Was wondering the same just a few days back. "CTEK 7002 EFB" is still in my google search history.

 

This one line from Varta needs more clarification:

Charging of a battery with EFB or AGM technology is identical, however, care must be taken that the device is suitable for batteries with start-stop technology.

 

My Honda came with an AGM battery but I'm still learning about it.

You can use your regular battery charger on AGM or gel cell batteries.
False. These batteries like to be charged slow and low. Many AGM/gel cell battery chargers have microprocessors that collect information from the battery and adjust the current and voltage accordingly. Some have different settings for charging flooded, gel and AGM batteries. Overcharging can kill these batteries. Also, alternators are not chargers. Don’t rely on an alternator to do the work of a charger. If a battery is discharged to the point that it cannot start the vehicle, use a charger as soon as possible to make sure the battery gets fully charged.

AGMs and gel cells can be tested the same way as conventional batteries.
False. These types of batteries have lower internal resistance than flooded batteries. Older capacitance battery testers/analyzers may not be able to accurately read these batteries. Most new battery analyzers have a special mode for AGM/gel cell batteries. Old-school load testers might not provide conclusive results.

AGM or gel cell battery replacement is the same as flooded battery replacement.
True and False. While the installation of the battery may be the same for the two battery styles, some vehicles require an extra step to tell the vehicle that the battery has been replaced. Newer vehicles have a Battery Sensor Module or similar systems. These systems require recalibration with a scan tool if the battery is replaced. If the system is not recalibrated, the alternator might overcharge the new battery and cause the battery to fail soon after replacement.

Based on some research, I know that I must use an AGM charger & maintainer.

 

My Honda came with an AGM battery but I'm still learning about it.


Based on some research, I know that I must use an AGM charger & maintainer.

Battery Tender (maintainer at 2A max) state on the package, going back almost a decade, they work for AGM charging.

 

I have a "smart" battery charger at home, and so I want to find out what the real issue is with charging EFB-type batteries. If it just means reducing the peak charging current, my charger lets me manually choose between 2, 4, and 6 amps. It has a microprocessor which monitors the battery voltage, to automatically go into a float / maintenance mode, once the battery is fully charged, and also has a "desulfation" mode.

The brand is Schumacher. I see that they have some newer models that have a switch to select between "standard" batteries, AGM, and GEL. But perhaps the correct charging regimen for EFB batteries is not that different from standard flooded cell batteries?

When I have a chance to get the specific model for my charger, I intend to contact Schumacher customer support and see what they think....

 

NOCO says to use "NORM" mode on their chargers - presumably that's the same as "Flooded" I doubt that this is truly optimized for EFB, but perhaps the idea is to do no harm.

Support Resources

no.co

Charge EFB batteries using the NORM Mode

 

Battery U doesn't say much, but EFB seems to be a lead acid flooded battery with some extra guts, and cheaper than an AGM. New Lead Acid Systems Information – Battery University

If you want a really slow charge, one of the lower amp battery tenders like the Junior or the 1.25 amp model might be good. https://www.amazon.com/gp/offer-lis...ld?ie=UTF8&mv_color_name=0&mv_size_name=2&mv_style_name=0&qid=1580945496&sr=8-4

and I see NOCO has some low amp models too

 

I e-mailed CTEK regarding charging the 2020 Subaru Outback XT with LN2 EFB battery and start/stop - even sent them a picture of the battery to make sure. Their response was this:

An Enhanced Flooded Battery has the internal structure of the standard lead acid battery so yes, you can use your MUS 4.3 (56-864) on that type of battery.

CTEK Quality Technician in the USA

 

So there's a different battery being used as a replacement now. It's also EFB but a higher CCA.

