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I park my coach in the RV Lot in our community and have never had an issue with the chassis batteries going down until the last week, I went to move it to my driveway to work on it and discovered everything was dead.  Got a jump from Coach-Net, parked it in my driveway and plugged into 50A outlet, everything came up full overnight.  After a few days at home I moved it back to the lot, this time I turned off both chassis & house disconnects, went back a day later and chassis batteries are dead.  While at home I did no electrical work on the coach.  When the chassis battery disconnect is turned off does it actually kill power to everything?

 

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Posted (edited)

On my 2000 Dynasty, I believe the main power switches kills power to everything, except the solar panel still charging. 
 

Different years can be different…

 

since it happened twice - how old were the batteries… I say we’re because they probably need replaced. 

Edited by Rocketman3
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Last time my Chassis batteries acted up like that they wound up needing replaced. I nursed mine along for a few months but every time I sat for more than 5 days they died and had to be jumped.

Check the age of the batteries. Mine looked completely normal during that time. Unfortunately, they don't last forever.

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16 hours ago, Neil Loveless said:

I park my coach in the RV Lot in our community and have never had an issue with the chassis batteries going down until the last week, I went to move it to my driveway to work on it and discovered everything was dead.  Got a jump from Coach-Net, parked it in my driveway and plugged into 50A outlet, everything came up full overnight.  After a few days at home I moved it back to the lot, this time I turned off both chassis & house disconnects, went back a day later and chassis batteries are dead.  While at home I did no electrical work on the coach.  When the chassis battery disconnect is turned off does it actually kill power to everything?

 

First.  No to yiur question.  The chassis battery kills on the large draw items, as well as the ability to start (as in the relays).  You still have parasitic loads like the “ECM” on the engine and the Transmission Control Module”.  This keeps the various electronic modules in “standby”.  Ordinarily, folks get a few weeks without any issues.

Second, and this is making some assumptions, you probably have a 8 bank House set or 4 banks of two six volt batteries in parallel.  There are also parasitic loads….and Monaco, as well as Beaver, did a whole lol of different wiring “types”. The House bank is always connected to the inverter.  You have to pull yhe jumpers to kill the parasitic load in the inverter….the house switch, with Eve bit and the inverter “off” STILL uses power as the inverter is in STANDBY. Then the House Switch kills most of the DC appliances.

Here is where it gets tricky.  There were two types of circuits for maintaining battery life.  One is the BiDirecfional Charging, where there is a large, often called called Big Boy which is actually your Battery Boost solenoid/relay or solenoid that is used for “jumpering” both banks.  There are electronic controls so if one bank starts to run down, the system opens the 200 Amp or so solenoid and whatever load is on the bank going down does not drain the other one,

The other system is a “Maintainer”, which is wired to “steal” a little bit of charging current from the House Bank and give it to the Chassis bank to keep them charged.  Unless you are the original owner, some folks had added a maintainer as a backup.

You need wiring diagrams and the ability to understand which system you have to start trouble shooting.  It also helps to have a clamp on digital meter that is accurate in tenths of an ampere as well as large loads,  Then, after both banks are charged, you start to measure the current draw and then find the component or item that has excessive drain.

Not knowing your skill level or MH experience, it is hard to be more specific.  But, I will make a few comments….or suggestions…

First, if you do not use the house bank much and keep it plugged in, then the batteries get lazy.  The suggested rule of thumb is to exercise or run them down to about half (50% State of Charge or SOC) at least annually.  Now if you boon dock, that counts.  Since you leave the MH parked without power or low capacity Solar, if you have a panel, then they should have been “exercised”.

The next question is whether you have a bad battery or a bad bank or something that is all of a sudden drawing too much power.  

ONE LITTLE overlooked issue can be the Alternator.  All alternators have diodes in them.  If a diode goes bad, then it will, in a heartbeat, drain a good chassis battery bank, I know…that happened on a boat and drove me crazy.  There is a rule of thumb that a properly working alternator will draw or back drain the battery if the parasitic load inside the alternator exceeds 40 or so milliamperes,  Mine was almost 200 MA.  The trick of the trouble shooting is to have all the parasitic loads on the  chassis battery removed….which means that the ECM and TCM and all OTHER directly connected (fused of course) have to be removed.  Not for the novice.  BUT, there are good alternator shops that can do this.  BUT, under no circumstances, if you have an alternator with bad diode(s) let them sell you a new alternator, unless it is the SAME Leece Neville and an exact replacement,  Have it rebuilt, but specify that they only use Leece Neville parts….not aftermarket.  We could write a book about folks that bought others or got “imported” parts.  

