Charge batteries during storage

[Sierrapapa]

I have the luxury of storing my 2008 SS International inside by 110 power. Is just leaving it plugged in between the trips I take every 30 days or so the smart way to keep the batteries topped off? Is this hard on my inverter or my batteries? Is there fire danger? Is there a smarter way to charge them up? Like a battery minder or something?

[Mexray]

You can pick up a cheap 'float' charger to hook directly to your batteries so you don't have to keep the converter plugged in during storage...

Here's a cheapo that Harbor Freight sells - I've use these with success...

Automatic Battery Float Charger

Ray

[Sierrapapa]

Originally Posted by Mexray

You can pick up a cheap 'float' charger to hook directly to your batteries so you don't have to keep the converter plugged in during storage...

Here's a cheapo that Harbor Freight sells - I've use these with success...

Automatic Battery Float Charger

Ray

I appreciate the idea. I do use these float chargers on other vehicles I keep in my "toy shed". I just wondered if there is a downside to plugging in to 110 and leaving it plugged in. It is the least hassle way for me to go, but if it causes problems the float charger would be my next option. Thanks

[2airishuman]

the onboard charger works FINE for extended periods.

the primary issue is battery type and maintenance.

flooded wet cells NEED water.

so one SHOULD check and fill the cells as needed and this could be monthly in some setups.

agms don't have that requirement.

the agms in my unit have been juiced by the ONBOARD charger 24/7 when stored and when not boondocking.

((and as a side note the fridge is ON 24/7 when in storage too))
__________

one can also plug the umbilical into a TIMED outlet...

so that the charging only happens at some interval (hours/days/weeks) defined by the owner.

using a traditional garage/starter battery FLOAT charger has issues too.

why not use the system A/S installed and designed for charging.

cheers
2air'

[bryanl]

The inverter in the AS is probably OK for moderate storage needs but not optimum.

Float is old tech.

A modern battery maintainer will keep a full charge (but not too much as that corrodes plates) plus stir the electrolyte and do things to prevent sulfation. That will help you get the most from your batteries.

If you need to add water more than once or twice a year, the odds are pretty good you are overcharging your batteries.

Look for something like the Battery MINDer (tm) that uses a technique Home Power published about ten years ago or the Chargewizard thing that does a periodic charge bump coupled with a conservative float (WFCO or Progressive Dynamics inverters).

re: "why not use the system A/S installed and designed for charging." -- because it was not designed for either charging or maintenance from what I can tell. It is more of a power supply than a battery charging and maintenance device, I think.

[2airishuman]

the "why not" was offered in comparison to using a generic starter battery float charger with alligator clips on the battery posts.

not as a counter/question related to all other possible charger/converter possibilities.

the oem p-lax C/C IS intended to provide CHARGE...

for a variety of batteries and in a variety of settings.

it's adequate and works fine for basic charging and converter needs in these trailers.

can something 'better' be assembled, used or installed...sure.

but tossing OUT the onboard setup for a new/more refined set of gadgets isn' the question i read in the op.

and there are pages of threads that explore that topic.
________

back to the op...

IF regular camping trips are planned on a monthly basis and the batteries kept at moderate temps...

the LEAST hazardous and SIMPLEST approach may be to just use the DISCONNECT switch.

3-4 weeks of tiny phantom loads (the lp gas detector) shouldn't deplete the 2 on board interstate batteries much.

and that's easy to check during the first month as a trial.

the local AC power could be connected to the unit days b4 travel to fully REcharge the batteries.

cheers
2air'

[RLS]

I was just getting ready to start a thread like this one to show what happens when a battery is left charging on the Airstream. I was amazed at what I saw when I pulled this out.
I do have one question, can the other AGM battery that still is together but without any water be filled back up with distilled water? Man these are expensive!!! Another lesson learned the hard way

[Mexray]

First, AGM's don't have distilled water like flooded cell batteries - you can't 'refill' the electrolyte in an AGM or GEL type, sealed battery - if you disturb those 'caps' on the top of your AGM, you'll lose the seal...

