Need Battery Help!

[foakes]

We purchased our used ‘09 FF 189FBS 16 months ago.

Due to Covid, travel/campground restrictions, and wildfire danger up where we live in the Sierras — we have only had it on (5) trips for a total of 30 nights.

And we have enjoyed those trips immensely — plus have a few more planned for the next few months.

To the battery issue —

Bought a new, large deep cycle Interstate battery from Costco 14 months ago. Worked OK for (2) trips — then has been degrading over the last (3) trips.

Just returned from a (9) day, 1900 mile trip out to the Southwest of Arizona, New Mexico, and Southern Utah. Discovered that the Interstate battery would show a full charge after driving — then drop very quickly to around 9.3 volts after just using the interior lights for 30 minutes — sparingly.

This was supposed to be a maintenance-free battery — but it had the typical (2) lids on top to add water. Upon checking the water level — it was low or dry in (4) of the (6) cells. I added purified water — it took 32 ounces — two bottles. On the rest of our trip, it still would not hold a charge after driving, plugging in to AC, or running the 2200i Honda generator.

Looked online — found many reports of bad issues with the Interstate batteries.

Took it back to Costco yesterday — even though it was out of warranty by (2) months — to hopefully get a store credit so I could buy a different brand. Since I was assured that the new line of Interstate batteries was as good as the old tried and true Kirklands I had bought from Costco for over 20 years — I figured they might help me out.

The guy behind the counter said that I should not have added water to it — it required acid also to be added by a professional — and I should not have touched the battery — and they would not help me with an adjustment/return.

Asked to speak to the store manager — after explaining quickly the issue — he made an adjustment of 50% and gave us a store credit of $67.43.

Now, after researching which new battery to purchase — I am officially confused and dizzy!

Looking for advice from more experienced members as to which battery to buy.

With my usage — half boon-docking, half staying in established campgrounds — it seems like a decent quality large (100Amp?) AGM Deep Cycle 12V battery would be the best.

But which one?

Ideally, I would hope to get information on a decent AGM battery in the $150 to $200 range — with a 2 or 3 year warranty — but with our member’s experience would last 5 or 6 years. It would be recharged with the vehicle, campground AC, home AC, a trickle charger, and our Honda 2200i generator.

I really don’t want to do 6V batteries, have extra cables, switches, and more stuff to buy.

Just a well-recommended 12V Deep Cycle AGM battery that our members have used successfully without issues.

Appreciate the assistance!

Best Always, Fred

 

[profdant139]

Well, I am not an expert, but this is what I have been doing with batteries for the last 15 years, and it really works for me! And we do a lot of boondocking. I totally agree with your wish to keep things as simple as possible, as you will see below.

First, I get 2 group 31 deep cycle batteries from Napa. They have a 110 amp hour capacity, which means 55 amp hours in real life. But I only use one of them at a time – – and if the first battery ever gets
too low (below 12.1 volts when resting), I switch out and use the second battery.

There are folks who say to use both at once because of the Peukert effect -- look it up. (It has to do with optimizing total amp hours from a set of batteries hooked together.)

I don't do that, because in case my main battery dies, I want to have a reliable spare. If you hook them together, and one dies, your other battery drains out and you are stuck.

Second, these Napa batteries allow you to add distilled water yourself. I check the batteries monthly at home -- rarely add water -- maybe an ounce? Be sure to check all six cells. Add water slowly until the meniscus shows up -- it looks like an eye staring back at you.

Third, I check specific gravity in each cell every few months. If the SG drops in a certain cell, that is an early warning that the battery is getting ready to die.

I get about 5 years from a set of batteries, which is about 400 nights of camping.

Also, I have a portable 120 watt solar panel, which tops us the battery every day (especially in California and the southwest). Keeping the battery at a high state of charge will prolong the life of the battery. We park the trailer in the shade, put the panel in the sun, and clip the panel to the battery. (The controller is built in to the panel.). Very, very simple -- truly plug and play.

I mentioned testing the battery when resting -- if you test the battery under load, you will get an artificially low reading. So I often test them when we get back to the trailer in the late afternoon, after having been away all day, with no lights on in the trailer. (Once every few days.). I use an ordinary multimeter. There are fancier gauges that you can install, but this simple device works for me.

When not camping, I keep them on a BatteryMinder Plus in my garage. The BMP supposedly extends the life of the battery by minimizing sulfation of the plates. It pulses. Whatever you do, don't do what I did my first year of camping -- I let the batteries run down during the winter. They died. That's when I got the BMP trickle charger.

