another 12v question

[napalm204]

OK everyone, I know this question will possibly make you laugh, but I am still learning about my old motorhome.  So I recently read some posts about other 12v problems and those posts led me to ask this goofy question:  Although I am plugged into shore power, will I still have 12v problems if the coach batteries are degraded?  To be frank, I thought I could power the 12v system through the converter even if the house batteries were removed.  So someone please educate me here and I will be very appreciative.

If in fact my 12v problems are directly related to degraded chassis batteries, then my problems are solved.  (I think)  However, IF when connected to shore power I should be able to get energy to my 12v system, even if house batteries are bad, then I have other problems.

Please remember what Will Rogers said:  "Everyone is ignorant about something."  (smile) 

 

[SeilerBird]

OK everyone, I know this question will possibly make you laugh, but I am still learning about my old motorhome.  So I recently read some posts about other 12v problems and those posts led me to ask this goofy question:  Although I am plugged into shore power, will I still have 12v problems if the coach batteries are degraded?  To be frank, I thought I could power the 12v system through the converter even if the house batteries were removed.  So someone please educate me here and I will be very appreciative.

If in fact my 12v problems are directly related to degraded chassis batteries, then my problems are solved.  (I think)  However, IF when connected to shore power I should be able to get energy to my 12v system, even if house batteries are bad, then I have other problems.

Please remember what Will Rogers said:  "Everyone is ignorant about something."  (smile)

Hey no need to be embarrassed about asking a question here. That is the only reason for forums like this to exist. The only stupid questions are the ones never asked. There are dozens of people reading this forum that don't participate that want to know the answer to your question also.

I don't know what the answer is. My coach batteries have been shot for several years. I am parked and everything 12 volt still works.

 

[Wigpro]

It really depends on how your unit is wired....in mine even with the batteries disconnected completely the 12 volt system works, as the converter powers everything...in my friends the converter charges the batteries and then downstream of that it goes to the panel from the batteries and therefore when we removed his batteries the system did not work...

You will have to do some testing....

Only stupid question is the one not asked so feel free to ask all the stupid questions you like, it gives us old farts sitting in the rain, something to do....

Good Luck,

Jim

 

[Ned]

Whether you can use just the converter without a battery depends on the converter.  Some require a battery to function while others will work without one.  Tell us the make and model of the converter and someone will be able to give you a more specific answer.  In either case it's a good idea to have a battery in place to power things like the refrigerator, furnace, gas water heater, and lights when shore or generator power isn't available.  Even the air conditioner requires 12VDC to function.

 

[napalm204]

OK, I am almost certain that my converter powers my 12v system when I am plugged into shore power.  That being said, I must have an open circuit somewhere.  Some of my 12v lights work and others do not.  My water pump works, but the HWH does not.  My a/c's and refrigerator work great, but the porch light does not.  I replaced the Battery Disconnect switch, but I still do not have a glowing red light.  It is stuck in the "on" position.  I cannot seem to turn it off.  I have limited electrical experience although I can work a multimeter and have determined that some lights are not getting power.  That seems to suggest an open circuit, but I still cannot seem to grasp where to start to find the opening.  Many of light wires are enclosed in the cabinetry.  Where should I start?  And please be very obtuse in your answer.  I am a novice, especially with electrical problems. 

 

[Wigpro]

I would check one that does not work that is easy to get to...take the light fixture or switch apart and check for voltage....

But I would first make sure every fuse is good....and I would check them with a meter - sometimes they look good but aren't.

Question - are all the non-working things on the same side of the trailer - could be a broken wire or ground....

Good Luck,

Jim

 

[Gary RV_Wizard]

A few of the oldest converter/chargers require a battery to be present, but most do not. I would be much surprised if the one in your 1995 Dolphin needs a battery. However, the 12v system is usually more stable with a working battery in place.

That said, a sufficiently bad battery can cause the charger to malfunction, especially the older ones that lack sophisticated digital controls. A simple example would be a battery that is internally shorted. That typically causes the converter to go bananas trying to charge it, and may actually cause it to overheat or trip a breaker or fuse internally (depending on the design of the converter).

Your symptoms all point to wiring problems, e.g. corroded connectors, broken branch circuits, or even a flaky terminal strip (multiple bad connections).

 

[bucks2]

OK, I am almost certain that my converter powers my 12v system when I am plugged into shore power.  That being said, I must have an open circuit somewhere.  Some of my 12v lights work and others do not.  My water pump works, but the HWH does not.  My a/c's and refrigerator work great, but the porch light does not.  I replaced the Battery Disconnect switch, but I still do not have a glowing red light.  It is stuck in the "on" position.  I cannot seem to turn it off.  I have limited electrical experience although I can work a multimeter and have determined that some lights are not getting power.  That seems to suggest an open circuit, but I still cannot seem to grasp where to start to find the opening.  Many of light wires are enclosed in the cabinetry.  Where should I start?  And please be very obtuse in your answer.  I am a novice, especially with electrical problems.

