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Old 11-23-2017, 11:20 AM   #1
Rivet Master
 
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Battery Storage Voltage

My batteries are isolated with a cut off switch. After fully charging to 12.8 and disconnecting with a battery cut off switch they drift to 12.46 after a week.

Should I just let them stay or drift to a lower voltage or should I charge them up ever week or so ?

Thanks, Dave
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Old 11-23-2017, 11:24 AM   #2
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You should not let the get below 12.1-12.2 as that is when damage can occur. There is another thread going that claims a loss of 15% per month with no load but you are much higher than that. Maybe batteries are bad.
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Old 11-23-2017, 11:26 AM   #3
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When you say 'cut off switch' are you referring to the "Use/Store" switch in the trailer, or do you have a manual cut-off switch installed at the batteries?

If it's the Use/Store switch, in "Store" there are still draws on the battery. The propane detector for sure. Some have tested and found that the inverter, even if turned off, draws some current in standby mode, and the subwoofer as well.
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Old 11-23-2017, 11:46 AM   #4
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Battery Storage Voltage

Both the inverter and propane detector will draw down the battery even in “store mode”. Many discussions on the forum about this.

If you don’t install a manual disconnect switch at the battery then you need to disconnect the battery leads to remove the batteries completely from the system if you plan to store for more than 1-2 weeks otherwise you will wreck the batteries by discharging repeatedly past 50%.

Here is a diagram of how to wire a proper battery disconnect switch. Mine is located in the battery box.
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Old 11-23-2017, 01:51 PM   #5
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Hi

Since most of the country starts to get cold this time of year ...

The magic "12.7 Volts" and "12.1 Volts" numbers are valid in the vicinity of 70F. If it gets really cold (like freezing) both voltages move up by about 0.6V. Exactly how much they move is (like the magic numbers themselves) a bit dependent on the exact battery chemistry.

Batteries are a big lump of "stuff". They respond to temperature slowly (as in hours). Air temperature and battery temperature may be two different things. That makes compensation "interesting" no matter how you do it. Probes that attach to the battery are better than "hanging in air". A probe that is buried inside the battery would be better still. Even that may not be perfect .... I have data on that from many decades ago ...

The obvious gotcha is that a battery at 12.4V could be in the "ok" range at 70F and well into the "I'm in trouble" range around freezing. At least considering battery temperature when you take a reading is a really good idea.

While I've been harping on cold, hot matters as well. If you get into the 120F region, everything moves about 0.6V the other way. Again, getting exact numbers on what the voltage change is .... not so easy. It's rare to find a manufacturer signing up to a specific set of voltages.

A charger that is not temperature compensated will have trouble getting a battery charged at freezing temperatures. The charge voltages also go up at lower temperatures. Any un-compensated charger is a risk on a very hot battery.

One way to address this is to bring the batteries indoors in the winter. Another is to move to Florida when it's cold A final answer is to get a charger that does the temperature compensation and clip it on to the batteries in storage.

If you shop for super duper chargers, some have probes and compensation. Some claim compensation but have no probe. Most have a temperature range over which they are supposed to compensate. Most battery manufacturers put a "don't do this" note in about charging very hot batteries. To me that overrides whatever the charger guys might claim.

The stock solar charger is claimed to do temperature compensation. Since it's inside the trailer that will only work if you are not running heat. I have never monitored what it actually does in the winter. It could do an excellent job for all I know.

Lots of variables ....

Bob
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Old 11-23-2017, 10:06 PM   #6
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With most flooded and AGM, your goal is 13.2 during storage. It's not always possible but that is ideal for me. 11th year maintaining mine at that voltage is what I base it on. 40 years fooling with batteries confirms it to me but have to argue all the time with the internet experts. It doesn't mean you won't see great battery life with other variables you choose. You have to use the tools you have. Some folks just don't have a way to maintain during storage. It's a price to pay but you can minimize loss being smart about it. Sometimes you have to eat a few months of battery life for your situation. It's not the end of the world after 5+ years. Temp comp has not impressed me yet in the US. No data.
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Old 11-24-2017, 06:48 AM   #7
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This Battery School site is good for general information:

http://www.batteriesnorthwest.com/batteryschool.cfm

Voltage levels in the middle of this page:

http://www.batteriesnorthwest.com/ba...cfm?TID=1#ANC1

As others have said there are many active threads, and I will post links later this morning.

