Relay Hot From Battery Cutout Switch

[beamer704]

I have a 2008 Diplomat & after changing the 4 house batteries.

I noticed that the relay from the battery cutout switch was hot. This is a Trombetta 12 volt solenoid or relay located in the battery compartment.

By hot I mean the brass bracket that wraps around the solenoid to hold it in place is so hot that if you put your finger on the bracket for more than 2 seconds, it will burn. If you only touch the solenoid itself, it's warm. I just replaced it with a new one & it is just as hot as the old one.

Can someone out there physically go out & touch your bracket & solenoid to see if it is hot as well ? We have been parked on a site in Florida for the past 4 months so the batteries are on flow charging.

Thanks for any help.

Paul

[corkey05]

I have the 08 HR Endeavor, the twin to the Diplomat. Same relay, same temp situation, .. I've been told by dealer techs and the Monaco factory service in Coburg, OR the hot temp is normal. It's a bit unsettling but after 5 years it still works, .. and it's still hot.

This comes up every so often on the Monaco bulletin boards, and all say it's normal, so we're not alone. I stopped worrying about it a long time ago.

[desertdeals69]

It sounds like a poor design or miss application of the solenoid. I have Intelitec which is a switching relay that only draws current when switching. No heat ever.

[dickandlois]

The Solenoid is in a 50 to 70 amp 12 volt circuit. That can generate a lot of heat, think it feeds one of the main 12 volt power panels; plus one of the sub panels that power the slide out circuits and some others.

That is a total of 600 to 800 plus watts. That much power will make things get hot. the cables are #2 or 4 Gauge running between the battery and solenoid an between the solenoid and DC power Box.

Rich.

[hermanmullins]

Any time you have high amperage with D/C cables it is a good idea to go up in size. If you have a #2 cable getting warm then going to a #1 cable or even a #1/0.

Herman

[ticat900]

I have a 2008 Diplomat & after changing the 4 house batteries.

I noticed that the relay from the battery cutout switch was hot. This is a Trombetta 12 volt solenoid or relay located in the battery compartment.

By hot I mean the brass bracket that wraps around the solenoid to hold it in place is so hot that if you put your finger on the bracket for more than 2 seconds, it will burn. If you only touch the solenoid itself, it's warm. I just replaced it with a new one & it is just as hot as the old one.

Can someone out there physically go out & touch your bracket & solenoid to see if it is hot as well ? We have been parked on a site in Florida for the past 4 months so the batteries are on flow charging.

Thanks for any help.

Paul

What does this mean? The batteries are on flow charging?

[wolfe10]

Given his description (plugged into shore power for 4 months) he means they are at FLOAT voltage (not bulk or absorption).

My first question is what is the amp rating of the solenoid and what amp load are you drawing?

If the amp rating of the solenoid is marginally more than actual load, spec the next larger (higher amp rating) solenoid.

[dickandlois]

Herman, A # 4 stranded cable is rated at 70 amps and a # 2 is rated at 95 amps. Going to a 1/0 wire would raise the current-carrying ability to 125 amps. A current that is way beyond what the the circuits should need.

Beamer, could you post the size(s) of all the fuses in the primary 12 volt power panel in you Coach or just post the total current of all the fuses not including the main buss fuses.

Then post the main fuse size(s) if by chance there a 2 main fuses.

One could find a DC current prob at Lowes. They have them that can read 600 amps AC and 400 amps DC in the 40 to 50 dollar range if I remember. I have an Ideal # 61-768 and its been discontinued. Google it to see what it looks like !!

The closest one would be the 61-746 at $ 69.00 from Amazon. Could be $100 to $140 more at some outlets. Man things have gone up since I got mine.

Well , That might not be an option for you. Should you fined someone that has this type of meter, they can read the current flowing in the circuit. The total current draw through the Solenoid / Relay could lead you to an issue in a sub 12 volt power panel. Reading the voltage difference across the Solenoid / Relay.

Low resistance equals lower heat (low power loose). High resistance equals High Heat ( High power loose) Bad relay contacts. Time to replace the relay, but in your case you have replaced the relay. So that is not the issue unless you got a bad one and that could be determined by just reading the voltage on the input and output. Big difference, go back to the store, the one you got could be bad.

By chance could you attach a picture or 2 of the solenoid and the wiring around it ?

That much heat means a lot of power going somewhere, and the where is the real issue. The real interesting item is, being plugged into shore power; a charger is generally running at 30 to 40 amps.

Question, do you see any unsubstantial drop in the battery voltage level(s) ?

Rich.

[beamer704]

Thanks for all your input but after talking with several other Diplomat owners, they have the same thing going on with their solenoid.

The voltage is the same across the solenoid & there is no drop in voltage anywhere. Everything seems to be working ok.

Thanks for all your comments.

[tomgauger]

I believe that everyone is talking about the dreaded "Salesman's Switch" which is going to fail at the most inopportune time you can imagine. In my '01 Monaco Exec there are two large relays in the same compartment with the battery isolator. One of the 12v relays handles high current items, the other is for low current devices. The high current relay has always been hot to the touch but is designed to run continuously. Bit are turned on and off by a switch in the entry stairwell.

When they fail (and they will!) you are left without any house power and that includes heating and air conditioning as the thermostats are fed 12v off these relays.

The simplest fix is to simply wire directly to the house 12v located in the same compartment.

If you wish to kill the house DC you can do so in the battery compartment with the large switches located there.

This is a simple fix.