Coach Batteries

[kketterling]

We've be parked about a week and half plugged in and this morning received warning that engine batteries were down to the point I needed to use house batteries for a boost. I know I have the system that charges house batteries first and when they are charged it will charge the coach but that didn't happen. I started the coach and all of a sudden my inverter indicated plus amps of 86. House batteries are at float level. I ran the coach about 6 minutes turned if off and fired right back up. Coach is off now still showing about 46 amps on inverter and I believe this is because it is now charging the coach batteries. Note coach battery posts clean and not low on water.

My question is it possible the switch that should have enabled it to jumped over to the coach batteries after house were charged got stuck? Not sure if this is part of the inverter or a relay or what. Anyone able to point me to the device that does the switching so I can keep an eye on it if fails?

Thanks

[bdpreece]

I suspect since your coach was also made by monaco that it will probably be the same or at least similar to mine. See my post http://www.irv2.com/forums/f115/dead...tml#post878319

Read the thread all the way through and check out the pictures.

[Gorlininc]

There is a big boy relay, usually in the battery compartment. It's a solenoid that one positive from the house batteries on one side and the other side attaches to the positive side of the chassis batteries. It is activated by your booster switch or automatically controlled by your IRD or BIRD depending on your system.

[kketterling]

Thanks. I'm going to see how it starts in 5 or 6 hours from now. If it starts good I will do some testing of the trombetta as well as the big boy relay. Right now the big boy relay is warm to touch but not hot and the trombetta is cool to the touch. Inverter still showing 23 amps.

I believe what drained the coach batteries in the first place was the running of my back up compressor for the air leveling system. Have air leak and after few days pump runs several times a day to keep level.

[kketterling]

My BD relay looks like this which I believe is the trombetta relay discussed in your thread bdpreece if so were do I find one like this if this turns out to be the problem? Amazon didn't have one like this that I could see. Sorry photos upside down.

[kketterling]

Ok found the relay in the picture on the internet and determined it is not the trombetta relay its the Intellitec Battery Disconnect Relay. Found the trombetta relay and it is cool to the touch so will keep and eye on it.

[bruceisla]

Originally Posted by kketterling

Ok found the relay in the picture on the internet and determined it is not the trombetta relay its the Intellitec Battery Disconnect Relay. Found the trombetta relay and it is cool to the touch so will keep and eye on it.

Before the nomenclature gets everyone confused, Intellitec Big Boy, Trombetta, White-Rodgers, and a bunch of others are trade names or manufacturers of relays. Without a part number or model the names are not very relevant. The exception is the Big Boy which typically refers to a specific model of an Intellitec relay. Trombetta however, manufactures hundreds of different relays.

To have some relevance, the relay needs to be identified by FUNCTION.

[bdpreece]

Your coach may or may not be exactly like mine. My relay was labeled Trombetta 114-1211-010. I replaced it with the heavy duty model 114-1211-020. This is a constant duty relay that will be hot to the touch if picked. If you remove one of the bigger wires from the top, when picked you should have the same voltage on both posts. If you do not you most likely have a defective relay like I did. As stated by others you may have a relay by another manufacturer all together.

[bdpreece]

Originally Posted by kketterling

My BD relay looks like this which I believe is the trombetta relay discussed in your thread bdpreece if so were do I find one like this if this turns out to be the problem? Amazon didn't have one like this that I could see. Sorry photos upside down.

Trombetta 12 Volt Bear DC Contactor Part No. 114-1211-020: Amazon.com: Industrial & Scientific

[kketterling]

Thanks bdpreece. The number on my Trombetta is 734-1221-020. The two wires you are referring to are the big red power ones right? I should turn off the house batteries and be hooked up to 50amp service to test this right? If so will test this when I get home. Again right now this unit is cool to the touch. I should add that I just started the coach after running it only six minutes earlier (when I needed the house batteries to start it) and then continued to let it sit plugged into shore power for about 6 hours. Seems like something was stuck and is now working. But for how long is the question.

[harris155]

kketterling
Did you end up replacing your Trombetta 734-1221-020 constant duty relay?
Mine is also going south, I would like to get the same relay as it is connected by bus bars and would like the same footprint.
I have having trouble finding the exact model # .

[RobtShetland]

Originally Posted by harris155

kketterling
Did you end up replacing your Trombetta 734-1221-020 constant duty relay?
Mine is also going south, I would like to get the same relay as it is connected by bus bars and would like the same footprint.
I have having trouble finding the exact model # .

I just bought a Trombetta 734-1221-020 from Amazon for less than $35. It arrived quickly and replaced the OEM solenoid exactly. Whoopie!

These Trombettas are inexpensive/cheap units and run VERY hot, as they have no "Economizer" circuit, like the quality parts we use at work. I now expect mine to continue to fail every 6-8 years, like the last one. Autopsy revealed that it is NOT a contact rating problem, but rather a solenoid coil overheating issue, which an "economizer" will solve. I do not expect to find a ready-made economizer for this solenoid, but I can&will design my own.
A quick search on "economizer" will get you a lot of info.