If possible we recharge at 12.5 volts, and always at 12.2 for our flooded cell OEM batteries.

Good luck,

Peter
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Old 11-24-2017, 07:36 AM   #8
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Thumbs up New for this Winter...

This is the first Season that I'm leaving the Lifelines in the AS.
In use mode with lpg off. 10/28 full chg after 24hr 'rest'.

The next cycle I'll unplug the V/minder to ck draw.

So far...








Bob
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Old 11-24-2017, 09:48 AM   #9
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PS -- FYI here are those recent threads with discussions of the inverter/battery issues:

http://www.airforums.com/forums/f449...ut-175152.html
http://www.airforums.com/forums/f37/...de-175156.html

Also the Batteries etc. sub-forum is worthwhile to check:

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

Cheers,

Peter
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Old 11-24-2017, 10:38 AM   #10
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I have installed a true battery cut off switch as Wulfratt has described. I have a pd 4655 installed. Temp was 47 f at last measurement. I keep the pd 4655 off and the batteries disconnected except when I want to charge them back up.

There is nothing more I can do till I replace the batteries. My question was pertaining to my current batteries is how low do I let them discharge before turning on the PD 4655 and letting them charge back up and it seems from the above comments that 12.2 is about it.

Thanks,

Dave
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Old 11-24-2017, 11:50 AM   #11
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quiecent battery drain in store mode

Last week did extensive battery draw tests. Using Lab type Fluke MM and discovered
All sorts of surprises. May post all findings when time. VERY revealing results.

In "Store" mode our 2005 25ft Intl draws .06amp. Times 24 hours = 1.44amps per day.
This is only powering the LP alarrm. After 30 days of no charging, 43.2 amps of use.

With a standard fully charged new AS 80 ah x2 rated battery at 50% recommended depletion draws
1/2 of reserves. Older / damaged batteries even less backup.
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Old 11-24-2017, 12:01 PM   #12
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Quote:
Originally Posted by NoResults View Post
. . .
My question was pertaining to my current batteries is how low do I let them discharge before turning on the PD 4655 and letting them charge back up and it seems from the above comments that 12.2 is about it.
. . .
If you have the option of going back on shore power at 12.5 [90% +/-], that is supposed to prevent some damage which might affect the life expectancy of the batteries, as I understand things. Our AS is in the driveway in the back yard, so we have that option.

The Battery School linked in Post #7 calls this "shallow cycle" recharging, and suggests that " . . . the shallower the cycle, the more cycles the battery can deliver . . . "

Our old 1985 25' AS had standard OEM flooded cell batteries which lasted about 8 years (as of when we sold her), with similar battery care FWIW.

Peter
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Old 11-24-2017, 01:39 PM   #13
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point of order...

I'm almost always on SP when camping so I've never looked but since the micro pulse has been recently replaced I'm paying a bit more attention to it.


The micro pulse indicates E which I always I presumed 100% depleted and the 1/2 = 50% depleted.

However since 12.2 is (generally) considered dead would one expect E to indicate 12.2VDC on the meter as opposed to 11.76VDC?

On a separate note since purchase 8/2015 a few months after purchase, I began to suspect the batts were not well cared for on the lot. It was a 2014 sold in 5/2015 so seems reasonable.

Finally after some documented abuse but he local dealer, they swapped on to two net group 24's Deko Marine's.

I was astonished at the voltage stability. With the old Interstates on my bench, after a full charge on a smart charger, it would settle to around 12.82 or so but drop about .04 per DAY. So it wouldn't take long to get to 12.2. The new batts start out abut the same at around 12.79/12.78 but after 3 weeks has only dropped to 12.77. Essentially the new would drop in a month what the OEM's (2 mo after delivery) in a day.

