Sealed Lead-Acid Battery

[Michael GilliganParticipant @michaelgilligan61133]

I’ve had this for several years now … purchased second-hand, together with an ‘intelligent’ trickle charger.

.

.

 

It’s nominally a Golf-Cart battery, but has served me as a general power supply for testing stuff.

Quite suddenly, it is now failing to charge above 13.9v and that falls to about 12.4v if left disconnected overnight.

Am I correct in assuming that I now have a useful paperweight, not a useful battery ?

.

MichaelG.

 

[duncan webster 1Participant @duncanwebster1]

No, it’s just not as good as it used to be

[DiogenesParticipant @diogenes]

IIRC I’ve twice seen parsimonious friends try to revive / restore this kind of sealed lead-acid battery (i.e. “swill out deposits surmised to be shorting the bottom of the plates in one cell, and replace the acid”) – neither were successful.

The internal shape of the casing usually prevents satisfactory draining of contaminated electrolyte, and (if IIRC) the plates in these batteries are very fine and once eroded are never quite the same again/likely to start disintegrating if exposed.

 

[duncan webster 1]

On duncan webster 1 Said:

No, it’s just not as good as it used to be

I suppose you are technically correct, Duncan … it is still “a Battery”

In practical terms though, the real problem is that the dedicated charger keeps trying [and therefore gets hot] instead of settling-down to ‘trickle mode”

.

.

MichaelG.

.

Edit: The stated DC Output voltage of the charger is obviously “nominal” … else it wouldn’t actually charge a so-called 12v Battery !

[noel shelleyParticipant @noelshelley55608]

These batteries can range from the very good to not very ! Not too expensive and very handy, as Michael has said. I have one that came off a childs toy car, neglected for years in the garden, then recharged and works fine – and it’s 20 years old ! I have others that were bought new, good ones (yuarsa ) and failed in 4 years.

Pot luck ?  Just buy another one. Noel.

[Michael GilliganParticipant @michaelgilligan61133]

Almost certainly the right answer, Noel

… the one I have “owes me nothing”

MichaelG.

[duncan webster 1Participant @duncanwebster1]

Michael, you’ve changed the question! Sort of thing my missus does.

[noel shelleyParticipant @noelshelley55608]

Michael can buy a new battery, but what are you going to do Duncan ?  Noel.

[duncan webster 1Participant @duncanwebster1]

I tried sending her back but after nearly 50 years the warranty had run out

[duncan webster 1]

On duncan webster 1 Said:

Michael, you’ve changed the question! Sort of thing my missus does.

It’s a bit early for the Pantomime season, Duncan … but I must declare

“ Oh No I haven’t “

What I have done, is added a little more detail … but the original question [verbatim] was explicitly

Am I correct in assuming that I now have a useful paperweight, not a useful battery ?

MichaelG.

[Robert Atkinson 2Participant @robertatkinson2]

It’s not even good a as a paper weight. The acid fumes will damage the paper. They will often continue to deteriorate and can split and leak even more.
Its not clear exactly clear what type it is but sealed lead acids generally use a gelled electrolyte. They are not recoverable.
Take it to your local scrap merchant and get some cash for it.

Robert.

[Michael GilliganParticipant @michaelgilligan61133]

Thanks, Robert … That puts a whole new layer of ambiguity on the word “Sealed”

…i shall heed your advice !

Now an open question … especially in view of Noel’s observations: Can anyone recommend [or alternatively warn-against] any particular make of 12v battery with roughly this specification ?

.

.

MichaelG.

 

 

[Michael GilliganParticipant @michaelgilligan61133]

Google lens gives some useful answers to the picture  plus this text:

best equivalent to this battery, uk

But I would welcome comment from real people !

MichaelG.

 

[Michael GilliganParticipant @michaelgilligan61133]

This one looks a reasonable match to my likely use-case

https://www.alpha-batteries.co.uk/lucas-34ah-27-36-hole-golf-trolley-battery/

… but what do I know ?

MichaelG.

[Robert Atkinson 2Participant @robertatkinson2]

While I don’t know the maker or seller, based on the description that seems a good choice. It’s an absorbed glass mat (AGM) which is more durable than the gel type. If you are leaving it on charge all the time a simple constant voltage charger is better than a “smart” one.

Robert.

[Michael GilliganParticipant @michaelgilligan61133]

Maker is apparently Lucas [Prince of Darkness], in Vietnam.

.

My ‘Automatic’ charger isn’t particularly clever … it just does one thing rather well

With the LED showing Amber, it is recharging the battery … when the LED turns Green it has reverted to trickle-charging.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

[ UPDATE ]

I have just developed my discussion with Google, and the AI responses are rather good … here’s an extract:

Me: I should have better-explained my use-case for this Battery

It: Please don’t worry at all! It is incredibly common with batteries like this, as they look identical from the outside but are built very differently on the inside depending on how they are used. [1, 2]
Please tell me about your specific setup! To help narrow it down perfectly, you can share:
What equipment is the battery actually powering? (e.g., a golf trolley, a mobility scooter, a solar backup system, an electric gate, a toy car, or something else?)
How often do you use it? (e.g., every day, once a week, or just as an emergency backup?)
How far or how long does it need to run on a single charge?
Once I know what you’re using it for, we can make sure … etc.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Me: It will not be doing many deep- discharge cycles, but will be an impromptu power source for testing whateverAND a standby 12v source for my small static inverter … I therefore need a battery which will happily stand long periods on trickle-charge. … Does that affect any of your previous comments ??

