What is low voltage on the 12V battery

[MOS]

Have a 2016 FC 28W.
What is considered low voltage on the monitor panel for the due 12V battery ?
When should I be concerned about battery power ?
thanks

[BoldAdventure]

Rule of thumb, don't go below 50% - for best battery life on a 12V battery don't go below 70%.

[cwf]

When on AC, and converter working, the converter will supply your 12vdc circuits just fine..

I have a 12vdc monitor plugged into an existing
12vdc outlet in the Airstream Search for similar on Amazon...

Zeltauto LCD Cigarette Lighter Digital Car Voltmeter 12V/24V Vehicle Voltage Gauge Monitor for Auto Car Truck (1piece)

Follow the chart above for voltages with converter "off"... And on. Note difference.

It is normal for voltage to drop when DC items power up.

Batteries
3 years old.

Edit: my voltage runs 13.0-13.5 converter on... 12.3 with full "load" on battery only. Remove load and battery goes back to 12.4

[NoResults]

my 2016 23' drops to 12.3 within 3 hours of disconnect from ac power. Are my batteries going bad. Only a few months old I purchased used. Dave

[OTRA15]

Originally Posted by NoResults

my 2016 23' drops to 12.3 within 3 hours of disconnect from ac power. Are my batteries going bad. Only a few months old I purchased used. Dave

Your trailer may have misc. parasitic loads draining the batteries, like the propane detector etc.. There are existing threads on this, and those more informed than me can guide you better. Scanning this sub-forum's list of thread topics will reveal possible relevant ones:

http://www.airforums.com/forums/f449/

If your battery water levels are all OK, you might consider buying new batteries before you take a major trip. The prior owner, or the dealer, may have not treated the batteries well IMO.

[Rich Jenkins]

Originally Posted by NoResults

my 2016 23' drops to 12.3 within 3 hours of disconnect from ac power. Are my batteries going bad. Only a few months old I purchased used. Dave

In addition to the suggestion from OTRA15, check that one of the compartment lights is not on.

Sounds strange, but I found I had left one of mine was left on in storage for two months.

[idroba]

Another large drain that some don't realize is there is the inverter, if you have one. Many of them take 1.75 to 2 amps just sitting there doing nothing, and all there is to see is a little green light on the inverter control panel to know it is running.

Be sure your inverter is off when you are not using it, and don't use a 600 or 1000 watt inverter to power your 120 volt cell phone charger, which takes about 10 watts maximum.

[Sodbust1]

Some clame 11.8 volts but anything under 12 volts starts to eat on the battery plates..
I try to limit it around 12.2 volts..
Sodbust

[JCWDCW]

Deep cycle batteries can handle down to 11.5 volts easily. Consider the battery dead at 10.5 V and at that level you have basically knocked 10% off the battery capacity, so don't plan to run them down, and get them charged up as soon as possible as I believe the battery will suffer from sulphation if left in a discharged state.
JCW

[lewster]

Might as well jump in here a bit:

Almost every manufacturer of lead based batteries recommends that you should not draw batteries below the 50% depth of discharge level if you expect any type of longevity from your batteries. True deep cycle batteries (NOT marine deep cycle, dual purpose or any other concoction of naming confusion) will tolerate deeper draws on occasion, but the more you do it, the fewer charge cycles and related battery life you can expect.

Lifeline AGMs have a nice charge in their tech manual that depicts this nicely with graphing. Their 50% level is 12.2 VDC (this level varies with the battery manufacturer and type, as does the 100% charge level, which is 12.8VDC for Lifelines) and the chart shows an expected 1000 charge cycles at that level of discharge.

The deeper you draw the batteries, the fewer charge cycles you get. Conversely, if you only draw the batteries to 10% of their capacity, the longevity jumps up to 5000 charge cycles!

Of course, all of this is predicated on you fully and completely recharging the batteries after each discharge, as sulfating on the plates will occur if you leave them in a discharged state for any period of time which again, depends on the manufacturer and chemistry of the battery in question.