Some folks say that the BMP is a gimmick and it does nothing. My thought is that if this were really a fraud, the company would have been sued and would be out of business. It's doing fine, and there is no hint of fraud litigation that I can find online. So I think it must be a useful product. It is sure easy to use -- hook it up and forget it.

Let us know if you have any other questions -- this is an important topic!

 

[profdant139]

I should add that to test specific gravity, I use a hydrometer, also from Napa. It is a very simple and cheap device -- you squeeze a rubber bulb and the battery water rushes into the chamber.

Just don't let battery water drip onto your favorite jeans. Don't ask how I know this.

 

[foakes]

Thanks, Prof139 —

That is great information —

Wanting to keep my post short and not full of drama — it is also important to me to not get a battery online — but rather from a large retailer. So when on the road — if a failure occurs — it is easier to get a replacement battery.

NAPA fits right in with this scenario —

From reading many reviews, pros & cons, pricing, specifications — I have pretty much settled on a NAPA 12V Deep Cycle AGM Group 31 size. They are made by Penn here in the US — and hopefully will do a good job for a few years.

Plus, this month (November) NAPA is doubling the AAA discount. So it will be a 20% savings.

Now I need to find an old core — to save the $27 core charge — since I left the Interstate battery with Costco.

Appreciate the help!

We are doing a 5-Day trip up through the Gold Country at the end of next week.

Best, Fred

 

[Dakota 1120]

I use a blue top OPTIMA battery in my camper - 8 years now - and very pleased with the results...it replaced an Interstate Battery that died in 2 years.

Also have only replaced batteries in my vehicles with an OPTIMA battery. Before traded off a 1994 Ram 2500, the OPTIMA in it was 9 years old and never failed to start the Ram with a V-10 motor. The pickup always sat outside and here it can get 30 below or more in the winter months.

 

[foakes]

Thanks Eagle!

Yes, I looked at those also — but the price was pretty high, at least for me.

Picked up a Napa 12V AGM Series 31 Deep Cycle today.

With the 20% discount through AAA — it was $131 + tax.

We will see how it holds up.

Made by East Penn in Pennsylvania.

My Honda 2200i Generator weighs 47 pounds — and is enough for me to carry out of the truck toolbox. This battery weighs 60 pounds!

Best, Fred

 

[foakes]

This is the Napa Battery

This is the Napa Battery.

Best, Fred

 

[foakes]

Part of My Battery Research

Part of my research — Likely more than we need to know — but for me, with our member’s help — it helped me make what I think is a good choice — value-wise, and hopefully performance-wise. Time will tell…. Best, Fred

—————————————————————————————————-

In this article, we’ll compare the AGM vs lead acid battery and see how they stack against each other. We’ll then expand into some FAQs for additional details on these car batteries.

This Article Contains

AGM vs Lead Acid Batteries: 12 Key Differences
9 Battery FAQs
What’s An AGM Battery?
What’s A Flooded Lead Acid Battery?
What are Sealed Lead Acid Batteries?
Is A Gel Cell Battery An AGM Battery?
Is An EFB Battery An AGM Battery?
What’s A Deep Cycle Battery?
Are There Lithium Car Starter Batteries?
Can I Use AGM Or Lead Acid Batteries As A Battery Bank?
What’s A Reliable Fix For My AGM Or Lead Acid Battery?
Let’s start.

AGM vs Lead Acid Batteries: 12 Key Differences

Before we begin the comparison, it’s important to note that the AGM battery has its roots in the traditional lead acid battery. As a result, they do share a few similarities.

Now, let’s see how each battery type contrasts, beginning with its inner workings.

1. How AGM vs Lead Acid Batteries Work

The AGM battery and the standard lead acid battery are technically the same when it comes to their base chemistry. They both use lead plates and an electrolyte mix of sulfuric acid and water and have a chemical reaction that produces hydrogen and oxygen as a byproduct.

However, this is when they start to diverge.

Here’s how:

A. Flooded Lead Acid Battery

The flooded lead acid battery (FLA battery) uses lead plates submerged in liquid electrolyte. The gases produced during its chemical reaction are vented into the atmosphere, causing some water loss. Because of this, the electrolyte levels need regular replenishment.

