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 11-30-2014, 11:02 AM   #1
Senior Member
 
Join Date: Aug 2011
Location: Wyoming
Posts: 321
rv vs 12v charging from alternator

Okay, I did some searching but didn't find an answer. It's time for new batteries, SO:
1. Do I stay with 12v or make the switch to 6v?

2. If I make the switch to 6v, how do I wire them so I can charge them while running the vehicle? I understand how to wire something in series, but then where do I connect the 12v line from the separator/starting battery?

The goal here is to gain Amp Hours. I have a furnace, fridge, stereo, lights (LED), 12v outlets, etc. Not a huge demand, but with 212ah I'm waking up in the morning with my charge controller blinking red telling me low batteries.

Any help would be great.
Thanks!
C

c7train is offline   Reply With Quote
Old 11-30-2014, 12:08 PM   #2
Senior Member
 
1der's Avatar
 
Join Date: Apr 2013
Location: San Francisco, CA
Posts: 3,259
Re: rv vs 12v charging from alternator

Only way to gain amp-hours is by adding more batteries or providing input (eg solar or generator) from alternate source.

For AGM/flooded: 212 aH sounds like a single 4D 12volt. That gives usable 106 aH. You first should look at what your electrical usages are for a 24 hr to 48 hr period, then size your battery bank from here. Re: 6 or 12 v? Not sure it matters as to achieve for example 220 aH total, you can have four 6v golf cart style at 110 aH each or two 12 v group 31's at 110 each or one 12v 4D at 220. To achieve 440H, you would double all those quantities. I personally would stay with 12v rated batteries for simplicity and go w/ AGM. We just have to be very careful to monitor drawdown and charging to get good life out of lead acid based batteries. Good monitoring systems are pretty much essential in our set ups.

Now, if you go Lithium (if your van.bankacct can tolerate the $$ withdrawal) things change quite a bit. You can draw down a Lithium battery by 90%, so the usable capacity of a 125 aH Li batttery is about equal to a 212 aH AGM or flooded battery. It also weighs about 75% less than an AGM. Some reported downsides are poor charging charteristics in cold weather, which would be an issue where you are. Upsides are something like ten year life.

Some else cna answer the connection question if you decide to go 6 volts.

Ray
__________________
Ray
Beastie 3: 2002 7.3 EB Cargo: Agile TTB, CCV High Top, Custom Walk Through, Lots of stuff added. www.BlingMyRig.com
1der is offline   Reply With Quote
Old 11-30-2014, 12:20 PM   #3
Senior Member
 
Join Date: Aug 2011
Location: Wyoming
Posts: 321
Re: rv vs 12v charging from alternator

Thanks Ray!
c7train is offline   Reply With Quote
Old 12-01-2014, 07:27 PM   #4
Site Team
 
daveb's Avatar
 
Join Date: May 2007
Location: Turlock Ca
Posts: 10,407
Garage
Re: rv vs 12v charging from alternator


Results = 12v @ 220ah not 440ah

Some factors to think about:
What is the quality of the lead used.
How many cycles does each type have.
How deep can you discharge the battery.
How well does each stand up to off road use.
How fast does the battery charge up.
How many connections that can fail.
How difficult are they to maintain.
What effects does cold weather have on each type.
Self discharge rates.
How long will they last.
Price.

For me it was a no brainer... 12v 220ah AGM. But YMMV.
This is from the FAQ in this section and there are a few posts you can look at too.
http://www.solar-electric.com/deep-cycl ... y-faq.html
Attached Thumbnails
2x6VoltinSeries.gif  
__________________
2006 Ford 6.0PSD EB-50/E-PH SMB 4X4 Rock Crawler Trailer

Sportsmobile 4X4 Adventures..........On and off road adventures
daveb is offline   Reply With Quote
Old 12-01-2014, 07:32 PM   #5
Site Team
 
daveb's Avatar
 
Join Date: May 2007
Location: Turlock Ca
Posts: 10,407
Garage
Re: rv vs 12v charging from alternator

Quote:
Originally Posted by 1der

Now, if you go Lithium (if your van.bankacct can tolerate the $$ withdrawal) things change quite a bit. You can draw down a Lithium battery by 90%, so the usable capacity of a 125 aH Li batttery is about equal to a 212 aH AGM or flooded battery. It also weighs about 75% less than an AGM. Some reported downsides are poor charging charteristics in cold weather, which would be an issue where you are. Upsides are something like ten year life.

