I may have killed RV deep cycle sealed chassis batteries installed by dealer?

[ak2handr]

Two issues herein...

After having my dealer do a fluids & filters service (around $1,100) I asked them to check the chassis batteries because of occasional (apparent) insufficient cranking performance.

They replaced the two, 12-volt chassis batteries with RV deep cycle, sealed batteries.

I'm a long-time radio comms tech (commercial & amateur) so engines aren't my forte. I thought I understood the difference between construction & service demands for RV batteries. The dealer assured me that, "They're what we use for everybody."

Really? Uhh, OK. In case they're right, on to my problem:

So after a cross-country (NC -- WA) in 2018, "Bertha" sat at the dealer a year for body repairs (hit & run by a DOT forklift) about 13 months. Six months after I got it back, when it was time to renew the registration, I charged the house batteries after properly filling them all properly. That was via the shore power line & equipped inverter/charger, and all went well.

Next day I walked confidently to the battery bay, ensured the master was off, & attached my ~15-amp charger to the two paralleled 12-volt Deep Cycle RV batteries that had recently been installed by the local dealer as chassis batteries. My confidence was jarred somewhat at the exciting ten-second light show I caused by having hooked up the terminals *backwards." After waiting an hour, I hooked the charger up *correctly" this time. The outboard charger showed max charging current (somewhere around 18 amps) for the ensuing 12 hours. 

Next morning the charger was still cranking out around 9.5 amps. When I read the open-cell voltage on the two batteries, it read 11.1 vdc. It didn't occur to me to uncouple the paralleling jumper, so I don't know if I killed both new batteries, or just one.

So, two questions, I guess:

Did my "big chain dealer" dump the wrong style batteries on me, figuring I wouldn't know the difference? And,

Assuming these *are* acceptable chassis batteries, what'cha think my next troubleshooting step(s) should be?

Many thanks & 73 de Barney KL7HNY/4

[Tom Wallis]

I won't consider deep cycle RV batteries the best choice for chassis batteries. They can work but won't give the best performance or life because they're designed for a different purpose.

Hooking up your small charger backwards briefly is not likely to have any negative effect on them but it seems they do have a problem. Also, charging them while hooked in parallel is not a problem but you will need to separate them in order to test them.

Since they're sealed you can't use a hydrometer. Once they're separated charge them one at a time and see if the voltage comes up. A 15 amp charger is pretty small for those large batteries especially when they're hooked together but individually they should be much higher than that after 12 hours. You should also disconnect them from the chassis while charging just to make sure your not fighting any parasitic loads. Ideally I would want to charge them with a larger 3 stage charger until the go into float mode. Then let them sit a few hours until the surface charge is gone. If at that point they're not at least 12.6v then they're not likely any good.

[Ivylog]

NO way would I accept deep cycle batteries… you want starting batteries with only a CCA rating. 15 amps is not going to overpower (hurt) 2 batteries. Maintenance free are not… under the hard plastic top are caps for each cell. I add water to my starting batteries every 4-5 years.

[ak2handr]

Tom & Dick,

Gentlemen, thanks very much for the quick responses! Tom, I shall isolate the two batteries from one another & the chassis, to charge and test them individually. And Dick, I shall peek under the caps to check water levels -- and *then* trot down to my local CW shop with pics to speak to the manager....and maybe call the owner's hotline as well.

I'll let'chas know what happens.

Gratefully,

Barney, from Alaska but now in NC

 

 

 

[cbr046]

Do a Google search on "deep cycle vs starting battery".  The feedback is very enlightening. 

You might consider finding another dealer.

- bob

[Guest Ray Davis]

15 hours ago, ak2handr said:

So after a cross-country (NC -- WA) in 2018, "Bertha" sat at the dealer a year for body repairs (hit & run by a DOT forklift) about 13 months. Six months after I got it back, when it was time to renew the registration, I charged the house batteries after properly filling them all properly. That was via the shore power line & equipped inverter/charger, and all went well.

I'm confused about the time line.  Were those batteries installed before it was in the body shop back in 2018 or after you got it back.