B. AGM Battery

The AGM battery uses fiberglass mats sandwiched between lead plates. It’s where the battery gets its name – Absorbent Glass Mat (AGM). The glass mat wicks the electrolyte solution, keeping it suspended in place, so it’s not free-flowing.

Because the AGM is a sealed battery, there’s minimal to no off-gassing.

Gases produced during the chemical reaction recombined with the electrolyte.

And if there is excess gas (such as when the battery is overcharged), a vent releases it to maintain internal pressure.

2. Maintenance Needs

The AGM battery is maintenance-free and can be placed in more enclosed areas as there’s no off-gassing except for the occasional venting. It’s suited for use in vehicles with batteries in trunks and under seats or in locations where maintenance can be hard to do.

On the other hand, the flooded battery requires regular electrolyte servicing and needs to be in a well-ventilated area as it releases gases and steam.

3. Durability, Vibration And Shock Resistance

The AGM battery tends to be built harder than the flooded lead acid battery, as it originally served military and aviation use.

The sandwiched configuration of glass mat and battery plates in the AGM battery translates to components that don’t fall apart easily. This structure results in a battery that’s shock and vibration resistant — making them favorites in race cars and motorcycles.

Forceful movements and heavy vibrations can damage flooded battery plates, and they need to be mounted securely to minimize these effects.

4. Mounting Flexibility And Spillage

The glass mat technology in the AGM battery makes it spill-proof and position insensitive. You can mount it in many configurations (just don’t turn it upside down).

However, the flooded cell battery has a liquid electrolyte, so it must always be upright to prevent spills. Spilled electrolyte can cause corrosion if not cleaned up.

5. Internal Resistance and Power Output

The AGM battery’s internal resistance is among the lowest of the various lead acid batteries. While a new flooded lead acid battery can have an internal resistance of 10-15%, a new AGM battery can be as low as 2%.

Low internal resistance translates to increased battery voltage output.

It also means a reduced loss of heat as power circulates in the system.

AGM batteries also respond to loading better than flooded lead acid or gel batteries. They handle large power demands so well that they’re the go-to lead acid variety for start-stop vehicles.

6. Charging Time

Low internal resistance also grants the AGM battery faster charging times. Not as fast as a lithium battery, but up to 5x more than a flooded lead acid battery, when using the same power source.

7. Depth Of Discharge

AGM batteries have an 80% depth of discharge (DoD), which is better than the 50% DoD offered by a flooded cell battery. This makes the AGM battery well-suited to deep cycle applications.

Even so, it’s not recommended to discharge either battery type below 50% of its capacity — unlike the lithium battery, which can be fully discharged.

Note: Depth of Discharge indicates how much battery capacity can be discharged safely without damaging it.

8. Temperature Tolerance

The AGM battery generally performs better in all temperatures and tends towards good Cold Cranking Amp (CCA) ratings.

The electrolyte that’s held in the glass mat doesn’t expand like a liquid while frozen. This makes AGM batteries resistant to cold weather damage. So while the battery likely won’t work in a frozen environment — it won’t crack, at least.

Flooded lead acid batteries, on the other hand, will freeze in the cold. The battery plates can crack, and the cases can expand and leak.

In extreme heat, the flooded lead acid battery will evaporate more electrolyte, risking the battery plates to atmospheric exposure (the lead plates need to stay submerged).

9. Sensitivity To Overcharging

Flooded lead acid batteries are much more tolerant to overcharging than AGM batteries.

The sealed aspect of AGM batteries makes them more prone to thermal runaway, which can be triggered by overcharging. Even if you discount thermal runaway, overcharging will shorten an AGM battery’s lifespan faster.

So, when charging an AGM battery, use a regulated battery charger to control the voltage and current going into the battery.

Note: Thermal runaway is when a battery generates too much heat than it can dissipate. The battery will dry out and melt, release toxic chemicals, and cause fires or explode in extreme cases. Nearby batteries will be affected and may result in a domino effect.

10. Lifespan And Self-Discharge

AGM batteries generally last longer than standard lead acid batteries. Because of their low self-discharge rate, AGM batteries also last longer than their flooded counterparts when not in use.

A well-maintained AGM can last up to 7 years, while flooded batteries typically last around 3-5 years. You’ll know your battery has issues if your car has trouble starting.

11. Corrosion And Sulfation

The flooded battery is more prone to corrosion than the AGM battery because it can vent acidic steam and is likelier to spill and leak electrolyte liquids.

