New battery- what type for future solar system?

[LizP]

I am going to check out a potential purchase tomorrow and the seller informed me the battery is dead. I want to bring a new battery with me (so we can get the puppy fired up), and I would like to purchase one that will accommodate a solar system, should I decide to install that in the future.

What type of battery should I buy? And what type of store sells it (I'm a newbie)?

The Scamp has a furnace (I believe it is the original factory one) and a fridge. No a/c.

Thanks in advance for any help!

[peterh]

What you're looking for is a "deep cycle" or "marine" battery, not a regular automotive battery. The difference between the two is a deep cycle battery design is optimized to provide a steady discharge over a long period of time, while car batteries are designed to provide short but high-current bursts of power to run a car's starter motor. There are also "hybrid" batteries that can do either task.

Beyond that, there are several battery technologies. The cheapest and most common for our application is the "flooded cell" battery that has six compartments (cells) with lead plates inside. The cells are filled (flooded) with a strong acid-water mix called electrolyte.

Unless you're moving to solar right away, I'd probably buy a flooded cell battery from Walmart. They're comparatively cheap, and if you kill your battery (by running it down a time or three, which kills most batteries) you can take it back to Walmart any time within the warranty period and they'll replace it.

A more modern battery technology are "absorbed glass mat" or "AGM" batteries. Like flooded cell batteries, AGM have six cells with lead plates inside them, but packed in-between the plates is a layer of fiberglass cloth. The fiberglass cloth separates the soft lead plates, protects them from bumping into each other, and does some other nifty things, like hold the chemical byproducts of charging and discharging the battery closer to the lead plates. These things, when taken together, make AGM batteries more durable and long lasting, make them more efficient for charging and discharging (important when you're using solar), and a heck of a lot more expensive.

I use a particular variant of the AGM battery called a Spiral Cell with our solar setup. My battery's brand name is Optima, and you'd be looking for a "yellow top" (hybrid) battery. The "red top" and "blue top" Optima batteries are automotive starter batteries.

[kevin61]

I am going to check out a potential purchase tomorrow and the seller informed me the battery is dead. I want to bring a new battery with me (so we can get the puppy fired up), and I would like to purchase one that will accommodate a solar system, should I decide to install that in the future.

What type of battery should I buy? And what type of store sells it (I'm a newbie)?

The Scamp has a furnace (I believe it is the original factory one) and a fridge. No a/c.

Thanks in advance for any help!

Liz,

Another option, depending on the space you have available and $$ you wish to spend is to install two 6-volt golf cart batteries in series. These are the "flooded cell" technology that Peter is talking about. This will give you one 12 volt deep-cycle battery.

A good brand of golf cart battery is Trojan. I believe the model number is T105. A google search for your area should supply you with a list of retailers.

http://www.youtube.com/watch?v=NH9HITYmtSY

[Roy in TO]

I was initially going to get a yellow top based on the Optima literature I read last year. What Peter posted got me wondering, so I did some more research. Now I am wondering if I should not seek out an alternative as it seems Optima does not make a "true" deep cycle battery. They seem to have leaned towards "dual purpose" batteries.


Not all "Blue Top" are suitable for trailers. Optima Technical Specs says:

YellowTop Type: D51 & D51R - D35 - D75/25 - D34 - D34/78
These batteries are dual-purpose. They are designed for engine start and cyclic applications and for use in vehicles with large accessory loads.



YellowTop Type: D31A & D31T
These batteries are dual purpose. They are designed for engine start and deep-cycle applications for use in vehicles with large accessory loads.



BlueTop Type: 34M
These batteries are designed for engine starting applications. They are NOT recommended or warranted for use in deep cycle applications.



BlueTop Type: D34M / D31M/ D27M
These batteries are dual purpose. They are designed for engine starting and deep cycling applications and for use in boats with large accessory loads.

It looks like the model should start with a D to be suitable.

