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Recharging strategy

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Edited

This site provides more information than you ever wanted to know about batteries.

BU-808: How to Prolong Lithium-based Batteries2

BU meta description needed...

tl;dr: “Similar to a mechanical device that wears out faster with heavy use, the depth of discharge (DoD) determines the cycle count of the battery. The smaller the discharge (low DoD), the longer the battery will last. If at all possible, avoid full discharges and charge the battery more often between uses. Partial discharge on Li-ion is fine. There is no memory and the battery does not need periodic full discharge cycles to prolong life.”

Deeper discharges put more stress on a lithium battery. You want less discharge per charge cycle rather than more, you want you charge more often rather than less. Waiting two days is unnecessary and counterproductive.

Edited

In reply to @jeffpa

On the Ford EV forum the is an engineer at SWRI who tests batteries for a living. The advice he offers from his extensive testing experience agrees with what I’ve read. I’ve also read peer-reviewed scientific papers that say the same. You’ve never mentioned the expansion and contraction of a cell lattice as the battery is charged and discharged and that’s a factor in lifespan and related to depth of discharge.

Sorry for the length of the following but note there are references to published papers.

Copilot:
Yes, chemical reactions in lithium-ion batteries can vary significantly at different states of charge (SoC) A. At very high and low SoCs, certain reactions can occur that are less likely at around 50% SoC B. For example:

  • High SoC (near full charge): At high states of charge, lithium plating can occur, where lithium metal deposits on the anode, potentially leading to safety risks and reduced battery life B.
  • Low SoC (near full discharge): At low states of charge, the anode material (often graphite) can become fully lithiated, leading to structural changes and potential degradation B.

These reactions are influenced by factors like temperature, current, and voltage B. Maintaining a moderate SoC (around 20-80%) is generally recommended to optimize battery life and performance.

Let’s just agree to disagree and leave it at that.

I have been wearing aids for 20 years and rechargeable aids for over 5 years. I charge my aids nightly. My devices like tablets, and phone i charge as needed.

In reply to @jeffpa

I’m not sure if this thread is intended to be for phonak only, but I have oticon moores, and my audi can replace the batteries in her office in 10 min. She told me that if the battery starts not lasting as long as it did she has the authority to change them under warranty. Once the warranty is up she will do it for a fee (I think she said something like ~$60 CAD per aid? but I might be wrong.) I don’t have any specific statement to this effect, only her word. But unfortunately the latest Oticons - the Intent have gone back to a battery that can not be replaced in the audis office. However I am told that it is still covered by warranty - although it has to be sent back.

In reply to @wilfried

the only problem with blanket statements, is they dont cover the myriad of variances involved. Charge rate, discharge rates just for starters, BMS specs, number of cells, matching of cells, etc

Much of what you folks quote is based upon hiC discharge and charge rates

I’ll leave it at that

In reply to @jeffpa

I’m not sure if all Li-ion batteries have the safety feature but more sophisticated ones have a chip and a monitoring system to tell when they’re completely drained and dangerously depleted. Then they use a small reserve of power to fry their charging circuit so they can’t be recharged because a dangerously depleted Li-ion battery is much more of a safety hazard if you try to recharge it.

My Sony camcorder batteries must have such circuits as they slowly deplete themselves whereas my Nikon DSLR batteries are much more stable to just sitting around.

I don’t know/remember all that much about batteries but it’s too bad one can’t have Li-ion batteries that you can just leave sitting and come back a year later and still find ~the same SOC. My rechargeable ReSound Quattros (my current backup ) and their charging case need to be charged up at least every few months to avoid having their batteries depleted. Kinda tedious…

That’s a BMS I mentioned earlier.

Manages charge discharge and cell balance.

A good BMS will not drain a battery.

I’ve had lithiums I’ve stored fully charged and months later remained at full charge.

You shouldn’t do that, but a well designed system will not drain.

@jeffpa said:

A good BMS will not drain a battery

So there is room for improvement in Phonak Roger microphones, because at least my Roger Select as well as Roger On V1 (non-IN model) can be partially discharged after a few weeks. Anyone have similar experiences?

I took a not=working Widex Com-dex hearing accessory apart.
The lithium battery had leaked so I pulled the battery apart and inside I found a couple of tiny silicon integrated circuit (chips).
When I looked up the markings on the chips, I found that they were designed for lithium battery management systems (BMS).
So I suspect that Widex hearing aids have rechargeable batteries where the BMS is an integral part of the batteries.
It’s likely that other manufacturers use rechargeable batteries where the BMS is inside the battery package.

In reply to @flashb1024

Something I’ve kinda kept quiet on, but you realize anyone employed in the field, is telling you a company approved statement (so to speak), and it may not be to your best interest but rather the companys

Just something to consider :slight_smile:

I’m no longer bound by my NDA so I can say whatever, as long as not exposing intellectual property :slight_smile:

In reply to @1Bluejay

@1Bluejay said:

WHOA! She’s a keeper! I wish my audi had the same skill with my Phonak Lumity Life rechargeables. I always thought it was some kind of rocket science.

The Oticon OPN S/More/Real all featured replaceable batteries, but the new Intent do not.
Phonak rechargeables are all hard wired, and cannot be replaced by the dealer.
So, now we’re back to square one.

@flashb1024 said:

Phonak rechargeables are all hard wired, and cannot be replaced by the dealer.
So, now we’re back to square one.

AUGH!!! And this makes sense? I just got my 312-battery Phonak Lumity Lifes back from Phonak repair … after EIGHT (count them out sloooowly now) WEEKS! My audi was outraged, shared that with her Phonak rep who was similarly nonplussed as to HOW these simple, battery aids could take so long in the shop.

I thought I could hang up my troubles with hearing aids after “mothballing” my rechargeables when I bought the 312s. Ironically, my TWO pairs of rechargeable aids had been sent in way last winter for the official battery swap at Phonak. They came back somehow mis-programmed, and that was a 6-mo saga for me and my audi to lump through.

The trend I’m seeing in living color is that Phonak (and perhaps other makers) are perhaps unintentionally making things more challenging for us with aids that can only be adjusted, set, sent in for repair and then re-tweaked by a middleman - unless you’re a DIYer.

It’s the same with the Roger mics. Not every user has the knowledge to add/remove licenses, so when that was done for my Rogers, the Phonak rep was at my audi’s to do that. Needless complexity.

Even so, it’s SO GREAT to have my beautiful Precious Pink 312’s back home again. :grinning:

In reply to @flashb1024

Your are not correct that the chargers are dealing with it perfectly. For example, iOS has a specific feature that charges your battery to 80% and then only charges it to 100% when you need it (based on behaviour). No hearing aid charger does this so it implies that there is latitude to improve battery life by mimicking it. Additionally, there is no question that if you manage your battery charge to between 40% and 80% and don’t run it right down or up to 100% frequently then it will improve battery life - that is true of any lithium battery.

In summary, you can improve your battery life by human intervention. Whether it’s worth the effort or not is an individual choice. Personally I turn off my hearing aids at night before putting them in the dryer. I then recharge them in the morning when I’m getting ready.

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