[Tom Cherry]

5 hours ago, ak2handr said:

Tom & Dick,

Gentlemen, thanks very much for the quick responses! Tom, I shall isolate the two batteries from one another & the chassis, to charge and test them individually. And Dick, I shall peek under the caps to check water levels -- and *then* trot down to my local CW shop with pics to speak to the manager....and maybe call the owner's hotline as well.

I'll let'chas know what happens.

Gratefully,

Barney, from Alaska but now in NC

 

 

 

Everyone has his on pet theory or opinion.  So, this is what I know....

First, YES....you have the wrong style batteries.  They are not going to last as long and will eventually die earlier than they should.  YES, being sealed, they do not allow you to do proper maintenance....so they will not (since you can't refill them) be easily restored.  BUT....This is what I would do...

ASSUMING you can't go back to the Big Box and tell them that you NEEDED a Starting Battery.  A Starting Battery , 

OK....I would offer a different approach to see if you can salvage them.  Since they are DEEP CYCLE, they need some "EXERCISING".  This will also tell you, with a DVOM, how good they are and what state of charge.  Here is what I would do.

Start the Generator.  Let it run for a while to charge the House Bank.  Next....you will need a pair of standard automotive jumper cables.  Hook up the Positive of the House to the Positive of the Chassis.  Do the same for the Negative.  Let the Genny run for maybe 30 minutes.  THEN, with the Genny RUNNING, start the Engine.  I'd think it will start.  If the starter does NOT turn over (have someone back there listening) of it does not crank (after the WAIT light goes out), then do the following.

OK....the Chassis even with the House is too puny.  THEN....you might have bigger issues with cables.....or all your batteries need to be fully charged....

If the ENGINE DID START....you can either drive it for a couple of hours.....OR   

LEAVE THE GENNY RUNNING and the JUMPER CABLES ON.  On the House Bank, remove one of the "Battery to Battery" short interconnecting cables.  That then kills the CHARGING for that bank of two Six Volts (which are now in series) and is the equivalent of a FULL 12 VDC flooded battery.  So, you have ONE bank of two six Volts in parallel with TWO (Chassis) 12 Volt Batteries.  If you let the Generator run...(or if you have 30 or 50 amp service instead), you are CHARGING the CHASSIS BATTERIES.  It should take about 3 or so hours.  If you really want to make sure....then use your DVOM and measure the Voltage or look at the Inverter Remote.  When you have around 13 VDC and/or the Remote SAYS.....FLOAT CHARGING OR FULL CHARGED....then the TWO House (still connected with its jumper short cable) as well as the Chassis are CHARGED.  

Driving it (you can pull the spring clip Jumper Cables) will then top off the Chassis Batteries.  Maybe an hour or so....OR LET THE GENNY RUN another hour.  That is the BEST you will get.  

NOW....the next step seems ILLOGICAL....but this is how you figure out "How GOOD are the CHASSIS (wrong kind) Batteries.  You have to TEST THEM like they were Deep Cycle.  That is TOTALLY different from how you test a Starting Battery.  SO....here is what you do.

You NEED to have the Jumper (Spring clamp) cables.  You HOOK UP THE Cables as before.  POSITIVE to POSITIVE...and Negative to Negative.  NOW, you turn off any AC power or the Genny.  Then you removed BOTH the HOUSE small interconnecting cables.  Those are the ones from Negative to Positive in each bank.  BINGO....you have NO HOUSE BATTERIES....BUT, your INVERTER THINKS you do....the Jumper Cables from the HOUSE to the CHASSIS have your Inverter running off the CHASSIS....

Now, use a table lamp or a TV.  Turn on a TV or turn on a lamp (needs to be incandescent).  Let it stay one for maybe 10 Minutes.  That will barely "draw down" the "House" bank (which is in reality....TWO DEEP CYCLE 12 VDC.  Then disconnect the POSITVE CABLE.  Let it sit for maybe 5 minutes.  You have knocked off the Surface charge....and let the battery recover.  Look at the chart I attached.  That is for TROJANS....but it is the SAME for any flooded cell.  If your batteries are reading around 12.7 or so....then they were recharged and they "popped back up" to 100%.  That is the ONLY way to test them....short of having a REAL (not a cheap one at a big box store) LOAD tester.  NOW....suppose they are in the 12.50 range....that is 80%.  If you THEN reconnect the Positive to Positive Jumper Cable....then the Inverter should come back on.  Read the voltage on the bank or individual battery.  It will still be close to what it was.  Your Inverter Remote will be a about 0.10 - 0.20 LESS.  That is because the remote has LINE LOSSES or a voltage drop from the Inverter.  They all work that way.