ENHANCED Flooded Battery. Replacement Battery EFB.
Part Number: SOA821B700
640 CCA

Picture of it here: https://www.subaruoutback.org/attachments/20200309_155543-jpg.480430/

SOA821B700 - Replacement Battery E - Genuine Subaru Part

Genuine Subaru Part # SOA821B700 - Replacement Battery E

parts.subaru.com

 

Interesting discussion.
If you search for that new part, it's "no longer available", and if you just search for the battery, it's listed as "NS" (no stock?).

If you try to find an "EFT LN2 battery", pretty much every site that sells car batteries just directs you to a compatible AGM, which will obviously work.
I wonder, if the EFB thing is a fleeting-moment type of deal, or similar, or maybe it's availability issue, with the current market (seems like at least some sites would still have placeholders though), weird stuff.

 

Is anyone seeing the actual battery part# though, anywhere?
Really, for me, it's academic, but I find it interesting, that no where on the sites like parts.suburu.com, or dealers' parts sites, is there a battery part listed, it's all "NS".

I'll just get a decent AGM when it's time, probably the biggest one I can fit into the tray, CCA-wise, but I wonder how the parts people order a replacement, for a repair (or if I just show up at the counter and want one for some reason)?

 

for the #900 here is the subru online part# SOA821B900 - Pb001993 replacement ba - Genuine Subaru Part

 

Not sure if it's related but are there any special considerations for start/stop batteries when it comes to choosing one of those battery banks/jumpstarters? Or can I just use any that are 640A and above?

 

That's something I hadn't even thought of, so I did a google search and couldn't find anything on that subject. It seems like it shouldn't matter, and start/stop systems that detect a weak battery shouldn't automatically stop so that after the jump you have to jump it again.

In reading about jump starting, I was noticing that there was a controversy over whether or not the donor car, where one car jump starts another, should be running or not. Most instructions say that the donor car should be off, yet it's been common practice for decades, for the donor car to be left running. It seems like modern electronics have made it much more likely that the donor car can have a problem if it jump starts another car while running, and it's not just wear and tear on the alternator. This article explains why:

Can a jump start damage computers?

In rare cases, a jump start can damage computers in your car. Find out about the risks of jump starter a modern vehicle.

ricksfreeautorepairadvice.com

It references this technical article, that's way over my head:

https://m.littelfuse.com/~/media/electronics_technical/application_notes/varistors/littelfuse_suppression_of_transients_in_an_automotive_environment_application_note.pdf

 

640CCA is a pretty beefy jump-starter pack (I don't think I've ever seen one that big, for a passenger car/truck rating).
A lot (most really, IME) don't actually put CCA ratings, they put total mAH ratings, at 3.7V (typical LiIon voltage), which is misleading, if you ask me, given that you need somewhere in the 12-13V range, for starting.
CCA means they can maintain voltage for 30 seconds, and actually start the engine, in most cases.

I did a LOT of reading/research, before I bought ours, because there are a lot of good brands with not-so-great specs out there, when you really dig-in. Research is key here, and it expires, fast, the manufacturers are constantly releasing new model #'s (perhaps not necessarily new models though)I think intentionally, because it makes it harder to track the research part.

 

Which one did you get?

 

Noco makes good jump starters

 

Yeah, I thought that, too, but if you look at some of the in-person reviews, they don't hold up, even close to the CCA-tests. Some of their best chargers were barely making it for 5-10 seconds, in testing, and unable to make a 2nd attempt, after that. When they were frozen to something in the 20F range, they were hardly even able to turn the engine, in testing.
At least this was the case, when I bought ours (replaced an older one, and got a 2nd for this car, given the e-brake thing in the 2020, plus the convenience), not saying that this years' models are good or bad.

I bought one of the CostCo EcoXGear starters, at the time, it was really highly rated, and had Bluetooth (parasitic, a little, but handy) status, and replaced the other one with a high-amp DBPower model, which also came out near the top of actual-crank tests.

I bet neither model is readily available anymore though, so I'm hesitant to claim their current-status here, or name them, because there's a decent chance that their newer models might not hold up to the same scrutiny that these did (see my earlier comment about model-rolling).

