Totally Dead House Bank.. Charged for 3 hours…Should batteries still bulk charging 95-100 amps . . .?

[Newcsn]

Decided to take our 2006 Dynasty out for a 100 mile ride today after having been in storage for 2 months. When I got to the coach I realized the keyless entry was not working. Unlocked the door manually, steps extended as usual and started the coach w/o a hitch. However, I noticed the 12v outlets in the dash where I plug in the TPMS were not powered - nor were the other 12 v accessories.

Was planning to put the genset through its paces while we had it out, so fired it up & turned all the AC units & fridge on. All of a sudden the 12v outlet/accessories had power.

Drove it 100 miles & left the gen running while we stopped for lunch - total run time on gen for round trip was ~3 hours.

Got back to storage, shut off all ACs & fridge & hooked it up to 110/15 amp and noticed it was bulk charging b/t 95-100 amps.

Shouldn’t the gen have bulk charged the batteries after 3 hours? Can’t recall ever seeing it bulk charging that many amps after driving/running gen for that long.

Am I missing something here? Thanks

[timaz996]

It depends on how much battery capacity you have and your batteries were obviously dead with no 12v. 

[Tom Cherry]

16 minutes ago, Newcsn said:

Decided to take our 2006 Dynasty out for a 100 mile ride today after having been in storage for 2 months. When I got to the coach I realized the keyless entry was not working. Unlocked the door manually, steps extended as usual and started the coach w/o a hitch. However, I noticed the 12v outlets in the dash where I plug in the TPMS were not powered - nor were the other 12 v accessories.

Was planning to put the genset through its paces while we had it out, so fired it up & turned all the AC units & fridge on. All of a sudden the 12v outlet/accessories had power.

Drove it 100 miles & left the gen running while we stopped for lunch - total run time on gen for round trip was ~3 hours.

Got back to storage, shut off all ACs & fridge & hooked it up to 110/15 amp and noticed it was bulk charging b/t 95-100 amps.

Shouldn’t the gen have bulk charged the batteries after 3 hours? Can’t recall ever seeing it bulk charging that many amps after driving/running gen for that long.

Am I missing something here? Thanks

Well, as my lawyers taught me to say….that depends.  

first….did you have power at storage and was it at least 30 A.  If not….then I assume you periodically drive it.  Your batteries were deader than the proverbial doornail or down to ZERO SOC.  Not good.  Your Genny must start off the Chassis, otherwise your situation would be more dire.

next….how many batteries in the house?  If 8, then no way they will recharge that quickly…. If 4, then you still might (maybe….probably will) be looking at  bulk charging after 3 hours.  I can get to absorb….maybe 25 A after 3 - 3.5 hours…. I have 4.

My recommendation…..go back.  Take Distilled water.  Replenish the cells.  You have a choice.  I don’t know if you have a full BIRD system….if NOT….  Take a jumper cable and hook up the positive to both banks and drive for maybe an hour.  Run the Genny as well.  Amps coming in will be from both systems.  Turn off engine.  Pull cable.  Look at remote….should be better….

Next….when you get back to storage….you need a VOM.  Turn off Genny   Wait maybe 10 minutes with a few lights on….then pull the Jumpers.  Read each battery VOLTAGE….House…that is.

I highly recommend you read this before going back.  There is a chart where the VOM Voltage will tell you the SOC (AFTER recharging and surface charge knock off).  You should run down the house bank to 50% SOC or probably 11.8 or so AT THE BATTERIES.  They will recover to around 12.0 so you haven’t harmed them.  Check electrolyte after run down and replenish and recharge….repeat 2 more times…do this 2 or 3 times per year unless you really do dry camping and they Magnum remote reads 11.9 or so.

if you have a bad cell, that battery is toast.  If one battery doesn’t read in the 6 VDC Range and is 2 or 4…..after charging….bad shorted cell.  The hydrometer will tell you the condition of each cell.

running them totally dead is not good for them.  Once maybe or a few times.  I have NO idea how my OEM Interstates were treated from Coburg to a dealer to a CW Dealer…..and I took delivery new.  They ran down at a dealer…..and I found one shorted cell and a bad SG reading on a cell in another…both were TOAST.  I used the other 2 for awhile….then learned what I wrote in the file…..and years of reading here and talking to Trojan….and some other learned experts…..

That’s the best info and answer I can give you….

 

[Newcsn]

@Tom Cherry Thanks - as always - for sharing your wealth of knowledge with us Monacoers! Your detailed & thorough responses continue to help me understand the nuances of these animals and have saved untold time & money. Thank you!

