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Battery, exercise?

We have 3 8d batteries.  The photo of the top of one is attached.  About four months ago I cleaned up a bit of fluid on the top, about the same as shown in the photo.  I asked technical folks at MOT about the liquid before I took it in, they said it could be from an oil line above but we better check it out.

That battery and the other two test well under load.  They called a battery expert in and he said that he had seen this before on RVs left plugged in to shore.  You could tell a slight swelling of the case around the middle cell and upon closer inspect some faint traces of dried fluid going out about .5 inches from the cap.  The battery was not warm.

In the battery expert opinion, I need to about monthly or so turn off the shoreline and run on battery, letting them draw down some.  (and we just changed to all LEDs!).  David Whitehead and Mike Rodgers agreed that I could turn on the inverter, run the tv and a fan for a bit,  It is not necessary to pull the batteries way down, just use up some of the storage and then plug back to shore.

Perhaps some have other explanations or disagree that this is necessary?  Mike said they had not ever seen this or heard it needed.  They did check the charger output to be sure it was operating properly.

Ideas?  Any disagreement with the analysis or solution?  I seem to learn everyday, I hope it is mostly right!

Mike
Mike
2001 U320 4010 Build 5878 (Gus)
Wrangle Unlimited Toad
Nacogdoches

Re: Battery, exercise?

Reply #1 –
Mike,
I would unplug the coach for a couple hours w/o any major loads. If they read 12.8 VDC I would ignore that oil. I'm not a proponent of leaving the coach plugged in 100% of the time. Instead I would exercise all the electrical as well as the chassis every 30 days. And measure the voltage at the batteries once a week. If they need to be plugged in for 3 to 5 hours, then you can do so until the batteries are fully charged. Knowing your set up at home, you can do this very easily.
Peter & Beth Martin
No Forrest? What have you done?
MC# 15890 until Dec 2016; FMCA #F329677
Cincinnati, OH

Re: Battery, exercise?

Reply #2 –
Peter, couple of questions.

1.  To unplug I have been pulling the 50 breaker.  I hear from a friend to not use the breaker as a switch, but since I pull it to unplug, I guess that infrequent of monthly would be fine.  But what about, say, weekly?

2.  I did crank the engine monthly but after the discussion I had with Bret and then on the forum, you folks seem pretty unanimous to not do that unless you drive "25" miles.  Hard for me due to driveway but can be done.  Then I talked to Cummins, I posted that, and then one nice forum fellow sent me a PM that said these engines in grain trucks set up from season to season without the extra attention I may be giving by cranking so frequently.  So I forget....how did you feel about that exercise program, I guess that what you meant about the chassis exercise....or was it only those batteries?

3.  To measure the voltage, do I need to disconnect the batteries, measure each individually?

4. If I leave unplugged, what about the refrigerator?  I sense from the forum that it best to keep them running all the time?  Maybe I misunderstood.  I liked the plug in for that and I leave the AC set high (84), I recall Tim or someone said, you got the AC, might as well use it even under the cover.  Your thoughts please.

Recall how you helped with the aux compressor you found running at Xtreme that time?  I think all that worked thru, leveling doing great, dust seems gone but I vent the wet tank frequently and do see some dust but folks tell me that natural and why i need to keep draining it fairly often.

Cheers, miss seeing you guys.  Jackie going to take FOT driving class....yeah!.

mike
Mike
2001 U320 4010 Build 5878 (Gus)
Wrangle Unlimited Toad
Nacogdoches

Re: Battery, exercise?

Reply #3 –
I like the approach to monitor the battery voltage while the shore power is disconnected and only plug it back into shore power when the voltage drops from full charge (about 12.6 volts) down to about 12.2 volts.  Could go further down, but I just like to limit the drop in case I need to use it for some reason.  Battery monitors are relatively inexpensive and have an adjustable alarm setting.  I use the battery monitor to tell me when to plug in shore power, about every 3 weeks for a day or so.  Have a great day  ----  Fritz
Fritz & Kathy Johnson
1991 36'

Re: Battery, exercise?

