Coach Battery Life (Death)

[360true]

We are on shore power most of the time. When we are traveling, the engine keeps the coach batteries charged. The inverter runs the residential fridge.

My four coach batteries were replaced with NAPA deep cycle (not pure deep however) a year ago. Last week, I wanted to stop at a Walmart overnight but I was only reading 12.1 volts at the batteries and 11.9 at the source of the inverter - not enough to last the night.

Shouldn't coach batteries last longer especially if kept charged all the time?

What am I not doing?

Thoughts?

[BriaBeck]

A few things to check:


When you are not in your camper:


What items are still powered and drawing the battery down? Look at the Propane/CO detector, the "keep alive" circuit on the stereo, vent fans, refrigerator running on propane (still uses a small amount of 12V electric for control if you've got it turned on).


All of these things will draw your battery down over a week or three.



Lead Acid batteries don't tolerate being drawn down below 50% state of charge (about 12.1 Volts with no load) very well, and especially very often. Each time it occurs, it injures the battery, and reduces the capacity to a degree.


Drawing the battery down flat is even more damaging.

You might--should-- consider adding a battery disconnect switch, or just simply disconnect the battery when you're not using the camper. That will prevent all of those 12V items from drawing down the battery to damaging levels while you're away.

If you leave your camper plugged in all the time, it could be possible that the converter is overcharging your battery and cooking all the water out of it. Check the cells, if they are low on water, this is likely what is happening. Overcharging is just as damaging as over discharging. WFCO converters are reportedly notorious for this.

Just some things to check on that could be causing your issues... Good Luck with it!

[JS Stanley]

Not sure if this is helpful or not, but...
With my TT, I shut off all the AC breakers and then my phantoms disappear. I can only conclude it may be related to the inverter or convertor still drawing power even though off, because nothing else is even on, and the frig does not have that other power siphon mentioned throughout this site.
My power stays constant all night. But, if the breakers are on, I seem to have a slight drain. Although, I am still experimenting.

[360true]

Thanks for your ideas, but I need to provide additional info that might clarify the issue.

We live be full time in our Georgetown 378 coach. Except when we are actually traveling, we are plugged in to shore power. In the past year, the batteries have not been used except for brief power outages. Water is checked and filled if necessary on a 60 day schedule. They have never been drawn down.

The batteries are NAPA deep cycle, but again, not pure deep cell like Trojans or Lifetime.

When actually charging, the voltage is 13.4 +|-

This is why it is so confusing. Thanks.

[Reverse_snowbird]

I second what BriaBeck said "If you leave your camper plugged in all the time, it could be possible that the converter is overcharging your battery and cooking all the water out of it. Check the cells, if they are low on water, this is likely what is happening. Overcharging is just as damaging as over discharging. WFCO converters are reportedly notorious for this."
I'd suggest a battery disconnect switch when you're camping and hooked up to electric.
On our rig (which is much smaller than yours), the battery will show full charge on the panel, but that doesn't really show what the actual charge of the battery is.

Did you check the value of the batteries before you pulled out of your last campsite? Could something in the rig have pulled down the battery charge as you traveled?

The other possibility is that you got a couple of bad batteries. We're changing to gel cell to eliminate maintenance and get a 3 year warranty rather than 1 year.

[formerFR]

actually, your batteries are ALWAYS being used, since, of course, you have many, many 12v items within your coach that you are using, whether or not you are plugged in. These 12v items draw directly from the battery bank, even though the Converter is also Charging the batteries at the same time. It's an 'off-setting' effect, but the batteries are still going thru the draw and charge cycle constantly.

If your coach does not have the capability of allowing the Alternator to also charge the battery bank while driving, then your batteries are not being charged while driving, giving you a lower overall battery level when you arrive, depending on how long it's been since you 'un-plugged'.

Crank your generator and CHARGE your batteries - you'll be fine then for your overnight.

[formerFR]

... with the XL version of your Georgetown(we had the same 2015 model back in 2014), the Inverter will also draw down the battery bank if providing for your residential fridge when traveling, as well as any outlets that you are using.

If your coach has a Magnum inverter, and a Magnum or similar AGS(auto generator starter), you can set it to crank your generator automatically when the battery bank level gets to 12.0 volts, whether while traveling or during overnights.

[houstonstroker]

I would think you should be seeing over 14 volts either from your alternator when on the road or your converter.

[tomkatb]

Many possibilities.

One bad cell in one battery can do this. Cells can be checked with a tester or at auto places.

Regardless, you should park with the batteries reading well over 13 volts. One night should be no big deal. Two could be an issue with a residential fridge. Some of them use a ton of power. I would guess you have 200 amps available or less. That is 2200 watts with an inverter. There is a 10-20% power loss.