Second, your AGM has been subjected to overcharging - your particular converter/charger apparently isn't compatible with AGM type batteries! Extended charging actually 'boils' the electrolyte away from the plates, destroying the batttery - there's probably some notation on the battery about subjecting it to voltages higher than about 14.5 or so for extended periods...

As 2air mentioned above, an option when keeping your AS plugged into shore power during storage would be to put a timer on the shore power circuit so that the AS only received AC power for a small amout oif time each day - you can buy these plug-in timers at most big box hardware stores...

I use this method to keep the batteries charged on my boat, which is in the water all the time - the marine charger I have doesn't have a 'float' function, so I let the timer run the charger for only about 1-1/2 hours each day to keep the batteries from overcharging - I had to experiment with several settings till I got what I needed - this method has worked for many years...

I replaced our AS's original Univolt with a modern 3-stage converter/charger as one of the first projects - it's been almost three years and the original flooded cell batteries I installed with the new converter are still performing great during our Boondocking outings, and water loss has been very minimal....

That's a real bummer about the AGM's...I always advise my customers that insist on installing sealed batteries in their RV's or boats that they are voltage sensitive, and require charging equipment catered to AGMs for them to have a long life -

It's a touchy subject sometimes, as there's no warranty for overcharged batteries - that's a maintenance problem, not a manufacturing defect...there's a lot of misinformation out there about sealed AGM batteries -

I think some think that since AGM's cost so much more, that they are a 'better' battery, maintenance-free, and can be installed and forgotten about - not so, the proper equipment is required to make em' last - especially if solar panels are involved - the charge controllers also have to be set correctly for long AGM battery life...

I'm sorry, I really don't see the need to use AGM's in our AS's, unless installation requirements call for them - they cost OVER twice as much as flooded cell batteries, and I don't believe you'll realistically get any more life out of them in years - maybe 10% more, that doesn't come close to offsetting the much greater initial cost...IMHO

Ray

[RLS]

Ray, Thanks for all the info. The one AGM is still good so I will be using it plus a new reg. deep cycle one if it is OK to do so. Is there anything wrong with using both types of batteries? Will it mess up the Univolt or whatever I get to replace it?
I'm doing a search now on what to get for replacing the Univolt.

Thanks again, Bob

[2airishuman]

can't mix agms with FLOODED wet cells...

the dis/charging rate, internal resistance, and other specifications are sufficiently different.
____________

there is no univolt in your 2004 trailer.

this was basically a 'brand designation' for chargers used 30+ years ago.
____________

while the photo shows an expanded battery case which is often caused by OVER charging...

we've no clues to how or WHY this happened in this case.

the deca' battery pictured is aftermarket correct? as in NOT the oem battery?

agms from DIFFERENT makers have different charge tolerances

and one must be AWARE of this when matching battery to charger.

a/s using lifelines (agms) because they are compatible with the oem C/C

what else is not OEM on the trailer in question?

does it have after market solar?

is the charger the oem unit or something else?

what's the history of use, where is the unit STORED, and so on...

lots of variables and issue that a couple of photoz do NOT explain.

cheers
2air'

[Mexray]

Bob,

In the ideal situation, all the 'cells' of the batteries hooked together in 'battery banks', should be of the same size, age, and internal construction...

From the practical point of view, in your case, where you're trying to get the most out of the existing 'good' AGM, you may be able to get by with a flooded cell battery of the same 'Group' size, where the cells will be close in size to be able to co-exist as far as charging/discharging rates and capacities are concerned...

Understand that one of the batteries may not get charged to the same capacity as the other...AND you'll have two different 'aged' batteries as long as this 'pair' are used - and when one fails, and is replaced with a new battery, you'll still be hampered with two different 'aged' batteries...but the cell size will then be the same...