I will be running through the diagnostics you've suggested. Here's some feedback to your questions: 

We do drive it frequently (will be driving it more frequently since this experience). We have 8 house batteries. Unfortunately, no 30 amp service at current storage location - only 15 amp. I believe this is the second time (in the 2 yrs we've owned it) that we've had dead house bank. I don't know about how they were treated prior to our ownership. 

Any guess how long it should take to recharge 8 house batteries on a 15 amp service? I simply don't have availability to anything else currently. 

Thanks again for all your help!

[Tom Cherry]

2 hours ago, Newcsn said:

@Tom Cherry Thanks - as always - for sharing your wealth of knowledge with us Monacoers! Your detailed & thorough responses continue to help me understand the nuances of these animals and have saved untold time & money. Thank you!

I will be running through the diagnostics you've suggested. Here's some feedback to your questions: 

We do drive it frequently (will be driving it more frequently since this experience). We have 8 house batteries. Unfortunately, no 30 amp service at current storage location - only 15 amp. I believe this is the second time (in the 2 yrs we've owned it) that we've had dead house bank. I don't know about how they were treated prior to our ownership. 

Any guess how long it should take to recharge 8 house batteries on a 15 amp service? I simply don't have availability to anything else currently. 

Thanks again for all your help!

Appreciate the thanks….you’re welcome.

OK…if you have a true 15 AMP…NON GFCI service, then that is 1800 watts.  You want to hold the amp draw  to say 12 amps….or have 1,440 watts. If you use the 14 or so VDC Bulk rate….that is 100 amps.  SO….cut back on the charging rate. Personally, I don’t like to overtax my 14 YO Magnum inverter….many folks with experience and understanding will use 100% charging rate. I’d stay at 80%.  Time is not a concern.  

You actually only get about 90% SOC from running a generator for 3 - 4 hours to recharge from say 40 - 50% SOC….that is why over time, you need to drive or be on shore to push in that remaining 10%.

I just like having 30A if you want to run the Res refer (or the elements in a gas)….as well as the microwave….  But, 15 Amps, should do it.

Set your Magnum up properly….  I kept posting this and final someone said….write it up.

You need to verify your setup.  Make sure you set the Shore to 15 A.  You will have to change it (15 seconds to change back to 30A) when at a CG.  30A is the correct setting…it is based on the Circuit Breaker in the MH, NOT…the pedestal Amperage. BUT when in your case, you only have 15, then you downrate it….hope that makes sense.

OK…..My SWAG for your question….if your batteries are at 50% SOC….and you set the Magnum to 80% Charging Rate….it should take maybe 8 hours to get to 90%….and that will be some heavy duty pumping in the Bulk phase.  But since you lowered the Charging rate, you will not overload the 15 amp service…..that assumes no OTHER AC LOADS.  Unplug refrigerator.  Unplug all TV and Home Entertainment.  I have a power strip in front and rear.  The standby of them…even off is parasitic and will run down batteries.  I flip one switch….all the front HEC is off….same…another power strip in rear….no parasitic load.

NOW….pick a number….a week or so at low amp absorb or float to 100% SOC…maybe 4 days…

My concern for you was pumping in the amps to get the batteries back above 50%.  If you cycle or load drain, a 400 - 500 watt quartz halogen work light will be a good draw down….you want it to come down evenly, but not with 3 space heaters….will take, on the final cycle, assuming you get or can get full 100% SOC, around 2 - 3 hours.  Your under load voltage measurement AT THE BATTERIES is what you use.  11.8/9 will result, after the normal recovery, in a 50% depleted SOC.

Now, what the batteries are capable of…..that is the final Voltage or SG reading after the 3rd cycle and the surface charge taken off.  If you are in the 80 - 90 range….use them….if lower….then use and budget for a new set in the next few years.  If under 50%….time to think about new set.  NOW…by doing the voltage measurement on each battery…if you are unfortunate enough to have two bad batteries.  Remove them…or put them in a set with NO JUMPER.  You do  NOT charge or attempt to charge. 

Check them  NOW, jumpers removed, and verify that all 8 are in the 6 VDC range is the first step…otherwise you are wasting amps on them…I KNOW…and their “mate” ain’t getting properly charged.  Some take out a shorted cell battery….and then another shorted cell your worst (lowest VDC) battery  next to it.  NO JUMPER…these 2 are just “in storage” rather than take home…

That’s it…..good luck….