I found this description of the Blue Top only adds confusion:

Endurance an Issue?

The OPTIMA BlueTop battery is available as a starting or deep cycle battery for marine and RV applications and has all the valuable characteristics of its two brothers - the RedTop and YellowTop. It's perfect for boats with electric trolling motors, onboard electronics or stereo systems and RV's with “creature comforts” that tend to drain batteries quickly. The BlueTop is the battery for those who simply need a sure-starting, strong cranking, maintenance-free power source.

I'm the only thing that needs lots of power in my trailer to get started - I'm cranky enough thank you.

[Roy in TO]

Liz,
Here's an after thought.
Any 12V battery will suit the purpose for testing. Even jumper cables from your vehicle or one of the dual purpose portable power packs will do.
Once you get a trailer, you will know what size battery fits. By then you will have a better idea of what your needs are. Why put the cart before the horse?

[Pete Dumbleton]

Be careful of using the Marine designation by itself -- Basically all that means is it has wing-nut connections and different, more durable, interior construction.

Marine batteries, like other flooded lead-acid (FLA) batteries come in three flavors, Starting, Deep Cycle (aka Trolling) and Hybrid -- You want a Marine Deep Cycle as an RV house battery. Stop at a nearby Wally and examine the selection of Marine batteries, including the specs -- If it has Cranking in the specs, it is either a starter or a hybrid.

I am personally not convinced that the current AGM batteries are worth the cost difference -- The Optima line has fewer Amp-Hours available than the equivalent FLA deep-cycle marine off the shelf at Wally and auto parts stores -- They will last about the same time as a dollar-equivalent series of Wally-batts and have the risk of being stolen or otherwise severely damaged and losing your 'investment'.

The Ford starting battery in my '98 Ranger is the factory original, so it's possible for a FLA to last a long time.

OTOH, put an AGM in and forget about it for a long time -- It will recharge much faster and may be OK to discharge to lower levels -- It can be mounted in odd places, including on its side -- You can have a replacement delivered by UPS in a campground.

When they come down significantly in price, or the FLA's go up, I will be in the AGM market, but not until then.

BTW, you can mount a FLA battery on its side, but as soon as the acid drains out, it won't be of much use and a mess to clean up ! <big grinz>

[LizP]

Thank you, gentlemen!

Very educational and I very much appreciate the advice.

Wally World it is!

Liz

[Kevin H.]

I use a particular variant of the AGM battery called a Spiral Cell with our solar setup. My battery's brand name is Optima, and you'd be looking for a "blue top" (deep cycle) or "yellow top" (hybrid) battery. The "red top" Optima batteries are automotive starter batteries.

Not sure if it's ok to ask in this thread or if I should start a new topic, but I remember Peter h. describing his optima battery setup last year and saying that he had let it run down below a certain voltage and couldn't get it charged back up to it's original capacity using his solar panels.

I was wondering Peter, were you able to top up the battery fully using a regular battery charger once you got home?

And if not, do you think that a regular flooded cell battery would have performed better being discharged so low?

On a side note, I've recently purchased a couple Lithium-ion cordless drills and love how they hold their charge for months. I was so tired of going to use my older ni-cad drills after a just a few weeks and having to charge the batteries every time. So I am more than willing to pay the extra price for an Optima battery for the similar convenience.

Kevin

[peterh]

I was initially going to get a yellow top based on the Optima literature I read last year. What Peter posted got me wondering, so I did some more research. Now I am wondering if I should not seek out an alternative as it seems Optima does not make a "true" deep cycle battery. They seem to have leaned towards "dual purpose" batterie

Thank you for pointing that out. I have been mis-informed!

The Optima Red AND Blue tops are starting batteries, only the Yellow-Top battery is rated for deep cycle use. I will have to go back and correct my post!