I generally use a Two Year rule, if the older battery is beyond two years old, I don't recommend pairing with a new battery (internal capacity degrades with age)...

For optimum performance, two new, like sized batteries are the best situation - I see customers all the time only wanting to replace the one bad battery, for $'s reasons, and pair it with their multiple year old battery - it's really false economy, as the older battery is probably close to it's failure date as well, and the charging/discharging properties as mentioned above will degrade the entire system...

At the risk of being a 'Smart A$$', I usually mention that when the RV was built, the Mfg didn't install one new and one old battery in their rig!

So, you do what you can, and you take's your chances...it just depends on ones individual situation...

I guess this was just a long saga to advise getting two new batteries, and using the old AGM somewhere else for optimum performance - OR - do as you mentioned with one new battery and see how it works out - if you run into problems, you can always add a new battery in the near future and be back up to snuff again!

The main thing thing is to enjoy your AS this summer!

Regards, Ray

[RLS]

2air' & Ray, Thanks again for all the info. To answer 2air's questions, the power supply is a Parallax 7400, model 7455 which I'm assuming is OEM? I do not have the full history on this since I've only owned it for the past 2 yrs., but from what I can tell, it has never been under or in any type of shelter for storage. Just this yr. we were able to bring it to the house and keep it plugged in during the storage times. It does not have any solar system. I thought (that's always a mistake!) it would be best to keep it plugged in so the A/C unit could kick in once in awhile to cool things down a little. Same for the winter months with the heater.
The AGM's were put into service 11-06. I trust what both of you are saying, so 2 new batteries here I come.

I'm learning

[2airishuman]

ok rls, good info.

since this is the 3rd set of batteries in 6 years,

it might be wise to give the p-lax a through once over.

the specs and output parameters from this unit are online/in the owners manual.

with a multimeter one can check output.

if it's too high that's an issue.

that model is oem and i think there is a timer option available for the 74xx series which can be added.

IF plugged in at home it's important to determine the shore voltage is adequate too.
__________

i have no experience with the deca agms but others here do...

while pricey they appear to be much less $ than the well regarded choices in this category.

when shopping, the threads LINKED in post #2 here might be useful...

http://www.airforums.com/forums/f449...tml#post758501

agm batteries are expensive and without solar, special charging needs or other extra electrical issues,

the question become WHY buy/use them?

interstate makes a completely adequate group 27 that was probably the oem part...

lots of satisfactory choices really (in the grp27 size), so it might be best to find a LOCAL vendor with a good rep...

and get some fresh new flooded deep cycles with a sensible warranty and spend the savings on other a/s stuff.

IF the charger is putting out wacky voltage and not easily tweaked it makes good sense to shop these...

CW, online vendors and many of the larger rv shops carry the usa made PD gear which has a good rep here...

pd company site link/catalog...

cheers
2air'

[HiHoAgRV]

Originally Posted by 2airishuman

ok rls, good info...interstate makes a completely adequate group 27 that was probably the oem part...

lots of satisfactory choices really (in the grp27 size), so it might be best to find a LOCAL vendor with a good rep.....cheers
2air'

Keep in mind that Interstate makes TWO different Group 27 batteries...

The standard fare is a SRM-27 that has about 85 AH capacity

but

They also offer a SRM-27B that has about 13% more capacity in the same size case...only 2 lbs heavier...

I found this out AFTER I bought the lower AH size...

[2airishuman]

Originally Posted by HiHoAgRV

...I found this out AFTER I bought the lower AH size...

ouch.

good info!

what was the $$ difference?

it's a jungle out there.
__________

the OTHER thing just noticed in the photo (beside the correct spelling for deKa) is the battery model...

according to the makers website this is a 'starter/deep cycle' battery designed to provide both functions.

it's also a 'marine' rated battery

and my understanding is the parameters (charge voltage, capacity)

are established at a DIFFERENT ambient/operating temperature for marine deep cycles.
________

mehbe mexray or 1 of the other juice wizards can explain these things (marine and starter/deep cycle combos)


cheers
2air'

[Mexray]

It's a marketing jungle out there when it comes to lead-acid batteries...everything is fine until some marketing 'genius' decides to change names on existing products....