I was really surprised by the testing on the Noco models myself, as they've always gotten top-ratings for their chargers. Not sure what happened there, perhaps it was a QA-blip or something, and now their newer ones are fantastic, but that requires another round of research (reading various rags, looking for 'tube videos where people real-world test them, etc).

 

I've read the thread, but I am still unclear. I have the Schumacher charger with the "standard, AGM, gel cell" options. Is the AGM option correct for charging this battery? The vehicle has been sitting a lot more than usual what with COVID and winter.

 

It is confusing because battery makers say that AGM and EFB use the same charging algorithm, but Charger makers say to use the Flooded/Standard setting with EFB batteries. Schumacher told another member to use the Standard setting for the EFB battery. CTEK told me the same thing - use the Standard/Flooded setting.

 

My 2014 Sierra is old by today’s standards, and was going through batteries every 18-24 months. This time I tried an AGM, and the difference is amazing. Took about two days of driving for it to be fully charged, but now that it is it holds that charge forever. Even after sitting a couple days, it’s fully charged within 2-5 minutes. On trips it charges for 2 minutes every 45 minutes. So far its ability to rapidly charge after starting and then holding that charge has far exceeded any traditional flooded battery.

No issues with the battery yet on our Subaru after 1 year and 20K miles. If we need a free battery during the warranty period, fine, but after that I’ll be going AGM for sure because its ability to rapidly charge and hold that charge is perfect for start stop technology.

 

Huh. And I thought batteries were batteries.

 

I knew about AGM but EFB was totally new to me.

 

So what's a good and reasonably priced replacement, considering somehow my S/S system never activates?
I want to be ready, I don't think the battery Subaru installed in our Gen6 will last very long.

 

I would get an East Penn 600cca AGM - it's sold under many names including Napa which is 4 miles from my house.

https://www.napaonline.com/en/p/NBP9847

For a premium choice there's the Odyssey Performance Group 47 AGM

ODP-AGM47 H5 L2

Looking for an ODP-AGM47 H5 L2 (47-650) ODYSSEY Performance Series battery? Buy it online at OdysseyBattery.com - the official manfacturer's website. Whether it's a battery for your car, boat, RV, a powersports battery or a heavy duty / commercial application battery - powerful performance...

www.odysseybattery.com

 

You're covered under the 36k 3 year warranty.

 

Yeah. For our Gen5, Subaru ended up paying me $250 in the form of a parts and service coupon (still buying oil and filters at the dealer with that, lol) to get an aftermarket replacement battery. That was after the second OEM battery had leaked. Got the replacement from Costco, one of those interstate batteries. So far so good, knocking on wood!

 

Aggregate Glass Matt batteries are still the best ones. they handle current discharge better, live longer, and can better deal with repeated high current draws...

as for battery choice use what is recommended by the manufacturer or better if applicable. I have one car with a AGM battery and that thing cranks the 3,6L over fast even in in 30 temps with engine cold and dyno oil.

 

Yeah, I've been using AGMs for >25 years now, and IME (I'm sure there are some bad batches, just like ANYTHING out there, pretty much), they're pretty bomber.
If you charge them every so often, they last 5-6 years, easily; I don't think I've had a single Optima that's failed prior to 5. They're pricey (sort of, gap seems to be getting smaller these days), but there's something to be said for appliance-like reliability, and not having to think too much about it...

 

Yeah, I've been using AGMs for >25 years now, and IME (I'm sure there are some bad batches, just like ANYTHING out there, pretty much), they're pretty bomber.
If you charge them every so often, they last 5-6 years, easily; I don't think I've had a single Optima that's failed prior to 5. They're pricey (sort of, gap seems to be getting smaller these days), but there's something to be said for appliance-like reliability, and not having to think too much about it...