 

[Newcsn]

Thanks again @Tom Cherry! I’ve done the Magnum setup per the guidelines. One question on the AGS - Start Volts; it appears I can only select in “whole volt” increments (9, 10, 11, 14 . . .). How does one set it to 11.7/9 volts?

Regarding parasitic draw: I found the that controllers on our comfortaire-less bed were staying on continually - not powering off as intended. I unplugged the pump under the bed - so hopefully that parasitic draw is gone. And, all HEC is setup so we can switch off (as recommended).

However, what’s the easiest way to unplug the fridge w/o pulling it out? I imagine the plug is behind the unit.

Its been running on the recommended setup on 15 amp for about 4 hours and the remote says we’ve gone from bulk charging @ 95-100 amps, to absorb charging @ ~45 amps and we’re now float charging at 18 amps. Hopefully that’s a good indicator!

Thanks!

Also, how do I tell if I have a “full BIRD” system? Here’s a pic of the rear run box.

[Tom Cherry]

MANY…

first….your remote and AGS are different than mine. You probably have the original 4 knob AGS.  My remote was replaced in 2020 or so and has more features.  However, the newer features are actually built into the inverter or were there and as technology improved, Magnum made upgrades.  If you have whole volts.  Set to 12.  

NOW…DO NOT use the remote for measuring the load or rundown voltage. That meter is +/- 10%.  Use a good Digital VOM and measure directly on the battery terminals.  The loaded voltage can go down safely to 11.8/9 and the recovery will be 12.0 or so….so you did not run them down to 40%…

Look on page 285.  It says in confusing language, in charging situations, both are charged.  Yes you have BIRD charging…both… AND I KNOW that in 2006, Monaco totally updated the wiring and electrical systems….so that included Bi Directional charging….

There is a lower refrigerator access panel on the outside of the slide or wall where the refrigerator is located.  Open it up.  Unplug it there….leave the doors open to vent and prevent mold.  Inside that area is the water cutoff for the icemaker….study it.

read the section on battery maintenance in that section also. Goes into more details….this is why a good hydrometer with a scale and not balls or colors is important..$20 on Amazon 

 

 

[Ivylog]

Yes you have a BIRD…follow the small green wires from the BigBoy all the way to the right. If the BigBoy is hot to the touch, the BIRD is working (have to be on shore power and charger turned on). If not hot, check the two 7.5 amp fuses on the BIRD board. If hot, check that the voltage is exactly the same on the 2 big lugs at the bottom. In not the same, the contacts inside need cleaning.

[Newcsn]

@Tom Cherry Your patience with us non-engineer/electrical newbies is amazing! Thanks again!!!

Roger that - will use a digital VOM for taking reading. When testing individual batteries, do I assume correctly that it needs to be an isolated test? Each battery disconnected from the series?

And for give my lack of knowledge, but, what book are you referencing that I should be looking at on page 285? Thanks!

@Ivylog Thank you - I’ll be testing warmth & voltage shortly!

[Tom Cherry]

1 hour ago, Newcsn said:

@Tom Cherry Your patience with us non-engineer/electrical newbies is amazing! Thanks again!!!

Roger that - will use a digital VOM for taking reading. When testing individual batteries, do I assume correctly that it needs to be an isolated test? Each battery disconnected from the series?

And for give my lack of knowledge, but, what book are you referencing that I should be looking at on page 285? Thanks!

@Ivylog Thank you - I’ll be testing warmth & voltage shortly!

The book is your owner's manual.  If you do not have one go here and download it.  I do this all the time to find out what folks have or to give them a reference.

https://www.monacocoach.com/service-and-repairs/

Yes, you MUST do individual batteries.  Otherwise, you can't determine if you have a defective battery.  Read the section, as I said on batteries.  Your batteries have jumpers between them.  That way, you have two 6 V and it makes a 12 V.  When I said, remove the jumpers or the interconnecting cables, you effectively have NO connection.

ONE WORD.....and I should have said this.  TURN OFF the HOUSE Bank before you remove the Jumpers and leave it off until you reconnect.  Your Intellitec MPX (Multiplex System) will reboot each time (like unplugging a computer). You get a CLEAN ON/OFF when you turn OFF the House Disconnect switch....otherwise you may get an On - Off-On connection and upset the electronics.  Don't aske me HOW I know this.

Start reading your manual.....that is key.  

[Newcsn]

Thanks again @Tom Cherry  Perfect timing - downloaded the manual & will be doing some reading on my flight this afternoon! Truly appreciate the guidance!