Chassis batteries will read 12.0 volts then after awhile they will read 13.6 volts or higher

[TDaleABQ]

Hello and thank so much for this forum.

I have a 2007 Monaco SKT that I have owned since new.  I keep a top of the line trickle charger on it when parked.  All gauges and Aladdin read 13.6 or greater.  It is also plugged in to shore power and I do not think the Magnum really charges the chassis batteries.  Anyway at times I will start it and the voltage reads 12.0 give or take a little and the alternator light comes on and chimes.  after a while sometimes soon other times up to 5 minutes or so, the alarm and light go off and the gages read 13.3 or greater.

I have checked the voltage and the batteries when reading low and they do read correctly. 

Any ideas would be appreciated.

Thanks

Tim Dale

2007 Monaco Knight SKT

2014 F150 Lariat 

[Tom Wallis]

If the voltage measured on the chassis battery posts is 13.6v with the charger on then I'd say they're charging okay. Next I would disconnect the charger for a few hours or for about 5 to 10 minutes with the headlights on, that will eliminate the surface charge so you get an accurate reading. Now check at the posts again. Anything much below 12.5v and your chassis battery is weak and that could lead to the low reading after you crank the engine. However,  the alternator should bring it up to at least 14v quickly, like less than a minute. If not you may need to test the alternator.

Edited June 14, 2023 by Tom Wallis

[MyronTruex]

If this is in colder situations your Grid Heater is likely pulling the voltage low. The alternator may not kick in for a short time at the first as well.

IF you are connected to shoreline while the engine is running it is common for the Alternator Fail light and chime to come on. The two competing sources of charging voltage confuses the circuitry. It does no harm, just observed it on mine and have discovered it is a common complaint.

As a side note, I am a bit surprised your onboard charger does not charge both banks. Take a picture of your front run panel, (below the driver), and from the picture if close enough will discern what setup you have. 

You could have a bi-directional charging setup or basically one way but the board that controls that function is in the upper left quadrant of that panel.

That circuit board controls a large solenoid on the back wall of your battery compartment. That is a vey simple place to take a couple of measurements to find out if it is working correctly. That large solenoid does two things. It is your Boost start combing as well as your battery combining for charging. Very simple. If there is voltage on the purple wire, the solenoid should be engaged and combining the batteries IF it has not failed as most do over time. 

[Bill R]

@TDaleABQ Are you disconnecting from shore power when you start your engine?  If not, this may be causing your alarm.  I have a different rig, but that is what happens when I start the engine and leave on shore power.

[TDaleABQ]

Bill, Thank you for your reply.  It will happen sometimes when connected to shore power but mostly not.  Thanks again.

[TDaleABQ]

Bill, Thank you for your reply.  It will happen sometimes when connected to shore power but mostly not.  Thanks again.

Myron, No I do not have the heater turned on.  Meter shows it is only pulling 1 amp from somewhere.  I keep a trickle charge on the chassis batteries and they can show full charge but sometimes starting, it will drop to 12 volts and alarm.  After awhile something will "kick in" and will go right to 13.6 volts or higher?  I took some pictures of my "run panel". The first one is the complete panel.  Click on it to see full image.  The 2nd one looks like something you may have been explaining.  Note the fuse is missing on the left had side of solenoid?  The third is the solenoid in the battery compartment.  Thank you.

Tom.  I will check that.  Thanks.

[MyronTruex]

The "grid heater" I am referring to is not controllable by you. Unless you have something different. The grid heater comes on to heat the air coming into the engine when the engine is cold. It may cycle on and off for several minutes as the engine comes up to temps. The grid heater is a monster current draw and will pull the battery voltage down as it cycles. Your engine has just sucked many buckets of electrons out of the battery so is already in a lowered state, and then the grid heater keeps sucking them down like a drunken sailor on leave, and your alternator may not kick in immediately.

When starting mine even in good conditions, I push the aux start button to supply additional buckets of electrons. It just takes some of the load off the engine batteries.

Looking at your excellent pictures I can see why you use an external charger. You have an IRD board. Zoom in on the little board in the upper left and you cans see what is written on the ckt board. Isolator Relay Delay. 

