SCs anyway
john61ct is offline   Reply With Quote
Old 25-04-2019, 16:03   #9
Registered User
 
Group9's Avatar

Join Date: Sep 2010
Posts: 1,980
Images: 10
Re: Solar: Wattage output

We had 280 watts on our boat for five years. I think I figured a maximum theoretical 12v amperage at around 26.5. The most we ever actually saw was 22.1 with the sun at what appeared to be 90 degrees to the panels. Mostly. we seemed to max out at around 16 amps. Our panels were fixed and we never made any effort to aim them.
__________________
Founding member of the controversial Calypso rock band, Guns & Anchors!
Group9 is offline   Reply With Quote
Old 25-04-2019, 16:12   #10
Registered User

Join Date: Jan 2017
Posts: 10,454
Re: Solar: Wattage output

The key indicator is Ah per 24 hours.

Varies by seasonal day length of course away from the equator.

a 300W 12V nominal system averages around 100Ah in good conditions
john61ct is offline   Reply With Quote
Old 25-04-2019, 16:40   #11
Registered User

Join Date: Jul 2018
Posts: 125
Re: Solar: Wattage output

Quote:
Originally Posted by Fearnow View Post
I purchased 2-100 watt panels from Renolgy and seeing only 114watts on the best of sunny days. My MPPT controller measures what is coming off the panel along with battery absorption. I assumed I would get close to 200 and have made several calls to the seller but no response. Any ideas?
Are you panels tilted to flat? Also are you sure you have a real MPPT controller?
__________________
Gary
ohgary is offline   Reply With Quote
Old 25-04-2019, 18:23   #12
Registered User

Join Date: Apr 2014
Boat: Moody 425
Posts: 273
Re: Solar: Wattage output

+1 to what StuM said. In the summer you'll get a little more. But don't expect too much that far north. I was surprised when I wasn't getting what I thought I should get either in the upper Chesapeake. Get farther south and you'll start to see a difference.
Sailing Drummer is offline   Reply With Quote
Old 25-04-2019, 20:17   #13
Senior Cruiser
 
Captain Bill's Avatar

Cruisers Forum Supporter

Join Date: Apr 2008
Location: On the boat
Boat: Endeavourcat Sailcat 44
Posts: 2,565
Re: Solar: Wattage output

If your batteries are near full charge your controller may be throttled back. Since you didn't mention the specific controller we can't tell what information you are getting from it. If your controller gives you the the mpp and the current panel voltage and the panel voltage is higher then your controller is throttling your output. If they are the same then the controller is putting out as much as it can. Also you will only get maximum power near local solar noon which in your case is close to 1300 edt. If you are looking at any other time it will be less than optimal. Between 1200 and 1400 it won't vary too much but it will be significantly lower before and after that. If your panels are at absorption voltage then the controller is throttling your output and limiting your power production which is normal.
Captain Bill is offline   Reply With Quote
Old 25-04-2019, 21:01   #14
Registered User
 
Cpt Pat's Avatar

Join Date: Feb 2012
Location: Half Moon Bay, CA, USA
Boat: 1963 Pearson Ariel, Hull 75
Posts: 543
Re: Solar: Wattage output

That output (a little over 50% of rating) doesn't sound unusual. If you want 100% output, you'll have to test at the equator, on a perfectly clear sunny day, at noon, on either of the two days per year that are at equinox. I'm half kidding, but really, the ratings are for ideal conditions.

If you want exact numbers, here are the calculations: https://www.itacanet.org/the-sun-as-a-source-of-energy/part-2-solar-energy-reaching-the-earths-surface/

But generally, as a rule of thumb for mid latitudes, it's about 1,000 watts per square meter X the panel efficiency -- under ideal conditions. So a one square meter panel with 17% efficiency should output approximately: 1000 X 0.17 = 170 watts at 25 degrees C surface temperature (NOT ambient temperature). I'd be pleased to see 100 watts from such a panel on a clear day at noon at 38 degrees latitude, on summer solstice. You will never see the rated output unless the manufacturer was struck by a sudden desire to be overly honest (and therefore non-competitive with the other weasels).
Cpt Pat is offline   Reply With Quote
Old 26-04-2019, 04:04   #15
Registered User
 
Fearnow's Avatar

Join Date: Aug 2011
Location: Annapolis, Maryland
Boat: Lagoon 420
Posts: 260
Re: Solar: Wattage output

Haha, still laughing at some of the comments. I hope to be back in the Carib by November and will check the stats then.

I purchased a PowMr MPPT Charge Controller 60 amp 48V 36V 24V 12V Auto - Max 190VDC Input LCD Backlight Solar Charge for Vented Sealed Gel NiCd Lithium Battery【Software Update Version】(MPPT-60A) with Lithiums coming in the next week. I am planning to add another 800 watts, but wanted to see the quality of these panels first.

Really appreciate all the help!
__________________

Fearnow is offline   Reply With Quote
Reply

Tags
solar

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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
Solar ... Wattage ... Voltage and boat size SURV69 Electrical: Batteries, Generators & Solar 2 27-03-2016 21:29
Is there interest in bi-facial high wattage panels? jbpatents Electrical: Batteries, Generators & Solar 69 13-10-2015 16:05
double the inverter double the wattage? drousy88 Electrical: Batteries, Generators & Solar 21 27-03-2013 08:26
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 05:50
Series Wiring of Different-Wattage Solar Panels? Beausoleil Electrical: Batteries, Generators & Solar 8 24-11-2009 05:51



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 23:42.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.