Norcold Fridge Draining My 320S Battery on Propane

Pekoe1111

Battery was at 100% at 3p in afternoon when I disconnect my tow vehicle.  With nothing on but the fridge on propane, battery was at 42% at 7P the following day (28 hrs later).  Outside temps in the 50s-50s.  Is this normal with a one-year old battery?

Pekoe1111

Correction - stereo light was on too.  

pthomas745

Based on what measuring method? Victron app?  Was the battery "rested" or was it running the trailer when you noted the "42%".   What size and type of battery? What year trailer?

MuttonChops

@Pekoe1111 ;  As @pthomas745 noted additional details would be helpful.

In general what you are reporting is abnormal.
If a typical 320S draws 500mA (0.5 A) per hour - - - which is high compared to the real world typical.

Your battery would have been drained some 14 Amp-Hours . . . 14% if the battery is a 100-AHr [20% if a 70-AHr dealer basic was installed]. . . not 42%

So first reaction would be:

   == A ==  You have more 12VDC 'things' turned-on then you realize

   == B ==  How you are measuring the power loss/capacity is wrong. For example the KIB Tank Monitor
                   Battery LED Lights are worthless.

Pekoe1111

Thanks for your questions and suggestions.  The battery is a typical car battery and the camper year is 2014.  I have a Bluetooth battery app that measure battery level.  I’m sure it’s not exact but it seems to show general levels.

In terms of things left on, it’s just the stereo display light, smoke and CO detector, and fridge light.  I have a master kill switch at the battery but it seemed to turn off the fridge (running on propane but indicator light obviously needs power).  I wonder if you can run the fridge on propane with battery disconnected. 

So perhaps I have a parasitic drain or need to try another battery level monitor.

Pekoe1111

Battery is only two years old and I have kept it above 50% except for maybe once it drained all the way.

ScottG

@Pekoe1111, while I can't offer much insight into your specific issue, I can tell you that the 3-way fridge--even running on propane--does require 12V power to operate the internal electronics and circuitry. However, the amount is almost negligible and should not be causing any noticeable drain on your battery.

Also, I assume when you say you have a "typical car battery" you really mean a deep-cycle marine/RV battery. Car batteries are designed a bit differently and will likely drain quickly if used in an RV application. If you are using a car battery, that could be part of your problem.

Pekoe1111

@ScottG - thanks for this guidance.  I’ll double check the battery.

Pekoe1111

My battery is a deep cycle so I wondering what’s the best way to check for parasitic drains.  Any suggestions for an accurate battery monitor?

Thanks!

pthomas745

Show us a photo of the battery, or give us a description   "Most likely" it is a "stock" 80 amp hour lead acid battery, a "Group 24".  (You might see "24" as part of the model number).   It would be good to know the age of the battery.  A lead acid, if treated with tender loving care, might last 5-6 years.  If you don't have a good idea of how it might have been used in the past (was it allowed to drop to a low state of charge too many times, etc) that may also be an issue.

All the trailers have "parasitic drains".  My 2017 parasitic drain goes about 5-6 amp hours a day.  The Jensen head unit and TV  use a bit of power.  USB ports, etc, all use a bit of power with the battery switch on.  Probably the biggest parasitic drain is the gas monitor, which is connected directly to the battery. 

There are tools that show you what your parasitic drain may be.  One simple tool would be a "clamp meter".  YouTube tells me that making sure everything in the trailer is "off", and applying the clamp meter to the negative battery cable will show you the parasitic drain.

This one is a clamp meter and also can be used as a multimeter.

https://www.amazon.com/ANENG-Multimeter-Capacitance-Resistance-Continuity/dp/B0B9RKFJ2R/ref=zg_bs_g_5011680011_sccl_6/141-7368678-6884741?th=1

Another tool that will do this for you is a "shunt". A shunt basically sits on the battery negative post and measures everything that comes in and out of the battery, and will add the number of amp hours you have used.  On my Victron shunt, it shows me the "current" flowing out of my battery when everything is off and no charge coming in.  My "parasitic" draw is about .24 amps.  There are the bluetooth Victron shunts that can run 100 dollars or more, or the less than 40 dollar shunts with a simple display. Lots of owners here have this inexpensive Aili shunt installed.

https://www.amazon.com/AiLi-Battery-Monitor-Voltmeter-Motorhome/dp/B07CTKYFTG/ref=as_li_ss_tl?keywords=battery+shunt&qid=1578351402&sr=8-16&linkCode=sl1&tag=vehicledwelling-20&linkId=561e779cf1d881b2f2e2e8cdc753241b&language=en_US&th=1

MuttonChops

@Pekoe1111 ;  Before purchasing/installing an (expensive) in-line Battery Current Monitor.
You might consider getting a cheap clamp style Current Meter.
Clamp it to the Battery Negative terminal wire,
then you can measure the current with various combination of trailer 12VDC items turned-on or off.

Here is a $30 meter

A cheap price clamp on meter will be more than accurate enough for this project.