IF you get a 250 Watt  halogen work light of maybe a 100 Watt bulb and plug it in....then you will start to draw down of drain.  Check the Voltage on the meter and also with your DVOM.  WHEN the actual battery Voltage drops down to maybe 12.10 or 12.00.....then they are at 50% SOC.  STOP.....run the Genny to recharge them.

A set of DEEP CYLCLE Batteries need to be EXERCISED at least once per year.  They get LAZY....even plugged in.  I KNOW THIS FOR A FACT and I have talked to Trojan for a long period of time and this is how you keep them in good shape.  Each time you drain them.....and bring them back, they get a little stronger.  BUT, if there is NO change in the Voltage and they will not get up to 12.73....then they are ONLY as good as the FULLY recharged voltage....after you knock off the surface charge.

SO....my BET.  If the Deep Cycle SEALED were have way decent or quality batteries and you only ran them down ONCE....you may be OK.  The CAVEAT is that we can NO look at the Electrolyte level in the battery, nor add an DI water.  That is why most folks that understand batteries always get NON SEALED Deep Cycle.  NOW, it is REALLY hard to find an UNSEALED Chassis or starting battery.  BUT, they do NOT loose water like the DEEP CYCLE.

If they pop back....I would just DRIVE IT.  You DO need to put on a TENDER (not a high powered charger....if you use one of them and leave it on...you WILL KILL THE BATTERIES....you will boil off the electrolyte). A THREE stage tender with around 2 Amps will easily keep the Chassis charged and OK.  I know that for a fact....I get 8 years out of my portable genny and lawnmower batteries....and do NOT have any charger on them.  BUT, the tender does the trick..

That's it....

This may sound complicated....but it is what any Motor Home Owner needs to know about the DIFFERENCE....as well as how to "treat and maintain" their batteries.  Those that don't, unfortunately spend more money on batteries.  There are several of us here that routinely get 8 plus years from a House bank (Trojan T-105 Flooded) or our Interstate Sealed Chassis Batteries.  The Chassis Batteries are either being charged by a 120 Vac Tender or we have (which you do NOT) Bi-Directional Charging so that when the House is Charged....the Chassis is.  

Hope this help.  I think you may be better off than you realize....but, IF THEY FAILED....then there is typically a ONE YEAR warranty on Deep Cycle and a 2 - 3 year on Starting.  I would take the Deep Cycle back and say....BAD.  New ONES....but credit them against a REAL STARTING BATTERY....NOT a Deep Cycle....then you should be go to GO....Good LUCK

battery-state-of-charge-chart.pdf

[63Hotrod]

MODERATOR EDIT

Bill, this subject has been discussed many times in several different topics.  LOTS of good info here for you to consider.  Do a "Battery" search in Topics and you will get 112 pages of posts.  NOT THE FIRST TIME this question was asked.  This is merged into the last discussion.

End of Edit.

Our current set up is not holding a charge. They take a long time to reach full charge and drop voltage quickly running only a few lights and the residential fridge. They are 4 6 volt O Reilly's 75 amp 220 min Super Start  which came with the coach There 5 years old 

We do very little Boondocking 

Need some suggestions on replacement units

 

[vito.a]

Battle Born lithium batteries are popular, but are expensive and present a host of problems.  You cannot charge or discharge lithium in extreme temperatures and you should disconnect the alternator from them.  

I installed four Trojan T-105 six volt golf cart batteries.  I found them at our local golf cart store for $129 each.  Some sets of Trojan batteries are lasting almost 10 years.  

[Tom Cherry]

Couple of quick points.

Starting batteries will NOT last as House.  You need Deep Cycle Marine & RV types.

Lithium batteries for the novice may be a financial disaster. Many here believe that the Magnum Inverter is NOT suited for charging or maintaining and there are countless debates. MOST experienced folks that absolutely have to have Lithium and also some solar end up upgrading their charger with a supplemental and a new controller.