I would watch your battery bank voltage like a hawk.

Learn how it operates. The key to finding the issue. Just too many possibilities. Some coaches are mis wired and the inverter tries to recharge the batteries!

Finding stupid stuff like that is hard. Be patient.

My volt meter records and saves data. That would help.

Your converter should charge at 3-4 different voltages.

Not enough information.

I would get the gismo to check cells.

Then after being plugged in several days, disconnect the rv for 24 hours and record voltage hourly and see what is going on. My battery monitor for $40 has recording. Graph.

Find the usage of the fridge. RV companies have used some, poorly selected units. Power hogs. This could be the issue. A 500 watt fridge could wipe a battery bank out pretty quick in warm weather.

[360true]

All good info. My alternator does charge batteries while driving.

Another thought. The meter from the inverter (Freedom X by Xantrex) always reads .5 volts less than the battery meter. Is this normal?

Will try the 24 hour monitor or until my batteries get down to 11.9. don't think it will take very long.

Why do batteries for in a year of properly charged and kept watered?

[formerFR]

by what you're saying, the Inverter's readout is .5 volts below what you are reading at the batteries - which would make the 12.1 essentially 12.6 volts, which is not far off a 'full' 12.8 volts. While traveling, though, you could easily be using more output than your Alternator is providing for charging input, leaving you slightly lower when you arrive after driving.
I don't think your batteries are any issue, you may be overthinking it, especially since you 'rarely' are unplugged anyway.

I would simply run the generator for an hour after arriving, and see if that easily takes you through the rest of the overnight hours. You can use the generator run time to make dinner, microwave, or even allow the electric water heater to heat up water for later showers.

[wrapperman]

You are doing everything you you need to be doing.
I am assuming you are reading those voltages as soon as you stop at Walmart.
Things to check would be:
With the motor running check to make sure you are getting over 12.5 volts with properly charged batteries and up to 13.5 volts when they are low on voltage.
Disconnect each battery and see if you have a bad cell.
Check each cell's specific gravity.
You may need to take the batteries to a battery house to have a load test done on them.

[TitanMike]

Originally Posted by houstonstroker

I would think you should be seeing over 14 volts either from your alternator when on the road or your converter.

Many, if not all recent (post 2010) vehicles limit charging voltage severely to the auxiliary batteries. In order to cut load on the alternator (and harvest more horsepower) the current into the starting battery is monitored and when the starting current has been replaced, voltage drops.

This has brought the DC-DC battery charger into the marketplace. An inverter of sorts that takes the lower voltage being supplied by the alternator that has been throttled back to lower voltage (close to float) and gooses it up to higher voltage necessary to charge the deep cycle batteries. Kind of a variation of the MPPT solar charger.

Renology now sells some and Redarc units have been available for some time.


Older vehicles (like mine) still let the alternator put out 14 V plus and do a lot better job of charging auxiliary batteries although the farther they are from the main (starter) battery the more wire size becomes a factor.

[tomkatb]

Voltmeters read plus or minus. +/- 5%. Is .5 volts.

The problem with them is it is a delicate instrument often treated like a wrench.

So apply “Kentucky Windage”. As needed. Test the wife’s car after it sites overnight! Should be 12.6

On mine after sitting not charging over nite about 12.6. Using the converter, full bulk, about 14. Medium charge 13.6. Trickle about 13.1

After sitting 3 months mine ran the fan, converter fan about 30 minutes then dropped to 13.6. Two days later of being plugged in 13.1.

Check the fridge wattage. That could be the issue. RV manufacturers make mistakes.

[mlmay12]

Originally Posted by formerFR

actually, your batteries are ALWAYS being used, since, of course, you have many, many 12v items within your coach that you are using, whether or not you are plugged in. These 12v items draw directly from the battery bank, even though the Converter is also Charging the batteries at the same time. It's an 'off-setting' effect, but the batteries are still going thru the draw and charge cycle constantly.

If your coach does not have the capability of allowing the Alternator to also charge the battery bank while driving, then your batteries are not being charged while driving, giving you a lower overall battery level when you arrive, depending on how long it's been since you 'un-plugged'.

Crank your generator and CHARGE your batteries - you'll be fine then for your overnight.

Actually your 12V systems including your inverter are feeding off the Voltage Potential at the Battery Terminals whether this is from the battery itself or your converter/other power source. If you exceed the amperage being supplied by the converter then your batteries will begin to draw down. All power is put in or taken out at the terminals. If there is a 13.6V potential with your converter or generator or engine driven alternator then your batteries will only draw down if you exceed the amps going in.

[ppine]

Wet cell batteries do not last when used often. They should never go below around 12.3-12.4 volts. Consider stepping up to AGM batteries.