Now I have a bench mark of what to expect from a performance perspective.

Bob

p.s. Peter thanks for the link above. It's a good reference for battery info.
p.s.s. Good to know they're just up the road in Salem.
Bob

p.s.s.s. Since I have no AC at storage I generally bring home the batts until the next use....tho that span has been widened a bit.
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Old 11-24-2017, 02:57 PM   #14
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Did you receive a Micro Pulse owner's manual or guide, like his one?

http://www.catconproducts.com/pdf/Mi...itorManual.pdf

Not much detail on the battery! [Edit-- See PDF p. 5/8, or page 9 on the document]

Patrick at Colonial but not much on the battery that I can see [3:30]:



I think your interpretation may be giving them too much credit -- and would assume that the battery reading should stay above 50%, or green [see p. 9 as numbered on the PDF pages linked above], but who knows!

Have a good weekend.

Peter
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Old 11-24-2017, 04:32 PM   #15
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Thanks all. After charging to float level of 13.2 I let it set for 3 hours and reset the SOC (State of Charge) to 100% at 12.63 will monitor daily till it drops to 12.5.

Dave
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Old 11-24-2017, 10:54 PM   #16
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Quote:
Originally Posted by OTRA15 View Post
Did you receive a Micro Pulse owner's manual or guide, like his one?

http://www.catconproducts.com/pdf/Mi...itorManual.pdf

Not much detail on the battery! [Edit-- See PDF p. 5/8, or page 9 on the document]

Patrick at Colonial but not much on the battery that I can see [3:30]:



I think your interpretation may be giving them too much credit -- and would assume that the battery reading should stay above 50%, or green [see p. 9 as numbered on the PDF pages linked above], but who knows!

Have a good weekend.

Peter
First, my apologies if this is somewhat of a hijack of the original discussion.


[ ...or green....]Hence the problem for us color blind folks...red.>orange>green, say again...what were those colors again, they all look basically the same to me.


I've always thought like you...stay above the 50%, but then again, I'm almost always on SP so it's always pegged, but then again with the new batts...we'll maybe there are other possibilities. It all floated to the top when the MP kinda went wacko in Paso last year. I talked to the dealer...they didn't even ?? it and swapped it for a new one. Then the tech on the walk thru said....well ya know...flashing read doesn't really mean empty...there's still a few gallons. That's they way it's programmed so you don't come up short. Insurance for those that survived the 60's I guess.

BS.. I want empty to mean empty, not somewhere S of full. That got me to thinking that maybe the ele side was the same thought process.

I'm about ready to install a meter, jerk out the MP, toss in a bottle of leftover SUPREP and go with visual.


bob

Peter, again this for the link. Much better than the dealer walk-thru.
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Old 11-25-2017, 05:23 AM   #17
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Quote:
Originally Posted by uncle_bob View Post
Hi


The stock solar charger is claimed to do temperature compensation. Since it's inside the trailer that will only work if you are not running heat. I have never monitored what it actually does in the winter. It could do an excellent job for all I know.


Bob

The OEM Parallax only has temperature compensation if the 4400 TAU upgrade is added. The temperature probe attaches directly to the batteries. Installed one a month ago but have not had much chance to play with it yet, the weather has been the same since installation.

The usual price is in the $55 range, but found mine a lot cheaper in the a clearance bin.
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Old 11-25-2017, 09:09 AM   #18
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Quote:
Originally Posted by Mattirs View Post
The OEM Parallax only has temperature compensation if the 4400 TAU upgrade is added. The temperature probe attaches directly to the batteries. Installed one a month ago but have not had much chance to play with it yet, the weather has been the same since installation.

The usual price is in the $55 range, but found mine a lot cheaper in the a clearance bin.
Hi

There are two stock chargers on some AS trailers. One is the solar charger. The other is the charger / converter. It is my understanding that the solar charger (Intermountain or whatever) is compensated as supplied. It (unfortunately) does not do it with an external probe.

Bob
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