However, both batteries will suffer sulfation if left in a state of discharge for too long. AGM batteries are a little more resistant, though, partially because they have a slower self-discharge rate.

If you see extensive corrosion on your battery terminals, it’s probably time to contact your mechanic for a replacement battery.

12. Cost-Effectiveness

The flooded battery is cost-effective and reliable as a starter battery for standard cars. AGM batteries can be up to 2-3 times more expensive than a conventional battery.

Now that we’ve seen how the AGM battery and flooded lead acid battery compare, let’s go through some FAQs.

9 Battery FAQs

Here are answers to some frequently asked questions on car batteries:

1. What’s An AGM Battery?

The Absorbent Glass Mat (AGM) battery was developed in the early 80s as an alternative to NiCd batteries. It’s a type of sealed lead acid battery (SLA battery) that’s maintenance-free and spill-proof.

It’s used in all types of applications — from marine to off-grid power systems and in advanced vehicles with significant power demands.

2. What’s A Flooded Lead Acid Battery?

The flooded lead acid battery (FLA battery) is the most common lead acid battery type and has been in use over a wide variety of applications for over 150 years.

It’s often referred to as a standard or conventional lead acid battery. You’ll also hear these conventional batteries called a wet cell battery — because of their liquid electrolyte.

If you drive a regular car, chances are, you have a wet cell battery under your hood.

3. What are Sealed Lead Acid Batteries?

The sealed lead acid battery (SLA battery) is a subset of lead acid batteries. It’s also known as a Valve Regulated Lead Acid battery (VRLA battery).

Unlike wet cell batteries, the sealed battery offers no access to its internal compartment. Instead, it uses a one-way valve to regulate pressure resulting from internal chemical reactions.

4. Is A Gel Cell Battery An AGM Battery?

No.

The AGM battery is often confused with the gel battery since both are sealed battery types.

However, where the AGM battery uses a glass mat to hold its electrolyte, the gel battery uses a silica agent to suspend its electrolyte in gel form.

The gel cell battery is rarely used in cars as they don’t do well as a starter battery. It’s also very sensitive to overcharging, and the gel can be damaged if this happens.

5. Is An EFB Battery An AGM Battery?

No.

EFB is short for Enhanced Flooded Lead Acid Battery.

The EFB battery is a flooded battery designed as an improvement over conventional batteries that’s also cheaper than an AGM battery. It’s used in basic start-stop vehicles.

6. What’s A Deep Cycle Battery?

The starting battery delivers quick bursts of power to start a car engine.

The deep cycle battery is designed to deliver steady power over an extended period of time.

You’ll find the deep cycle battery in backup technology, as alternative energy storage, or in marine vehicles. In fact, it’s also known as a marine battery because that’s one of its most common uses.

All types of lead acid batteries — whether they are AGM, gel cell, or flooded — are used in deep cycle applications. All lithium batteries are “deep cycle,” too.

7. Are There Lithium Car Starter Batteries?

Yes. And no.

The lithium ion battery is typically used to power electric vehicles (EVs). It works differently than the conventional lead acid battery, and can’t be adequately recharged by the alternator fitted with a regular car engine.

However, there are lithium starter batteries — used for their lighter weight and compact size in motorsports. The lithium ion battery can also deliver constant power over any rate of discharge.

Will we see lithium starter batteries for regular cars anytime soon?

Probably not, as they’re pretty expensive.

8. Can I Use AGM Or Lead Acid Batteries As A Battery Bank?

Yes.

Both the AGM and flooded lead acid deep cycle batteries can act as a battery bank and charge up with a solar panel.

A flooded lead acid battery bank will be a cost-effective setup.

However, it’ll require regular maintenance and may take up more space because the batteries will need to sit upright.

An AGM battery bank would be easier to configure because they can lie on their sides.

They’re also maintenance-free. However, they’ll cost more than a flooded battery bank

 

[foakes]

Solar Charger

What type of Solar Charger do some of you members use?

We do a lot of boon-docking out in the Desert, Eastern Sierras, etc.

This looks like a good way to maintain the battery as we are off exploring.

Best, Fred

 

[Dakota 1120]

This is just my opinion as others may view it differently ....

I'd rather spend $240 for a battery that will last 9 - 12 years than $140 every 2 or 3 years for a new battery. It's simple math.

However - whatever works for each and best to all.

