Aux battery issue solutions?

[ANZAC]

Isolator is in series with alternator charge.... At least on my 2002 it is.

The batteries may have sulfated due to sitting discharged. There are some charges that will attempt to recover sulfated batteries. If they are badly sulfated, end of story, you will need new batteries.

[Roonie]

Originally Posted by MKRyan

I went with the same brand as I know it fits dimensionally and the former owner and I got almost 5 years out of it. $450 delivered to Pocatello, Idaho. I think thats a good price?) Local I can get same battery for about $400 without shipping so seems just right

Here's the real question: If I plug in a meter to one of the house DC outlets I'm getting a low voltage reading due to my battery, around 12v.Mine is the same usually after a week or so around 11.8 volts. When I turn on the SMB the battery separator clicks after 10 or 15 seconds or so and the voltage increases to 13.2. Mine jumps to 14.0 when I start the engine at idle. When I turn the engine off it slowly goes down to 12.6v and then the battery separator clicks again and it drops quickly down to the voltage prior to starting the engine. I believe that sounds right and my battery separator is working. Yes, battery separator is working same as mine.


I also checked my meter on the dash DC outlets which is reading 12.5v prior to starting the engine. Mine reads 12.2 prior to starting engine. When I turn the key to the aux. position it goes down to 11.5v (Mine goes to 11.8 with radio off) or so and when I start the engine it temperarily drops to 10.7v. Mine drops to 9.8v. Once the engine is running after a few seconds it reads 13.2v. Mine reads always 14.1v. This also sounds right according to posts I've read. So it sounds like my starting batteries are also good.

Does this make sense? If so, why wouldn't my 'not so good house battery' show an increase in volts after driving for several hundred miles? Even if it doesn't last very long. It at least shows higher volts when charged on shore power, even if it's only for a while. My cable connections and ground seem to be good.

I'm hoping by replacing my house battery, all will be well.

Any thoughts?

Thanks,

Mike

My answers in dark blue above..........

My house battery is the same vintage as yours and I am thinking I will need replacement soon as well. However even after a full night of reading lights, etc camping and it will still be right at 12v or so in the morning. This has been the way it has worked now for a couple seasons. I was concerned at first as well and talked to Sportsmobile WEst about it and they said life of the house battery is 4 years. I am right at the max life span so I too am thinking of replacing. It hasn't run dead on me yet. Also I run the van once a week (on errands) to charge it up.

Not sure why my idle voltages are higher than yours. Mine have always read 14.1 volts or 14.2 volts at idle on both batteries.

[MKRyan]

I appreciate the responses everyone!

Joey2cool, I agree, thats why I was originally thinking the battery separator wasn't working. After several hundred miles of driving it wasn't showing the same kind of temporary charge as when I was on shorepower. New battery will be in and installed next week so we'll know for sure then.

Roonie, battery was $315 and delivery from California was $135. Bought it from Best RV and Truck Supply out of Boise. (battery not in stock in Boise) They are the closest distributor for Lifeline to me in Idaho. I thought it sounded like a good price.

Also, when I bought the SMB it had only 17,900 miles on it and it was just turning 4 years old. Not too many miles for being that old so I assume it sat quite a while between trips and the battery probably suffered.

Mike

[daveb]

Sounds like everybody is correct here...looks like you need a new battery. Lifeline batteries generally last 6 years or more which is a few years longer than the other brands and have a better warrantee as well. How long a lifeline will last depends on how well you take care of it. I have one from 2005 (not in my van) and it still preforms almost like new.

Depending on what alternator you have, the voltages should range between 13.3 and 14.2. I've had 4 different manufactured alternators in my van and they all threw out slightly different voltages. The stock Ford read 14.3, a 200 amp was 13.4, a 230 amp I had in as a temp alternator measured 14.4 and finally the 240 Amp that I have now reads 14.2. I ran the 200 amp for several years and never had a problem until another issue took it out. I wish I could regulate the voltage and if I could would set it at 13.6. Lifeline suggests that your chargers should be set to around that voltage for best battery life. I've turned down my solar to about 13.6 for that reason but I can't control what the alternator puts out and in general don't worry about it.
Lastly, if you're concerned about the life of you battery read this which is also in the FAQ's here:
Battery info and I have several links on this page at this site including one to lifeline Part 10
Dave

[rockbender]

Thanks for the reminder on the links, daveb. If I can get on a soapbox real quick here... if you're letting your AGM battery drop below 50%, which is approximately 12.0 volts, then you are likely causing premature aging/failure. I read a lot about people dipping into the 11.5 to 11.8V range - to me this means that something needs to be adjusted either in capacity or usage to prevent such a deep discharge.

Right now I'm on the conservative end of the spectrum. I'm actually using a couple starting batteries as my house batteries (because they were free, not because I think it is a good idea) and they are even more susceptible to a shortened lifespan when deeply discharged (repeatedly). I'm trying to keep my depth of discharge to 40% or less to try to maximize the life of these batteries, so for me I don't want to see a voltage much lower than 12.3 before putting a charge back in.

[daveb]

When my van was in the shop, I called Ford and tolld them to turn off my refrigerator if they were going to keep the van inside but they didn't listen to me. When I finally got there they had let both 4-D's fall to around 9 volts I got the charger on them right away. After talking with Lifeline, the tech told me not to worry and that as long as this doesn't happen often I'd be OK. But he did caution me that leaving them at that state for over a couple of weeks w/o a charge would do heavy damage. They probably lost 2 or 3% of their life.

[jage]

Originally Posted by rockbender

I read a lot about people dipping into the 11.5 to 11.8V range

Until I got solar, I was never regularly ABOVE that, and I've replaced the batteries too- that's new Deka 4Ds, and shore power and/or alternator charging.

[daveb]

Originally Posted by jage

Until I got solar, I was never regularly ABOVE that, and I've replaced the batteries too- that's new Deka 4Ds, and shore power and/or alternator charging.

That's strange Jeremiah. When my solar was down, I never had a problem keeping my batteries up with the alternator...even went on a few weekend trips.

Back to Mike's problem, I've found correct charging methods do help extend the life of a battery and small solar systems like most have really do help. But depending on the load and while in use, many times the voltage will drop down below 12 volts and I don't want to scare people from letting the voltage drop into those zones. On the other hand, with no load or a light load, it's important not to let AGM batteries rest at lower voltages for long periods of time such as 2 weeks or longer. I still wouldn't want to take the batteries down to such a state on a regular basis and cycle them that heavy and probably means you need more battery reserve.
If a fully charged AGM battery reads 12.2 volts after it sits at rest with no charge for a day, it's on its death bed. Of course there are a few tricks to bring them back to life and if those work you might get a little more time out of them but eventually they all end up in that big battery box in the sky

[vlamgat]

I would add one more thing to all this really good battery stuff: if you have an inverter, make sure you switch it off or disconnect it. It will take down the battery even with all the breakers off. Some inverters also have a battery temperature sensor that reduces the charge rate with increases in o/s and battery temp. Besides the impact this has on the voltages discussed here its also relevant to the voltages you may see either while on charge or at rest. And at lower temperatures discharge rates are generally lower in my experience.