I have a 2019 Outback 2.5L and the OEM battery has blown a fuel cell. We moved from California to North Carolina needles to say a colder climate. I’ve been searching for an AGM battery but they don’t have one that fits the 2019. I thought since you know a little bit about the AGM would you think the AGM 35 or the 24 would work?

 

Optimas are reportedly not as good as they used to be so I no longer recommend them - used them back in the day though. Also used Odyssey batteries which are supposed to be still good.

 

Yeah, I've heard anecdotal talk of the same, but not much empirical evidence?
I think the industry has declined as a whole, becoming a largely commodity-index type of deal (instead of more evolving-engineering-based), but this seems to apply to almost all the brands.
Maybe Odyssey is better these days (they seem to have leveled a bit, in terms of price), but they also get anecdotally bad reviews, here/there?

 

Somehow, my inexpensive regular batteries have lasted 7+ years in most cars and our travel trailer, the Subaru being really the only exception. Maybe I was lucky.

 

I'm pretty sure that the "smart" charging algorithm is bad for batteries - your 2016 had the TSB right? I also suspect that battery quality has declined (battery manufacturers being bought by private equity) at the same time that electrical demands are increasing in cars - a perfect storm.

 

So I took my car to the dealership for a separate issue, but mentioned to them that my battery seems weak and that it registers low resting voltage like 12.2 when I expect it to be closer to 12.5 and I asked for a load test. So they claim my battery was at 12.68 volts and measured at 904CCA. I drive the car home and get 12.33 with my voltmeter.

 

Obviously the dealer charged the battery just before "testing" it and the 904 CCA tells me their methodology was flawed - it's not possible (someone correct me if I'm wrong). It would be like if they told me the battery was at 18 volts.

 

They probably disconnected a charger and then measured right after? Batteries will read high for some time.
I agree that the results are suspicious.

 

Don't know if you've seen this thread but it might be good reading: Gen5: Replacing the original battery with BETTER

Seems people like the group 24. Try to find the Odyssey one if you want the absolute best.

 

Thanks !

 

I remain concerned that my LN2 Battery may have premature failure. It continues to show <11.9V in Factory Mode after setting for 12 hours. If this battery is not replaced during the three year warranty then my plans are to replace it with an AGM Battery yet to be defined. I will list some of my random thoughts and summary about this topic.

1. The Battery Tender Plus, purchased 12/01/2012, says it will correctly recharge AGM, or any type lead-acid, batteries as confirmed by the included photograph of the package located below.
2. In November of 2019 I was able to find H5 Batteries with CCA of up to 650. Today, they are no longer listed at 650CCA for the same brand sites or on the shelves.
3. I am currently having difficulty finding H5 Batteries at Costco, Sam's, and Walmart. However, the H6 750CCA Batteries seem to be more available.
4. Different battery dimension charts may vary in their dimensions listed for the H5 & H6 Batteries so the replacement fit remains a big unknown. The current LN2 is rapped in a sleeve which could be unnecessary in some climates. I would like to install a 750CCA H6 Battery but not sure about the actual size of each option. Best case I found was a difference in length of 1.5". Also, the current battery tray length is approximately 10.1" and the smallest H6 length is listed at 11". The trays in my Toyotas were flexible and therefore allowed for battery overhang but not sure the same is true for the Subaru Tray. I would also need to obtain the center-line dimension for the battery posts because of concerns for connecting cables length being too short.

During the next 1.5 years I will continue to search for information about the installation, or attempted installation, of an H6, Group 48, Battery in a Gen 6 Outback. If that does not happen, then I will likely go to Costco to purchase a H6 Battery with the understanding I will be able to return it if I can't make it fit. I will also look at purchasing a battery tray from Toyota.

 

Group 47/H5/L2 Odyssey AGM battery is available through NAPA, or direct - Autozone also sells their batteries but doesn't list that size yet. Not sure if it can be special ordered.