Reply #4 –
Mike, here are my thoughts:

1. You do not need to shut the breaker to disconnect the shore power cord. Just disconnect the cord altogether with a smooth straight motion. I guess I do not understand the second part of the question. If you mean to leave the coach unplugged and then plug it in monthly, that would be just fine.  Again, it depends on the weekly battery voltage readings whether you need to plug in more often.  The disadvantage of leaving the coach plugged in 100% of the time is due to voltage spikes, lighting strikes, etc.  As you have a slide, you also need to ensure that you have the auxiliary compressor in good working order to keep the slide room bladder full.  This will drain the batteries as well.  Recall that these batteries longevity is measured in charge/discharge cycles.  So measure the voltage weekly if you decide to leave the coach unplugged.

2. I do not just crank up the engine to idle it or even run it on high idle. Cummins does not recommend this protocol.  I drive it 30 miles monthly give or take a week (due to weather mostly in the winter). I exercise the genset as well during the drive which can then run roof A/C's, heaters, etc.  I also run the dash A/C during the exercise period (usually one hour total).  As I winterize, I do not work any of the appliances that require water.

3. I do not measure each battery independently as this requires that you disconnect all cables.  I am only interested to check that the battery bank can deliver 12 volts.  Steady state reading for a fully charged battery is 12.8 VDC.  I measure both battery banks every 30 days prior to reconnecting them and then begin the coach exercise period.  (As I disconnect both battery banks while in storage, I do not measure weekly.)

4. I agree that the refrigerator should be left on all the time and never be shut off (unless you are forced to do so such as when you are at a fueling station or filling the propane tank).  I do not practice this procedure, I shut the refer every time I place the coach in storage as it is unattended at a storage depot near my home and propane valve is shut off at the tank.  But, you could let the refer run on propane when it is unplugged.

Since you live in a fairly hot & humid climate, it might be best to leave the coach plugged in to shore power just so you can dehumidify the coach by using the roof A/C's.  Or, you could purchase a room dehumidifier and use that appliance powered from an extension cord from the garage.  You can certainly close the entry door on any power cord from the garage outlet.

Any other questions, do not hesitate to ask...Miss you guys too.  Give my best to Jackie.
Peter & Beth Martin
No Forrest? What have you done?
MC# 15890 until Dec 2016; FMCA #F329677
Cincinnati, OH

Re: Battery, exercise?

Reply #5 –
Peter, I have an idea.  I think all you wrote makes sense, good guidance.  (The turning the breaker on/off I think came from some book about connecting at an RV park.....do not recall why to do this rather than just plug in live, but think I read that.)  I do have a regulator that is supposed to protect against voltage spikes.

Here is the idea, and it comes from seeing an HR's battery bay that had a battery disconnect switch.  What if I install a batter disconnect switch, then I could disconnect the batteries from the charger and leave shore power still running AC and the refrigerator, I think/guess?  Then as batteries fall below the target voltage you and Fritz mentioned, I could throw the switch and go back to the charger bringing the batteries up?    Bet I miss something.  And Fritz mentioned some monitoring system, need to see where to get that, sounds good.

{Strange that mechanics at MOT had not experienced this, had this question before.....perhaps mine was a rare occurrence with ruining the battery.  The battery folks that looked should know what they are talking about.}

mike
Mike
2001 U320 4010 Build 5878 (Gus)
Wrangle Unlimited Toad
Nacogdoches

Re: Battery, exercise?

Reply #6 –
Mike,
I think your method described above is plausible.  Not sure how the inverter/charger would behave with power to it and not charging/imverting to any load...You may need to shut down the inverter.
Peter & Beth Martin
No Forrest? What have you done?
MC# 15890 until Dec 2016; FMCA #F329677
Cincinnati, OH

Re: Battery, exercise?

