House Battery Problems

[StevoDevo]

Hi Guys,

I have a Majestic 23ft MotorHome and was having a problem with the house battery not holding charge so replaced it with a different battery (same group and cca) and now I?m not getting any 12v inside the RV at all.

I found this switch behind my circuit breaker board (nothing is tripped or blown there) and the little black switch on it doesn?t click or hold into place when I press it.

Does that mean the switch is bad? Or do you have any other ideas for me?

Thanks!

 

[John From Detroit]

I do not think that black button is a switch. I think it is a "latch" holding the assembly together.

The assembly is a thermal self-resetting circuit breaker

To test hook a test lamp to the battery negatibe then probe both posts on the device  BRIGHT BRIGHT = Good  DARK DARK no test. BRIGHT DARK bad.

 

[grashley]

Welcome to the Forum!

Not to be smart, but is the battery connected correctly?  Red to POS, black to ground and Negative.  Incorrect hookups have occurred!  If that had happened, there may be other "hidden" fuses that blew.

Check voltage with a meter at the battery (should be 12.6V) and at the main breaker / fuse box.

Do the lights inside work when connected to shore power?

 

[StevoDevo]

Welcome to the Forum!

Not to be smart, but is the battery connected correctly?  Red to POS, black to ground and Negative.  Incorrect hookups have occurred!  If that had happened, there may be other "hidden" fuses that blew.

Check voltage with a meter at the battery (should be 12.6V) and at the main breaker / fuse box.

Do the lights inside work when connected to shore power?

Haha good questions!! I?ve made sure red wire goes to positive terminal and black to negative about 100 times!! 

Lights do work just fine when on generator or shore power!  I don?t have my multimeter on me on this trip but am back home tomorrow and will troubleshoot further then!!

 

[John From Detroit]

Though Red and Black are NORMALLY Positive and negative respectively THERE IS NO STANDARD.  I have seen damage caused by people making the assumption that's how they were wired

 

[StevoDevo]

Ok so I'm still having this problem and here are my latest findings. I tested the battery and it reads 12 volts so it has charge. I hopped under the RV and followed the Red cable connected to the Positive terminal on the battery. It has 12v all the way to the point where it enters the RV (it has a number of other red cables all connected together at one point which I assume is the connection to the Land power and Generator.

When I go inside and I test the swithc at the bottom right of this image:

There is no voltage there at all. (I ground it to the ground cable sticking out of the black box. That black box is the fuse / breaker box.

Here is where it gets interesting. If I turn on the generator, or connect the RV to the land power, then I get 12v at that switch. If I leave it connected to land power over night, then disconnect it, I get 12v for a little bit (minute maybe) and then it slowly drops, over a period of minutes down to like 2v (over a period of maybe 5 minutes).

So why isn't the battery getting all the way in!

 

[Ernie n Tara]

You need to be careful with terms. For example 12V is a dead battery. Fully charged it would be about 12.6V. The Voltage from the converter will be in the range of 13.3-14.4V both at the converter and the battery.

Ernie

Ernie

 

[Gary RV_Wizard]

I tested the battery and it reads 12 volts so it has charge. I hopped under the RV and followed the Red cable connected to the Positive terminal on the battery. It has 12v all the way to the point where it enters the RV (it has a number of other red cables all connected together at one point which I assume is the connection to the Land power and Generator.

You have some misconceptions about 12v "battery" power in your RV.  First, 12.0v represents about 45-50% charge on a battery; it should read 12.6v at full charge.  With any charging source connected, it should read more like 13.0-13.6v and possibly as high as 14.4v  With the converter/charger on and shore or generator power present, expect to see a voltage above 13.0.  Second, the red battery positive cable will have no direct connection to the the Land (shore) power line or Generator (except to power the generator engine starter motor).  Land and Generator power is 120vac, not 12vdc and the two can never be directly connected.  The converter/charger is the interface between those separate power systems.  Those other red cables you see must be either (a) directly powering some of the 12v power needs in your RV, or (b) receiving 12v power from the charger.

 

[GaryA]

You need to be careful with terms. For example 12V is a dead battery. Fully charged it would be about 12.6V. The Voltage from the converter will be in the range of 13.3-14.4V both at the converter and the battery.

Ernie

Ernie

12V is NOT dead.  People say that but I can run lights and start my generator at 11.6

 

[StevoDevo]

Hi Guys,

Thanks for the battery level lessons.  My problem is not a charging problem, so I'm not concerned about getting 11.5v, 12.0v, 13.1v etc... I'm getting 0V from the house battery.  No lights, no ability to run the fridge, no ability to start the generator etc.  The battery itself is healthy and is testing at exactly 12.6v. 

That's the problem I'm trying to solve!!   

Steve

 

[Garyi]

Start with the basics. Start at the battery with all connections disconnected. Do you have 12.6v or higher?
If not battery needs to be tested/ charged/ replaced as defective. If a top post battery did you remove the protective plastic caps? I have seen many posts on forums where there was a whoops I did not take the caps off. If 12 volt power worked prior to replacing battery it can only be:
1 Battery bad or low charge.
2. Plastic caps still on posts of battery.
3. Battery hooked up backwards and a fuse or circuit breaker at the converter is blown.
4.Battery disconnect switch

 

[grashley]

SHAZAM!!  (I hope)

You have 12V power to the coach when plugged in to on generator, so 12V system is okay.

You have power at the battery and MOST of the way to the Power Center, but not AT the power center.

Sounds like a broken wire between the last place you tested on the under side and the first connection near the power center.

OR 

That connector in your picture - top left -  may be a faulty resettable breaker.  Do you have power on either side of the connector with battery power only?

Test using a KNOWN chassis ground.  That Cu wire may be a 120V ground and not a chassis ground.