[BoscoMN]

A couple of things I am considering may apply to your situation as well. I just got our 2015 19' FC parked in the driveway and am just getting it checked out but I believe that it uses a Parallax 7355 converter. Its maximum output voltage is only 13.8 volts so it can only provide a partial charge to my lead-acid batteries. Most lead-acid batteries specs call for a 14.7 volt charge for a certain period in order to fully charge (called the absorption charge). I plan on getting a more advanced (and costly) converter later. In the meantime I am using a 4 stage charger (Boost, Absorption, and Float charge, and a periodic Equalization Phase that protects the battery from sulfating and stratification). I used it to maintain the batteries in my basement over the winter. I will now use it to top off the batteries before each weekend trip. I'll carry it with me on multi-week trips to make sure that the batteries are charged before any boondocking.

The meter inside the Airstream is not able to measure the actual battery voltage to the accuracy I would like (too many voltage drops between the batteries and the meter). Given that the difference between 100% and 70% charge remaining is less than 0.3V I want an accurate and consistent reading. I will be putting in a TriMetric TM-2030 Battery System Monitor (it also supports monitoring a solar panel system). Right now I use a meter directly to the batteries to see how they are going.

[NoResults]

Day later battery meter reads 12.2 after 5 hours after putting the trailer in store mode. Nothing running. Going to dealer in morning. Will post results.

Thanks for the suggestions. Dave

[idroba]

I noted a possible inverter draw in my post #7 above. The use/store switch does NOT disconnect or shut off the inverter, so if it is left on by accident, it will eat into your batteries relatively fast. It has a 1.75 to 2 amp idle draw, that is on but doing nothing.

[twinklerai]

You will find different specifications on low voltages from various manufacturers. But it is advisable to follow the makers advice.

[MOS]

NoResults,
How did you make out at the dealer?
Mike

[NoResults]

They told me that the batteries are fine just need to charge them for three days to get them fully charged.

I had not let them charge for more than a day thinking, after reading these forums that it was not good to leave them charging.

They suggested that I buy a replacement charger for $500.00

I am looking at the replacement for the Paralax 8355 but not sure I think it is the Progressive Dynamics 4655 but have not received a reply to my email to Best Converters.

Can any one suggest another source that could confirm if this is the proper replacement.

I am sure I can do it myself and save $300.00

Dave

[lewster]

Use the Prog. Dyn. PD 4655 if you have 30 amp service in the trailer. Use the PD 9260 which is a deck mount unit if you have 50 amp service.

These are my go to units when upgrading the Airstream's charging systems when I don't use a Magnum inverter/charger.


Lew Farber
RVIA/RVDA Nationally Certified Master Tech
ABYC Certified Master Marine Electrician
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center*AMS Lithium Batteries
Lifeline AGM Batteries**Magnum Inverters
541-490-6357

[Tn Traveler]

Lewster is right on. About 12.2 volts is 50% charge in an AGM or flooded 12 volt DC battery. To get to the estimated state of charge the batteries need to be resting with no loads in or out. They should rest for an hour or two to settle near their true state of charge. That is why a SOC meter is so important to battery management. They give state of charge based on amps used and amps restored. It is very seldom that you will be reading your battery voltage after completely resting them. A SOC meter is only as good as the parameters you set up for it.

[NoResults]

Dealer says to keep me happy they will exchange the batteries. They also state that a drain to 12.2 from fully charged in 5 hours is normal? If they are correct should I just forget these batteries and bite the bullet for AGM batteries. I was not planning on adding solar at the present so the price and weight of the agm batteries need to be ruled out for the present.

How long should a fully charged battery stay charged from 12.6 when charged with no load other than the co2 detector.

PS: I did upgrade the converter to the 4655 with charge wizzard.

Dave

[lewster]

Their answer was way too vague. Battery draw is wholly dependent on the load being placed on them.

The battery industry used what is called the '20 hour rate' for battery capacity.

If you gave a pair of Gp. 24 Interstates, their 20 hour rate is 80 amp/ hours. Since you have 2 in parallel, you have a total of 160 amp/hours of which 50% is practical for usage.

5 hours of run time on fully charged batteries equates to a continual 16 amp load (80/5=16). That is a whole lot of battery draw continuously.

Even your energy hog furnace will not draw that amount.

Since you now have a quality converter, use them and see how it goes. Just be sure to FULLY recharge them ASAP after a deep draw and watch your water level.


Lew Farber
RVIA/RVDA Nationally Certified Master Tech
ABYC Certified Master Marine Electrician
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center*AMS Lithium Batteries
Lifeline AGM Batteries**Magnum Inverters***Victron Energy Components
541-490-6357