EFB batteries

[slomobile]

I recently learned Enhanced Flooded Batteries are a thing.
https://www.continentalbattery.com/blog ... o-use-them

Wondering if the resident expert has any thoughts.
Are they worth having in anything we use? Chairs, vans, ?

It sounds like they are flooded batteries which you cant add any water to. Plates separated by sweatshirt material.

Are any of the batteries we already use EFB but we didn't know?
Do they have a different charging profile?

[Burgerman]

ERROR 405 NOT ALLOWED.

Flooded batteries is another term used for wet or liquid acid batteries. If the electrolyte is soaked into something as in a glass fibre fabric or mat we call that AGM. If its soaked into something else then no idea what you would call that. If the electrolyte is thickened up by adding a silica gel, we call them gel batteries. If the electrolyte is there art all, and its still using lead then they all pretty much work the same way. These are methods used to make them safe for transport as they immobilise the electrolyte.
Then they figured out you can seal these batteries and add a 1 or 2 psi pressure reliaf valve. And s even safer for things like motorsport or wheelchairs etc.
That works as long as they are charged at a carefully controlled voltage just before the point where gassing starts to be an issue once charged. Up to that point they dont gas much and are capable of recombining this oxygen/hydrogen back to water at very low rates. Typically 14.1 gel, 14.6 AGM. And at below 1A or less once charged 100%. Then they are called recombinant.

When these are sealed, they are also called SLA batteries. If they are starter batteries they are called SLI for starting lights and ignition. Not built for deep cycle use normally...

So they will be some combination of the above. Theres lots. Some use silicone, some use carbon fibre plate reinforcenment, some add zinc, platinum, tin, nickel etc. Some use gel and AGM since you need something as a seperator and that works with liquid or gelled electrolyte. Much of this stuff is added to the descriptions, names etc for marketing the latest new "type" of battery. They are normally just the same old variation of lead acid though.

But your link isnt working so who knows! So when you hear terms like SLI or deep cycle, SLA, or sealed, or recombinant, gel, AGM, and whatnott then you know what it means.

[Burgerman]

https://www.varta-automotive.com/en-gb/ ... -do-i-need

EFB just seems to refer to old style flooded wet cells. With some chemical or something to help ("enhance") them perform better when cycled. But its not sounding very promising.

Varta for e.g recommend swapping for a normal sealed AGM type, for better performance. like odyssey for e.g. Its because the cheap wet acid battery manufacturers are struggling to sell wet batteries on modern vehicles that intermittently stop/start engines every time you stop and only charge them when the car is on overun so as to "save" the planet... Likely more marketing benefit than reality.

Do you have any battery specs?

[slomobile]

Apparently modern Toyotas have 2 selectable charge profiles now. The default is EFB/AGM and the other (selectable by diagnostic tool) is "Standard" which I assume means regular flooded. Lots of EFB batteries are being included in new stop/start vehicles according to unreliable internet rumor.
The Continental link works for me, but here is the text of the article copied.

February 4, 2025
What Are EFB Batteries? (And When to Use Them)
Conventional flood lead-acid batteries (FLA) have been the standard in the automotive industry for years. They remain a convenient and affordable choice to start the car and power most standard electronics on board.

But most of today’s cars are far from standard. According to Stryten Energy, the number of electrical devices in modern vehicles has increased 500% in the past 20 years. Car manufacturers are amping up the electronics, including everything from heated seats and onboard entertainment systems to start-stop technology and parking assist.

More power needs may need a more powerful battery. Enter the enhanced flooded battery or EFB.

What Is an EFB Battery?
As the name implies, an EFB is an enhanced version of the conventional FLA.

In both conventional FLA batteries and EFBs, a liquid sulfuric acid electrolyte creates electricity when it comes into contact with the lead plates. Although it’s still a wet cell battery, EFB is sealed and uses a polyfleece material to line the lead plates inside the battery. This offers additional protection for the lead plates and a more consistent energy flow than traditional batteries.

EFBs also have carbon additives in the lead plates and a specially designed grid structure that transfers electrons more effectively. All these features make EFBs durable and reliable.

Best Uses for EFBs
When compared to conventional FLA batteries, EFBs perform better for high-demand applications where frequent stop-start cycles, deeper discharges and rapid recharging are needed.

Stop-start systems. One of the primary uses of EFBs is in the increasingly popular start-stop systems found in newer vehicles. The start-stop technology automatically shuts down and restarts the engine to reduce the amount of time the car sits idling. A conventional FLA would wear out quickly if required to constantly restart the engine, especially in high-traffic areas, where idling is the norm. EFBs are designed to handle these stop-start cycles without compromising battery life.

Regenerative braking. Many electric and hybrid vehicles take advantage of regenerative braking to convert the energy usually lost during braking into electricity. The electricity is fed back into the battery. EFBs are built to handle the quick charge and discharge cycles brought on by regenerative braking.