It: Yes, this completely changes the recommendation! Your use-case is a standby/float application, not a heavy cyclic application.
The previous deep-cycle golf batteries are built with thick plates designed to be drained and recharged constantly; however, they actually degrade faster and lose capacity if they are kept on a continuous trickle charge. For your testing bench and static inverter setup, you need a Standby VRLA / AGM battery, which is specifically engineered to sit on a continuous “float” charge for years and deliver high currents on demand. [1]
As an added bonus, standby batteries are significantly cheaper than golf batteries and come with much longer warranties (typically 3 to 5 years instead of just 1 year).

Direct Standby Equivalents for the UK
Yuasa NP38-12V:Best for: Ultimate reliability and industrial-grade build quality Hardwarexpress.
Standout feature: Industry standard 5-year design life, exceptionally stable under continuous float charge, and slightly higher capacity (38Ah) for longer test runs.
Yuasa RE7-12 / REW series equivalents:Best for: Budget-friendly long-term standby.
Standout feature: Flame-retardant casing options and highly optimized for standby power delivery.
Ultracell UC33-12 / UCG33-12:Best for: A great balance of occasional testing use and standby.
Standout feature: Excellent performance on continuous float chargers with a 5-year standby life expectancy, available from UK electronics and power suppliers.
Powersonic PS-12350:Best for: High-quality general purpose bench power.
Standout feature: Heavy-duty abs case, recognized component status, and trusted across UK security and backup power industries.

Updated Advice for Your Setup [etc.]
 

Facebook·SUNSYNK Owners Group

Hi , can anyone help diagnose why my batteries are not …
16 Nov 2025 — Seems like the inverter sees the battery but just not doing anything with it. Battery stopped discharging at 0625 this morning wit…

Power Queen US

Deep Cycle Battery: Everything You Need to Know
26 Jan 2026 — Its thicker plates are designed to prevent material shedding and degradation during repeated deep discharges, ensuring a long cycl…

All About Circuits

lead acid battery specifications | All About Circuits
6 Oct 2019 — Cannot contact them because message I get is server misconfigured. Part of the specifications on the battery is that the standby u…

Ask about

Ask about

[Michael GilliganParticipant @michaelgilligan61133]

Now heading this way… if I can fond one at a good price

https://cdn.tayna.com/datasheets/Yuasa-NP-38-12-DataSheet.pdf

MichaelG.

[Dave HalfordParticipant @davehalford22513]

it’s interesting to note that the max 5 year life is @ 20C though the max ambient can be 50C.

I can testify that lead gel batteries used as power standby lost 75% of their capacity after 2 years use in single walled street cabinets. The equipment lasted 15 minutes during a area power cut instead of the expected hour. I was unable to keep my hand on the roof one in full sun even with the fans going full pelt.

[Michael GilliganParticipant @michaelgilligan61133]

I would welcome any anecdotal evidence like that … Thanks Dave

One thing I have learned since my previous post is that they also offer an NPL version of the 38-12 … which has a longer designed-life than the NP

MichaelG.

[peak4Participant @peak4]

Depending on your application and charging facilities, (and bank manager) it might be worth investigating Odyssey batteries.
https://www.tayna.co.uk/brands/odyssey/
They have a very long shelf life; i.e. low self discharge rate.

They do have an issue though, where a very low discharge load can shorten the overall battery life.
A car alarm/ECU drain does seem to cause a reduction of the life, but they are fine with a heavy discharge cycle such as an electric winch.
Also very good at low operating temperatures, due to the low internal resistance.

The manufacturers web site has a good English pdf download explaining about them;
https://eu.odysseybattery.com/battery-literature/

Some folk in the off road competition field use Optima, rather than Odyssey, though I’ve no experience of the latter myself.

p.s. I’m a happy customer of Tanya since we moved away from Sheffield, where I always used South Yorkshire Battery Services, but it looks like they have been taken over by a larger group  Veloris

Bill

[Michael GilliganParticipant @michaelgilligan61133]

Thanks Bill … that’s  given me another avenue t o explore.

MichaelG.

[Robert Atkinson 2Participant @robertatkinson2]

The very best is the SBS range formerly by Hawker. They are AGM. You pay for quality…
https://uk.farnell.com/enersys/sbs30/battery-lead-acid-26ah-12v/dp/2070725

Robert.

[Michael GilliganParticipant @michaelgilligan61133]

Out of my league, I’m afraid, Robert

by the way … I sent you an eMail earlier : hope you don’t mind

MichaelG.

[Author]

Posts