Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×


Reply
 
Thread Tools Display Modes
Old 01-15-2012, 06:13 PM   #1
Member
 
carbonman's Avatar
 
Join Date: Apr 2011
Posts: 43
Solar trickle with a battery switch.

I have asolar battery maintainer . Is there a switch I can use to disconnect the battery from the travel trailer and would connect it to the solar charger? Also is this maintainer large enough and do I need any controller for this charger?
carbonman is offline   Reply With Quote
Old 01-15-2012, 06:42 PM   #2
Senior Member
 
Fire Instructor's Avatar
 
Join Date: Jul 2010
Location: Upstate (Albany Area) NY
Posts: 832
IMHO, 1.8 watts is too small to do anything effectively for you. You're better off just charging the battery to full, then disconnecting.
__________________
Fire Instructor

2022 Coachmen Leprechaun 319MB
2022 Ford Ranger toad
Fire Instructor is offline   Reply With Quote
Old 01-15-2012, 10:39 PM   #3
Moderator Emeritus
 
Triguy's Avatar
 
Join Date: Aug 2010
Location: Southeast Wisconsin
Posts: 6,949
I had a nice post going but then the forum zonked out on me. I'll try to be short this time.

As for your questions on the disconnect, I would say you would want to disconnect the batteries or install a disconnect switch if your don't have one to avoid the parasitic draws in the trailer. I know nothing about controllers.

First, I'm not a solar expert but decided to do some of the math for my situation recently and this might help you decide if that 1.8W is enough for you.

Start by reviewing this article or Google others like it. Its basic but it gives a start.

Here's my math. I have two Trojan batteries with 260Ah. I live in Wisconsin and its winter so assume I should lose about 8% of my battery capacity each month or 0.69Ah per day (260 * 8% / 30 days).

I can expect between 3.5 - 4.5 of sun hours per day. You can look up solar maps for your area and the month here.

If I divide the total capacity loss per day (.69) by the total number of full-sun hours per day (4) I get 0.17A or 170 mA as the desired minimum current of the panel.

I don't know this, but I am sure the manufacturers are optimistic with their figures so I would plan to double that to 0.35A needed from the panel. It seems that a charger up to 5W would be sufficient for me.
__________________
Scott
DW, 3 Kids and our Goldens

2012 Shamrock 233S
2008 Toyota Sequoia 5.7L 4WD
Triguy is offline   Reply With Quote
Old 01-16-2012, 08:00 AM   #4
Site Team - Lou
 
Herk7769's Avatar
 
Join Date: Oct 2009
Location: South Eastern PA
Posts: 23,268
Quote:
Originally Posted by Triguy View Post
It seems that a charger up to 5W would be sufficient for me.
This seems reasonable to me if you just want to keep your fully charged, disconnected battery; fully charged.

There are many types of battery disconnects around from ones that mount on your battery post to ones that wire right into the hot or ground side of your battery cables.

If you plan on wiring your solar trickle charger up permanently, a double pole,double throw switch will totally isolate your solar charger and camper converter from each other and yet still give what ever charging source you are using full access to the battery.
Attached Thumbnails
Click image for larger version

Name:	camper 005.jpg
Views:	145
Size:	56.5 KB
ID:	9929  
__________________
Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
Herk7769 is offline   Reply With Quote
Old 01-16-2012, 08:51 AM   #5
Member
 
carbonman's Avatar
 
Join Date: Apr 2011
Posts: 43
Thanks every one. I will look for a bigger panel because I was also thinking of adding a second battery. Herk: that switch was originally made for 2 batteries and one load, so I am assuming that the "make before brake" feature is ok for switching the solar panel to the travel trailer? I don't see what it would hurt, it's all 12v anyway.
carbonman is offline   Reply With Quote
Old 01-16-2012, 11:47 AM   #6
Site Team - Lou
 
Herk7769's Avatar
 
Join Date: Oct 2009
Location: South Eastern PA
Posts: 23,268
Quote:
Originally Posted by carbonman View Post
Herk: that switch was originally made for 2 batteries and one load, so I am assuming that the "make before brake" feature is OK for switching the solar panel to the travel trailer? I don't see what it would hurt, it's all 12v anyway.
You misunderstood. I was showing my dual battery kill switch setup. I have two batteries and that switch can select battery 1, 2, none (off), or both at the same time (it's normal position) to power the camper. The grounds of both batteries are tied to the frame (through a shunt used by my battery monitoring computer).

This same switch could be wired differently to accomplish your goal. Put the Solar charger's positive output to battery 1 and the camper's red lead to battery two and the battery bank to the common of the switch. YOU MUST NEVER use "both"

All grounds must be tied at the frame.

The reason I recommend a dual pole dual throw switch (switchin both hots and grounds) is to totally isolate your solar trickle charger from the camper's converter. I would hate to burn out those cells with a mistake.
__________________
Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
Herk7769 is offline   Reply With Quote
Reply

Tags
battery, solar

Thread Tools
Display Modes

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


» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Forest River, Inc. or any of its affiliates. This is an independent, unofficial site.



All times are GMT -5. The time now is 02:49 PM.