This device controls that large solenoid you have pictured with the purple wire and is located in the battery compartment. Once your alternator is up and running and has stabilized the voltage a above a certain threshold it signals that large solenoid to kick in and combines both battery banks. The little ckt board has a delay built in to help prevent cycling the solenoid on and off as the voltages balance between the batteries.  Later model years the board was changed to be bi-directional charging. 

Since you indicate the voltage does come up after a few minutes I think you are just fine and things seem to be working as built. However, over time the engine batteries will become weaker and it may take a bit longer for the voltage to come back up.

As for the other solenoid with the seemingly missing fuse, which it is not, that is the solenoid that latches on when you cycle the switch near the entry door to activate the internal 12 volt systems. That solenoid is very often refered to as the "salesmans" solenoid, along with the "salesman switch", that controls it. That is a common failure item and is often bypassed.

The large solenoid in the battery compartment looks like the original and if so, I cannot recommend enough that you replace it. They fail often and cause all kinds of headaches. 

[Tom Wallis]

Myron is right about the grid heater. They can draw 200 amps while the engine warms up. Sorry I didn't factor that in. However, after the engine is warm an with no other chargers on your charging votage should be higher than 13.6.

Edited June 16, 2023 by Tom Wallis

[MyronTruex]

You mentioned when reading low they don't read correctly.

I do not understand that comment.

You should be able to go right to the battery posts (no shoreline or solar on), and get solid readings. With the engine running the alternator you should see close to 14 volts across both banks of batteries IF you have waited a couple of minutes and IF your combing solenoid/relay is working correctly. As mentioned, changing it is a good idea just based on its age. If I suggested you should change a fuel or oil filter you would do it, but for some reason people just cannot understand changing a part that LOOKS good. 

If you do not have the same voltage on both banks with engine running, measue at that solenoid large posts. One bank is connected to each of the large posts. If the voltage is not the same. Measure the purple wire. If you have 13 or so volts on that, change the solenoid.

The solenoid can work fine one time and not the next. The contacts may be very intermittent. 

[Les Hurdle]

I hope I'm jumping into the right thread here.

I have 2004 Cheetah been attached to shore power for a few months [house got flooded] I noticed fluid on the top of a couple of 6 volters a while ago .  Checked them and they appear to be ok......... think I read on a forum somewhere about overcharging the batts.......... so I turned them off.  Yesterday [aside from 120]  everything died.  Ooops.

Turned the batts on and a few minutes later all good.

I've read the manual but [with respect for all the knowledge shown on this forum] I genuinely do not want to understand the minutia, just the basics.  Simple things like, the coach panel, does it show what the batts are being charged at or something else. see pics. [lh pic is 13.62...].......

thnx

Les

 

[MyronTruex]

First picture, batteries are being charged. Good voltage.

Second picture, batteries are run down. Bad voltage.

If you have a Magnum Inverter/Charger, they can boil batteries if the battery temp sensor goes wonky. (Technical term used by professionals to convey a device is malfunctioning). Find or ask for a manual reference for this component. On my Magnum, it is a telephone like connection on the device. Not to be confused with a remote control connection. 

Based on your pictures, I doubt you have a Magnum.

Boiling batteries indicate overcharging, or perhaps overfilled batteries, or sick batteries. A hydrometer and voltmeter to check each battery will help. A checkbook should resolve or at least eliminate the possibility of bad batteries if they are aging. Aging can be two to longer for batteries in an RV. Most RV batteries commit suicide and are not allowed to live a nice comfortable life. Batteries are never really owned. They are merely rented and will need to be replace sooner rather than later. IF you are connected to shoreline all the time, you can get away with replacing two of the four house batteries to save a few dollars. I do not recommend this for Boondocking of course. I have been living with two house batteries for two years now and have had no issues. 

[jacwjames]

The second picture shows the chassis batteries at 11.97 volts so they aren't charging.  Do you know if your coach does have/had the ability to keep chassis batteries charged while plugged into shore power.  Some Monaco's did not. 

