Battery Drain with nothing on

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Mattmac1210

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Feb 27, 2018
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5
Hi all,

I'm new here and what a great place for questions.  Please forgive me if this topic has already been covered.  I have a 2001 Coachmen Leprechaun.  Just bough a new Interstate Deep Cycle battery and have been continuing to have an issue with battery drain.  My wife and I are boondocking and seven with a fully charged battery can only make it through one night before getting to "f" on the panel.  This is really only using the pump a bit and one or two lights for less than 3 hours.  I just bought a solar panel which allows me to read the voltage and overnight(without having anything on) it went from 12.1 to 11.9 volts.  I'm afraid that I'm going to continue to destroy batteries by letting them sink to low.  I thought that it could be the refrigerator(dometic) even though it has been set on auto and I felt like should only be using a small amount of power.  I was going to try to set,it,on "GAS" just to see if maybe somehow it was pulling from the batteries.  The only other thing that I think would be staying on overnight would be CO2 and propane detector.  So, still scratching my head here.  Thanks so much for any information you can provide.  Oh and another detail, is that I believe my converter is not actually working...which is why i purchased solar kit. 
 
12.1 volts is considered minimum, so if you are going to bed at 12.1 volts the battery is already "dead". With the converter (and I assume by that you mean the charger) not working, unless you bought a decent sized solar system I'm guessing your battery is not getting fully charged. It may well be that everything is fine, you're just not recharging fully. By the end of a sunny day, with the solar off or after dark, you should see about 12.7 volts. If not, you're already starting "half empty" and it will be difficult to figure out whether you have a battery drain issue or a charging issue. A drop from 12.1 to 11.9 (again, already dead) overnight with basic parasitic loads such as the fridge and LP detector running seems about right. Also, flooded batteries like to be fully charged soon after being discharged - it will shorten the life and capacity of the battery if this isn't done.
 
This may help you get a handle on your battery charging

https://handybobsolar.wordpress.com/the-rv-battery-charging-puzzle-2/
 
Mattmac1210 said:
Hi all,

I'm new here and what a great place for questions.  Please forgive me if this topic has already been covered.  I have a 2001 Coachmen Leprechaun.  Just bough a new Interstate Deep Cycle battery and have been continuing to have an issue with battery drain.  My wife and I are boondocking and seven with a fully charged battery can only make it through one night before getting to "f" on the panel.  This is really only using the pump a bit and one or two lights for less than 3 hours.  I just bought a solar panel which allows me to read the voltage and overnight(without having anything on) it went from 12.1 to 11.9 volts.  I'm afraid that I'm going to continue to destroy batteries by letting them sink to low.  I thought that it could be the refrigerator(dometic) even though it has been set on auto and I felt like should only be using a small amount of power.  I was going to try to set,it,on "GAS" just to see if maybe somehow it was pulling from the batteries.  The only other thing that I think would be staying on overnight would be CO2 and propane detector.  So, still scratching my head here.  Thanks so much for any information you can provide.  Oh and another detail, is that I believe my converter is not actually working...which is why i purchased solar kit.
Click to expand...
Well if you are starting at 12.1 volts like Sun2Retire is saying you are starting with a dead battery. You need to get your battery bank up to at least 12.6 and then see how it does.
Bill


.
 
if you are starting at 12.1 volts like Sun2Retire is saying you are starting with a dead battery.
Click to expand...

"Dead" may be a bit of overstatement, but 12.1v is only about 50% charge. You must have used a lot more than a couple lights to get down to 12.1 from [presumably] the 12.6v of a full charge.  Either that, or the new battery isn't up to par.  But in any case, another 0.2v was lost overnight when hopefully no lights were on. The LP and CO detectors will continue to draw power, but that's a tiny amount.

Your fridge uses a miniscule amount of 12vdc power for its circuit board and its about the same amount whether on AC or Gas power.

How did you conclude your converter/charger isn't working?  No lights or battery charging when plugged to shore power?
 
Gary RV_Wizard said:
"Dead" may be a bit of overstatement, but 12.1v is only about 50% charge.
Click to expand...

Gary's right and I shouldn't have used "dead" either. I should have said something like "effectively discharged".

For years and years as an RVer I had no idea what I was doing with batteries. Seemed like they were always dead (especially when I woke up on a cold morning), would barely run stuff overnight, didn't seem to hold a charge, etc. I used to figure that if it was a "12 volt" battery 6 volts would be a 50% charge right? If the lights came on (even if a little dim) and the pump worked, it wasn't dead right? But if the genset wouldn't start, now it was getting near "dead". Right? Of course, now I know better, and all of those assumptions are wrong.

I think the first thing that confuses newbies (or even those with some experience but that, like me, didn't understand batteries) is that a "12 volt battery" is actually a "12.7 volt battery". So when you see 12 volts on the meter the battery is not fully charged, its already heavily discharged. Second, for battery longevity a lead acid battery should not be discharged below about 50% which is about 12.1 volts. So that's all you have to work with, the range between 12.7 and 12.1 volts, not 12 volts and zero.
 
We dry camped for the first time last year. I perched a second battery and wired the two together and we were at the site 3 days. Never ran out of battery power. We ran the fridge on propane but used the TT lights and whatever else was on battery. But I started out with two fully charged batteries.
 
Thanks so much all.  Some very valuable information here for me as I'm still trying my best to learn about this.  Ill try to respond to all in one message here.  I had concluded that my converter was not working on because while plugged in my battery seemed not to charge.  The "c" light was on for about 12 hours but then when we unplugged it did not seem to have much charge.  Today, although it was a partly cloudy day, I was using my 100 watt solar panel for 12 hours.  I just read the voltage of battery after all this charging and it has only gone up to 12.2.  I'm wondering if I should bring this battery back to NAPA or whether I'm just not giving it enough of a chance to charge.  Thanks so much all I'm very appreciative of your responses as I try to figure this all out.  I've read many articles online but as a newbie still hard to pinpoint what is causing my exact issue here.
 
Just FYI, that 100 W panel will be doing very well if it averages 35% of that over a 12 hr period. That would be an average of about 33 W at a charge voltage of 14V or about 30 Amp hours less whatever consumption you have, not enough to fully charge even a small battery. It should be well suited to maintaining a battery in storage, but that is about all.

Ernie
 
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