I assume that you are aware that there is a host of parasitic loads on the House Bank and you need to disconnect all of them for storage.  Your TV’s and home entertainment components are never OFF.  The standby circuits draw, combined, a LOT of juice.  Most folks knowledgeable about this have surge protectors or power strips so they plug all them into that device…THEN TURN IT or THEM off as part of the shutdown.  They also unplug the microwave and coffee makers with clocks,  They pull all the phone chargers out….but AC and DC.  That really prolongs the storage time.

NOW, the suggestion about a bad battery or set is also good advice.  BUT, many folks have replaced banks that were probably OK and could have been exercised or recovered.  Taking in a set of 8 batteries that are abused and only need exercising and having them load tested will ALWAYS end up buying new batteries.  

Exercising them is a bit of a task, but not rocket science.  You need a digital voltmeter and a good specific gravity tester.  The SG tester  needs a scale….not colors.  I have attached a .Trojan SOC (State of Charge) chart.  The left column is the SOC and the others are the SG and Volts.

If you have 8 house batteries, assuming they are Wet Cells and NOT AGM’s, then the process is fairly simple.

Disconnect a Solar charger or just cover the panel with a opaque tarp or blanket or quilt.  Check the electrolyte level and fill to half the distance between the top of of,the plates and the bottom of the “well”….distilled water ONLY!  Recharge them.  Now DISCONNECT the jumpers between the batteries bank.  You should have 4 if you have 8 batteries,  NOW. Measure each .battery SG as well as voltage.  BINGO…you now can look up the SOC.  If there is a lot of variation in SG in the cells in one battery, then that is a sign of trouble,  BUT, if one battery only measure 4 VDC or so….BINGO.  That battery is GONE.  You don’t know this unless you have the disconnected and look at each line,  if one cell is REALLY low….then that battery is SHOT….or maybe headed that way. Reinstall the jumpers.

With all the power consuming items mentioned above are off….do your own load test.  Put a 500 watt load on the MH. A cheap quartz halogen 500 watt lamp works. One of these hooked up should drain your set of batteries, if they are “GOOD” to a 50% SOC in 9 hours or so.  Hook that up.  Use the inverter remote to read the battery voltage.  NOW, understand that you will have a LOWER displayed voltage than if you measured each battery directly with a volt meter.  Rule of thumb…when the remote reads 11.9 STOP. Odds are the real voltage at the battery is 12.0/1…or close to 50% SOC.

THEN…disconnect the jumpers again.  Let the batteries sit for maybe an hour.  Repeat your readings…record all the data.  Then refill the electrolyte….recharge for several hours.  Disconnect the jumpers and record the SG and Voltages….  

Then do it ALL AGAIN.  The readings after recharging should show the  SG closer within each battery and the batteries should be closer also.  It MIGHT take one more cycle…..then after recharging….with the jumpers removed…..read and look up the SOC and each battery.  They should all be within a 10% range….if one is worse, then at least you know.  Rule of thumb, the recharged, jumpers off, wait an hour SOC should be 80 - 90%.  If not….time to think about a new set.

edit…..changed the file picture for a better and newer “view”….from the Trojan Battery Manual.  Here is a link to one of the best reads on battery maintenance…..  I learned about the testing from a member here….and thanks to him….

https://www.trojanbattery.com/pdf/TrojanBattery_UsersGuide.pdf

I KNOW this works and greater scientific minds here, as well as the Trojan tech support folks, say this this is ONLY way to know.

Assuming that you have NO dead cells in a battery or a shorted (4 VDC) battery, then your batteries are as good as they ever will be.  I had one dead cell (voltage 4 VDC) in one battery and a very low SG reading in one cell of another battery.  They were shot.  I actually pulled them out. I hooked up only the good two. They were fine.  I decided to junk the whole set of 4 OEM Interstate bank and replaced them with Trojan T105’s…I am on my third set and I have used my MH twice or three times they average yearly numbers.  I have spent t least 5 weeks out every year and done a lot of short trips….some boondocking.

NOW, many will say JUNK and get AGM’s.  I understand their logic, but it also means that you have to have a PERFECT electrical system.  If you abuse a wet cell, it is more robust.  But, if you over or under charge an AGM….TOAST.  Yes, the prices are closer.  But you need to have a perfectly working charging system and be aware of when there are problems….and our motor homes are notoriously difficult to trouble shoot.

