Easy boost tip when 'Emergency Boost' relay doesn't work

[NorthOrSouth]

My dash switch has the Emergency Boost switch that is supposed to connect the house batteries to the chassis batteries to give them a boost if needed. After locating the Big Boy relay in the pic I realized that although it's still clicking the relay isn't working and I'll have to take it apart to clean the contacts or replace it.

The easy fix is that I just used a extra battery cable I had (or any heavy cable would work in a pinch) and connected the large nut on one side of the relay to the large nut on the other side as shown while my wife hit the starter. Worked great and it fired right up. Boosts both the generator or the engine so we just started the generator first and let it recharge the chassis battery.

The nice part is that it's under the rear bed so I didn't even have to go outside to boost, saving at least 10% of the pride I had left

I think the Big Boy relay is pretty common to Monaco's and other rigs of many ages - we're in a 92 Crown Royale.

[distaff]

NorthOrSouth - my coach is more than a decade newer, but if that is a BigBoy they sure have changed it.

BTW, is that picture under your bed in the coach? Looks like it is covered with road dirt. Is there an access panel you opened?

[YC1]

Welcome to the forum and thanks for sharing.

The "Big Boy" term is used for many of the large boost solenoids. Like calling tissues Kleenex for example.

You can also just pile the wires onto one side if there is room.

These cause so many problems and gremlins that one should consider just changing them or overhauling them every couple of years. Mine was bad from the beginning and I did not have schematics or this forum to help me figure out how the charging system works in my rv. That was a real head scratcher and I'm a qualified electronic tech.

[K7JV]

I actually believe that "Big Boy" may be a protected trademark of Intellitec. They are the people that manufacture at least the units that actually have "Big Boy" showing on the device. And yes, there are sizes and vintages. Monaco used a lot of Intellitec technology over the years so they are very widespread.

Myron, you are right. There may be a number of other heavy-duty solenoid operated contactors out there made by other people, but they are still a "Big Boy", just like a Scott tissue is a Kleenex.

[distaff]

Originally Posted by YC1

These cause so many problems and gremlins that one should consider just changing them or overhauling them every couple of years. Mine was bad from the beginning and I did not have schematics or this forum to help me figure out how the charging system works in my rv. That was a real head scratcher and I'm a qualified electronic tech.

Myron - that would not have been fun. Even with the schematics and help from this forum it took me 4 years to make my system work correctly. It involves the BigBoy (periodic rebuilds and cleaning required), the BIRD relay (so far not the source of a problem), some cheap relays to tie the BIRD and boost switch signals together to send one wire to the BigBoy (had one go bad - could tell because I wasn't getting engine charging and the boost didn't work), and most recently the inverter wasn't sending enough charge on float to trigger the BIRD, so I would have dead starters when I was on shore power. The last one took me 2 years to figure out - partly because we don't use the coach enough to remember why it failed the previous time. Turned out it was the temp sensor on the house batteries that connected to the inverter - it was sending a high value and that caused the inverter to reduce the float voltage.

Charging is almost the most frequent questions I see on here.

[NorthOrSouth]

Originally Posted by distaff

The last one took me 2 years to figure out - partly because we don't use the coach enough to remember why it failed the previous time..

That's me too. This is our first trip in two years and I had to figure out why my batteries were nearly dead even though I made sure to plug in the coach regularly for charging all winter. Turns out my battery isolator was shot so both house and chassis batteries were always connected which normally wouldn't be a big deal, however my house power relay switch was also not disconnecting which meant it was draining power 24/7. Finally got that all figured out and new batteries and then discovered the big boy is also gone.

My solution is to take a Sharpie and label everything I have figured out. The big boy relay now says "Emergency House and Chassis Connector" on the side so next time I don't have to figure this stuff out from scratch.

As the sign says, "The worst part about old age is memory loss, and also, memory loss"

[NorthOrSouth]

Originally Posted by distaff

BTW, is that picture under your bed in the coach? Looks like it is covered with road dirt. Is there an access panel you opened?

Yes it's all under the bed. Everything is open to the engine and road below. I'm surprised there aren't more connection issues because of that but mostly it just means things get dusty.

Living up north on salty wet roads, I'm just glad that this rig lived most of it's life in the desert in California so not every nut and bolt is rusted

[YC1]

Take pictures as you learn new things. Print them out and do annotations on them. Scan those back into the computer for future reference. In some cases I just slip the print outs into page protectors and place near the device.