Your Magnum Controller is NOT suitable for Lithiums.  The newer ME-RC remote has more options but folks feel it is still inadequate

Flooded cells are STILL the choice (mine) for many experienced users here. AGM required a knowledgeable setup and monitoring and any missteps or abuse will shorten their life as well.  YES, we are the old timey Buggy Whip Guys.  BUT, I know some, like me that are getting up to 8 years of more out of our Trojan T105's.  We MAINTAIN them and EXERCISE them.  We us a relatively inexpensive Battery Miser Cap (Amazon) so the electrolyte does NOT boil off, but condenses and drops back in.  We rarely add an ounce of DISTILLED water every six months or so.  Our batteries after 7 or so years will STILL charge back up to almost 100%.

I have included a Battery "Guide" that I put togehter. Many have read and like it.  It is a few pages long.  BUT, it explains what you need to know and also how to choose batteries and how to get the best life out of them.

If you plan to update (maybe you have) to a Res Refer, your FOUR bank set will do nicely.  Folks that are experienced all conclude that with the addition or replacement of the incandescent lights (we have INFO here) with LED's and also knowing that you need to TURN OFF (unplug or have a power strip) your TV's and such when you boondock, you easily get a full 24 hour cycle and you only run your generator for maybe 2 - 3 hours per day.

That's it.  Learn about Batteries.  Read before you buy.  Sometimes folks have GREAT results from Sams and Costco. Locally, I could buy Interstates cheaper at the Distributor than at Costco.  I use Interstate STARTING batteries.  

BUT, I only use Trojan T-105's for the house....and they last...and IF you happen to abuse them, they are forgiving.  AGM's a little.  LITHIUM....NOPE.  Kid gloves.  BUT if you understand that and take care of them and upgrade the system....they are the nuts.  BUT, not for me....

I uploaded my original copy...but this is the one that is in the files...

 

BATTERY 101 - BECOME AN EXPERT.pdf

Edited March 2, 2023 by Tom Cherry
Clarify that DISTILLED water is the recommended type

[cbr046]

1 hour ago, Tom Cherry said:

We rarely add an ounce of DI water every six months or so. 

 

An even quicker point . . . . DI water is so "pure" it will actually leach metals in the long run.  Best to stick with old fashioned distilled.

- bob

[Tom Cherry]

9 hours ago, cbr046 said:

An even quicker point . . . . DI water is so "pure" it will actually leach metals in the long run.  Best to stick with old fashioned distilled.

- bob

Good CATCH.  I meant DISTILLED and edited and corrected the post.  Too many years of writing capital projects for Deionized Water systems for electroplating operations in our manufacturing plants.  Distilled Water is readily available at most supermarkets or pharmacies,

DO NOT use the purified as it is just filtered and not suitable.

 

[MyronTruex]

Distilled water is a bit hard to find in the grocery store these days. That is crazy so I buy a few extra gallons when I find it.

Here is another primer on batteries someone may find useful.

Using true deep cycle batteries would never be my choice for engine batteries. They supposedly make some that are built for kind of dual service but everything is a compromise and for that monster engine I want as much grunt as possible to turn it over. 

I too have seen parallel batteries fight each other when one is sick. They used to parallel them on the early diesel pickups and it was a common problem with one battery going South. 

 

Battery Basics - Guide to Batteries _ BatteryStuff.pdf

[Paul J A]

Group 31 Deep Cycle batterys are the rceommended batterys for the Ch.assis. 

https://www.google.com/search?q=group+31+chassis+rv+battery&rlz=1C1PQCZ_enUS716US717&oq=Group+31+Chassis+RV+&aqs=chrome.2.69i57j33i160l2j33i299j33i22i29i30.12167j0j15&sourceid=chrome&ie=UTF-8

[cbr046]

On 3/3/2023 at 5:29 PM, Paul A. said:

Group 31 Deep Cycle batterys are the rceommended batterys for the Ch.assis. 

https://www.google.com/search?q=group+31+chassis+rv+battery&rlz=1C1PQCZ_enUS716US717&oq=Group+31+Chassis+RV+&aqs=chrome.2.69i57j33i160l2j33i299j33i22i29i30.12167j0j15&sourceid=chrome&ie=UTF-8

Says who?  That's just a list. 

