Question concerning the two battery systems

[RorySamuels]

Just bought a 2000 Monaco Knight 36Z. Having issues with the 12V Electrical systems. Is there anything that shows what is connected to the house battery system vs what is connected to the vehicle system?  I have a number of devices that are not working that I feel should be on the vehicle batteries such as the driver seat controls. I know that the batteries for the house system are bad and have not been able to get the generator working or hook up to AC. I have hooked up the batteries to chargers,but the house batteries do not accept a charge.

[Gary M]

I take it u do not have the wiring diagram’s for your coach. Check our download files to see if anyone had posted a copy. If you hook up to at least 110 AC your onboard charger/ inverter should pump your batteries up if they are still good.

[Tom Wallis]

1 hour ago, Gary M said:

I take it u do not have the wiring diagram’s for your coach. Check our download files to see if anyone had posted a copy. If you hook up to at least 110 AC your onboard charger/ inverter should pump your batteries up if they are still good.

And even if the batteries are no good it should provide enough power while plugged in to run all or most of your 12v accessories. If you have AC for chargers why can't you plug in the coach?

[bobdinsmore]

Rory, I think if you are able to buy new house batteries it will make your life much easier troubleshooting your electrical problems. I like Trojan T105. You'll get a gazillion opinions on which batteries....    🙂. Once you get troubleshooting there is a huge wealth of experience on this forum. You'll enjoy your motorhome and all you will be able to see and experience. I've been camping my entire life and it's been an amazing lifestyle. Eighty three years and still going strong: my wife and I are very lucky to be healthy enough to continue!

[Chuck B 2004 Windsor]

Working with dead batteries can be hazardous to your being.  Trying to charge them might cause them to Explode.  Replace all the batteries in that battery bank because weak batteries will cause the new ones to discharge sooner.

[Tom Cherry]

Comments for Newbies….

The Chassis cranks the Engine.  All of the “switches” you use in driving are on that battery.

The House provides power so you can boon dock.  The 4 bank set has a lot of info in your manual.

The SHORE cord provides AC through the Automatic Transfer Switch (ATS) to the main AC panel in the motor home.  Read manual and familiarize yourself with it.  The Genny provides AC a power via the ATS when you are NOT on Shore.

The internal AC outlets and Microwave go through the Inverter/Charger.  If it is a Magnum, and perhaps another brand, you have got to have something resembling a battery to get 115 VAC to the outlets.  There is a 30 A breaker in the AC panel.  That provides power to the Inverter/charger.  There is an ATS a on the main board of the Inverter.  The 120 VAC outlets and Microwave will not work, even plugged into shore power it the Inverter does not “measure or sense” a battery.  

FIND THE ATS.  See your Manual.  It will have three large pieces of plastic flexible conduit.  if it says IOTA 50R, it is a fire and safety hazard and could burn down the MH.  It should be replaced,  the ESCO LPT50BRD is the recommend and most used…but there are other brands.  There is a post or thread on that.  Learn how to search topics and read it.  ANY FURTHER TROUBLE SHOOTING OR RUNNING THE GENERATOR MAYNOR CAN RESULT IN AN OVERLOAD AND THE IOTA MIGHT CATCH FIRE….OK…NO IOTA…PROCEED…

Put on SAFETY glasses or goggles.  Take a picture of your House Bank.  There is a Jumper running from two batteries….negative to positive.  You have TWO (2) 6 VDC batteries connected like that…or two 12 VDC banks.  In series, these are the same as a 12 VDC battery.  Disconnect the jumpers.  Now use a volt meter and measure the voltage of each battery.  They should be in the 6 VDC range,  if any measure 4.5 or so….they are toast.  They can NOT be charged.  They will NOT WORK.  If you have TWO good or reading 6 VDC batteries even if they are weak and barely reading 6 VDC, then remove the other two.  Hook them up like a back.  The jumper linking the Positives (on the side) must be removed….to prevent arcing.  The Negative is chassis ground….it is ok. NOW you should, using shore power, have 120 VAC inside as long as the inverter is ON.  If you have a Magnum brand inverter, there may be one or three pin type external circuit breakers.  Push them IN…they might not move….which means they are OK.  Now, with AC shore power, push and hold the main power button on the Magnum.  Read the manual or download one for your inverter.  Holding it in for 15 seconds does a soft start or soft reboot.  NOW….you should be OK.  