As to the chassis batteries.  Yes…they are sealed.  You exercise them each time you start them.  A quick way to see if you have bad batteries is to drive for a few hours in summer heat.  Then shut it down….maybe 15 to 30 minutes,  Listen to the “sound” when you turn the key….if there is a hesitation…or really long lag…it’s getting that time.  The idiot “LOW BATTERY” warning light will come on with a new, totally charged bank after a minute or so….and you have no lag….

WAY TOO MUCH…but your issue is not cut and dried.  The more you understand, the more you can monitor and take care of your rig.  The Patriots wee really nice…
 

 

 

00C04878-2DBB-45BD-813B-40A3C6594C4F.png

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9 hours ago, Rick A said:

Can I get a degree after that? Thanks I read it 3 times, interesting.

Only if you reread the post and download the picture of the SOC….and then study the Trojan Battery Maintenance Manual…I revised the original post and put in a better picture and also a link to the manual.  THEN, you get your degree.

Thanks for reading….I hope it benefits many…. 

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How many times can you discharge a battery before you kill it.

I've had to replace my chassis battery twice.  Not sure if the battery was original to my 2002 coach when I bought the rig in 2008.  I had to replace in 2012, it died on my wife as she was driving the coach from Tn to UP of Michigan.  She was able to start the coach by using the battery boost switch and the alternator seemed to keep up.  Not many places sold a large battery like I needed but found one at a Car Quest store in Marquette.   Unfortunately that only lasted ~3 years.  I then replaced with a Duracell from Battery Plus, it's now 7 years old and still going strong. 

Last year I was concerned about my battery maintainer system which used the BIRD, Lambert 415, and Isolation relay.  I started noticing the chassis battery wasn't being charged like it should and the Lambert was clicking on and off and at one point went to clicking none stop.  So instead of worrying about whether it was working or not working I just replaced with the Bluesea.  Simple install and a great modification. 

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2 hours ago, jacwjames said:

How many times can you discharge a battery before you kill it.

I've had to replace my chassis battery twice.  Not sure if the battery was original to my 2002 coach when I bought the rig in 2008.  I had to replace in 2012, it died on my wife as she was driving the coach from Tn to UP of Michigan.  She was able to start the coach by using the battery boost switch and the alternator seemed to keep up.  Not many places sold a large battery like I needed but found one at a Car Quest store in Marquette.   Unfortunately that only lasted ~3 years.  I then replaced with a Duracell from Battery Plus, it's now 7 years old and still going strong. 

Last year I was concerned about my battery maintainer system which used the BIRD, Lambert 415, and Isolation relay.  I started noticing the chassis battery wasn't being charged like it should and the Lambert was clicking on and off and at one point went to clicking none stop.  So instead of worrying about whether it was working or not working I just replaced with the Bluesea.  Simple install and a great modification. 

My experience....others might differ....no guarantee of future performance....LOL  I have 30 amp power in storage and keep it plugged in at all times when there...as well as 50 amp at home and mostly on the road....and we have 66K on the MH.  We have made 62 trips.  Some long...some short. We have broken camp 250 times so far.  That averages 2.5 nights per campground..... We bring it home a few days prior to the trip and keep it there a few days to unpack.  So, the Engine gets started a WHOLE BUNCH.... 

Original Owner.  Build July 2008 OEM Interstate 31LHD.  This was the LOW (L) cranking range.

Jun 2015 - Replaced with Same Interstate....EXCEPT....I upgraded to the 31 MHD.  The Dynasty in 2007 through bankruptcy had the 31 MHD for my EXACT ENGINE.  Cost cutting on Monaco's part.

Oct 2021 - Had a failure of the Intellitec BigBoy BIRD (200 Amp) solenoid.  PROBABLY just some contact issues and after a power outage, the BigBoy did not work.  Chassis Batteries Dead...but House MARGINAL.  OK.  I followed the HOLD ON procedure where you do a flash charge or surface to the Chassis.  I also had the genny running so that there was high current charging to the House.  Then I tried to start and the starter was turning....so I bumped the Boost and the engine hit so I quickly let off.  That did TWO things.  First it actually hit the Big Boy's contact with a huge current draw.  That probably then arced or cleaned them.  Second, I was either going to replace the Big Boy or clean it.  We were headed on a trip in 2 days....and I did not want to risk a failure. in the field.  I had NO issues on the trip as the Big Boy appeared to be working.  I did replace it after we got home.  I serious DOUBT that my Chassis batteries were "toast", but was not willing to recharge and risk it.  I lucked into a deal with the Interstate Distributor...and only paid $120 each for them...a BARGAIN....

