Dead engine batteries and a Dumb Question

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Dead engine batteries and a Dumb Question

August 25, 2012, 07:45:43 pm

I just replaced all three engine batteries, two year old AGM gels. From what I've heard, this was too short of life for these babies. I think the cause was too frequent complete discharge caused by the people who monitor my storage turning off the Boost switch- red light scares them. I'm thinking the Trik-l-charge would solve my problem. Question: Where is the battery Isolator located in my coach?

Re: Dead engine batteries and a Dumb Question

Reply #1 – August 25, 2012, 07:48:28 pm

It should be onthe back wall behind the engine. It has been there on all three of my coaches.

Re: Dead engine batteries and a Dumb Question

Reply #2 – August 25, 2012, 08:11:14 pm

by the way you either have Gell or AGM --2 different types
John h

Re: Dead engine batteries and a Dumb Question

Reply #3 – August 25, 2012, 08:27:42 pm

Showing my ignorance, I thought the G was gel. I'm going out to find the iolator.

Re: Dead engine batteries and a Dumb Question

Reply #4 – August 25, 2012, 08:32:31 pm

John is correct, they are either AGM's or gels. And, for engine start batteries I am partial to the Optima Spiral batteries-- lots of cranking amps for the size.

But no battery will last long if allowed to deeply discharge and stay that way. Put on a trickle charger, solar charger, etc.

Re: Dead engine batteries and a Dumb Question

Reply #5 – August 25, 2012, 08:43:00 pm

No matter what batteries you have, it is doubtful there are 3 engine batteries. Probably 2 for house and 1 for engine. And the isolator only has to do with charging while driving, not while parked. Battery management is important.

Re: Dead engine batteries and a Dumb Question

Reply #6 – August 25, 2012, 08:45:59 pm

I found I was cooking my batteries as they were too close to my Muffler. THey were on the drivers side on my current coach vs the passenger side. I put a piece of light weight sheet Aluminum to reject the heat but after my resonator upgrade, I have not had any issues since the Muffler was gone.

I have three engine batteries and have had three in all but my 270.

Re: Dead engine batteries and a Dumb Question

Reply #7 – August 25, 2012, 08:52:38 pm

It's your money but makes no sense. Your boost switch will give you 3 start batteries IF you need them. I have always used a single 8d, saved some bucks and never had a problem. I agree with Wolfe, though, 2 Optimas will give you 1600 cranking amps with almost no weight.

Re: Dead engine batteries and a Dumb Question

Reply #8 – August 25, 2012, 09:04:37 pm

Your boost switch is only rated at 100 amps so it will not start the coach if you need three. A M11, especially in the winter takes three batteries to start and to turn the motor. It has to get up to temp before the fuel solenoid will open. Also, cummins specs 1800 amps to start the engine. So you are right at the edge with two batteries at 900 CCA.

Re: Dead engine batteries and a Dumb Question

Reply #9 – August 25, 2012, 09:19:52 pm

I probably need a complete battery tutoral. My wiring diagram (B-2126) shows 3 batteries labelled "engine batt" and 3 batteries labelled *coach battery". I replaced the 3 batteries on the hanging platform pn the engine compartment which I assumed were the engine batts and were dead as a door nail. The replacements were were VMF31S_7 900CCA. From reading the forum, it was my impression that if the coach was sitting with shore power,the boost switch should be on to maintain the engine batteries. My next dumb question was to be "Where are my coach batteries located?"

Re: Dead engine batteries and a Dumb Question

Reply #10 – August 25, 2012, 09:31:36 pm

Quote from: LBoyd – August 25, 2012, 09:19:52 pm

My next dumb question was to be "Where are my coach batteries located?"

Ours are accessed from the half-depth bay on the passenger/curb side (second bay back from the coach front). Look for a panel on the rearward bay wall that can be removed. The 3 8D house batteries should be behind that panel.

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Michelle

Re: Dead engine batteries and a Dumb Question

Reply #11 – August 25, 2012, 10:09:48 pm

Thanks, I also found the the battery isolator on the rear bulkhead, A successful day!

Re: Dead engine batteries and a Dumb Question

Reply #12 – August 25, 2012, 10:54:29 pm

You do not leave the boost switch on all the time but once a week or so.

Re: Dead engine batteries and a Dumb Question

Reply #13 – August 26, 2012, 10:11:06 am

Boost switch on 24 hours once a week.

Re: Dead engine batteries and a Dumb Question

Reply #14 – August 26, 2012, 02:32:37 pm

We keep out coach plugged to shore power during storage. For a few months, I kept our chassis batteries charged by leaving the boost switch on all the time. Most folk recommend against leaving the boost switch on for very long periods of time. The recommendation of 24 hours/week is from an experienced Foretraveler.

I added a 5A Battery Tender smart charger that is dedicated to maintaining the chassis batteries. It supplies an appropriate charge to the batteries whenever 120VAC is available. I have found the Battery Tender be an excellent solution for our circumstances. I have used a 1A Battery Tender to maintain the AGM battery on my motorcycle. That six year old battery is still working well.

By searching this forum, you can find several recommendations for maintaining chassis batteries. Find one that works for you.