I'll stick with a chassis batt w lots of cranking amps and leave the deep cycles for the house portion.

- bob

[Ivylog]

14 minutes ago, cbr046 said:

Says who?  That's just a list. 

I'll stick with a chassis batt w lots of cranking amps and leave the deep cycles for the house portion.

- bob

I’m with you and IF he’d left off “deep cycle” then yes the group 31 size battery is what’s usually installed for starting.

[Paul J A]

5 hours ago, Ivylog said:

I’m with you and IF he’d left off “deep cycle” then yes the group 31 size battery is what’s usually installed for starting.

Yep. My mistake. Thanks for clearing it up. 

[Tom Cherry]

Walmart and others sell a “one size”.  I had mine replaced twice as my Winnie seller had a receipt.  I have friends that got snookered with the DEEP cycle & Starting battery flim flam and I had them buy true Deep Cycle RV & Marine Batteries for their trolling motor and a regular starting battery for the outboard and a Pulse Technology multiple battery maintainer..  no issues.

Deep Cycle batteries are not rated or recommended for starting. From Trojan’s FAQ’S….

What are the differences between a deep cycle battery, a starting battery, and a dual-purpose battery? A deep cycle battery has the ability to be deeply discharged and charged many times during its service life. It is designed specifically for powering electrical equipment for long periods of time. An automotive or starting battery is designed for brief bursts of high current and cannot withstand more than a few deep discharges before failure. This is why you can't start your car if you accidentally leave the lights on more than a few times. For applications where both engine starting and light deep cycling are required, a dual-purpose battery is often used. This type of battery is neither a starting nor a deep cycle battery but rather a compromise between the two that allows it to perform both functions adequately. Only deep cycle batteries should be used in renewable energy applications.

Sums it up.  We have separate systems on our MH.  My Winnie gasser only had one bank and the combo’s failed if left in storage without a supplemental tender or maintainer.  

[amphi_sc]

On 3/6/2023 at 6:51 AM, Ivylog said:

I’m with you and IF he’d left off “deep cycle” then yes the group 31 size battery is what’s usually installed for starting.

Just food for thought.  I prefer AGM and have been happy with Lifeline in the coach and the similar Concord line in the plane.  Looking at the footprint of group 31 in the tray, 2 would fit.  Whereas 4 1400's arrange in a nice rectangle.  The 4 smaller 12v batteries could deliver more cranking amps ( 4 x 850 ) than the 2 31's ( 2 x 880 ).  The 4 battery arrangement weighs the same as the 2 group 31's.  As it is on the chassis, I'm looking more toward immediate demand amps rather than reserve capacity.  Another factor for me is there is a Lifeline distributor warehouse less than 40 miles away when we are home.  AGM - no corrosive gases, no water level to watch, etc.

FWIW

[Ivylog]

1 hour ago, amphi_sc said:

The 4 smaller 12v batteries could deliver more cranking amps ( 4 x 850 ) than the 2 31's ( 2 x 880 ).  The 4 battery arrangement weighs the same as the 2 group 31's.

AGM - no corrosive gases, no water level to watch, etc.

I haven’t found corrosion to be a issue for starting batteries… yes for house and agree AGMs there is worth the $$$.
 Most 31s starting batteries are 950 cca and some even 1150…the $450 Lifeline GPL-3100T AGM is 1120 cca, BUT at 70 degrees, not 32. Not sure how 4 batteries that weigh the same, put out more amps ??? 4 1400 X $235=$940. I just bought 3 950 cca 31s for $105 each… $315 and 2850cca.

What amphibious plane do you have? I also use AGM in my airplane 

Edited March 7, 2023 by Ivylog

[Tom Cherry]

Re the food for thought, you bring up a subject that is hotly debated.  AGM V Flooded.  Playing Devil’s advocate….many of the upper end MH today have AGM.  If the original “battery” system was properly designed and maintained for AGM, I would keep AGM there.  This next statement might ruffle feathers but this is one way to look at AGM.

