Suitable charger for AGM battery ?

[Bazil]

Hi all;

looking for some collective wisdom on what battery charger to use for an AGM battery. Mine is only 12 months old and not holding charge, so I understand it needs a charger to whack it with at least 6 amps. My current (hah!) charger is only 4.8 amp and so not up to the job. I suspect it doesn't give it a big enough whack for enough time, and then puts it on float / trickle charge.

There's lots of chargers at all sorts of prices, and many claim to be "intelligent" and have staging to rejuvenate AGM batteries. Is that what I really need, or just an old fashioned "dumb" charger to scare the bejesus out of my battery to grant it new life ?

There's stuff like c-tek chargers for about $ 150 which sound like they do the job, or much cheaper ones like these for much less :

https://www.ebay.com.au/itm/Giantz-12V-Battery-Charger-Inverter-20-Amp-Car-ATV-4WD-Boat-Caravan-Motorcycle/390737992494?_trkparms=ispr%3D1&hash=item5af9cc9b2e:g:1oMAAOSwvT1dccV~&enc=AQAEAAACQBPxNw%2BVj6nta7CKEs3N0qX9gwyVUIxhs7w3RaT2axrzU3c2NOl%2B5qncJs%2FWNbC0UukvK0yo1Raz85N3u9fcAve4H4Wb%2BUkVFVxHicPYngfRjFCNOxpbFLfk2iguUGabQU%2B8GrMQK16MDEIhL%2FgJQPhLBw2JB2ZD270586monci%2FIe8huWBBkz%2FgzIbfgKQJ1dF%2Br%2Fqpg%2FM%2BfFe6%2F%2Fw0Vdcc0bIiIH4%2BMjAm2awm9%2FTIPUrr1C1WwAAJNu%2BSnlobnuqFfoRXs4QhmZ9JlsvLHyXx1p2VHbIuihXPw7UwZ4wKTN1vzCMJEYSjpXaBtfarvtr0X1M9cwF5kYLOIMJzVYNCUHXxf7UkXND%2Bz9ZMjqeImd7vZSs2PzmL88FgR9Tm8xoEAZ5HYmIquTzAB%2FOz2JNmFNIQ3Sgb0GPuKFT5I26b0HVKF72Ic%2F4JK%2Bvyo13%2F%2BiyDUrXnKsNeCjx49zNyNeoykqCDuxfZetfRHkzYyymZI9ID4VylIIIIeymvyixCQNXYTDeuH1GVkqqMC592bqntX9FNkCeadxl3lKMi4vGYW7w26j%2Fw1qY3g9wrjeYygH65poW7DraJftdlmzigauIXza4xcIj2nwE%2F7kEvJoMKtiSO3l%2FNanCoUj0lAQs5f%2B6fOl7X3%2BT6irKjLKL%2BpiOzd3B2QolFWRIsRlbMmG5KAbCfqEyoRjsgN%2FI5MEdkew4kKQWgllwlUcYIP97ZvY4cGW4JjYbqOU2CrDHDk2UIC08B0Afeo7LgzbrBYsEgVg%3D%3D&checksum=390737992494d4594d3c6ab942058391682acaef4730&enc=AQAEAAACQBPxNw%2BVj6nta7CKEs3N0qX9gwyVUIxhs7w3RaT2axrzU3c2NOl%2B5qncJs%2FWNbC0UukvK0yo1Raz85N3u9fcAve4H4Wb%2BUkVFVxHicPYngfRjFCNOxpbFLfk2iguUGabQU%2B8GrMQK16MDEIhL%2FgJQPhLBw2JB2ZD270586monci%2FIe8huWBBkz%2FgzIbfgKQJ1dF%2Br%2Fqpg%2FM%2BfFe6%2F%2Fw0Vdcc0bIiIH4%2BMjAm2awm9%2FTIPUrr1C1WwAAJNu%2BSnlobnuqFfoRXs4QhmZ9JlsvLHyXx1p2VHbIuihXPw7UwZ4wKTN1vzCMJEYSjpXaBtfarvtr0X1M9cwF5kYLOIMJzVYNCUHXxf7UkXND%2Bz9ZMjqeImd7vZSs2PzmL88FgR9Tm8xoEAZ5HYmIquTzAB%2FOz2JNmFNIQ3Sgb0GPuKFT5I26b0HVKF72Ic%2F4JK%2Bvyo13%2F%2BiyDUrXnKsNeCjx49zNyNeoykqCDuxfZetfRHkzYyymZI9ID4VylIIIIeymvyixCQNXYTDeuH1GVkqqMC592bqntX9FNkCeadxl3lKMi4vGYW7w26j%2Fw1qY3g9wrjeYygH65poW7DraJftdlmzigauIXza4xcIj2nwE%2F7kEvJoMKtiSO3l%2FNanCoUj0lAQs5f%2B6fOl7X3%2BT6irKjLKL%2BpiOzd3B2QolFWRIsRlbMmG5KAbCfqEyoRjsgN%2FI5MEdkew4kKQWgllwlUcYIP97ZvY4cGW4JjYbqOU2CrDHDk2UIC08B0Afeo7LgzbrBYsEgVg%3D%3D&checksum=390737992494d4594d3c6ab942058391682acaef4730