Re: Dead engine batteries and a Dumb Question

Reply #15 – August 26, 2012, 04:10:11 pm

Quote from: LBoyd – August 25, 2012, 07:45:43 pm

I just replaced all three engine batteries, two year old AGM gels. From what I've heard, this was too short of life for these babies. I think the cause was too frequent complete discharge caused by the people who monitor my storage turning off the Boost switch- red light scares them. I'm thinking the Trik-l-charge would solve my problem. Question: Where is the battery Isolator located in my coach??

I might be way off here, but if the boost switch is turned off your 3 AGM starting batterys (provided they are in good condition) should not discharge in 2 or 3 weeks unless there is a small draw on them. I know mine will set for month and still start the coach. I do however try to turn the boost switch on for a couple days now and then.

Re: Dead engine batteries and a Dumb Question

Reply #16 – August 29, 2012, 09:20:41 pm

My principal problem is the result of storing in a commercial storage facility about 100 miles from my home which I visit once a month or so in the winter. I was attempting to follow the recomendations in section 8 of my manual by turing everything off and remaining plugged into a 110 outlet. After a month s1tting ( with boost off) the engine batteries were very low. Coach batteries maintained Recently, I started using the boost switch and the engine batteries and coach battries would stay up. I'm assuming my early replacement of the engine batteries is due to the repeated almost total discharge due to not using the the boost switch. If I can't just leave the boost on, I'm going to need an alternate such as
tender, etc. The Trik-L-Start was one possibility. Any suggestions?

Re: Dead engine batteries and a Dumb Question

Reply #17 – August 29, 2012, 09:48:59 pm

I don't view leaving the boost switch on 24/7 as nearly as good a solution as a Trick-L-Start, Xantrex Echo charger, etc.

Re: Dead engine batteries and a Dumb Question

Reply #18 – August 29, 2012, 09:53:30 pm

Trickle start, easy, no need for separate plug. Before I got mine I toyed with the idea of a battery tender brand unit

Re: Dead engine batteries and a Dumb Question

Reply #19 – August 29, 2012, 11:21:10 pm

Trik-L-Start is easy to install and works. However, my understanding is that it will charge to about 0.6V less than the voltage on the house batteries. I prefer to float the AGM chassis batteries at a higher voltage than 0.6V less than the float on the AGM house batteries. I installed the Battery Tender. Other folk have installed manual switches or specialty relays to maintain the chassis batteries by connecting them to the house batteries.

I put the 5A Battery Tender on the bed pedestal where I could see the indicator lights. It plugs to an outlet near the foot of the bed. The hookup wires go through a (caulked) hole into the engine compartment where they connect to wires that connect to the chassis batteries. It was an easy installation of a relatively cheap smart charger. It is pretty much worthless (extremely slow) for charging the house batteries, but excellent for maintaining them.

Re: Dead engine batteries and a Dumb Question

Reply #20 – August 30, 2012, 12:03:34 am

Quote

Trik-L-Start is easy to install and works. However, my understanding is that it will charge to about 0.6V less than the voltage on the house batteries. I prefer to float the AGM chassis batteries at a higher voltage than 0.6V less than the float on the AGM house batteries. I installed the Battery Tender. Other folk have installed manual switches or specialty relays to maintain the chassis batteries by connecting them to the house batteries.

I have AGMs for house and chassis.

But I'm trying to understand what's wrong with using the boost switch to keep the chassis batteries charged (assuming pedestal or solar charging to house batteries).

Say by boost switch on 24hrs once a week.

best, paul

Re: Dead engine batteries and a Dumb Question

Reply #21 – August 30, 2012, 01:23:53 am

Curious if anyone has looked into this kind of product?

Maxwell Technologies Engine Start Modules Ultracapacitors Application Specific

May be overkill, but pretty much guarantees you eliminate battery issues.

Re: Dead engine batteries and a Dumb Question

Reply #22 – August 30, 2012, 01:29:33 am

RE " But I'm trying to understand what's wrong with using the boost switch to keep the chassis batteries charged (assuming pedestal or solar charging to house batteries). "

Paul, there is nothing wrong with your above idea and it is the best way to manually keep start battery bank charged.

Unless one does not turn boost off before an unplanned shore power lost which can lead to both battery banks going dead, assuming generator auto-start does not do its job.

Many prefer to have these regular chores automated to eliminate having to remember turning the switch on & off. And risking running both banks down too low.

Shore power loss can occur during the night or when coach is unattended.

Re: Dead engine batteries and a Dumb Question

Reply #23 – August 30, 2012, 01:24:29 pm

Quote from: Paul Smith – August 30, 2012, 12:03:34 am

But I'm trying to understand what's wrong with using the boost switch to keep the chassis batteries charged (assuming pedestal or solar charging to house batteries).

Say by boost switch on 24hrs once a week.

This is what I do... but generally only 24 hours every two or three weeks. My coach is only 2 blocks away and I'm usually there every day so the manual system works fine for me. For those who are not close to where their coach is stored an automated method might be preferable.

I should note (as a big proponent of solar energy) that solar panels and a good charge controller can eliminate the entire problem.

Craig

Re: Dead engine batteries and a Dumb Question

Reply #24 – August 30, 2012, 01:41:57 pm

"I should note (as a big proponent of solar energy) that solar panels and a good charge controller can eliminate the entire problem."

That's my plan. And I don't think I have to worry about no sun when our Foretravel is stored in El Centro, CA ;o)

best, paul

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