 

FWIW, I started having trouble with my charging system which was suppose to keep the chassis batteries charged.  I started seeing fluctuations in voltage.  So I bit the bullet and installed a Bluesea MLACR.  This latching relay combines both batteries whenever there is a charging source shore/generator or alternator.  Now I can simply look at the remote switch on my dash and know both batteries are combined and as long as I have voltage for lights etc I know the chassis battery is good. 

[Tom Cherry]

Les, I think you’ve posted this concern a few times before.  Myron pretty much nailed it.  Your batteries are probably overfilled.  No one can, or at least I can’t, tell you without you doing some tests and using a VOM, if your charger is working OK.  ODDS ARE….IT IS….OK….So….back to  basics.

Read Battery 101.  Link below. 

Read or download the manual for your inverter and set it up properly.  I don’t think you have a Magnum, but we have manuals in the files for most that Monaco used.  Put the name brand of the charger in the search box.  Click on EVERYWHERE….choose files.  Download.  IT HAS TO BE SETUP PROPERLY.  If you have 4 batteries, then you have around 400 - 450 Amp Hours of capacity….Two batteries in series is the same as ONE….225 OR so.  You have 2 sets or banks of “two batteries in series”.  So you add the two banks….225 + 225.  Use that for the setup.  Edit.  I found an ad for your Cheetah.  Here is the manual for it.

https://xantrex.com/wp-content/uploads/2021/12/445-0193-01-01-Rev-A-online-revisedFreedom-458-Series-Owners-Manual.pdf

the one above is a little more complete and has your remote in it.  Here is a link as to what is in our files.

Spend 10 minutes or less, and make yourself a simple wooden dowel “battery electrolyte dipstick”.  If your batteries are overfilled, a common occurrence since folks always believe “MORE IS BETTER….GO HIGH”…., then order a hydrometer as that is also used to suck up electrolyte….and you can lower the level to the proper level….or go buy a turkey baster or other squeeze bulb “eye dropper”. Folks that eyeball, or folks like me that can’t exactly “see” where that INFAMOUS “Halfway mark between top of plates and bottom os well” is….tend to overfill.  I’M GUILTY.  We are also supporting the Rustoleum (part of WD-40) company as we will eventually need to scrape and clean and repaint our battery trays…. LOL!  I did that many years ago.  Quit overfilling.  No more issues….

The poor man’s way is to turn back on your inverter & charger….and then let the electrolyte “vent off.  Use a few paper towels and absorb the excess…..the level will go down….just quit adding and let it settle in, use your dipstick, and don’t overfill.

That’s it.  BTW…If you follow the recommendations in Battery 101….and buy good quality batteries, you will easily get 6 plus years and don’t have to clean and repaint the battery box every 5 years.  Pay me now….or pay me later….

 

[Georgia Mike]

These caps also help with water loss.

 

[Les Hurdle]

Hi Tom and everyone.... can't thank you all enough and will download all.

I'm going to beg forgiveness.  Our house was flooded last Nov, just got over the Bobcat fire of 3 years ago........ lost most things.  We had a Southwind Storm which was basic and simply never stopped, but 1998 etc etc.  When the house flooded my very understanding wife and I moved into the Storm, thinking a few weeks ;-))  It became obvious our contractor was not top draw but up in the mountains choice is limited.  Months went by.  We needed space, hence the 2004 Cheetah.  I'm 80+ and still working many hours per day my wife works so 'looking after' where we live was not top of the list ,Sadly.

However, 2 weeks ago we fired the contractor and took over the 'remodel'............. now things are getting better......... of-course big fights to come, contractor / ins etc... oh well.

We had a trip planned for mid Oct and we will go in one motorhome or the other, so TODAY is the first day of really checking out the Monaco.  Tech will come on  Tuesday and fix suspension and other things I do not want to do.  So will get his help re batts etc if I can't figure it out

I had asked the previous owner about Batt chargers-equip etc he had no idea and I have yet to find one, but then I've only scratched the 'surface'.  Local auto store declared batts ok...........  if the beast fires up today and I get it outside I can take a good look in the daylight and see what is what.

I'm super rich [ha ;-( ]  so will go buy new batts if need be, then see what happens to them.

New floor planned for end of Oct !!