IF you do NOT have shore power, you can use a single jumper cable between the HOUSE POSITIVE & CHASSIS POSITIVE.  Then you can start the Genny….

Reading the owners manual, it is on the Monaco Coach Site is extremely important.  Take it and go outside and identify where things are.  Here is the link…hopefully you DO have the hard copy….good luck…

https://www.monacocoach.com/resources/media/manuals/2000_Knight.pdf

 

[RorySamuels]

Thank you, Tom and everyone else who has replied.  The reason this has all come up is that I don't have possession of the motor home. It is at a truck repair garage to get it running enough to drive it. I asked for a repair estimate and for them to go through all main engine, braking and steering systems. When I tried to move the MH a steering hose broke and the brakes didn't work. I found that the driver seat did not work as well but it did work when I jumped the house batteries. The reason I asked the question was because I don't want to pay for trouble shooting that will lead back to the house batteries that I now know need to be replaced. Measured voltage was 0.27 V per battery.  The manual shows that the brakes have a 12 V motor attached to the master cylinder. Just want to make sure that it isn't connected to the house system like the driver's seat.

On another note but similar vein:  Previous owner told me the batteries were new. The date code on the Optima batteries installed in the house system is 606540597T. The first digit is the year of manufacture, the next three digits are the Julian day of the year. Per that date code the batteries were manufactured around March 6, 2016 0r 2006.  In either case not new.   Do you think the term new with battery means it should still be under warranty as a minimum? 

Thank you in advance for your reply and sharing your knowledge.

 

[Tom Cherry]

45 minutes ago, RorySamuels said:

Thank you, Tom and everyone else who has replied.  The reason this has all come up is that I don't have possession of the motor home. It is at a truck repair garage to get it running enough to drive it. I asked for a repair estimate and for them to go through all main engine, braking and steering systems. When I tried to move the MH a steering hose broke and the brakes didn't work. I found that the driver seat did not work as well but it did work when I jumped the house batteries. The reason I asked the question was because I don't want to pay for trouble shooting that will lead back to the house batteries that I now know need to be replaced. Measured voltage was 0.27 V per battery.  The manual shows that the brakes have a 12 V motor attached to the master cylinder. Just want to make sure that it isn't connected to the house system like the driver's seat.

On another note but similar vein:  Previous owner told me the batteries were new. The date code on the Optima batteries installed in the house system is 606540597T. The first digit is the year of manufacture, the next three digits are the Julian day of the year. Per that date code the batteries were manufactured around March 6, 2016 0r 2006.  In either case not new.   Do you think the term new with battery means it should still be under warranty as a minimum? 

Thank you in advance for your reply and sharing your knowledge.

 

New batteries would mean that they were within the warranty of the Manufacturer.  Obviously, and not knowing OPTIMA, that is usually only one to two years.

The rest will be between you and the seller.  A new set of Trojan T105 or even the original OEM Interstates....both of which are in the required 220 or so amp hour range should be in the $700 - $800 range.  Trojans would be my pick.  Do NOT recommend SEALED or Maintenance Free Deep Cycle for the House.  I run Interstate ML-750 or something like that. I have two of them....CCA is 750 Amps and they are great.  Just not sold on the Interstate Deep Cycle batteries....as the Trojans have a much better track record and are also more forgiving if you abuse or accidentally do something wrong.