or this :

https://www.ebay.com.au/itm/12-24V-8A-Touch-Screen-Smart-Pulse-Repair-LCD-Battery-Charger-Car-Motorcycle-AU/153602024937?epid=17034066164&hash=item23c364e5e9:g:AdMAAOSwNCNdgEk0

or this :
https://www.ebay.com.au/itm/12-24V-8A-Touch-Screen-Smart-Pulse-Repair-LCD-Battery-Charger-Car-Motorcycle-AU/153602024937?epid=17034066164&hash=item23c364e5e9:g:AdMAAOSwNCNdgEk0

What do you think ?

cheers

Bazil

[BRG-BIRD]

I have a Deltran battery tender that works well, not cheap but works well.

[zebraranger]

You need a 2 amp battery maintainer, not a battery charger. A 6 amp charger will charge the battery, but that amperage is high for a motorcycle battery. If you use a 2 amp battery maintainer with pigtail, your battery will always be fully charged and will last much longer. By the way, that link really screwed things up.

[wicks]

I use Battery Tenders on everything (like 12 machines). There are different amperage ones, can find variants on Amazon. All the bikes (except for the 6 volt DT) are on the ganged ones and the Porsches are on independent higher power units.

Curious though, which AGM battery crapped out after one year?

[80CX100]

Hey Bazil, Not sure what it is about your first ebay link you posted, but it went on forever and caused all sorts of grief on my monitor and display, curious if it's affecting any other computers.

There are all sorts of smart battery chargers now, I have the CTek 4.3 and rotate it on all my batteries. It seems to be durable and working all right, I like the idea that I can select different programs designed, to give the best performance and service life for different types of batteries, small regular batteries, on mc's/small engine equipment; regular car/truck batteries;AGM batteries; even has a conditioning/rejuvenation program, fwiw

Kelly

[Kiwi_Roy]

Yes it messed mine up as well, I had to scroll away to the right to find the text box.
A 12 Volt wall wort off an old printer is all I used for years, it would put out about 1-1/2 Amps and didn't care how flat the battery was.

I also have a so called "Smart charger" but it doesn't know what to do if the battery is really flat, I need to call on the wall wort for those.

[fossil]

A good AGM - prepared charger? Bosch C3. It also charges 6 V batteries (think old Hondas with the Cub - engine).

[ozarquebus]

The problem with battery chargers in general is that they continue to charge the battery when they don't need it.
This wears the battery out prematurely simply by running a small current constantly across the plates,
causing an electrolytic process which forms a layer on the surface of the plates which is  a dull passivated layer of inactive oxides.

Smart chargers are better, but as far as I have seen, they all continue to charge at a very small current even when at 100% state of charge.
After working in the aerospace battery research and development for many years, the only way to maintain a lead acid battery at full charge without wearing it out is a computer controlled charger.
AGM batteries only self discharge at an open circuit voltage of about 0.02 volts per day.
A disconnected AGM battery at full charge with clean terminals, sitting on a non conductive mat, should not self discharge to the critical 10.5 volt level for many, many months.
 Granted, it may need to be recharged to start a reluctant bike, but the battery will not be damaged or degraded by storage in that case.
Many bikes will have a tiny discharge that will kill a battery without leaving it on a trickle charger.