1. Any deep cycle battery will 'start' an engine (depending on the size and type, of course), it just doesn't have as many CCA's as a pure 'starting' battery...'starting' batteries have many, thin plates to cram as much 'plate area' inside the battery case a possible...Deep cycle batteries have thicker plates and special separators between the plates which means fewer plates in the same size battery case - less 'plate area', so it's CCA's aren't as high as a pure 'starting' battery - but it will still start an engine!

2. Some battery Mfg's sell a 'Marine Starting' battery - which is nothing but a 'starting' battery with additional marine type terminals on the top of the battery similar to most deep cycle marine/rv type batteries - don't be fooled in buying this battery for deep cycle applications it's much lighter and has thinner plates than a deep cycle - the 'Marine' wording fools some buyers...

3. In the most common types of Marine/RV batteries on vendors shelves that you'll see, there really isn't any difference inside the battery - they have deep cycle plates with appropriate plate separators and are used in both applications - the feeling that thicker plates stand up to the bouncing around many boats experience, as well as some RV's...

4. buy the heaviest deep cycle battery you can fit in your application - heavy means more battery plates... More plates in a deepcycle battery means higher Amp Hr ratings for extended running of your 12 volt stuff...

Ray

[bryanl]

Battery design trades off cost, capacity, and 'ruggedness' and manufacturers provide a line of batteries so customers can make the choice to best suit their needs. The differences in modern batteries of the sort used in RV's and commonly available at retail tend to be fairly small compared to what you can find in individual batteries from cycle to cycle variance, temperature, use profile, aging, and so on.

As far as batteries you are going to be able to use in your RV, the talk about 'deep cycle' and 'thick plates' and other such things (especially solid plates) is marketing hype. Look at the specifications and you'll see why.

Capacity for wet cell lead acid batteries is about 22 watt hours per pound with AGM's usually a bit less dense. If you want more capacity that means more weight. That usually means larger volume as well.

Don't get lost in the internal construction stuff. Look for reliable measures related to how you actually use the battery. These include cost, warranty, size, and capacity measures.

[RLS]

Thanks again everyone for ALL the good info I went ahead and got 2 size 29 reg. Marine/RV batteries Had to notch out the lower framing in front a little (about 1/4"), but after doing this, they fit perfect Also put a timer on the converter set for 2 hrs. on daily.

[JBinKC]

Like Sierra Papa in the original post, I store inside near 110V. I leave the battery disconnect "off" in storage. Every month I charge the batteries overnight. Otherwise, the batteries are disconnected through the winter. My batteries are two years old and no worse for wear, which included 120 nights of camping this year. I'd say that storing batteries in moderate temperatures, periodic charging (rather than a constant drain and recharge) and good electrolyte levels are the ways to extend battery life, not expensive AGMs, aftermarket chargers and inverters.

[dznf0g]

Originally Posted by JBinKC

Like Sierra Papa in the original post, I store inside near 110V. I leave the battery disconnect "off" in storage. Every month I charge the batteries overnight. Otherwise, the batteries are disconnected through the winter. My batteries are two years old and no worse for wear, which included 120 nights of camping this year. I'd say that storing batteries in moderate temperatures, periodic charging (rather than a constant drain and recharge) and good electrolyte levels are the ways to extend battery life, not expensive AGMs, aftermarket chargers and inverters.

Um, if your 07 is wired like my 07, your OE "battery cutoff switch" does not cut off the batteries from the charger. It simply disconnects the coach systems from the charger and batteries. In other words, the charger, batteries, and some keep alive 12 circuits are all UPSTREAM from the cutoff switch. Unless you have added a cutoff switch at the batteries, they are still receiving a charge while shore power is hooked up and converter/charger is plugged in.