Reply #7 –
I do not think I would do that.  I leave men plugged in all the time when in storage. No ill effects on them. A disconnect would need to be pretty large and may become a failure point. No issue with throwing the breaker.  Easy simple and not error prone.
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: Battery, exercise?

Reply #8 –
Here is a good read about the care and maintaince of Deep Cycle Wet Cell Batteries from US Battery:

U.S. Battery - Care & Maint p.1

Cheers

Ted
"97 40' U320 build 5035

The best things in life are not things.... It's fulltiming in a Foretravel.

Re: Battery, exercise?

Reply #9 –
For battery monitors, Google "battery monitors" and you will get a bunch to pick from.  I forgot where I got mine, but it was around $30 and does all I need done.  Have a great day  ----  Fritz
Fritz & Kathy Johnson
1991 36'

Re: Battery, exercise?

Reply #10 –
You don't use the breaker as a switch, because it is one of the thinks that wears out a breaker.  It is not designed for continuous switching.  It is designed to disconnect the circuit when the circuit has to much draw going through it.  It you use it for switching, it will quickly wear out and not stay switched when you put it into the on position.
1994 U225
build #4514

Re: Battery, exercise?

Reply #11 –
Quote from: Michael & Jackie –


Here is the idea, and it comes from seeing an HR's battery bay that had a battery disconnect switch.  What if I install a batter disconnect switch, then I could disconnect the batteries from the charger and leave shore power still running AC and the refrigerator, I think/guess?  Then as batteries fall below the target voltage you and Fritz mentioned, I could throw the switch and go back to the charger bringing the batteries up? 
Are you thinking that you are smarter than a 4 stage smart battery charger's internal processor in knowing the needs of your batteries???  I think that they will stay charged better, and live a longer life,  if left plugged in and left to their own design.
1994 U225
build #4514

Re: Battery, exercise?

Reply #12 –
FWIW...I have been told that a battery disconnect switched will NOT stop some drain from your batteries...Will have to check with FOT in the AM and see if I am posting correctly..
We are only strangers until we meet; however, some of us are stranger than others

Re: Battery, exercise?

Reply #13 –
I am not thinking that I am smarter than the processor but I figure the battery "experts" that went to MOT to examine the battery are smarter than me and maybe know something I needed to know.  And MOT, two senior technical folks, said in all the years they had never heard that nor recall seeing the battery do this.  So given that, I hoped to check here on the forum about the difference of opinion but I will go talk myself to the battery folks and maybe to FOT too.

 
So my inclination was/is to leave it plugged in.  But then a few on the forum suggested that not best either.  I believe at the moment leave it plugged in, take the chance that what happened was a fluke.  I had also asked MOT, is there a chance that my really smart charger/inverter system with age and was not monitoring the battery and doing the right things?  They said they checked that, that was not the case. 

And besides the help I sought and got, I hoped others might learn from what happened here, and perhaps avoid a problem or learn an alternative way to manage the batteries IF that is necessary.  In this I also learned of the device Fritz talked of, for example.  And from Peter and others that I can check the voltage of the batteries without disconnecting from the terminals.  My learning continues.

Thanks to all for your time, if I learn something from going to the battery folks, I will advise.  (It is a Deka Dominator gel extreme deep cycle battery.)

mike
Mike
2001 U320 4010 Build 5878 (Gus)
Wrangle Unlimited Toad
Nacogdoches

Re: Battery, exercise?

Reply #14 –
Just for info  ----  A monitoring device similar to the one I use is available from "Battery Failsafe Devices".  It is a little more expensive, at around $50, but looks like it would do well.  I connected mine to a circuit fed by the house batteries in the fuse panel in the dash.  However you choose to keep your batteries in good condition,  knowing their state of charge at all times and not letting them get overly low for any length of time is an important factor.  Have a great day  ----  Fritz
Fritz & Kathy Johnson
1991 36'