Aux start button

[Mike Canter]

I agree that a 10 gauge emergency jumper wire is a great idea. You just have to remember that you CANNOT crank the motor with that jumper in position without also push the AUX START button. If you don't then it is going to look like Edison's first light bulb filiment for a fraction of a second.

Bbeane, all that jumper wire is doing is to tie the two positive sides of the chassis and house batteries together. The AUX START is a high amperage solenoid and on a lot of MHs is the Big Boy solenoid and by jumping across it from large post to large post is not a bad thing and does not need a fuse. There is no fuse in that solenoid which does the same thing. As KIX said the only danger is that while driving one end of the jumper wire could come off due to vibration and it may do some damage if it shorts out against anything.

[Rick Long]

Hold it down while turning the key to start. It tie's them together ONLY while held down.

Holy smokes!!! There were NO answers when I started mine!!!

[ahicks]

Something to consider regarding the emergency start solenoid itself. MANY are not designed to be engaged for more than a few seconds. They can/will cook internally if held for more than a few minutes.

[Billieg]

Originally Posted by bbeane

You should understand how the Boost/aux switch is actually wired and it's intended purpose before you start jumping things with wires lest you burn something up. Consult your owners manual and 12v wireing drawings, or have a good truck elec tech look at it and explain how it works. The house batterys are usually deep cycle as such they don't have a lot of cranking power. Your system may or may not be momentary, if the switch will stay in the on position it's on, if you have to hold it down it's momentary on. Any time you place a jumper wire in a 12V+ circuit you should have it fused see above.

You are correct. I replaced my relay and realized the center wire was connected to the battery boost button. When you press the button 12v is sent to the center post turning on the relay and connecting all the batteries. I made a 12v jump wire (#18) to connect to the center post in case I needed to keep it on so I don't have to keep the button in all the time. If your alternator quits you can use this jump wire and run the gen to charge the main battery. All the 10 gauge wires are already connected in the correct way.

[Billieg]

Originally Posted by ahicks

Something to consider regarding the emergency start solenoid itself. MANY are not designed to be engaged for more than a few seconds. They can/will cook internally if held for more than a few minutes.

You could be correct with some relays but when I purchased my MH the wires were jumped (leaving the batt. boost relay on)because the alt. was bad. That relay was on for over 8 hours and worked fine. I bought a relay kit that included the 2 main relays so I replaced both of them but the jumped one still worked fine. I guess you could also use a set of jumper cables to connect it all together too in an emergency.

[Stogie]

I always make sure the Generator is running before using the Aux start switch, that way I don't end up with dead batteries in the Chassis and Coach.

[KIX]

In my coach and many others the AUX START (BAT BOOST) energizes the same solenoid as the one energized when charging both battery banks from either the battery charger or the engine alternator. Keeping the AUX START continuously engaged is not an issue. Why? because the solenoid is a continuous duty solenoid. The issue comes when it's energized and de-energized. That causes arcing on the contacts which causes pitting and eventually renders the contacts in the solenoid useless.

[ahicks]

Originally Posted by KIX

In my coach and many others the AUX START (BAT BOOST) energizes the same solenoid as the one energized when charging both battery banks from either the battery charger or the engine alternator. Keeping the AUX START continuously engaged is not an issue. Why? because the solenoid is a continuous duty solenoid. The issue comes when it's energized and de-energized. That causes arcing on the contacts which causes pitting and eventually renders the contacts in the solenoid useless.

Yes. That was my point. Depending on what type solenoid was installed (continous vs. non), you may or may not have a problem with extended use. Some are simply old Ford starter relays. Hold one of those engaged for a few minutes and they get pretty hot - just before the coil burns out.

[KIX]

Originally Posted by ahicks

Yes. That was my point. Depending on what type solenoid was installed (continous vs. non), you may or may not have a problem with extended use. Some are simply old Ford starter relays. Hold one of those engaged for a few minutes and they get pretty hot - just before the coil burns out.

Maybe you can help me out here.........why would a battery isolator solenoid be a non-continuous type solenoid? Sounds self-defeating to me.
I'm guessing you are trying to say that some coaches have a battery isolator AND a separate AUX START (BAT BOOST) ??

[SargeW]

I guess I should have elaborated. A good set of jumper cables would suffice in an emergency situation. Such as a chassis battery being dead and near dead house batteries. I would definitely recommend a dedicated proper gauge jumper for a long term hook up. But I appreciate the advice!

[ahicks]

Originally Posted by KIX

Maybe you can help me out here.........why would a battery isolator solenoid be a non-continuous type solenoid? Sounds self-defeating to me.
I'm guessing you are trying to say that some coaches have a battery isolator AND a separate AUX START (BAT BOOST) ??

Exactly. I struggle making the assumption the Aux./Emer. Start circuit uses a constant duty solenoid on ALL coaches. Not arguing the fact that what you are saying isn't possible.

If you don't know one way or the other, and you are in some type of situation, rather than rig the switch to hold the solenoid engaged, I'd rather see it jumped. You could also move the wires to one side of the solenoid pretty easily?

[KIX]

Originally Posted by ahicks

Exactly. I struggle making the assumption the Aux./Emer. Start circuit uses a constant duty solenoid on ALL coaches. Not arguing the fact that what you are saying isn't possible.

So, what you are really saying is that the coach operator should know if the AUX BOOST (etc.) solenoid is continuous or momentary before energizing the coil. And, if it's momentary it can't be used as continuous without damage.

[4Knights]

Originally Posted by KIX

So, what you are really saying is that the coach operator should know if the AUX BOOST (etc.) solenoid is continuous or momentary before energizing the coil. And, if it's momentary it can't be used as continuous without damage.

IMHO, it doesn't matter if I know it's continuous duty or not, as long as when I have an alternator failure or dead coach battery I can push it and start the vehicle I'm good. Replacement at auto zone is $14.00 so if that's all it costs to replace when it burns out I'm thankful.

[ahicks]

Originally Posted by KIX

So, what you are really saying is that the coach operator should know if the AUX BOOST (etc.) solenoid is continuous or momentary before energizing the coil. And, if it's momentary it can't be used as continuous without damage.

That's about it...