Replacing coach & Chassis batteries in 2016 Winnebago Navion

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Driver555

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Jan 10, 2019
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I have bought 3 brand new batteries for the coach and am getting ready to install them.  I have been told by a local RV dealership that when replacing batteries, the Mercedes onboard computer needs to be updated as well.  Is this true?  Anybody have any experience changing out old batteries with new?
 
Can't help with the update question but I will make a suggestion.

Take pictures with your cellphone BEFORE you disconnect anything. I'fe seen more than one post where people have hooked up their new batteries wrong.

I'm curious why you are replacing the batteries. 

 
Welcome to the forum.  Great idea to take pictures!!!

I can't imagine the ECU needs to have a firmware upgrade due to a loss of power - that makes no sense to me. Call Winnebago Owner Relations and ask them just to double-check.
 
I will say that my Yukon XL throws a fit when I change the battery.  It throws my front and rear HVAC system out of wack.  Sometimes I have to disconnect and reconnect, a couple times.  They actually make a little gizmo that plugs into charging port to keep electronics powered while you exchange battery.  I've often thought you could probably, CAREFULLY, take some jump leads and have a second battery connected to the cables and accomplish the same. 

As John stated, a quick call to Winnebago  :))

One more comment:  a 2016 and batteries bad ???
 
For such a new coach, I don't see why you'd need an update. Are you switching to AGM or lithium batteries?
 
Thanks so much for your replies.  Not switching to AGM or Lithium.  Just back to the good old lead/acid again.  My batteries are 3 years old, and I have not taken care of them very well.  Didn?t realize that I needed to pop off the top caps occasionally and adding distilled water. 
 
I will take a picture before starting.  I probably would be one of those to get the wires mixed up on reinstall...  You guys are great in my book. 
 
I can't explain why...But the Nissan work van I used had to have 12 volts fed into the power point before the battery could be swapped.
This was done by the auto parts store that sold us the battery. When I asked him why it needed the 12 volts and he replied the computer tells them which vehicles needed the 12 volts.

Note: The installation was free as was the use of the 12 volt box.
 
Driver555 said:
Thanks so much for your replies.  Not switching to AGM or Lithium.  Just back to the good old lead/acid again.  My batteries are 3 years old, and I have not taken care of them very well.  Didn?t realize that I needed to pop off the top caps occasionally and adding distilled water.

So sorry you didn't know about the maintenance of the batteries. Nothing wrong with lead acid batteries other than the hassle of remembering to check the fluid level and add distilled water. 
 
Driver555 said:
... Didn?t realize that I needed to pop off the top caps occasionally and adding distilled water.
The beauty of AGM is they are completely sealed and can even be operated on their side. If you don't want to keep up with checking battery electrolyte then AGMs are an obvious choice. They also charge faster and self-discharge slower than lead acid. I got seven years out of my first set and I replaced them just because.

Bottom line is they are a significantly battery chemistry than flooded cell.
 
John, when researching comments on coach battery choices I saw your favorable  comments on AGMs. I have been on the fence about switching to AGMs now that my 18 mo old 6 V flooded batteries cannot even run my refrigerator on LP overnight. I have kept the electrolyte where it needed to be, but without a place to plug in they self-discharged to below 50% from time to time. I expect that this destroyed them.

I have now bought 90watts of portable solar which, together with the meager 10 watts on the roof, maintains my batteries in storage very well. Now that maintenance in storage will be less of an issue, my objective is to buy the maximum capacity pair of batteries to fit the space my batteries occupy under my entry steps to enable a single night of boondocking. I don?t want to give up any basement space for more batteries.

Should I just replace these with inexpensive 6V wet cells or go for AGM?  I know that AGM can be discharged to something a little less than 50%, but AGM seem to have less watt hours for the same dimension battery. Isn?t that the case? If so, and I boondocked overnight from time to time, would I be more likely to damage the AGM than the wet cell during that interval when the sun isn?t shining? I only need to run the refrigerator on LP, the furnace on LP if it is cold,  a few LED lights and perhaps a ceiling fan if it is hot.
 
JoelP,ies
The furnace is probably the biggest 12 volt consumer in your RV .  It'll suck the life out of your batteries quickly.
 
Hi Joel, ChasA is spot on - the gas furnace is a huge consumer of precious amps. Use an extra blanket at night and set the furnace to 55 or 60 degrees.

AGM battery chemistry has to be evaluated and judged in the big picture.  It will tolerate deeper discharges than flooded cell but as you noted not quite the amp hour capacity for the group size. They will charge faster and due to lower internal resistance they self discharge at a slower rate. Lifeline AGMs have been improving their capacity for a group size.
 
IMO, the value of AGMs for the average RVers is essentially zero maintenance, which for most owners translates into a relatively long trouble-free life with little or no effort.  Let's face it - most owners aren't gung-ho on the tech maintenance stuff, especially between trips.  There may also be an advantage in being a sealed battery (no venting required, oddball positions are ok), but that's important for only a few uses.

Compared to the commonplace Marine/RV battery, an AGM lasts longer and performs better, but compared to a golf car deep cycle it is merely expensive and slightly less capacity. The only significant advantage there is the lack of maintenance worries.  Vs a 6v golf car battery, any improvement in charge cycles or depth is tiny (if any at all).  All lead-acid batteries suffer from depth-of-discharge effects; the further and more often they are discharged deeply, the shorter their lifespan. Marine/RV hybrid batteries are especially harmed by that, but a quality flooded cell deep cycle and an AGM are pretty much the same.
This may sound as though I am anti-AGM, but that is not the case. I bought them for my own RVs.
 

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