Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 13-08-2017, 11:11   #1
Registered User

Join Date: Apr 2007
Location: New England
Boat: lagoon 380 s2
Posts: 483
2 solar panels to one battery bank, but at different states

So I have 2 285 w solar panels adjacent to each other each going to a separate eco worthy mppt controller ( manual if you want to see it http://eco-worthy.com/catalog/download/20AMPPT.pdf ).

From each controller I go to a 3 blade fuse holder to the pos terminal of my battery bank. So each controller should be reading the same battery voltage.

Yet when I checked yesterday (under a berth, so not so easy to see all the time), one was in float, the other was not, one was at 14V the other at 13.7V. Both are programmed for the same voltages per stage, so this is very confusing to me. Since the panels are right next to each other, I would think they should be getting close to the same sun (they are both over the dinghy davits), they should be putting out the same V. Am I wrong in assuming this?
__________________

__________________
jbinbi is offline   Reply With Quote
Old 13-08-2017, 15:11   #2
Registered User

Join Date: Jan 2017
Posts: 1,615
Re: 2 solar panels to one battery bank, but at different states

Should be based on battery state and absorb time, not panel state.

Not exactly top tier SC, maybe variability. Same wiring? Make sure programming the same?

And why those voltages? What model battery?
__________________

__________________
john61ct is online now   Reply With Quote
Old 13-08-2017, 15:54   #3
Registered User

Join Date: Apr 2007
Location: New England
Boat: lagoon 380 s2
Posts: 483
Re: 2 solar panels to one battery bank, but at different states

same wiring, same programming.

exide dual wet cells, bulk at 14.8, float at 13.5-8.
__________________
jbinbi is offline   Reply With Quote
Old 13-08-2017, 16:23   #4
Registered User

Join Date: Jan 2017
Posts: 1,615
Re: 2 solar panels to one battery bank, but at different states

Not really deep cycle, how old?

I wouldn't worry much, but if you want to diagnose, try one at a time.

Bring float a bit lower so it's more clear. You really should be able to hit that Bulk setting.

Also, what are you using to monitor volts, and ideally amps? Don't trust the SCs, or really any charge source.
__________________
john61ct is online now   Reply With Quote
Old 13-08-2017, 17:42   #5
Registered User

Join Date: Apr 2007
Location: New England
Boat: lagoon 380 s2
Posts: 483
Re: 2 solar panels to one battery bank, but at different states

thanks for the input. Not sure why you think not deep cycle? stock house battery from lagoon. 2 years old.

the controller tells V and I; I also have put a voltmeter on it, and the battery.Since it is under the berth , a pita to see. Don't monitor amps continously yet, have ammeters, but not yet installed between controller and battery yet.
__________________
jbinbi is offline   Reply With Quote
Old 13-08-2017, 18:03   #6
Registered User

Join Date: Jan 2017
Posts: 1,615
Re: 2 solar panels to one battery bank, but at different states

Quote:
Originally Posted by jbinbi View Post
Not sure why you think not deep cycle? stock house battery from lagoon. 2 years old.
Exactly. Manufacturers cut corners, cater to the bottom line.

True deep cycle are not available in consumer retail big box channels, at least not in 12V. The term is widely used fraudulently.

http://www.pbase.com/mainecruising/deep_cycle_battery

Learn more about the topic before you buy your next bank, in the end they are consumables. If your bank has been worked hard, and not brought up to 100% full most cycles, that may be sooner rather than later.

Quote:
Originally Posted by jbinbi View Post
the controller tells V and I; I also have put a voltmeter on it, and the battery.Since it is under the berth , a pita to see. Don't monitor amps continously yet, have ammeters, but not yet installed between controller and battery yet.
I would do that, ignore the SC readings in the meantime, and confirm/calibrate your instrument's accuracy with a pro's tools.
__________________
john61ct is online now   Reply With Quote
Old 13-08-2017, 21:42   #7
Registered User

Join Date: Jun 2013
Location: canada
Posts: 1,604
Re: 2 solar panels to one battery bank, but at different states

Obvisuily if both controllers are connected to the same fuse block. The v out will be identical. Even though it says they are not. Unless you have a bad connection at the fuse block. Measure the voltage direct at output of controller and at fuse block.
__________________
smac999 is offline   Reply With Quote
Old 13-08-2017, 22:00   #8
Senior Cruiser
 
CaptWil's Avatar

Cruisers Forum Supporter

Join Date: Jul 2015
Location: Australia, Malaysia
Boat: Van Der Stadt Seal 36
Posts: 122
Re: 2 solar panels to one battery bank, but at different states