6 year old batteries, not maintained....and are virtually dead....have all the Lead Oxide coating dissolved or flaking off the plates. That then is like sludge in the bottom of each cell.  That sludge contacts the plates and shorts them out.  Thus....it is like having a battery with 3 shorted out or defective cells....and there is NOT a fix....save recycling.  

Good Luck...

[RorySamuels]

Thank you again Tom.  I re-read the owner's manual and the brakes have hydraulic boost from the power steering pump. The brake electrical pump is in case the power steering pump fails.  

I do have the wiring diagrams that I downloaded from this site. Just having issues with reading and interpreting them. I appreciate all of the assistance. I used to camp with my parents in a 23' Prowler Travel Trailer. This motor home thing has a lot more moving parts.   

[waterskier_1]

Just a quick comment.  If your house batteries drop below around 11.0 Volts, the charger (built into the inverter) will disconnect the batteries to prevent damage to either the batteries or the inverter.  In such case, you must recharge the house batteries above around 11.5 Volts before the charger will reconnect and resume charging the house batteries.  

  -Rick N 

[Tom Cherry]

8 hours ago, waterskier_1 said:

Just a quick comment.  If your house batteries drop below around 11.0 Volts, the charger (built into the inverter) will disconnect the batteries to prevent damage to either the batteries or the inverter.  In such case, you must recharge the house batteries above around 11.5 Volts before the charger will reconnect and resume charging the house batteries.  

  -Rick N 

To qualify what Rick said....  You have a Trace Inverter, per the manual.  I have NO experience with it.  I understand Magnums and can offer this.

Magnum sets the Low Batter Cut Off, by default, at 10 VDC.  Now that seems ridiculous....but the last time that I talked, extensively, to a Magnum tech about that, he said it was 10 VDC...and I asked why.... "BECAUSE".  OK...being one to trust but VERIFY...I pulled the Remote manual for my almost new RC-50.  BINGO....he is correct.  It IS set to 10 VDC....which can really play havoc.  SO....unless someone is knowledgeable, as I would hope most posters are, NEVER install a new item that requires setup without reading the manual. I installed mine.  Put power on the MH, then watched the remote say good morning to the Magnum....then did a SOFT start....just to get the inverter "tuned up" and then reset all the parameters.  

SO....for your TRACE....read the manual.  It MAY (probably) does have a similar feature....the Low Batter Cut Off (LBCO) function is there to protect, but it MIGHT be adjustable and it MIGHT (probably is) TOO LOW.

My advice to folks is to set the LBCO to around 11.6 or maybe 11.7.  That way you are NOT harming your batteries.  NOW....folks will say, correctly, that below 12.0, which is 50% State of Charge (SOC), you can have issues. BUT, at least on the Magnum's the remote reads, due to the distance, about 0.1 to 0.15 VDC LESS than what you read with a VOM on the Batteries.  So, when I do my RUN DOWN TEST, I make sure that the LBCO is lower.  The batteries will actually "bounce back" some also when you pull or reduce the load.  So, setting the LBCO to the mid 11.0 range is not a concern.  Magnum also uses a PURE value.  IF the limit is reached....it is BINGO.....OFF.  I would have hoped that the system will be upgraded so that an occasional "Blip" of value a tenth below would have to have a HOLD or a Continuous Reading of say 11.5 if it were set to 11.6.  NOPE....I asked Magnum. A lot of industrial controls have low level alarm points....say 11.6.  BUT, if you hit 11.5, the value starts a timer (which you set)....so that an occasional OPPS....does not set off an alarm.  Magnum is NOT that sophisticated.

Hope this adds a little more insight into Rick's point....which is well taken....but "all inverters" might not be the same...and not everyone has a Magnum....