My comment....you should be good to go.....the Blue Seas device seems more bullet proof than the Intellitec BIRD system...  

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6 hours ago, Tom Cherry said:

Only if you reread the post and download the picture of the SOC….and then study the Trojan Battery Maintenance Manual…I revised the original post and put in a better picture and also a link to the manual.  THEN, you get your degree.

Thanks for reading….I hope it benefits many…. 

 

17 hours ago, Tom Cherry said:

First.  No to yiur question.  The chassis battery kills on the large draw items, as well as the ability to start (as in the relays).  You still have parasitic loads like the “ECM” on the engine and the Transmission Control Module”.  This keeps the various electronic modules in “standby”.  Ordinarily, folks get a few weeks without any issues.

Second, and this is making some assumptions, you probably have a 8 bank House set or 4 banks of two six volt batteries in parallel.  There are also parasitic loads….and Monaco, as well as Beaver, did a whole lol of different wiring “types”. The House bank is always connected to the inverter.  You have to pull yhe jumpers to kill the parasitic load in the inverter….the house switch, with Eve bit and the inverter “off” STILL uses power as the inverter is in STANDBY. Then the House Switch kills most of the DC appliances.

Here is where it gets tricky.  There were two types of circuits for maintaining battery life.  One is the BiDirecfional Charging, where there is a large, often called called Big Boy which is actually your Battery Boost solenoid/relay or solenoid that is used for “jumpering” both banks.  There are electronic controls so if one bank starts to run down, the system opens the 200 Amp or so solenoid and whatever load is on the bank going down does not drain the other one,

The other system is a “Maintainer”, which is wired to “steal” a little bit of charging current from the House Bank and give it to the Chassis bank to keep them charged.  Unless you are the original owner, some folks had added a maintainer as a backup.

You need wiring diagrams and the ability to understand which system you have to start trouble shooting.  It also helps to have a clamp on digital meter that is accurate in tenths of an ampere as well as large loads,  Then, after both banks are charged, you start to measure the current draw and then find the component or item that has excessive drain.

Not knowing your skill level or MH experience, it is hard to be more specific.  But, I will make a few comments….or suggestions…

First, if you do not use the house bank much and keep it plugged in, then the batteries get lazy.  The suggested rule of thumb is to exercise or run them down to about half (50% State of Charge or SOC) at least annually.  Now if you boon dock, that counts.  Since you leave the MH parked without power or low capacity Solar, if you have a panel, then they should have been “exercised”.

The next question is whether you have a bad battery or a bad bank or something that is all of a sudden drawing too much power.  

ONE LITTLE overlooked issue can be the Alternator.  All alternators have diodes in them.  If a diode goes bad, then it will, in a heartbeat, drain a good chassis battery bank, I know…that happened on a boat and drove me crazy.  There is a rule of thumb that a properly working alternator will draw or back drain the battery if the parasitic load inside the alternator exceeds 40 or so milliamperes,  Mine was almost 200 MA.  The trick of the trouble shooting is to have all the parasitic loads on the  chassis battery removed….which means that the ECM and TCM and all OTHER directly connected (fused of course) have to be removed.  Not for the novice.  BUT, there are good alternator shops that can do this.  BUT, under no circumstances, if you have an alternator with bad diode(s) let them sell you a new alternator, unless it is the SAME Leece Neville and an exact replacement,  Have it rebuilt, but specify that they only use Leece Neville parts….not aftermarket.  We could write a book about folks that bought others or got “imported” parts.  

I assume that you are aware that there is a host of parasitic loads on the House Bank and you need to disconnect all of them for storage.  Your TV’s and home entertainment components are never OFF.  The standby circuits draw, combined, a LOT of juice.  Most folks knowledgeable about this have surge protectors or power strips so they plug all them into that device…THEN TURN IT or THEM off as part of the shutdown.  They also unplug the microwave and coffee makers with clocks,  They pull all the phone chargers out….but AC and DC.  That really prolongs the storage time.

NOW, the suggestion about a bad battery or set is also good advice.  BUT, many folks have replaced banks that were probably OK and could have been exercised or recovered.  Taking in a set of 8 batteries that are abused and only need exercising and having them load tested will ALWAYS end up buying new batteries.  

Exercising them is a bit of a task, but not rocket science.  You need a digital voltmeter and a good specific gravity tester.  The SG tester  needs a scale….not colors.  I have attached a .Trojan SOC (State of Charge) chart.  The left column is the SOC and the others are the SG and Volts.