I bought a yellow top for our trailer because I wanted a second "cranking" battery around in case the tow vehicle's battery went dead because the lights got left on or somesuch. It turned out this was a good thing, too, because our TV's alternator went out during one of our trips and the truck died on the way home. We were able to make it the rest of the way home because I switched the trailer and tow vehicle batteries.

More on my take on the Optima batteries in a moment.

[Bigfoot Mike]

Have you looked at True Deep Cycle AGM batteries?
http://www.lifelinebatteries.com/rvd...ebatteries.php

They are kinda spendy but last very long and can take a deeper discharge.

[Pete Dumbleton]

A little terminology might be in order -- Absorbed Glass Mat (AGM) batteries are in a class known as Valve-Regulated Lead Acid (VRLA) batteries, with the acid contained in a sponge-like glass mat instead of as a liquid in the case of conventional Flooded Lead Acid (FLA) batteries. Gel cells are also VRLA batteries.

This means AGMs are far less likely (but not impossible) to vent gasses, hence the large number of places and positions where they can be mounted compared to the FLA type, however they cannot be mounted upside down as that would interfere with the valve operation. It also means that one cannot add water to them, but is very unlikely to have a need to do so. IOW, pretty much an install it and forget it battery; I doubt even the terminals need cleaning.

Because they have a higher initial cost, if I were to be using an AGM, I would mount it inside where it would be less likely to 'disappear' in a storage situation, mounted out there on a trailer tongue (Had that happen with a Wally-batt -- Fortunately for me and unfortunately for the thief, it was nearing time to replace it anyway -- I had abused it by letting it discharge far too low for far too long).

Some AGM/VRLA batteries have flat plates and some are spiral wound and the Optima batts are in the second group, having that distinctive six-pack shape.

According to the Optima site, the Yellow Top is a dual-purpose (aka hybrid) Starting and Deep Cycle battery, as is the Blue Top, with Red Top being a Starter -- No "pure" deep cycle:

http://www.optimabatteries.com/optim.../yellowtop.php

http://www.optimabatteries.com/optim...ts/bluetop.php

http://www.optimabatteries.com/optim...cts/redtop.php

All three claim to outlast two plate batteries (not sure if they mean plate FLA or plate AGM here; the statement is vague -- However, other sources indicate they are likely comparing AGM to FLA).

The Blue Top seems to have better specs -- The Yellow, Blue and Red have Capacities (C/20 rate) of 55, respectively, in the smallest size -- Yellow Top also comes in a commercial version.

http://www.optimabatteries.com/optima_edge...nical_specs.php

As I see it, Optima batteries got their opening popularity from the serious 4WD crowd because extreme off-level operation (including Involuntary Inversion ) didn't result in acid spills and recharge times are very quick.

BTW, one paper I ran across was comparing AGM batteries to GEL cells, and gave their lives as 5-10 years, and 10-15 years, so that would be a consideration for a solar system.

www.battcon.com/PapersFinal2007/RuschPaper2007.pdf

QUOTE
From a user’s point of view, for a low cost UPS battery with an expected life of 5 to 10 years, the AGM battery is a good choice.

For applications where life times exceeding 10 years are expected, GEL batteries are the better choice. Flat plate GEL types are for high current discharges, and tubular plate types should be used for discharges of one hour or more. This allows a choice for different application and environmental conditions. Not only battery life time should be evaluated, but also the critical nature of the site, re: the cost for dropping the site from open circuit, should be taken into account.

For all high cycle applications (solar, load levelling etc.), the GEL batteries are best suited.
END QUOTE

[peterh]

I was wondering Peter, were you able to top up the battery fully using a regular battery charger once you got home?

And if not, do you think that a regular flooded cell battery would have performed better being discharged so low?

My Optima seems to have recovered its ability to hold its full charge. I was going to buy a desulfation charger, but the one I ordered never arrived, so I just left it on the house charger and that seems to have done the trick.

Would a flooded cell battery perform better? No, it would have fared much worse.

