Low Voltage

gilbutler

Since I’ve received so much good information from this forum, I’ll suppress my embarrassment and post my last T@B trip experience for anyone who didn’t pay much more attention to page 4 of the WFCO Power Center manual than I did.

We spent our first night at Van Damme State Park, below Mendocino, California. Then we went to Patrick’s Point State Park, above Eureka, California, for two nights before

Heading toward Coos Bay, Oregon.  Because of the weather, we turned back to Turtle Rock RV Resort at Gold Beach, Oregon, for two nights.  This was our first location with water and electric service. The following is the sequence of events, but I didn’t put it together until after I returned home.  

Having not camped with city water hookup before, Cathy turned the water pump on, and turned it off when she heard it go a bit wild.  That night, we decided to watch a movie for the first time in our T@B.  The picture was a bit strange and when the DVD stopped, I checked the voltage and was surprised by the low voltage (11.3V on the 12V outlet).  When I connected the tow vehicle at idle, the voltage went to just over 14V, but when I hooked to my (new) generator instead, the voltage returned to about 11.3V.  After returning home at night, I disconnected the tow vehicle, turned everything off that could be switched off, and pulled the battery fuse.  In the morning, I started trouble shooting by checking the battery and was surprised to find it at a healthy 13.6V.  After connecting to my house 110AC, the T@B 12V system indicated 13.7V.  After re-reading page 4 of the WFCO manual, I realized that running the water pump while connected to city water must have created an overload detected by the Power Center, which then went to fold back or shut down.  When I pulled the battery fuse and disconnected all power inputs (for the first time) after returning home, the Power Center was allowed to reset, returning the systems to normal. 

TabyDD

Hi Gill, I'm experiencing a similar phenomenon in that I am charging and recharging from my house (shore power) to keep the battery charged and to also observe some of the draw from using power while I have the advantage of being at home.  Normally when plugged into ShoreP it would float around 13.62.  When unplugged it would rest around 12.65.  Now after another week or so on ShoreP her first reading is at 12.53.  Can you think of a reason it's lower?  In case you can't tell, I am electrically challenged.  Thanks for any input out there.  DD
 

gilbutler

I'm certainly not an expert in this area, but I can tell you what I guessed.  I think my Power Center reduced output because of a temporary overload.  I think restoring the higher output required removing all voltage, including the battery.  I would try removing shoreP and pulling the battery fuse, then plugging both back in. If that doesn't work my next move would be an email to Little Guy at the address in the T@B contact numbers.  They are very quick and complete in their responses.

RZRBUG

When you are not connected to shore power, 12.6 - 12.7 is the maximum you will get, and that is normal.  Gotta run.  If someone doesn't beat me to it, I will be back later to explain.

TabyDD

L and B  That is my concern is I'm at 12.54 not 12.63?  Should that be a concern?  I was going to connect my Norcold to see how much time I would have with my battery fully charged.  Just testing all my systems.  Can you clarify?  DD

RZRBUG

Following is the technical explanation Michigan Mike gave me when I was asking similar questions earlier.  I don't really understand it, but what I did get (along with the rest of the discussion) is that 13.6 Volts is normal when connected to shore power.  Remember that the battery is a 12V battery, so anything over that means that it is fully, or almost fully, charged.  Your 12.5V  would indicate a fully charged battery.  If after charging, and nothing is on (including the little lights on your TV, stereo, etc.) and your voltage continues to drop and fail to again fully charge, I would check the fluid levels in the battery.  Pry off the cell covers (wearing gloves and eye protection) to see if the fluid is about 1/4 inch from the top.  If not, fill to that level with DISTILLED water.  I would also disconnect the cables and push them out of the way while doing this just to be sure you don't short them across accidently.  Oh, and be sure to mark the cables so you'll know which post to reconnect them to.

Technically speaking Larry, the electric converter converts the 120 VAC 60 Hz from the outlet to 120 VDC after it passes through Diode Rectifier #1, the Capacitor then filters the ripple voltage. This 120 VDC voltage is then fed to an Electronic Switching Circuit that converts it back to AC and increases the frequency from the original 60 Hz to 3,500 HZ. This high frequency AC voltage is then fed to a step-down transformer where the output voltage is reduced to approximately 13.6 volts AC and Diode Rectifier #2 converts the AC to 13.6 Volts DC and the Capacitor filters out the ripple.   

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gilbutler

I won't try to disguise my embarrassment by explaining why I answered as I did since excuses help no one.  I agree fully with Larry and appreciate him providing an accurate answer.  Thank you Larry.

RZRBUG

 I had that duh moment right after I got the T@B, and asked the exact same question DD did.  It's how I ended up with the answer.

Mercator

When you are connected to shore power and read the voltage at a 12V outlet you are reading the voltage that the converter is supplying to the system (around 13.6v), NOT the voltage of the battery.  In order to get a good voltage reading on the battery, after charging, it needs to rest for at least an hour before measuring the voltage.  A 'smart' charger will decrease the amount of charge going to a battery that it senses is nearly full and increase the charge to a battery that it senses is heavily discharged.

ChanW

DD, 9/100 of a volt isn't a big change in your battery reading. It could be the result of an outdoor temperature difference, or some small device on your 12v system that's drawing power (maybe the CO/propane sensor). As others have said, If it continues to drop, but more significantly, then check it further.

TabyDD

I may have it!  After reading Chan's comment, I have had a utility light (low watt) plugged in to deter would be burglars and to keep the edge off on cold and damp nights.  Seems strange however, that after unplugging from SP that would immediately (1 hour) show up in my volt reading.  hummm  will check water level as suggested.  Is the converter box making any noise at some point?  When does it start doing it's 'dance'?  Appreciate.  DD

Michigan_Mike

Some of the LED lights in these trailers do draw voltage even when they are switched off.  I have a galley light in my silver shadow that has a faint blue glow to it and over time it does draw down the battery some.  You could be experiencing something similar and what is known as parasitic draw or drain.  Could possibly be something in the trailer as simple as a TV/stereo circuit (note the lights that remain on on some of these devices), etc.  

Irregardless of the above, a battery DOES lose a charge over time when sitting idle and not attached to any load, so battery drain does occur and is a normal phenomenon.   Cold weather will impact a battery and hot weather is tough on batteries too.  

TabyDD

Appreciate.  Do you have a 'routine' for not using the battery.  In other words, do you turn some things on just to use the battery in your 'off' season?  Yes, the blue light is omnipresent as it were and I'm sure taking up some juice.  Thanks Mike.  DD

Michigan_Mike

Mine is an experiment of sorts.  I did disconnect the positive terminals initially after I had fully charged up my battery and had planned to leave it that way for the winter.   But after installing my solar charge station, reconnected the battery and watched the effects of the parasitic draw from the LED light in my trailer and the subsequent recharging via solar.  I was away from home for ten days, the temperatures have been below freezing for some time and yet the battery voltage remains normal and my solar panel continues to charge the battery daily.  I am very impressed with the set-up and the ability to keep the battery fully charged, even in extremely cold conditions and off the grid.  Before the installation was built I was periodically plugging my trailer into shore power to keep it charged up as the voltage dropped via the LED light drain.  The slight voltage drop encountered really isn't seen until at least 3 days without a charge.  But know that if left unplugged for any lengthy duration my battery would be dead over time.