Batteries are like mechanical machines in the sense that the more work they do, the faster they wear out. Leaving them on a typical 'trickle' charger or a 'battery maintainer' is like
leaving a car idling in the driveway.

If a lead acid  (PbO)  battery voltage is monitored and recharged at a low rate whenever it reaches a 85% state of charge, it will last decades.
Every time a battery reaches a 0% state of charge (dead) or 10.5 volts for a AGM PbO battery and is recharged, it puts significant wear on the battery and it only has a finite number of those cycles in its life.

The perfect battery charger would be controlled by a computer chip which contains software that will only monitor the voltage like once a day and recharge at a low rate (trickle) ONLY when it
drops below a preset OCV (open circuit voltage) like 11.8 volts. This will maintain a battery healthly and be ready to start a normal bike.

Is there a smart charger that actually stops charging completely once reaching  approximately 14.3v volts, monitoring the battery till it needs a charge,
 then giving it an hour or so of low rate charge every couple of months?

Most cheap computer chips will not last in continuous operation as long as a the life of a well stored lead acid battery.

I have not seen a battery charger, smart or otherwise, that does not continue to charge at a low rate continuously.

I disconnect the battery through the winter and recharge it once a season unless I forget or get too lazy. This usually last about four years, but the battery generally gets accidentally killed from some other mishap,
like leaving the key on. Once an AGM gets below 10.5 volts battery even once, it is greatly compromised and cannot be relied on.

[fossil]

C3 does. And as far as I know several Ctec and AEG models also do.

[Chuck in Indiana]

We've done a fair amount of AGM research on the V11LeMans forum. I bought an Odyssey charger. The problem with AGMs are mainly not being fully charged when first put into service.
An AGM wants to be "conditioned." To do this, the battery is discharged, then charged with a suitable charger.. at least 6 amps and not over 15 volts.
It may take as many of 3 cycles of this until the battery will sit for very long periods over 12.65 volts. At that point, they will last for years in normal service.
My Odyssey charger has "brought back" two AGMs that wouldn't hold charge. Pretty good buy at 100 bucks.

[Wayne Orwig]

Odyssey states that where the high current charger comes into play, is if the battery has been discharged deeply, like left sitting for months, or a load left on it, THAT is when Odyssey wants you to bring it back to life with a LARGE current. If you are simply maintaining it, the high current is NOT needed. This is all in the tech manual, page 14.

That being said, I have had a couple of Odyssey batteries last for over 10 years in my motorcycles. Generally, I use the motorcycle charging system, and to maintain them, I use a BatteryMinder desulfation charger.

https://www.amazon.com/BatteryMINDer-Model-12117-Maintainer-Desulfator/dp/B000P23HZS/ref=sr_1_10?keywords=batteryminder&qid=1572616444&sr=8-10

I also have an Odyssey battery on my back porch (long story). I use it to power a laptop when I am back there. It has a small solar panel near it to charge it. Not much current there. It has been used for years, with a low current charge, though it is a smart charger. I have not seen any loss of capacity over the years.

[acogoff]

     What works for me is a Ctek 4.3. I'm sure there may be newer technology then them out by now but at this point I would buy another of the same. I own 2 now and they are in use every day on the farm and their life is not an easy one.

[Wayne Orwig]

Most cheap computer chips will not last in continuous operation as long as a the life of a well stored lead acid battery.

I have not seen a battery charger, smart or otherwise, that does not continue to charge at a low rate continuously.

Once an AGM gets below 10.5 volts battery even once, it is greatly compromised and cannot be relied on.

No idea what you mean about cheap computer chips in continuous operation not lasting. I have designed a number of products with PIC chips that cost under $1, that run non-stop. Including a charge controller using a PIC12F510.

A good charger will switch from an absorption voltage around 14.7 volts to a float voltage around 13.6. That is low enough to prevent outgassing, and high enough to fully charge the entire plate area and prevent sulfation.

10.5 volts is way too low to a sitting battery.  Here is a quote from an AGM manual. “If the battery voltage drops to 12.0 volts (35% state of charge) it should be recharged immediately to avoid permanent battery damage.”