Circa 2008 or so a lot of the lower end Monaco MH HAD A BIRD (Bi-Directional) charging systems.  I think that 2006 was the first year in the revised Chassis and the “all electric” front and rear bays with some 20 odd boards.  There is an Intellitec board in the Dynasty and up to provide BIRD and a 200 A Big Boy to proved Boost as well.  This was state of the art.  Yet we have many topics from owners about “my batteries” won’t stay charged.  The Intellitec boards are well designed, but they still break down. The Big Boy is robust, but requires periodic  disassembly to clean the contacts.  If there is a power surge or the remote goes bad on the Magnum, then that prevents the Magnum from resetting and then both sets are not being charged.  So, the Dynasties and up are not 100% failsafe.

That is the perfect or best reason to NOT switch to AGM.  AGM were designed and devoted to be pure maintenance free and in OEM applications with the charging systems upgraded.  In our MH, THE CHARGING systems were flooded.  Without painting the group, based on the numerous posts, there may be a mindset ….as well as how AGM’S are marketed….  Switch to AGM.  NEVER HAVE ANOTHER DEAD BATTERY.  The real world or truth is quite the contrary.  A flooded cell will take abuse such as over or undercharging or such and may be salvageable.  You can add electrolyte and exercise. 

I called Trojan, just out of curiosity, to verify what I read in the “Trojan Users Guide”.  They were adamant.  For a MH user to get max life and performance, if the battery is on trickle (float) charge in storage, it MUST BE EXERCISED prior to use.  The rules and theories are the same for Flooded vs AGM.  DISCHARGE the batteries at the expected rate when boondocking.  Quit discharging when the SOC, at the battery, measured with a volt meter is 40 -50% as that is the “load” voltage and when the battery has no load, and is disconnected for at least half an hour, it will recover.  Thus 40% will probably read (voltage) 50% later on.  Fill the electrolyte and recharge.  Unplug and test voltage and specific gravity.  Put on a quick small load, like 5 seconds with a cup of water in the microwave.  Disconnect.  Measure Voltage and Specific Gravity after 15 minutes.  Use the chart and record the SOC.  You mat have to do this 2 - 3 times….then that is the real SOC.  When you discharge, the plates get warmer and 5ge pores open up.  This is required at lease every 4 - 6 weeks.

AGM vs Flooded Cells…..same routine.  But folks are lead to believe that once they go to AGM…..NO NEED TO WORRY.  Quite the contrary.  If a car came with an AGM, then the charger is designed for it.  And in a car, you exercise it.  But most let their MH SIT. NOT GOOD. I had a 2000 Corvette and it sat in the garage a lot.  I researched the LIFELINE AGM.  There were more issues with disgruntled owners about spending more, discharging and ruining an AGM down actually was worse.  So you spent 50-75% MORE and got less life.

The Camelots in 2007/8 had an Intellitec BIRD system.  It was pretty robust, but I did have an incident where I should have cleaned the contacts on the Big Boy and lost the Chassis.  I opted for new battery and a new Big Boy as I wanted reliability for a long trip.  I do exercise mine.  I got 8 years from a set of Trojan T-105.  One member did that…maybe longer and is almost there again and they pop back to 100% SOC.

IF one has coaches older than a 2006 or so Dynasty(up) or a lower end WITHOUT A FULL BIRD, then those systems are less reliable and popping in AGM’S without understanding what killed the batteries is real an exercise in futility as well as spending more money and putting in batteries that are more prone to fail.

There is  a BATTERY 101 that file or primer or how to that will be updated later this week to emphasize the IMPORTANCE of exercising as well as dwelling on the hidden pitfalls of just putting in AGM’s and being disappointed.

Edited March 7, 2023 by Tom Cherry
Left off photos

[Ivylog]

Read the above twice and still scratching my head. In the summer we dry camp a fair amount and only got 10 years out of Interstate 31 starting and AGM house batteries in our 04 Dynasty with BIRD and BigBoy… yes, had to clean the contacts every 4-5 years. Had to change the battery type in the Magnum to AGM2 instead of flooded.

[Tom Cherry]

4 hours ago, Ivylog said:

Read the above twice and still scratching my head. In the summer we dry camp a fair amount and only got 10 years out of Interstate 31 starting and AGM house batteries in our 04 Dynasty with BIRD and BigBoy… yes, had to clean the contacts every 4-5 years. Had to change the battery type in the Magnum to AGM2 instead of flooded.