Rick just posted a followup….so I’ll add…on the Magnum, you will have a LBCO error or message.  Sometimes you can reset it from the Remote.  Then, since the batteries probably “popped back”, you might be OK.  On the Magnums, the safest and most reliable method is to clear the remote’s error…but then, with AC (House or Genny ON), do a soft reset.  Hold the power button the Magnum case for 15 seconds or so.  That clears sup any cobwebs inside and also refreshes the Remote.  You MAY have to turn ON the charger by pushing the ON a button….but then all should be well.   Good point, Rick.  Thanks 

[waterskier_1]

7 hours ago, Tom Cherry said:

To qualify what Rick said....  You have a Trace Inverter, per the manual.  I have NO experience with it.  I understand Magnums and can offer this.

Magnum sets the Low Batter Cut Off, by default, at 10 VDC.  Now that seems ridiculous....but the last time that I talked, extensively, to a Magnum tech about that, he said it was 10 VDC...and I asked why.... "BECAUSE".  OK...being one to trust but VERIFY...I pulled the Remote manual for my almost new RC-50.  BINGO....he is correct.  It IS set to 10 VDC....which can really play havoc.  SO....unless someone is knowledgeable, as I would hope most posters are, NEVER install a new item that requires setup without reading the manual. I installed mine.  Put power on the MH, then watched the remote say good morning to the Magnum....then did a SOFT start....just to get the inverter "tuned up" and then reset all the parameters.  

SO....for your TRACE....read the manual.  It MAY (probably) does have a similar feature....the Low Batter Cut Off (LBCO) function is there to protect, but it MIGHT be adjustable and it MIGHT (probably is) TOO LOW.

My advice to folks is to set the LBCO to around 11.6 or maybe 11.7.  That way you are NOT harming your batteries.  NOW....folks will say, correctly, that below 12.0, which is 50% State of Charge (SOC), you can have issues. BUT, at least on the Magnum's the remote reads, due to the distance, about 0.1 to 0.15 VDC LESS than what you read with a VOM on the Batteries.  So, when I do my RUN DOWN TEST, I make sure that the LBCO is lower.  The batteries will actually "bounce back" some also when you pull or reduce the load.  So, setting the LBCO to the mid 11.0 range is not a concern.  Magnum also uses a PURE value.  IF the limit is reached....it is BINGO.....OFF.  I would have hoped that the system will be upgraded so that an occasional "Blip" of value a tenth below would have to have a HOLD or a Continuous Reading of say 11.5 if it were set to 11.6.  NOPE....I asked Magnum. A lot of industrial controls have low level alarm points....say 11.6.  BUT, if you hit 11.5, the value starts a timer (which you set)....so that an occasional OPPS....does not set off an alarm.  Magnum is NOT that sophisticated.

Hope this adds a little more insight into Rick's point....which is well taken....but "all inverters" might not be the same...and not everyone has a Magnum....

I really didn't want to get into nuts & bolts of inverter/battery charger operation, but much of what Tom says is true.  Many Inverters can be "set" or "programmed" to voltages you want.  The concern is not so much the reading of the remote my be different from what the inverter "sees", is when large, but limited duration, loads are put on the inverter.  For example, you want to heat up a cup of coffee in the microwave.  That 60 seconds will likely draw down even a charged battery bank of less that 400 Amp-Hours below 12-volts WHILE THE MICROWAVE IS RUNNING.  It will then "bounce back" to it's real value when the microwave is shut down.  This becomes a judgement call, since none of the inverters I've worked on (Trace, Xantrex, Magnum, and Victron most recently) have timers for how long the duration of the load is applied.  I set mine a bit lower when I was using Lead Acid cells (FLA or AGM) than I do with my LiFePO4 Lithium batteries.  That why I said "about" when referencing the voltage.  Many were set (not sure if Factory or by someone's direction) to drop out just over 11.0 volts, and not re-engage until above 11.5 volts.  As normal, your setting may be different.

My basic point was simply to remind that if you do exceed whatever that Low Voltage Cut Off value is, most inverter/chargers will disconnect the batteries and not reconnect the batteries until they are charged to a level higher than the Low Voltage Cut Off.  May can't figure out why they can't charge their batteries when they run them down.  

  -Rick N.