ODP-AGM47 H5 L2

Looking for an ODP-AGM47 H5 L2 (47-650) ODYSSEY Performance Series battery? Buy it online at OdysseyBattery.com - the official manfacturer's website. Whether it's a battery for your car, boat, RV, a powersports battery or a heavy duty / commercial application battery - powerful performance...

www.odysseybattery.com

https://www.napaonline.com/en/p/ODBODPAGM47H5L2

@blaydesglobal has one GEN 6 Battery POWERTHREAD

@evgzyx has one GEN 6 Battery POWERTHREAD

I'm trying to get one myself but the local NAPA says they can't get them yet.

 

Group 47/H5/L2 Odyssey AGM battery is available through NAPA, or direct - Autozone also sells their batteries but doesn't list that size yet. Not sure if it can be special ordered.

ODP-AGM47 H5 L2

Looking for an ODP-AGM47 H5 L2 (47-650) ODYSSEY Performance Series battery? Buy it online at OdysseyBattery.com - the official manfacturer's website. Whether it's a battery for your car, boat, RV, a powersports battery or a heavy duty / commercial application battery - powerful performance...

www.odysseybattery.com

https://www.napaonline.com/en/p/ODBODPAGM47H5L2

@blaydesglobal has one GEN 6 Battery POWERTHREAD

@evgzyx has one GEN 6 Battery POWERTHREAD

I'm trying to get one myself but the local NAPA says they can't get them yet.

Thanks I will need backups for my plan which is likely not to go as "planned."
I am thinking Costco because of their return policy, which is difficult to beat for the average consumer.

 

Sometimes threads are so long that it's hard to really get a good idea of what's happening unless there's a summary/FAQ type of thing.

The sizing question is still confusing but there are three different sizing metrics - BCI Group Size, DIN, and EN, which may not be exactly identical down to the millimeter but do cross-reference:

https://www.continentalbattery.com/assets/DIN_EN_Chart_2010_BCI.pdf

It seems that BCI Group 47 and DIN H5 L2 both refer to the same size, but not every battery that's group 47 says it's H5 and vice versa, but many do. Another oddity is that H5 also cross references to an unusual BCI group 97R which has a different dimensions in millimeters, so how can this be so?

To add to the mystery, there's L2 and also an LN2. What's the difference? It might be due to Carbon chemistry in the lead, like in an EFB battery, but you can get an AGM that's either L2, or LN2 - does an AGM with LN2 have carbon in the lead?

But for practical purposes the main take away is that if a battery says group 47 (BCI) it will definitely physically fit in a Gen 6 Outback 2020/21 whether or not it has H5, L2, or LN2 (DIN) or 55L2 (EN), and that the best type of battery is AGM, second best is the OEM EFB type, but a regular flooded lead acid is not designed for high charge acceptance, low resistance, high cycle life and the electrical demands of start/stop like in our cars. Since our cars have a charging algorithm presumably optimized for the characteristics of an EFB, even if you have start/stop disabled it's probably not a good idea to use a regular flooded battery in our cars.

Battery manufacturers say that the charging algorithm for EFB and AGM are the same, but battery charger companies say that if you have an EFB battery, use the flooded setting and not the AGM setting. Why there is this disconnect is a mystery, but in-car charging and external charging are different so maybe that's why.

It's also worth noting that the chemistry of AGM batteries are different - for example Enersys/Odyssey uses 99% pure lead, while East Penn/Deka uses Lead-Calcium. Each brand claims superior chemistry.

Another consideration is the cranking amps - the way one battery has more cranking amps than another for the same size of battery is to have more surface area (usually more plates) per cell in a 6-cell 12 volt battery. To get more plates in a battery of the same size, the plates are thinner, but thin plates don't do well for deep cycling - so more cranking amps isn't necessarily better across-the-board. That's why some batteries are called "starter batteries" designed for high cranking amps only, but others, like those used in golf carts, or marine environments are deep cycle. Some batteries claim to balance both needs - both East Penn Intimidator and Enersys Odyssey AGM batteries are like this.