Now you're confusing us. Does HWH mean HWH brand of levelers or Hot Water Heater? IF you mean Hot Water Heater are you talking about the gas side or the 110v electric part? If a/c's are Air Conditioners, you know they run on 110v with the thermostats on 12v. Do you mean that the thermostat panel doesn't light up? You replaced the Battery Disconnect switch but the new switch doesn't move from the on position? Or did you change the latching relay and moving the switch doesn't cause the relay to operate?

But the hardest part for us to understand is "And please be very obtuse in your answer." The dictionary says obtuse is:

1
a :  not pointed or acute :  blunt
2
a :  lacking sharpness or quickness of sensibility or intellect :  insensitive, stupid
b :  difficult to comprehend :  not clear or precise in thought or expression

Please help us understand exactly what the problem is. We understand if english language is a problem, and we can work thru that, but please be more specific with the problem so that we know how to help.

Ken

 

[napalm204]

OK guys, excuse my oversight.  To me, HWH means hot water heater.  I am not sure if my hot water heater problem is the gas side or the 110v side.  That is why I am seeking help.  But because I am having other 12v issues, I thought the hot water heater might be connected somehow.  I use a/c to describe air conditioners, although I realize a/c might be an abbreviation for a lot of things.  But my air conditioners are working fine.  I do not have a thermostat panel.  I have a regular "house" type thermostat for each of my air conditioners.  The light I am referring to is the red glowing light on my battery disconnect panel.  It normally glows red when my coach batteries are being utilized, but goes out when they are in storage mode.  That newly replaced battery disconnect switch is "on," but the small red light is not glowing as normal.  If my battery disconnect switch has a "latching relay," I have no idea where it is.  I used the term obtuse because I wanted a blunt answer.  I am not proficient in RV lingo and/or phrases, so I need straightforward, very clear instructions.  I am sorry if I used the word "obtuse" in a confusing way.

I realize it is difficult to get into someone's head by reading a post, but like I said, I am basically ignorant about RV systems and how to troubleshoot them.  So how I describe my problem will not have the clarity of someone who understands these systems.  I am proficient in some things, RV technology is not one of those things.

 

[Gary RV_Wizard]

Your HWH should have both a gas and electric mode, with a separate on/off switch for each. You can use either mode, or both at the same time. The mode that itis running in depends on which switch was used to turn it on.  If you don't occasionally hear the gas burner running, you are probably using (silent) 120v electric mode. When the 120v electric mode is turned on, it uses no 12v power, but in LP gas mode it uses 12v power for the gas controls.

Your battery disconnect light problem may be as simple as a minor wiring problem on the switch, i.e. the switch works but the light does not.  Clearly the battery is switched "on", since you do have 12v power in some places.  Be aware that the switch does not directly connect/disconnect the battery power. It operates a relay, which in turn does the actual switching. Just think of the battery disconnect wall switch as a remote control.

You should start diagnosis at the main 12v power panel, which will be wherever the 12v fuses are. In your vintage of coach, that's probably on the same panel as the 120v circuit breakers. Make sure all the fuses are good and each circuit has power at that point. From there on, it's a question of getting physical access to the dead circuits wherever you can and looking for volateg at various points, to determine what portion is good and where power stops. No magic, just grunt work. You may have to remove cabinet backs to get at things.

 

[Just Lou]

The light associated with the Disconnect switch is powered via a fuse on the Disconnect Solenoid itself.  It is meant to indicate that the solenoid has been deactivated (batteries activated), however, if the fuse is blown (open) the solenoid may still operate, but not indicate.  On your rig, the solenoid(s) are located in a box, called a BCC (Battery Control Center), mounted somewhere near the batteries.

There exists additional circuitry (fuses) in that BCC box that feed power to the disconnect switch that could also be blown, thus preventing you from turning the batteries OFF (Disconnect ON).

 

[bucks2]

Thanks for clearing that up. Now I think you're getting the help you need. As Gary says, it's a matter of going from point to point to find out where there is power and where there isn't. The 12 volt panel is a logical starting point.

Ken

 

[fredbon]

The link is to NRV Brochure information.  http://www.nationalrv.org/.  While the '95 Dolphin info is not present the "sister" Sea Breeze indicates the standard water heater is LP, with the option of LP/Elec. NRV liked to keep the product lines very similar, just changing the interior/exterior options to separate the models.