 

[profdant139]

I have a 120 watt version of the Renogy -- but mine is a no-name knock-off of the Renogy:

Renogy 100 watt suitcase panel

 

[twinster2]

The OP indicated that the first battery had several cell the were significantly low on water. That condition can be caused by overcharging the battery. Secondly, it's unlikely that you change the specific gravity much from original solution when adding water. The sulfuric acid gets more concentrated as the water is converted to hydrogen gas and oxygen gas. By adding water you are diluting to the originaly concentration. Only thing I would say is that ionized or distilled water should be used.

 

[profdant139]

twinster, I agree that measuring specific gravity just after adding water is not a great idea. But routine use of a simple hydrometer can give you an early warning of battery failure -- if one cell has a lower specific gravity reading than the other ones do, it is time to start shopping for a new battery.

Don't ask how I learned this. They say that good judgment comes from experience, and experience comes from bad judgment. (Or in my case, bad battery maintenance habits.)

 

[foakes]

Update

Thanks Twinster —

I think you are correct. My 20 year old charger likely overcharged the battery that I returned. Just ordered a Ampeak that has some charging safety features that my current charger does not have.

Thanks for the link to the Solar, Profdant —

I’ll do a little more research and report back my solutions.

You are correct about the Math, Eagle —

However, there are other factors in the mix…

Over 50 years of installing batteries in vehicles, RV’s — I have seldom gotten over 3-4 years maximum out of a battery. Yes, I know the technology has improved drastically — however, I figure I’m not sure if I want a battery for $240 that might last the typical 3-4 years, or maybe go 9-12 years, if I take really good care of it. (Not sure if I would last as long as the battery).

However, if I get 3 solid years out of a battery for $140 — for 50 nights in the TT a year — that is solid for me. It is $3.89 a month. I pay more than that for a gallon of gas.

Anything above the 3 years with dependable power at 100% with no issues — is a bonus to my way of thinking.

Like most of us, I can afford to buy whatever battery system is available. But we are simple folks coming out of back-packing wilderness camping, day hiking, exploring, tent, and a Six-PAC cabover camper lifestyle. So the luxuries we have now, we are very happy with — and just looking for the most simplistic, dependable, and reliable way to have 12V power on board that will work with the Funfinder’s systems.

Appreciate everyone’s ideas so far — please keep them coming, as they will further help me — and others in the same situation.

Best, Fred

 

[APD]

I'm not much help here. Our battery is a wet cell and was in the camper when we bought it. Not sure what brand it is but according to the date on top it's 11+ years old. Works fine, holds a charge.
I use AGM's in my vehicles and when the camper battery dies I'll be getting one to replace it.

 

[JimboFunFinder]

Sorry to hear of your issues!
As previously mentioned AGM batteries have better discharge characteristics compared to Maintenance Free batteries used to start autos.
Your issue is likely that your TV was not totally charging your batteries.in the trailer. Perhaps there was voltage drop or a poor connection due to the long distance from the TV battery to the battery in the trailer. I have found that the Converter in the trailer also does a poor job of fully charging the trailer batteries. To solve both problems I purchased a Renogy DC-DC 12V 20Amp charger and mounted it in the front storage area near to the batteries. It does an excellent job of charging the trailer batteries whether I am towing or connected to shore power. I reported on the Renogy installation on this forum and you can search for my post.

 

[foakes]

Thanks, Jimbo

Thanks, Jimbo —

I purchased a NAPA Large Amp AGM battery.

Costco gave me $50 back after discussing the issue with the store manager regarding the Interstate Battery. Clerk said that deep-cycle RV type batteries they sell have only a 90 day warranty. That is not what I recall being told. But I also bought a truck battery at the same time — so it may have been me mis-understanding.

Also bought an AmPeak smart charger that has settings for regular, deep cycle, AGM, and Gel batteries. Winter mode, maintenance mode, 2, 8, & 15 amps, auto sensor, LED easy readout for charging progress, restoration mode, voltage level, etc..

Set up a charging station in the corner of one of my outer shops for basic charging, air, hitches, and trailer accessories.

We are loading the trailer right now to leave tomorrow morning for 4 days over at San Simeon.

The new charger will go with us.

Best, Fred

 

[JimboFunFinder]

Have fun camping!
When you return you might want to disconnect your smoke alarm while it is parked to avoid that current draw. Mine has a battery disconnect switch but the smoke alarm is not wired to disconnect.
You can look up the discharge specs for the AGM battery but you should probably stop using it before it gets to 11VDC to avoid damaging it.