Warmer climates. The typical FLA lasts about 58 months in northern climates, but as you head south, where temperatures are hotter year-round, that number drops to as low as 41 months. EFB batteries have a higher heat tolerance, making them longer lasting than FLAs; they even tolerate high temps better than AGMs.

FLA vs. EFB
FLA EFB
Sealed No Yes
Lifespan 3-5 years Up to 6 years
Cycle Life 250-500 cycles 500-1000 cycles
Duty Cycle 50% DOD 60% DOD
Best for Traditional engine starts, basic accessory loads Small- to mid-range systems with stop-start technology, hybrid systems


EFB vs. AGM
EFBs were designed as a middle ground between standard batteries (which cannot handle the energy demand many modern vehicles have) and absorbed glass mat (AGM) batteries, which are powerful but can be expensive.

Compared to AGMs, EFBs have a lower cost upfront and a longer cycle life. EFBs also outperform AGMs in temperature tests, making them ideally suited for warmer climates. On the other hand, AGMs offer more electrical energy and can recharge up to five times faster.



EFB vs. AGM
EFB AGM
Sealed Yes Yes
Lifespan Up to 6 years 5-8 years
Cycle Life 500-1000 cycles 400-600 cycles
Duty Cycle 60% DOD 80% DOD
Best for Small- to mid-range systems with stop-start technology, hybrid systems High-powered vehicles like electric cars and trucks


When to Choose an EFB
First, look at the type of battery factory-installed in your vehicle. Many cars still come with a conventional FLA battery, but manufacturer-installed AGMs and EFBs are becoming more common.

An EFB may be a suitable upgrade for a standard FLA. However, swapping out EFB or AGM batteries for a conventional FLA is not advisable. Before replacing your battery:

Consult your owner’s manual and a battery specialist.
Consider your vehicle’s electric demand. If you have a start-stop system or other advanced electronics, an EFB may be better suited to your needs.
Check size, capacity and CCA. The size and terminal configuration should match your original battery. The capacity and cold cranking amps (CCA) should match or exceed the original battery.
The Future of EFB
EFB adoption is steadily growing in the United States, but the batteries have been used widely in Europe since 2008. Today, about half of European cars come standard with EFB batteries, but EFB is set to overtake AGM (which held market share previously) in the near future.

As U.S. manufacturers continue to integrate more technology into vehicles that make them safer and more comfortable, the more energy they will need. Over the next five years, the stop-start battery market, which includes EFBs, is expected to see a growth rate of about 19%.

Clearly, EFBs are more than a passing fab. They are carving a significant niche in the automotive industry and beyond. The emergence of EFBs represents a move towards smarter, more resilient automotive solutions and a reliable and efficient future for drivers.

[slomobile]

Here is a group 24 EFB deep cycle example
https://www.interstatebatteries.com/pro ... uctline=rv
24M-EFB BATTERY
$209.95srp (usd)
Group Size 24M
590 Cold Cranking Amps (CCA)
Group Size 24M
700 Cranking Amps
140 Reserve Capacity (RC)@25 Amps
77 Amp Hours (AH)@20 Hr
2 Year Warranty

[Burgerman]

So 590 Cold Cranking Amps (CCA)
Is very average for a grp 24, and it doesent say what the deep cycle specs are.

If its 450 cycles to 80% DoD or better, then its probably OK as a powerchair as long as you dont care that its a wet battery. Which shouldnt be used in a chair really. Less safe.

An odyssey AGM for e.g such as the smaller GRP34 68Ah battery has 400 to 500 cycles at 80% discharge, as well as about half the impedance (so lower peukert) as well as higher CCA too. And its a sealed, AGM safer technology. That low impedance means it will likely give about the same range as the bigger EFB batt in your link at high discharge rates even though its smaller and lighter.

So you get what you pay for. A worse battery but cheaper.

The thing with batts is that its a balance of 3 things. In any given volume you can only fit so much!

So theres IMPEDANCE (closely related to peukert so lower is much better and it allows more currebt with less voltage drop off)
Then theres Ah CAPACITY. The amount you can get out over a 20 hour long discharge.
And then theres CYCLE LIFE.

With an expensive optimised battery theres a limit. Make any of these 3 things better and one of the other 2 or both of them must get worse.

So for e.g lower impedance because stronger acid electrolyte means that it deteriorates when deep cycled faster.
More thinner plates means greater cranking amps, and lower impedance too. As above. But now you cant get as much Ah as many thin plates have less internal volume to paste active material. So these degrade faster (warping, shedding etc) when deep cycled too.
So thicker stronger plates that have high internal lead past volumes have greater deep cycle resistance, and weaker acid does the same. But now its higher impedance... So less capacity at high loads like the 2 or higher hourly discharge rate we need.

So theres no way to win. a century of optimisation has it all as good as it gets.
Its quite easy to make a WORSE battery though and save some cash. And that can be worse in all 3 ways! Less Ah, higher impedance, low cycle life. By using bad construction and build quality less pure base materials, etc.

Like most of the cheaper chinese made recycled less pure cheaply made lead batteries.