HI
May I ask why you simply did not use 1 solar controller instead with higher amps rating?
I have the same capacity wattage from 2 solar panels directly to 1 solar controller 40 A and it works well recharging my 300 Amps trojan T31 house bank in less than 3 hours on a sunny day, about 6 hours on a cloudy day. Probably will increase the house bank to 400 A soon
Cheers
William
__________________
CaptWil is offline   Reply With Quote
Old 14-08-2017, 10:52   #9
Registered User

Join Date: Aug 2016
Location: Bainbridge Island, WA
Boat: Hallberg Rassy 39
Posts: 27
Re: 2 solar panels to one battery bank, but at different states

You are wise to install 2 MPPT controllers so that if one panel is shaded, the other one will have full output. This is what I plan to install on my boat. Regarding the difference in voltages, maybe one controller is seeing voltage from the other and I am curious as to how the 2 controllers work together to charge the batteries at the proper rate.
__________________
Mr O is offline   Reply With Quote
Old 14-08-2017, 11:09   #10
Registered User

Join Date: Jan 2017
Posts: 1,615
Re: 2 solar panels to one battery bank, but at different states

As long as they have the same or similar setpoints, no problem.

And no major issues even if they don't.
__________________
john61ct is online now   Reply With Quote
Old 19-08-2017, 13:42   #11
Registered User

Join Date: Apr 2007
Location: New England
Boat: lagoon 380 s2
Posts: 483
Re: 2 solar panels to one battery bank, but at different states

Quote:
Originally Posted by CaptWil View Post
HI
May I ask why you simply did not use 1 solar controller instead with higher amps rating?
I have the same capacity wattage from 2 solar panels directly to 1 solar controller 40 A and it works well recharging my 300 Amps trojan T31 house bank in less than 3 hours on a sunny day, about 6 hours on a cloudy day. Probably will increase the house bank to 400 A soon
Cheers
William
Redundancy. I also went with an inexpensive controller, $99 each for 20A. In theory I can get a bit more than 20A from a 285 W panel , though not very much and I need perfect conditions. I had considered a victron high quality controller, but to get 40A, it became much more expensive than I thought I needed. But maybe not....
__________________
jbinbi is offline   Reply With Quote
Old 19-08-2017, 14:42   #12
Registered User

Join Date: Jan 2017
Posts: 1,615
Re: 2 solar panels to one battery bank, but at different states

If you are willing to experiment, and have a way to accurately and independently measure charging amps, a Victron 75/15 is under $100. It will self-limit to ~220w in peak conditions, but I wouldn't be surprised if the better quality circuitry didn't get you greater overall output.

Perfect conditions for an A/B test keeping all other variables constant. And you could purchase from a vendor with a NQA returns policy, just cost you the return shipping.
__________________
john61ct is online now   Reply With Quote
Old 20-08-2017, 19:38   #13
Registered User

Join Date: Apr 2007
Location: New England
Boat: lagoon 380 s2
Posts: 483
Re: 2 solar panels to one battery bank, but at different states

Quote:
Originally Posted by john61ct View Post
If you are willing to experiment, and have a way to accurately and independently measure charging amps, a Victron 75/15 is under $100. It will self-limit to ~220w in peak conditions, but I wouldn't be surprised if the better quality circuitry didn't get you greater overall output.

Perfect conditions for an A/B test keeping all other variables constant. And you could purchase from a vendor with a NQA returns policy, just cost you the return shipping.
Not a bad idea. Actually, just looked at victron controllers, for $300, they have a 50A controller. Now thinking about using just a single controller for both panels. Their 20A are $200 each, so it would be $400.
__________________
jbinbi is offline   Reply With Quote
Old 20-08-2017, 19:39   #14
Registered User

Join Date: Jan 2017
Posts: 1,615
Re: 2 solar panels to one battery bank, but at different states

Redundancy rules.

Plus I've seen the 75/15 for as low as $85

But really I want to see the results of that experiment 8-)
__________________

__________________
john61ct is online now   Reply With Quote
Reply

Tags
battery, panels, solar, solar panels

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
Solar Panels - one big one or two small ones ADMPRTR Electrical: Batteries, Generators & Solar 29 05-03-2013 14:38
Charging 48v battery bank with solar panels Hankthelank Electrical: Batteries, Generators & Solar 3 05-10-2008 13:55


Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 10:55.


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.