Dead Battery Question

[Hodgy]

Originally Posted by JRTJH

Right or wrong, if the switch were wired at the factory to disconnect all power, the batteries might last longer in storage, but how many people would wind up towing without any means of stopping a runaway trailer? It sort of comes down to the question of convenience at what cost to individual and public safety?

One of the first things I do is move the slide over on the brake controller to see if it is working.

But, I guess there is a warning label on hair dryers not to use them in the bathtub for a reason !

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[dcg9381]

Originally Posted by Hodgy

One of the first things I do is move the slide over on the brake controller to see if it is working.

Pull the battery and run the same test. Your brakes will work.
Break-away won't work without a battery, however....

[Hodgy]

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I know that . . . .

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[dcg9381]

I know you did.. :-)

Somehow my RV came back from the factory sans batteries, so not everyone seems to be checking this stuff. :-)

[JRTJH]

Originally Posted by Hodgy

One of the first things I do is move the slide over on the brake controller to see if it is working.

But, I guess there is a warning label on hair dryers not to use them in the bathtub for a reason !.

I don't know if you're aware of this, if so, just endure me for a moment, I'm positive there are a number of RV'ers who aren't aware so it's aimed at those who might not know.....

The brake controller is NOT wired to the break-away switch. The break-away switch gets its power from the trailer battery, NOT from the brake controller.

So, when you start to tow and "move the slide over on the brake controller to see if it is working" you do not check the emergency braking system, you only check the "normal trailer braking system".... When you move the brake controller lever the brakes will function whether you have a trailer battery switch on, off or even if there is no battery in the trailer at all.

The only way to functionally check the break-away system is to either hitch the tow vehicle, (do not plug in the 7 pin unbilical) pull the break-away switch pin and drive forward. You should feel the trailer brakes as they activate. THEN IMMEDIATELY REINSERT THE BREAK-AWAY SWITCH PIN so you deactivate the system. You can also jack a trailer wheel, pull the pin, spin the wheel and if it stops (or you can't turn the wheel) the brakes are applied. Don't forget to reinsert the pin in the break-away switch..... You might also hear the brake magnets "click" or "hum" if you don't jack the wheel. DON'T PULL THE BREAK-AWAY SWITCH PIN WITH THE UMBILICAL CABLE CONNECTED, YOU MAY DAMAGE YOUR TRUCK WIRING AND/OR BRAKE CONTROLLER......

Anyway, my point is to bring to the front, the fact that the "normal braking function" and the "emergency braking function" are independent and if there is no battery power in the trailer, your trailer emergency system can't stop the trailer and you don't check that system with the brake controller located in the tow vehicle.....

I'm not "picking on you" but hopefully bringing something to light that might help someone who doesn't understand their trailer braking systems: both of them.......

[Hodgy]

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You know JRTJH you are right. I did not see the runaway trailer in your post and I went off down some turkey trail.

Pick away, that is how we all learn. We learn how things work and in my case, on this post, I learned I should read for understanding not speed.

Thanks, Hodgy.

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[Mikesamoose]

Originally Posted by JRTJH

You can "repurpose" the switch, but remember that when you remove "all power" from the trailer, you lose your ability to monitor for LP leaks and in some trailers, you also lose the ability to monitor CO and smoke/fire. Additionally, if you use your radio presets and time function, they will all be "reset to zero" when you turn power back on at your "re-purposed" switch.

In some trailers, you may also lose any presets on an automatic leveling system and the remote (if you have one) may also lose connection between the handset and the receiver.

Thank you for your insight. What I am running into since I can't plug the unit in when I store it all of these things are losing power anyway because the battery is dead by the time I get back to it to use again. My thought was to allow the jacks and remote to remain powered as long as they don't draw when turned off, but shut down the rest of it. The alarms mean nothing as it sits in storage with no one to hear them go off and at this point it has been a week my battery is gone. I get that the factory has a certain amount of CYA to think of but in reality this switch is worthless and right now one more thing to remember to turn on when I take off on a trip.

[ctbruce]

Mike, if it was me, and it was with my first 2 trailers which did not have the battery disconnect, I'd leave the battery disconnect on and remove the negative cable from the battery.

Sent from my SAMSUNG-SM-N910A using Tapatalk

[Chief Mole]

Electrically, a deep cycle lead acid battery will self-discharge when left open circuit after a prolonged period, starting about six months or so. The carbon black used in the construction of the battery case is a conductor, poor as it is after being mixed in the hard vulcanized rubber of the case. Similar to why certain weather conditions will lead to a static shock from the car when you touch it while most of the time you don’t.
For me, since we store at home, I’ll just keep shore power rigged and check water level every quarter.

[Hodgy]

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Staying with the lack of a charged battery to operate the break away.

Assuming the battery is capable of holding a charge and all trailer and TV wiring is intact and connected. Anyone want to hazard a guess how long it would take for the TV alternator to charge a dead battery back to a state capable of operating the break away ?

Anyone ?

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[JRTJH]

Originally Posted by Hodgy

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Staying with the lack of a charged battery to operate the break away.

Assuming the battery is capable of holding a charge and all trailer and TV wiring is intact and connected. Anyone want to hazard a guess how long it would take for the TV alternator to charge a dead battery back to a state capable of operating the break away ?

Anyone ?.

Way too many variables to even make a WAG (Wild A** Guess) much less a SWAG (Scientific WAG)...

That said, it depends on the condition of the battery, if discharging it completely caused a shorted or "bad" cell, it may never recharge enough to be capable. If there are two or more batteries in the system, they all "share the charge, so two would take twice as long as one to reach a specific charge state. If there is any corrosion on the terminals, that would affect the charge rate, if there is a problem with the 12VDC auto reset breakers, if electrical components inside the trailer are producing a load that the truck wiring is providing, less power would be available to use in charging the battery.... As I said, too many variables....

Typically, if everything is operational, the battery "could be" at sufficient charge state in an hour or so. If you're trying to run the furnace to warm up the trailer, run the refrigerator monitoring circuitry, run slides in and out to load, use the hitch jack or other electrical loads, all of them will dramatically affect how fast the battery charges....

Remember that you can't run the "full 85 amp capacity" of your truck's alternator through a 16 ga or a 14 ga "power lead through the umbilical 7 pin connector" The most you're going to get through that wire is about 4 or 5 amps "sustained" charge capacity, so really it's not a lot more than a typical "trickle charger".....

[menltkns]

I bought one of these for less than $10 to disconnect at the battery. Was the CO sensor still pulling juice?

https://www.amazon.com/Graceme-Batte...SIN=B074J7RCH9