Will report

Thanks again.

 

Les Hurdle [still a Womble].

 

[jacwjames]

With the house batteries charging/full you can use the battery boost button to tie the house and chassis batteries together to start the rig.  Hold the button down for a couple minutes to give the batteries a little time to equalize. 

[Tom Cherry]

42 minutes ago, Les Hurdle said:

Hi Tom and everyone.... can't thank you all enough and will download all.

I'm going to beg forgiveness.  Our house was flooded last Nov, just got over the Bobcat fire of 3 years ago........ lost most things.  We had a Southwind Storm which was basic and simply never stopped, but 1998 etc etc.  When the house flooded my very understanding wife and I moved into the Storm, thinking a few weeks ;-))  It became obvious our contractor was not top draw but up in the mountains choice is limited.  Months went by.  We needed space, hence the 2004 Cheetah.  I'm 80+ and still working many hours per day my wife works so 'looking after' where we live was not top of the list ,Sadly.

However, 2 weeks ago we fired the contractor and took over the 'remodel'............. now things are getting better......... of-course big fights to come, contractor / ins etc... oh well.

We had a trip planned for mid Oct and we will go in one motorhome or the other, so TODAY is the first day of really checking out the Monaco.  Tech will come on  Tuesday and fix suspension and other things I do not want to do.  So will get his help re batts etc if I can't figure it out

I had asked the previous owner about Batt chargers-equip etc he had no idea and I have yet to find one, but then I've only scratched the 'surface'.  Local auto store declared batts ok...........  if the beast fires up today and I get it outside I can take a good look in the daylight and see what is what.

I'm super rich [ha ;-( ]  so will go buy new batts if need be, then see what happens to them.

New floor planned for end of Oct !!

Will report

Thanks again.

 

Les Hurdle [still a Womble].

 

WHOA….lots of INFO…but here is reality.  Unless the Previous Owner installed some sort of “Thief” system…or such….your Chassis Batteries will NOT be charged when you are plugged in to Shore….Your inverter charges the HOUSE.  These thief devices were marginal at best…or that has been the experiences here. Even if you have one…and it ain’t working, there is better technology…..but don’t buy a new “old technology” replacement.

YES, if your Boost switch is working…and you don’t have good Chassis Batteries….then you need to follow the instructions from the manual.

I think it is simple….overfilled HOUSE.  Suck out a little electrolyte.  Now that is SULFURIC ACID….be careful and don’t get it on your clothes or mix with Bourbon..

NEXT.  i would NOT spend any money on fixing or replacing the Amp-L-Start or the thief since they are marginal.  Let the tech look at the inverter.  Probably fine. 

THEN, use a pair of Jumper Cables between the two Banks for a few days.  Positive to Positive and Negative to Negative.  That will allow the Inverter to charge BOTH. Your Chassis will be recharged….driving it will do the rest.  Remember, when you drive….the HOUSE is not being charged….unless the Genny is on.

Take the 10 minutes to measure and make a dipstick.  I’m gonna bet…you are 3/4 way up…(overfilled) and not the proper half way up (top of plates to bottom of the well)…

Have fun…

[96 EVO]

Have YOU added water to the batteries in these last few months?

If not, you probably have an issue with your charger boiling your batteries.

[Les Hurdle]

Hi

 

Yes I have added distilled water [DW].....checked today and the levels were down. I added DW and will await to see what happens.  Volts are about 6.4....... main batt once the motor started [11.9] went up to 12.36.........  however I see they are 2018 so time to get new me thinks !

[Tom Cherry]

6 minutes ago, Les Hurdle said:

Hi

 

Yes I have added distilled water [DW].....checked today and the levels were down. I added DW and will await to see what happens.  Volts are about 6.4....... main batt once the motor started [11.9] went up to 12.36.........  however I see they are 2018 so time to get new me thinks !

