Maximum life of an sla battery

[Graniterich]

So I have a 35 ah battery that is five years old. Other than around twenty trips of a couple of days on the road it has been on a battery tender three stage with float charger. When off the charger it reads 13 v. I also have Solar when out. I have rarely gone below 12.7. I have read that five years is what to expect if taken care of properly.

So two questions, what is the longest that you have heard of a battery lasting?

I assume that end of life signs would be reduced holding capacity vs one trip having no lighting do to catastrophic failure.

Kind of frugal, need to watch expenses do to life situations.

Thoughts?

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[tony.latham]

SLA? Do you mean an FLA?

I bought a Group 27 FLA in 2013. It's still strong. Probably because it was a bit too much battery and I never ran it down much. Always charging from solar. It went away with that teardrop but I told the new owner I'd buy her a new one when it was kapoot.


T

[Graniterich]

No I believe that is called a sla

Not the exact, but very similar
https://www.amazon.com/Mighty-Max-Batte ... QEEVSZY7Y1

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[GTS225]

SLA = sealed lead acid
FLA = flooded lead acid, (not sealed)

[RJ Howell]

With most SLA's you can pop the cover and get at the cells to maintain them. Chances are after 5yrs you're fairly low on water and may have plates exposed. A very simple test to see where your at is to charge to full (as full as you get), let it rest at least till next day and read the voltage. Here's a chart of voltages.



If you're still in the upper reaches, then I'd pop the top and add some water. Properly maintained, PbA's can last many years, my longest lasting were just over 15yrs. Capacity was just getting too low. I've serviced a few SLA's in the past and each one was too low on water and the plates exposed and corroded, making them beyond retrieval.

If you let it wear down (reduced capacity) with age and not notice, then one day of no power will happen. Current will just be too low.

[tony.latham]

With most SLA's you can pop the cover and get at the cells to maintain them.

I didn't think you could actually open up an AGM? I've owned one for six months is all.

Tony

[John61CT]

Some batteries are such good quality, cared for well and shallow cycled, can last well over 20 years.

SLA covers many many radically different categories of batteries,

besides the very different levels of quality.

For most "normal" batteries, treated "normally", five years is a good replacement schedule.

But really this questiin is "how long is a piece of string?"

To know for sure, measure Ah capacity, and compare to when brand new.

75-80% SoH is a good replacement point.

Beyond that, risk of unexpected failure dramatically increases.

If you notice weaker performance you are already likely past that point.

[RJ Howell]

With most SLA's you can pop the cover and get at the cells to maintain them.

I didn't think you could actually open up an AGM? I've owned one for six months is all.

Tony

I've always played with LA's. Didn't even realize there was a thing as a SLA that is AGM.. won't that be a SAGM??

[MtnDon]

With most SLA's you can pop the cover and get at the cells to maintain them.

I didn't think you could actually open up an AGM? I've owned one for six months is all.

Tony

You are right about AGM. We should not try to open them.

Regular lead-acid batteries have easily removed caps or a gang of caps that are meant to be removed to be able to add water. They also spill quickly if tipped over.

A sealed lead-acid battery is sealed. No caps to remove. That are also known as VRLA batteries (valve regulated lead acid). The valve is a vent valve that releases pressure if necessary. They are sealed and therefore unspillable.

A maintenace free battery has a sorta hidden strip of caps that can be removed, but are usually not removed. These batteries could have water added or the sp. gr. taken to determine charge. They are the common type of starting battery that are used in cars. Not really sealed tight. If tipped they can leak electrolyte.

AGM are also VRLA and can be mounted upside down if wanted as their electrolyte is absorbed in special sponge-like glass matting between the plates.

[MtnDon]

As for the original question, I believe that 5 years is a pretty good life expectancy from a good quality lead acid battery that is vehicle or trailer mounted and experiences some elevated temperatures. Here is NM I use best quality batteries and change them every 5 years because I do not like unexpected surprises, like not having enough "ooomph" to do whatever I was expecting. I have got 9 to 10 years out of flooded lead acid batteries in a stationary application and in a climate where the ambient temperature might hit 75 to 80 F for a few hours a day in summer, but fall back to the 50's overnight. Temperrure and vibratuon can shorten life just as over-discharging can.

By stationary use I mean like for an off grid cabin. In the mtns of NM the daily summer max temp is not too high in summer. The last set of batteries should have been replaced at the 9 year mark but we got an extra 6 months. A friend in the much hotter low altitude desert in AZ can only manage 2 years before a drop off in performance is noted.

[featherliteCT1]

MtnDon,
Wow! I knew heat was bad for batteries but had never seen the effect quantified. Thanks for the real life data.

[John61CT]

FLA vs SLA

Within SLA, the only decent chemistries for true deep cycling are AGM and GEL. Both of those are VRLA.

battery-life-expectancy-zone-300x274.jpg (16.71 KiB) Viewed 1935 times

[bdosborn]

The general rule of thumb we use is every 15F over 77F halves the battery life.

Bruce

[Graniterich]

I can unplug, let stand for a day and still have 13v on two different meters, not a high quality vom, but the same reading for five years, put under load all good. Thanks for all the input, I will wait for things to change and keep this thread updated. Hopefully a while down the road

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[Graniterich]

It has been stored in the shade under a roof mostly in the pacific northwest, so I have a generally low storage temperature going for me!

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