Nothing Works When Not Plugged In

theweave · 05-22-2012, 07:44 PM

I just got a used 2008 Cherokee and this is my first ever trailer so I am a rookie at this.

The battery is fully charged but nothing will work in the trailer unless plugged in. Slides won't work, jack won't work, no lights nothing.

I realize this is probably an easy solution, but I can't find the answer even on google.

Helping a rookie would be appreciated!

OldCoot · 05-22-2012, 07:50 PM

1. is battery connected to the trailer wiring
2. is battery charged
3. is there a battery disconnect switch

jtstromsburg · 05-22-2012, 07:54 PM

If those the options aren't the fix, check and see if you have a in-line fuse near the battery?

theweave · 05-22-2012, 07:55 PM

Quote:

Originally Posted by dunnnc

1. is battery connected to the trailer wiring
2. is battery charged
3. is there a battery disconnect switch

1. Sure looks like it
2. Yes the meter in trailer shows voltage
3. That I am not sure of (first trailer!)

**Herk7769** · 05-22-2012, 08:35 PM

Quote:

Originally Posted by theweave

1. Sure looks like it
2. Yes the meter in trailer shows voltage
3. That I am not sure of (first trailer!)

When you say it shows voltage which light or lights are on on the display?

**bikendan** · 05-22-2012, 10:57 PM

how do you know the battery is fully charged?
if you're depending on the idiot lights that are on the monitor, don't rely on it.
do a hydrometer test on the batter or take it into an auto parts store for testing.

**Terier** · 05-23-2012, 12:26 AM

Quote:

Originally Posted by bikendan

how do you know the battery is fully charged?
if you're depending on the idiot lights that are on the monitor, don't rely on it.
do a hydrometer test on the batter or take it into an auto parts store for testing.

"Idiot lights" is a term not often used by the younger generation...guess you are older too.

I have to say I was a little surprised to learn that the battery light on the display didn't have much to do with the level of the battery charge. I forgot to ask the service tech if that light serve a purpose even in theory?

PrairieBoy · 05-23-2012, 12:34 AM

I would unplug the power to the trailer then do your battery test at the monitor again and see what it reads.

cardinal4fun · 05-23-2012, 04:50 AM

I would guess its either battery disconnect switch or in line fuse. The battery disconnect will be located somewhere in one of your outside storage areas. Once you see it you will know what it is as it will say battery disconnect. The other is inline fuse just look around the battery for it, it could be anywhere.

TURBS · 05-23-2012, 06:21 AM

YOU cannot check battery level on indicator panel when hooked to shore power!
The converter will make it show full.

Although indicator will show General battery condition when UNPLUGGED from shore power.

Ilneed to use hydrometer or load tester

**Herk7769** · 05-23-2012, 06:53 AM

Quote:

Originally Posted by Terier

"Idiot lights" is a term not often used by the younger generation...guess you are older too.

I have to say I was a little surprised to learn that the battery light on the display didn't have much to do with the level of the battery charge. I forgot to ask the service tech if that light serve a purpose even in theory?

Ter,

The lowest light when "battery" is selected with the button means there is "at least" 6 (yep SIX) volts on that 12 volt battery. If the last light is out it means there is NO battery connected.

**Herk7769** · 05-23-2012, 06:58 AM

As an "add", the battery's condition can ONLY be checked after a
charge "equalization" period of about 30 minutes of being disconnected from the charger.

The plates in a deep discharge battery are THICK. The charge has to have time to migrate into the core of the plate from the surface of the plate (hence the term "surface charge") to get an accurate voltage reading.

This time is much less in a starting battery as the plates are MUCH thinner. They are designed to give up electrons quickly and in large numbers. In a storage battery, the plates are designed to give up electrons slowly over a long time.

**Herk7769** · 05-23-2012, 07:01 AM

While we are here, this is how you check "how FULL" a battery is by accurately measuring voltage using a digital voltmeter AFTER the equalization period.

Note the difference in capacity as a percent of charge is in TENTHS of volts.

comfun1 · 05-23-2012, 08:27 AM

Lou, you seem to know a lot about batteries, so tell me, is there a way to tell in advance if a battery is about to fail and leave you unable to start your vehicle? Or maybe I should have said is there a way to tell when you need to replace your battery before it fails?

**Herk7769** · 05-23-2012, 01:52 PM

Quote:

Originally Posted by comfun1

Lou, you seem to know a lot about batteries, so tell me, is there a way to tell in advance if a battery is about to fail and leave you unable to start your vehicle? Or maybe I should have said is there a way to tell when you need to replace your battery before it fails?

Carnac the Magician (Johnny Carson) holds an envelope to his forehead...

As batteries are designed with a specific number of charge/discharge cycles for that style and manufacturer of batteries.

That "by design" age is an upper limit. What you do with that battery determines how long it will last.

A "design" charge cycle is a discharge to 80% capacity and a full recharge every time. Seriously EVERY TIME. 80% You have to be kidding me; who does that?

Well, anyone who wants his batteries to last the 1000 or so cycles the manufacturer determines is the age limit on their battery.

During normal use of a car battery for instance, as long as the car starts in one or two cranks you will never discharge it below 90% or so and then drive it long enough to replace the charge you used. Typically, about 6 years of use. If you drive long distances you will get longer life from your battery because you will fully charge it before you need it again.

Ask someone who drives a couple of miles to and from work in the dark how long HIS battery lasts. The battery never gets a full recharge and winds up deeply discharged at some point. Then one cold winter morning 2 or 3 years later... nada.

So, how do you know if age is unreliable? If your battery does not "hold a charge" you could be in need of a new battery or it could just be deeply sulphated from being in a low charge state for a long time. A battery load test will let you know if it is healthy enough for continued use.

Read up on charge charge cycles and battery health.
Several good files here in the FAQ and elsewhere.

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