Battery Boost Switch

I have a 2007 Adventurer. If the engine battery is low or dead, while plugged into shore power, can the battery boost switch be taped open to permit the battery to be charged off the house batteries?

If you are referring to the "momentary" switch on the dash, then the answer is yes, according to a post on another forum that claimed the info was from Winnebago.  However, Winnie started installing a Trick-L-Start on coaches starting in 2006.  Have you checked your 12V breaker box to see if one is there? 

It also depends how dead the battery is. The momentary switch is intended to boost a battery that is just a little too low to turn over your motor.  If the battery is really dead, like 9 volts or so, then you won't get your  battery charger to charge the battery no matter what. 

I have read where some folks have stuck a match stick under the momentary switch to provide power to both sets of batteries.  I have not had the need, so I have not had to test the theory.

Sarge

Though the answer is yes.. I'm not so sure..

Then there is the other issue.. (Letting a battery, epically a starting battery, get that low.. NOT GOOD)

Trick-L-Start (lower price) or the xantrex Echo Charge (Higher price) very good idea in my not very humble opinion
(For rigs that do not already charge both banks off the converter)

Simple 3-wire hookup

Hey tallyho!  Welcome!

Sarge is correct - the solenoid that bridges both battery banks is rated for continuous duty.  Sarge is also correct about the Trik-L-Start... Winnie started installing the Trik-L-Start with the 2006 model year, but I don't know how far down the model chain they went.  Give Winnie owner relations a call to find out if you have one.

Thanks for the info......

On behalf of Sarge and me, you're welcome and don't be a stranger!

We took another route to insure all batteries can be charged by shore power.  We replaced the momentary switch with a 3 position one (per a suggestion of a Winnebago rep at the 2008 GNR). 

In the "normal" operating position (the lower end of the switch depressed) the alternator charges both sets of batteries (when the engine is running) and shore power charges only the house batteries. 

In the center position all batteries are disconnected from all charging systems. 

When the upper end of the switch is depressed shore power charges both the coach and house batteries.  This would be the same as taping or manually holding the switch in the "Battery Boost" position.  I also added a small pilot light that indicates when the switch is set to charge all batteries from shore power.

This change may be more important in a coach the age of ours.  Through at least 2001 the 12 volt power ports were connected to the chassis battery.  That means every time you charge a personal radio, cell phone, or plug your computer into a 12 volt port you're running off the chassis battery.  Over time you can discharge the chassis battery without even knowing it.  A few years later (I'm not sure of the exact year) they changed the power ports to the house batteries.  With this system there should always be power to start the coach no matter how often you charge your toys or plug in your computer.

We find it useful to put the switch in the "Battery Boost" position whenever we stay in one place more than a couple weeks.  It seems that we always need to plug in some 12 volt accessory and this allows us to keep the chassis battery up to the task. 

hikerdogs said:

We find it useful to put the switch in the "Battery Boost" position whenever we stay in one place more than a couple weeks.  It seems that we always need to plug in some 12 volt accessory and this allows us to keep the chassis battery up to the task.

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Wow, that is a really great idea.  I have an external trickle charger that I plug into the rig (on shore power) and attach to the chassis battery when camping for more than a few days.  But it sure seems like it would be easier to replace the Boost switch so it will stay in that "boost" position indefinitely (rather than the momentary design).  Would there be any reason not to leave the chassis and house batteries connected like that all the time?

Scotty:

You run the chance of discharging all your batteries if no charging source is available.

Jeff said:

You run the chance of discharging all your batteries if no charging source is available.

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True... italicized segment added to my question...

Would there be any reason not to leave the chassis and house batteries connected all the time when connected to shore power?

Off hand I can't think of any negatives for leaving the switch in the boost position when hooked to shore power.  You just have to remember to put it in the "normal" position when you drive the coach.  That's why I added the pilot light.  I'm sure by now I would have forgotten to flip the switch if there hadn't been some prompt to do so.

Having said that we only leave the switch in the "Boost" position long enough to get a full charge on the chassis battery.  Once it reaches the 12.8 volt mark on the One Place panel we put the switch back in the normal position.  We've been in a couple campgrounds that lost power.  As mentioned if all the batteries were hooked together for extended periods without shore power they might all be dead.

