Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 08-24-2012, 03:05 PM   #1
Junior Member
Join Date: Aug 2012
Posts: 1
Question Battery Help

I have a 300 Amp 12 volt alternator on my 6v92 Eagle Bus power plant with 3-12volt starting batteries. The 300amp keeps them fully charged, but I have 4-8D AGM batteries for house that powers a 12 volt inverter. How do I run the same 300 to keep house batteries up and floated off with same 300 amp source without messing up the starting batteries? Help!!!!

sparky34 is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 08-24-2012, 03:20 PM   #2
Senior Member
trackman's Avatar
Join Date: Oct 2011
Posts: 1,136
You cannot do it with the inverter. You are going to have to feed the house batteries off the 300 and have a switch to transfer and then cut off when charged. Those big boys will hold charge for quite a while. Wire the batteries with a manual cutoff switch and moniter the drain. That will tell you the frequency to set the charge.

trackman is offline   Reply With Quote
Old 08-24-2012, 03:22 PM   #3
Senior Member

Join Date: Aug 2000
Location: Walnut Creek Ca USA
Posts: 640
You can add a large relay that powers up with ignition that then is wired to the batteries and alternator. Whenever the ignition is on and the engine running the relay allows charging of the house batteries.They can be had on line or at camping world.
There are also solid state dividers that are in effect a large diode but there is a small voltage drop across them.
-Paul R. Haller-
Paul R. Haller is offline   Reply With Quote
Old 08-25-2012, 07:14 AM   #4
Senior Member
Join Date: Nov 2007
Location: somewhere in the west
Posts: 1,168
First I would look up the charging requirements for the AGM's. Now do the same for the starting batts. I believe you will find that the requirements are quite different, and that you run the risk of the agm's entering early death if not charged correctly, and certainly not cabled to lead acid batts without some kind of voltage limiter.

Ed-Sommers is offline   Reply With Quote
Old 08-25-2012, 09:49 AM   #5
Senior Member
Damon Owners Club
Workhorse Chassis Owner
Join Date: Mar 2009
Posts: 21,174
Oh, I see, a bus converted into a motor home...

Visit your RV parts place and discuss a device called an ISOLATOR. Now one word of warning: If your bus uses a 24 volt system, disregard this, the bus must use a 12 volt sytem for this to work.

The isolator (There are two types and several sub types) is either a RELAY (Solenoid or contactor at the kind of current we are discussing) or a Diode box (I recommend the former)

A diode box is 2 or 3 "one way" valves for electricity, they let alternator power flow TO the batteries, but do not let power flow battery to battery. They do, however, introduce voltage loss, so the 3rd one-way valve is for the voltage regulator, Many alternators today the regulator is internal and these will nto work well with a diode box.

The solenoid is an automatic switch, IT usually has a delay, You start the engine, the timer counts down and CLUNK, the batteries are now in parallel.

Some of them have a bi-direcitonal system.. You plug into shore power, the house batteries charge and when they are near full... CLUNK, the batteries are parallelled.

This is the best kind, called a BIRD (BI Direcitonal Relay Device) as 2 weeks after you pull into the campgroudn you go to start the bus back up.. and it starts.
Home is where I park it!
wa8yxm is offline   Reply With Quote
Old 08-25-2012, 10:32 AM   #6
Senior Member
Join Date: Nov 2011
Location: Full time RV'er
Posts: 1,238
Here's some info from Optima on the AGM batteries: Optima Battery Charging - AGM Battery Charging

'02 Winnebago Journey DL, DSDP, 36' of fun.

Visit my RV Travel & Repair Blog at : http://chaos.goblinbox.com
Jim_HiTek is offline   Reply With Quote


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
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

» Virginia Campgrounds

Reviews provided by

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 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 04:38 PM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.