=== WARNING: SCIENCE CONTENT AHEAD ==
Stop reading now if you don't care! You have been warned!

One of the advantages of gel and AGM batteries is their ability to resist a process called sulfation. Batteries store energy through a reversible chemical process; as a lead-acid battery discharges sodium ions attach to one side of the lead plates in the battery and form a thin layer of lead sulfate, releasing a flow of electrons from the battery.

Later, when the battery is recharged, the process of pushing electrons back into the battery forces the sulpher ions to break free, returning the lead plate back to pure lead. The problem is that there are two types of lead sulfate, a "good" lead sulfate and a "bad" one.

Think about carbon for a moment. Pure carbon comes in many different forms: the soft, crumbly "lead" in a pencil is actually a pure carbon called graphite, but icy clear, "diamond hard" gemstones in an engagement ring are pure carbon, too.

"Good" lead sulfate in a battery is like graphite. It's soft, crumbly, and when you charge the battery by pumping electrons back in the soft lead sulfate is easy to break back down into the pure lead of the lead plates and sulpher ions floating into the battery electrolyte. "Bad" lead sulfate is more like diamonds, hard little crystals that resist being broken down and block the transfer of sulpher ions to and from the lead plates and battery electrolyte.

When batteries are new thay have little or no hard lead sulphate crystals on the lead plate surfaces. The lead plates in a "dead" battery, on the other hand, are covered with shiny white lead sulfate crystals.

As a battery is discharged the pressure on the little particles of lead sulphate to migrate across the surface of the plate and collect into crystals increases, and the water-like electrolyte in a flooded cell battery does nothing to slow the process down. The cool thing about the thick gel in a gell cells and the fiberglass mat pressed tightly against the lead plates in an absorbed glass mat (AGM) battery is they create barriers that resist and slow the sulphation process. That translates into a battery that can survive more cycles of charge and discharge and deeper cycles of charge and discharge without forming these hard lead sulphate crystals.

Which is why having a conventional flooded battery during our trip last summer would have doomed our entire vacation in Yellowstone and why my AGM battery saved it.

Gel and AGM batteries have other advantages that increase their efficiency when storing and releasing stored electricity, but I think I've gone on long enough on this topic. Hope this helped you understand why I like my AGM battery so much. (Though, as Pete D points out, a gel cell would perform in much the same way.)

[Kevin H.]

Thanks Peter, that is the best description of sulphation I've read anywhere. Your explanations are very much appreciated.

The optima blue tops come in 2 versions, one marine starting and one in marine dual-purpose. I haven't looked hard enough to find the difference between the blue dual purpose and the yellow tops. I'm leaning towards the blue top dual purpose simply because they're on the shelf at my local walmart. It seems like they're about twice the price of a flooded deep cycle, but let's say that's $100, over a 10 year lifespan that works out to the price of a couple ice cream cones per year, or a cheap bottle of wine - easily worth the convenience/performance.

Kevin

BlueTop Type: 34M
These batteries are designed for engine starting applications. They are NOT recommended or warranted for use in deep cycle applications.

BlueTop Type: D34M / D31M/ D27M
These batteries are dual purpose. They are designed for engine starting and deep cycling applications and for use in boats with large accessory loads.

[Pete Dumbleton]

Kevin, before you make up your mind, compare the Amp-Hour specs on the Optima to the Marine Trollers there at Wally.

However, ignoring that, if the Optima has come down to $100, they are worthy of economic consideration -- IIRC, last time I looked, a Wally Marine Troller was about $60, so two would be $120 -- I have faith that the market will sort things out eventually.

[Roy in TO]

I am going to check out a potential purchase tomorrow and the seller informed me the battery is dead.

Liz,
How did the trailer check out?

[LizP]

Liz,
How did the trailer check out?

Hi Roy,
Weather conditions were not favorable for a Chicago to Minneapolis trip. So, I had to bail out.

Thanks for asking,
Liz