[MR.M]

Originally Posted by 360true

All good info. My alternator does charge batteries while driving.

Another thought. The meter from the inverter (Freedom X by Xantrex) always reads .5 volts less than the battery meter. Is this normal?

Will try the 24 hour monitor or until my batteries get down to 11.9. don't think it will take very long.

Why do batteries for in a year of properly charged and kept watered?

Could just be bad batteries . they sulfated and no longer hold a charge like they should

[camaraderie]

Look... you need the right test equipment and the right process to get to the bottom of this. You need an AC/DC clamp meter. $50 Amazon.

First step is to check the charging amps and voltage from the alternator. After a night in the walmart or unplugged you should see over 14 volts (14.2-14.4) at your battery terminals when you start your engine. (Allow 5-10 minutes of run time for voltage to come up. ) At the end of the day of driving...you should still see 13.6V minimum.
Now you have roughly 400 amp hours of battery capacity...so your batts when depleted can accept up to 100 amps of charging current. After checking for the 14.4 V output You should now clamp your meter around the red battery wire and you should see WELL into double digits of current...even with the crappy thin wiring.
All good? Fine...you have no on the road charging problem.



Now...is your converter working properly when plugged in? Same routine...unplug and run your fridge all night. Now in the AM plug back in and take your voltage readings. Again...a minimum of 14.2 volts should be seen and somewhere close to 40 amps should also be seen within 5 minutes. Then after a few hours...13.6-8V and then after 6 hours...13.2V and very few amps.
If all that is good...you have no charging problems and you need to stop paying attention to voltage as a measure of battery state of charge IN USE. You need a real battery monitor that will tell you the actual state of charge...like the Victron or Trimetric. Around $150 and no more worries or questions. EASY to install.

Finally...batteries used like yours will tend to sulfate and stratify when NOT cycled. Suggest that you unplug once every couple of weeks and run them down with the fridge...then plug in and put on a good bulk charge to keep the plates clean. Do not STORE plugged in. Disconnect negative wire when fully charged and leave them for up to 3 months.

[360true]

Originally Posted by camaraderie

Look... you need the right test equipment and the right process to get to the bottom of this. You need an AC/DC clamp meter. $50 Amazon.

First step is to check the charging amps and voltage from the alternator. After a night in the walmart or unplugged you should see over 14 volts (14.2-14.4) at your battery terminals when you start your engine. (Allow 5-10 minutes of run time for voltage to come up. ) At the end of the day of driving...you should still see 13.6V minimum.
Now you have roughly 400 amp hours of battery capacity...so your batts when depleted can accept up to 100 amps of charging current. After checking for the 14.4 V output You should now clamp your meter around the red battery wire and you should see WELL into double digits of current...even with the crappy thin wiring.
All good? Fine...you have no on the road charging problem.



Now...is your converter working properly when plugged in? Same routine...unplug and run your fridge all night. Now in the AM plug back in and take your voltage readings. Again...a minimum of 14.2 volts should be seen and somewhere close to 40 amps should also be seen within 5 minutes. Then after a few hours...13.6-8V and then after 6 hours...13.2V and very few amps.
If all that is good...you have no charging problems and you need to stop paying attention to voltage as a measure of battery state of charge IN USE. You need a real battery monitor that will tell you the actual state of charge...like the Victron or Trimetric. Around $150 and no more worries or questions. EASY to install.

Finally...batteries used like yours will tend to sulfate and stratify when NOT cycled. Suggest that you unplug once every couple of weeks and run them down with the fridge...then plug in and put on a good bulk charge to keep the plates clean. Do not STORE plugged in. Disconnect negative wire when fully charged and leave them for up to 3 months.

Follow-up.... Had the coach batteries tested. No load 12.6 with load 11.9 for each individually +/- .1 NAPA says they are fine.

Research: my xantrex inverter draws 1.3 amps. My fridge draws 1.5 running with 8 amp starting with ice maker off. There is other phantom draw like smoke detectors etc.

Test: unplugged shore power. All lights, fans etc off. Just the inverter and the fridge. Start battery bank 12.6 volts which dropped to 12.4 in a couple of minutes.

Then steady regular drop of available voltage testing every 15 minutes. Hit 11.9 in only two hours, when inverter beeped to warn of low power. Restored shore power charging voltage 13.4.

This help anyone figure out why only two hours with four 12 volt batteries only one year old?

Thanks. Signed Confused....

[camaraderie]

Originally Posted by ppine

Wet cell batteries do not last when used often. They should never go below around 12.3-12.4 volts. Consider stepping up to AGM batteries.

Simply not true. All of it.
You should NOT upgrade to AGM for cycle performance...they have no such advantage.