I apologize if I didn’t make a concise and meaningful closing.  Your experience is great and you probably would have gotten a similar life from a set of flooded cell Trojans.  The need to exercise is crucial.  We have never taken a poll or added a questionnaire about your usage.  If you dry camped frequently you did the much needed exercising.  If you try to “figure” out the knowledge level of some members with battery failure or charging issues, they may not be as knowledgeable as you.

But if you ask folks the advantages of AGM V Flooded….or if you read the responses “hey get yourself a set of AGM and they will last longer and not require all that stupid maintenance”.  It would take a carefully set up experiment to determine longevity of the AGM v Flooded.  I remembered reading this when I was searching for a replacement for my original Interstate’s in 2013.   I said….OK decision made.

I found this oN IRV2 and copied it….

My charger will do all three. Im leanig towards the T-105 flooded Trojan batteries.
I have since read this from the Trojan site:

What are the advantages and disadvantages of gel, AGM, and flooded lead acid deep cycle?

Generally, gel and AGM batteries have about 20% less capacity, cost about two times more, and have a shorter cycle life than comparable flooded lead acid batteries. However, Gel and AGM batteries do not need watering, are safer (no acid spilling out), can be placed in a variety of positions, have a slower self-discharge characteristic, and are more efficient in charging and discharging than flooded batteries (see table below). Gel batteries are more suitable for deep cycling applications whereas AGM batteries are more for light cycling and engine-starting applications.

Flooded
Gel
AGM
Charge/Discharge Efficiency 
89%
98%
99%
Self discharge rate (per month) 
13%
1-3%
1-3%
Finish Voltage 
15.3-16.0V
14.1-14.4V

The self discharging rate surprised me.  Again a C&P from a post so I’m assuming it is correct.

My point, and I am recovering from a shoulder replacement and my DW is poking Percocets in me every 4 - 6 hours…per the label…is this.

Most  members may not be as knowledgeable and meticulous as you.  You also have a more Sophisticated BIRD charging system that my “simple” BIRD module.  Your Big Boy will be warmer to the touch and noisier.  Frank McElroy and I have debated and discussed that….but in reality, that’s a fact. Monaco had requested or Intellitec recommended the specific control board (can’t remember the #) and they do fail and Frank , as well as M&M and other members, have repaired them.  Maybe pulsing so the “average VDC’ to the coil is in the 6 -8 (read on a VOM) RANGE and ..my Intellitec DIESEL 2 BIRD module is 3 - 4. Has an advantage ….don’t know.  They both work and both drive the Big Boy.  

BUT your system was designed to work with am AGM.  MINE was designed to work with an AGM.  The older coaches might work, but folks have issues with the IRD as the hybrid ones with an original INTELLITEC BIRD.  I have seen differences in the prints in the same years….and when the DISIEL2 came out, there was a wiring change in the installation instructions.  The first ones warned NOT to run the Genny when on Shore and ther was a Genny running wire hooked up.  Next year….no wire and no wire on the points.  M&M who is the tech support could not get a straight and concise answer,

Bottom Line.  My intent was to point out that just popping in a bank of AGM and not knowing how to adjust your inverter setup and not exercising them and not doing any PM or not understanding how the charging system works is a recipe for disappointment and failure and will cost you more as the AGM’s are more fragile and easier to abuse.  AGM is not the savior.  Folks like you, and we have many that understand what is needed and have newer systems that allow the setup to include AGM, fine and happy using AGM…. As are folks like me that stay with Flooded.

But the sales pitches and testimonials often slough over that and the details are lost and a member spends more money without knowing how to properly maintain and then gets less life.

I hope that clears it up and appreciate your comments and experience.

Thanks.

[amphi_sc]

Hello Dick,

The plane, a Comanche, is not amphibious.  But I do have a few amphibious cars...boys and toys...thus the old moniker.  As for the amps, I just looked at the Lifeline site.  I do carry a spare Big Boy and clean the contacts annually as part of normal maintenance.   As I drive the Aladdin helps me insure the Big Boy is connecting both banks by watching the house charge from the alternator.

[Ivylog]

Tom, thanks for the additional info…guess I assume too much. Hope the pain gets better soon.