[kingoffleece]

AGM manufactures are good at recommending what charger to use.  I have a Ctek 7000 that has a specific setting for AGM batteries.  And it can be left connected for as long as needed.  All year if necessary.  You may also want to check your charging system output.  AGM will require more that a conventional battery.  As good test is after a ride of a good distance (30 plus miles) park the bike and leave it sit without connecting it.  In 24 hours your voltage needs to be at least 12.85v.

[Tom H]

ozarquebus,

I have a Vikinig 63299 charger that I bought from Harbor Freight that I do believe shuts off when done. HF seems to not sell it anymore, but Amazon has it under a different name:

https://www.amazon.com/Automatic-Battery-Charger-Maintainer-Clamps/dp/B07Q3VF9DC/ref=ac_session_sims_23_1/139-3475507-1203462?_encoding=UTF8&pd_rd_i=B07Q3VF9DC&pd_rd_r=d2a3bbf3-d119-4144-a4c4-f6d1a942ade6&pd_rd_w=K3URE&pd_rd_wg=H4UQS&pf_rd_p=48085047-4138-436e-b581-f015f2ded99a&pf_rd_r=ZRYKXG8CE581NGY4YHYG&psc=1&refRID=ZRYKXG8CE581NGY4YHYG

Next time I do an auto-charge, I'll have to check if it does "stop" charging. The unit does look like it's off, the screen shuts off when done.

Tom

[Bazil]

Thanks for all your replies.

Sorry for the flaky eBay link.....

My battery is a SSB Power sport agm
. It was put into service straight out of the box 12 months ago without conditioning, so that's probably the first problem. I replaced a dodgy regulator six months ago, so that wouldn't have helped.

I don't keep it on a tender over winter, but give it a charge when I remember, which sounds like it should work.
So, I'm thinking the go would be to discharge then recharge at high current, then discharge and repeat a few more times, to recondition it?
The charger I have is a three stage, which sounds like would work for maintainence, but because it is only 4.8 amp, may not be enough to recondition. I had the local auto elected give it a charge and they said after a few days it came up fairly good.

I'll give that a shot and check voltage drop over time.

Doesn't sound like a charger replacement is needed except to intially condition, or to recondition, if I've understood correctly.

Thanks to all

Bazil

[kingoffleece]

Again, AGM batteries have a very specific set of parameters they need to see.
Look at the tech section at Odessay for complete info and explanation.  The 12.85 I gave you above came from a rather long chat with their tech dept.

[ozarquebus]

The last thing I would want to do is start a flame war over batteries and their chargers similar to previous ones that have occurred here on oil or on methanol in fuel, but I feels I must interject.

Lead acid battery technology with flooded cells has been around since 1859. AGM variant of the flooded lead acid is very similar in basic principle and was patented in 1972.
This is relatively simple stuff and is very much a mature and perfected science.
Everything you would ever need to know about lead acid batteries including AGM can be gotten out of a small text book. There are not really any trade secrets.

Having worked for years in aerospace batteries and AGM lead acid battery and charger research and development and testing, I can tell you it is not really  'rocket science'.

On most forums I have visited, it appears that almost all the information tossed about has a common source: the manufacturers.

After having been on the manufacturer's end of things as well, I can tell you that they are careful and selective on the information they publish.

The priority of the manufacturer is to sell their product, not make sure the customer has a firm grasp of the science behind batteries and chargers.

They oversimplify, and do not divulge facts that may support competition or lead to civil suits as their main goals.

All this while finding the absolute cheapest way to do everything.

Is this someone you would trust to bring you the best product and information?

[Wayne Orwig]

Again, AGM batteries have a very specific set of parameters they need to see.
Look at the tech section at Odessay for complete info and explanation.  The 12.85 I gave you above came from a rather long chat with their tech dept.

Yes, things like an equalization charge is a bad thing for AGM generally speaking. And charge voltage in generally needs to be a bit more tightly limited. With flooded batteries, you can just put in a bit of water if the voltage is a bit too high, but an AGM may vent and dry out.
I just checked online, and last night the voltage of my AGM battery dipped to 12.55V. It was below 35F out there. It is definitely 100% charged. In hot weather, I usually see closer to 12.8V after sitting all night. It impacts what my charge controller does.