Some else cna answer the connection question if you decide to go 6 volts.

Ray
I agree Ray and I can't wait until the price of those go down.
__________________
2006 Ford 6.0PSD EB-50/E-PH SMB 4X4 Rock Crawler Trailer

Sportsmobile 4X4 Adventures..........On and off road adventures
daveb is offline   Reply With Quote
Old 12-01-2014, 11:25 PM   #6
Senior Member
 
jage's Avatar
 
Join Date: Apr 2007
Location: Parker, CO
Posts: 7,643
Re: rv vs 12v charging from alternator

A 117lb battery or two doesn't make that much difference in a 10,000lb vehicle.

Also if I switched to 6v say, that would at least four in my house bank and I have enough trouble with the two I've already got.

If I was building from scratch and only needed two 6v I'd probably give it a go, but just swapping I'll stick with the big AGM.
__________________
it was good to be back
jage is offline   Reply With Quote
Old 12-03-2014, 01:34 PM   #7
Senior Member
 
boywonder's Avatar
 
Join Date: Jul 2013
Location: So Cal
Posts: 4,045
Re: rv vs 12v charging from alternator

2 6V 200Ah batts = 12V/200Ah (with roughly 100Ah +/- usable) Series wired

2 12V 100Ah batts= 12V/200Ah (with roughly 100Ah +/- usable) Parallel wired

The above batteries should be roughly the same size (volume) since it's mostly about energy density, so TINSTAAFL.........

Obviously, if you only have room for one battery, the 6V solution won't work.

One disadvantage of 6V wired in series is if you have one go bad, you are left with no power. With 12V there is the possibility of limping by on one.
__________________
2008 E350 RB passenger 4WD SMB penthouse
2013 KTM 350 EXC
2008 KTM 250 XCF-W
2003 Honda Element
boywonder is offline   Reply With Quote
Old 12-03-2014, 03:42 PM   #8
Site Team
 
daveb's Avatar
 
Join Date: May 2007
Location: Turlock Ca
Posts: 10,407
Garage
Re: rv vs 12v charging from alternator

The single 4-D 210ah battery I had was a bit too small for me so I added a second. I barely had enough room to add another battery box. One of the best upgrades I've done but not cheap by any means. If I wouldn't have had the room I would have looked into going with an 8-D but two 4-D's are way more amp hours (420) than a single 8-D (255). The bad thing about multiple batteries in a bank is if one fails, it takes any others in the loop down with it. The other battery or batteries might not be destroyed but in many cases it will weaken them and it's not a good idea to add a new battery with old ones. Multiple battery systems can be very costly if you don't frequently monitor their charge status and keep them all up to par.
__________________
2006 Ford 6.0PSD EB-50/E-PH SMB 4X4 Rock Crawler Trailer

Sportsmobile 4X4 Adventures..........On and off road adventures
daveb is offline   Reply With Quote
Old 12-03-2014, 06:33 PM   #9
Senior Member
 
Tapatio's Avatar
 
Join Date: Nov 2010
Location: California
Posts: 1,012
Garage
Re: rv vs 12v charging from alternator

200ah Lithium $2,399

http://www.lithiumion-batteries.com/...m-ion-battery/

__________________
2006 E350 6.0PSD 5R110, SMB 4X4, RB-50, ARB lockers front/rear, Aluminess galore, AMP steps.
Callsign KK6GIY
Tapatio is offline   Reply With Quote
Old 12-03-2014, 08:31 PM   #10
Site Team
 
daveb's Avatar
 
Join Date: May 2007
Location: Turlock Ca
Posts: 10,407
Garage
Re: rv vs 12v charging from alternator

Quote:
Originally Posted by Tapatio
I'll buy one tomorrow
__________________
2006 Ford 6.0PSD EB-50/E-PH SMB 4X4 Rock Crawler Trailer

Sportsmobile 4X4 Adventures..........On and off road adventures
daveb is offline   Reply With Quote
Reply

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

» Sportsmobile Registry

Margot

FCAshevlle

[HOONIVAN]

Shaggy
Add your Sportsmobile
» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3
Disclaimer:

This website is not affiliated with or endorsed by Sportsmobile SIP or any of its affiliates. This is an independent, unofficial site.


All times are GMT -6. The time now is 12:06 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.