OK….unless you have a broken inverter, then the “boiling” or the vapor or water condensation on the battery tops is self inflicted.  Do the simple think.  Use a dowel snd measure the distance from the plates to a known mark on the battery cell.  Then put the dowel down and align it with the bottom of the well.  These two marks should be maybe 1 - 1/14” apart.  Divide the distance by 2.  Add 1/16.  Mark or score a line up from the bottom of the dowel.  That is the FILL LINE.  If you overfill and get the liquid too high…it will escape and cause grief.  Our chargers have 3 differnt stages.  As long as you set up, read the manual, the charger…it should NOT boil or overcharge. Folks put on a $50 supplemental charger.  It cooks or overcharges.  Half the cost of the inverter is the charging section.  It goes through 3 stages….

NOW…your Chassis batteries.  Do NOT measure the voltage on the Chassis until at least 5 minutes of RUN TIME.  There are electric toaster elements inside the air intake.  They absorb or use every ampere of the alternator.  Once, after the engine has been running for 5 minutes or so, the air intake heaters shuts off.  NOW, you measue…typically in the 13.5 to 14.1 range….if NOT….you need to find a GOOD Alternator and Starter shop.  Have the Altermator REBUILT.  Do NOT buy an aftermarket “guaranteed to work” new one.  The shop needs to buy ONLY Leece Neville OEM parts.  Brushes and Diodes and whatever.  Have ALL NEW DIODES….and all new parts.  Otherwise….you will be posting about flashing lights and won’t charge….

Thats the basics.  Don’t make it complicated. Properly FILL (measured….not eyeballed) your batteries….the water will go away or you use an eye dropper or a turkey baster and lower the level to the right level on your dipstick..

Check your Chassis after running for at least 5 minutes….your voltage should come up.  The. DRIVE ON.  If you get a hesitation when the engine is really hot and been sitting for a few minutes….THEN time to think about new Chassis batteries. Carry a set of Jumper Cables…you can jump start…

[96 EVO]

2 hours ago, Les Hurdle said:

   however I see they are 2018 so time to get new me thinks !

I've found the older they get, the more frequent they need water.

1/4" below the bottom of the fill tubes.

[Tom Cherry]

5 minutes ago, 96 EVO said:

I've found the older they get, the more frequent they need water.

1/4" below the bottom of the fill tubes.

Maybe....depends on the battery and the height of the plates and the bottom of the well.  NOT ALL BATTERIES, like Monaco's are built the same.  Trojan has redesigned their wells to have a FILL HERE DUMMY LINE.  The Trojan techs said the wooded dipstick was a great idea....and that low electrolyte was OBVIOUSLY the cause of MOST issues, but complaints of "corrosion" and liquid was the second most complaint....as in MORE IS BETTER...then it bubbles.

The water issue is not something that many of us have observed.  Now, the reason....maybe...  MOST of us use the Battery Water Miser caps.  We rarely add an OZ of DW every 6 - 9 months.  The electrolyte (DW) collects in the top of the cap...like a distillation chamber...then just "drips down" like a still.

Great devices.  Most of the folks that swear by them also get 6 - 8 years (one is going on 9) out of a set of Trojan T-105's

[Les Hurdle]

Trojan or Interstate..............  I think I'll buy new next week.

 

 

 

[96 EVO]

6 minutes ago, Les Hurdle said:

Trojan or Interstate..............  I think I'll buy new next week.

 

 

 

Rolls / Surrette !

Edited October 2, 2023 by 96 EVO

[Tom Cherry]

6 minutes ago, Les Hurdle said:

Trojan or Interstate..............  I think I'll buy new next week.

 

 

 

Interstate cranking.  Don't know HOW many you have or what size.  If you have TWO, you want the 900 CCA ones.  The 750's are too puny.

Trojan House - Trojan T105's.  Best there is out there.  We have folks with 6 - 8 years on them....one is past that and they STILL are 100% State of Charge....as in they are like NEW and still have the SAME amp hour capacity as when he bought them.

Get Battery Water Miser caps for the House.  Amazon has them. They will take care of all that "ooky pooky" acid water on top.  They are the greatest.  Many members....and these are the ones that have been MHing from years and are our EXPERTS here.

That's the deal..

Good Luck...

BUT....don't rush out and buy until you STOP and MEASURE the Voltage, after the Engine is running for 5 minutes or so, on the Chassis.  See my post.  That tells you that all is well with your electrical system.