If you have 8 house batteries, assuming they are Wet Cells and NOT AGM’s, then the process is fairly simple.

Disconnect a Solar charger or just cover the panel with a opaque tarp or blanket or quilt.  Check the electrolyte level and fill to half the distance between the top of of,the plates and the bottom of the “well”….distilled water ONLY!  Recharge them.  Now DISCONNECT the jumpers between the batteries bank.  You should have 4 if you have 8 batteries,  NOW. Measure each .battery SG as well as voltage.  BINGO…you now can look up the SOC.  If there is a lot of variation in SG in the cells in one battery, then that is a sign of trouble,  BUT, if one battery only measure 4 VDC or so….BINGO.  That battery is GONE.  You don’t know this unless you have the disconnected and look at each line,  if one cell is REALLY low….then that battery is SHOT….or maybe headed that way. Reinstall the jumpers.

With all the power consuming items mentioned above are off….do your own load test.  Put a 500 watt load on the MH. A cheap quartz halogen 500 watt lamp works. One of these hooked up should drain your set of batteries, if they are “GOOD” to a 50% SOC in 9 hours or so.  Hook that up.  Use the inverter remote to read the battery voltage.  NOW, understand that you will have a LOWER displayed voltage than if you measured each battery directly with a volt meter.  Rule of thumb…when the remote reads 11.9 STOP. Odds are the real voltage at the battery is 12.0/1…or close to 50% SOC.

THEN…disconnect the jumpers again.  Let the batteries sit for maybe an hour.  Repeat your readings…record all the data.  Then refill the electrolyte….recharge for several hours.  Disconnect the jumpers and record the SG and Voltages….  

Then do it ALL AGAIN.  The readings after recharging should show the  SG closer within each battery and the batteries should be closer also.  It MIGHT take one more cycle…..then after recharging….with the jumpers removed…..read and look up the SOC and each battery.  They should all be within a 10% range….if one is worse, then at least you know.  Rule of thumb, the recharged, jumpers off, wait an hour SOC should be 80 - 90%.  If not….time to think about a new set.

edit…..changed the file picture for a better and newer “view”….from the Trojan Battery Manual.  Here is a link to one of the best reads on battery maintenance…..  I learned about the testing from a member here….and thanks to him….

https://www.trojanbattery.com/pdf/TrojanBattery_UsersGuide.pdf

I KNOW this works and greater scientific minds here, as well as the Trojan tech support folks, say this this is ONLY way to know.

Assuming that you have NO dead cells in a battery or a shorted (4 VDC) battery, then your batteries are as good as they ever will be.  I had one dead cell (voltage 4 VDC) in one battery and a very low SG reading in one cell of another battery.  They were shot.  I actually pulled them out. I hooked up only the good two. They were fine.  I decided to junk the whole set of 4 OEM Interstate bank and replaced them with Trojan T105’s…I am on my third set and I have used my MH twice or three times they average yearly numbers.  I have spent t least 5 weeks out every year and done a lot of short trips….some boondocking.

NOW, many will say JUNK and get AGM’s.  I understand their logic, but it also means that you have to have a PERFECT electrical system.  If you abuse a wet cell, it is more robust.  But, if you over or under charge an AGM….TOAST.  Yes, the prices are closer.  But you need to have a perfectly working charging system and be aware of when there are problems….and our motor homes are notoriously difficult to trouble shoot.

As to the chassis batteries.  Yes…they are sealed.  You exercise them each time you start them.  A quick way to see if you have bad batteries is to drive for a few hours in summer heat.  Then shut it down….maybe 15 to 30 minutes,  Listen to the “sound” when you turn the key….if there is a hesitation…or really long lag…it’s getting that time.  The idiot “LOW BATTERY” warning light will come on with a new, totally charged bank after a minute or so….and you have no lag….

WAY TOO MUCH…but your issue is not cut and dried.  The more you understand, the more you can monitor and take care of your rig.  The Patriots wee really nice…
 

 

 

00C04878-2DBB-45BD-813B-40A3C6594C4F.png

Wife had oral surgery this morning, just saw your post.  What a tremendous amount of information, THANKS, now I've got some work to do, but I'm pretty sure these "old batteries" need to be replaced, the coach sat at a Detroit Deisel/Allison Transmission house for 5 months while waiting for a part for my old hydraulic pump driven off the tranny PTO, and the batteries were dead, since then they've been dead two more times.  I'm heading out on a 1,500 mile trip and will feel better with a new set to start.  If I have issues after that I'll have a lot more knowledge on where to start!

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