I suspect part of your elec. problems are related to the interlock relay on the 12V Battery Control Center  circuit board.  I am not sure where the panel might be located, however on lots NRV gas units it's in the compartment just forward of the entry door.  The relay is a very standard 12V continuous duty relay, used in golf carts as a battery disconnect, like these http://www.amazon.com/s/ref=nb_sb_ss_c_0_8?url=search-alias%3Dautomotive&field-keywords=12v+continuous+duty+solenoid&sprefix=12v+cont%2Caps%2C258&rh=n%3A15684181%2Ck%3A12v+continuous+duty+solenoid&ajr=2

Here is a picture of a NRV panel http://webhosting.web.com/imagelib/sitebuilder/misc/show_image.html?linkedwidth=actual&linkpath=http://www.pdxrv.com/sitebuildercontent/sitebuilderpictures/111979.jpg&target=tlx_new&title=Battery Control Center, by RV Custom Products, 01033-10

Hope this helps.

Fred

 

[Just Lou]

[quote author=fredbon]..... The relay is a very standard 12V continuous duty relay, used in golf carts as a battery disconnect, like these http://www.amazon.com/s/ref=nb_sb_ss_c_0_8?url=search-alias%3Dautomotive&field-keywords=12v+continuous+duty+solenoid&sprefix=12v+cont%2Caps%2C258&rh=n%3A15684181%2Ck%3A12v+continuous+duty+solenoid&ajr=2

Here is a picture of a NRV panel http://webhosting.web.com/imagelib/sitebuilder/misc/show_image.html?linkedwidth=actual&linkpath=http://www.pdxrv.com/sitebuildercontent/sitebuilderpictures/111979.jpg&target=tlx_new&title=Battery Control Center, by RV Custom Products, 01033-10 Hope this helps.  Fred  [/quote]
Fred, you are mixing terms here.

• The "standard 12V continuous duty relay" that you reference is used as a Battery Isolator/charge relay, NOT a "Battery Disconnect".  Those are totally separate and different functions.
• The "Battery Disconnect" relay, as used in the OP's rig, is a mechanically latching solenoid.
• The Battery Disconnects are located, electrically, between the batteries and their respective selected loads.
• The Battery Isolator is located, electrically, between the house and chassis batteries.

 

[fredbon]

Thanks Lou, I was trying to indicate the probable cause was the interconnect relay. 

Fred

 

[Just Lou]

Thanks Lou, I was trying to indicate the probable cause was the interconnect relay. 

Fred

Okay Fred, I see now where you were going.  I guess I missed your point, as the symptoms didn't lead me to the same conclusion.

 

[John From Detroit]

I will amplify Lou's last post a bit.
For the disconnects they use magnetic latching relays because you feed them current one way to turn them ON (Close the contacts) and the other way to turn 'em off.. Magnets hold them in either position without any load on the battery from the solenoid

Isolator relays are what is called Continuous duty because when they are engaged there is ALWAYS a power source (Alternator or Converter) other than the battery so they too do not load the batteries.

STARTER relays are not continuous duty.. Engage them for more than a minute (30 seconds is the rating) and the next time you go to use them they may well not work having burned out the coil.

 

[Just Lou]

I will amplify Lou's last post a bit.
For the disconnects they use magnetic latching relays because you feed them current one way to turn them ON (Close the contacts) and the other way to turn 'em off.. Magnets hold them in either position without any load on the battery from the solenoid

John, not to kick the proverbial dead horse, but your description of the latching solenoid is not at all accurate.

• Passing current in EITHER direction through the coil will CLOSE the contacts.

The difference is:

• Passing current in one direction (positive voltage on the "I" terminal), will CLOSE the contacts, AND create a magnetic field to PULL the magnetized mechanical latch into position so that the contacts will remain closed when voltage is removed.
• Passing current in the opposite direction (positive voltage on the "S" terminal), will also CLOSE the contacts, BUT will create a reversed magnetic field that will PUSH the mechanical latch out of the way so the contacts can OPEN when voltage is removed.

The latch is held in place mechanically, not magnetically or electrically.
For information accuracy only......

 

[KC1BUD]

A few of the oldest converter/chargers require a battery to be present, but most do not. I would be much surprised if the one in your 1995 Dolphin needs a battery. However, the 12v system is usually more stable with a working battery in place.

That said, a sufficiently bad battery can cause the charger to malfunction, especially the older ones that lack sophisticated digital controls. A simple example would be a battery that is internally shorted. That typically causes the converter to go bananas trying to charge it, and may actually cause it to overheat or trip a breaker or fuse internally (depending on the design of the converter).

Your symptoms all point to wiring problems, e.g. corroded connectors, broken branch circuits, or even a flaky terminal strip (multiple bad connections).

F-I-L's 1975 Winnebago will run all day long with out the house battery. In fact the house battery has been in the garage for last few years. Now he is 93, and selling his motorhome we just put it back in last week. In the last 30 years, with experience with two different brands of pickup campers, one class "C" and 4 class A's I have never had a problem running without house batteries to run the lights and other 12 volt as long as I had shore power. I agree it is possible that there is a short in one of the batteries cells? If you disconnect the batteries, insulate the plus lead (the red one) do you still have the same problems? Just a thought.