In general, paralleling batteries is a terrible idea - a problem in one cell of one battery can cause the entire bank to completely discharge, or fool the charger into thinking the batteries are discharged and it then pumps lots of current into the banks and causes gassing.

RVs usually have parallel banks due to the ease on installation and simplification.  On our last boat, I had two battery switches and never had more than one battery on-line at one time - making this scheme work would be a little more difficult on the typical RV - hence we have parallel batteries.

However, I don't mind my three Lifeline AGMs being in parallel too much since they are premium batteries.

I agree paralleling all the batteries may have a potential downside; however it's the only way to recharge the chassis battery in our coach short of running the engine for several hours or adding a seperate charger.  Under normal conditions it would require the engine to be running a minimum of 2 hours to restore the chassis battery to a full state of charge. 

I check the specific gravity of all the cells in all the batteries on a regular basis.  Should a problem develop I believe it could be resolved before any damage is incurred.  Also the charger in our coach is located in the galley under the stove.  There is no doubt as to when it starts to work and when it shuts off.  If it were to run an inordinate amount of time it would be fairly obvious.  Keep in mind we only activate the "Boost" switch when the meter in the panel shows the chassis battery needs to be charged, and shut it off when the job is done.

SargeW, Yess Winnie began putting in the Trik-L-Start on MOST units 2006. Did not put one on my 2007 26P as thot it too small to have much drain.  Was one of the first things I did to it.

maddog348 said:

SargeW, Yess Winnie began putting in the Trik-L-Start on MOST units 2006. Did not put one on my 2007 26P as thot it too small to have much drain.  Was one of the first things I did to it.

Click to expand...

To clarify, Winnie installed Trik-L-Start units in 2006 only on DP's....no gas coaches.

Welcome Tallyo!  I've enjoyed your posts "over there", and look forward to them here! 

I have read many posts of owners that do put something under the momentary switch to charge the batteries, but I agree with John in that it is NOT a good idea.  Installing a small trickle charger on your "chassis" battery (or a Trik-L-Start) is the best way to keep it charged....not the battery switch. 

From John Canfield

"In general, paralleling batteries is a terrible idea - a problem in one cell of one battery can cause the entire bank to completely discharge, or fool the charger into thinking the batteries are discharged and it then pumps lots of current into the banks and causes gassing."

The more I thought about this statement questions started to come to mind.  It seems we already paralel all the batteries anytime the coach is running.  At least on our coach the solenoid that parallels all the batteries is activated whenever the ignition switch is in the "ON"position.  Also if you have more than 1 house battery (like 2-12 volt batteries or 4-6 volt batteries) they are charged in parallel either from the engine alternator when the coach is running, or the charger when hooked to shore power.

I don't see much difference between what the coach does automatically and what I'm doing on a manual basis.  Am I missing something?

The difference is time. 

In one case the batteries are in parallel only while the engine is running; the other case is using the boost switch on a long-term basis.  Winnie uses the solenoid not for its technical elegance, but because it is a relatively inexpensive way to charge all batteries while the engine is running.

The other negative aspect of paralleling house and chassis batteries is they are usually different kinds of batteries - deep-cycle and starting batteries.

I think the (BIRD) Bi-Directional Relay Delay function provided by, either the Intellitec or RV Custom Products Battery Control Centers is by far the superior system.  What does it do?  It picks the aux start solenoid

Sure, the final result is that the batteries are paralleled with a simple solenoid, but there is a charge voltage threshold and a timing element that must be satisfied to prevent picking the solenoid when it is not appropriate.

Just as important (maybe more so) is the action of these thresholds to cause the parallel connection to drop out when no charge voltage is present and one battery bank might be drained by the other.

In the Ignition on position, the engine must be running and the alternator charging above 13.2v for more than 12 seconds for the solenoid to close.  This prevents overloading the alternator on initial start up.

The same thresholds have to be met to allow paralleling the batteries and charging the chassis battery from shore power.

Just a bit more sophisticated than a jammed switch or a "Trik-L-Start?"