My Scheme for Doubling the Lifespan of ReSound Quattro Li-ion Batteries

My scheme is pretty basic and simple. Don’t charge either the Quattro Storage Case/Charger Li-ion battery or the Quattro’s themselves above ~80% charge.

According to the Android battery monitoring app AccuBattery, if you don’t charge a Li-ion battery above 80%, you double the lifespan of your Li-ion battery. Certain laptop manufacturers such as Lenovo and HP recognize this by, at least on certain laptops, allowing you to set a charging limit when plugged into AC, say, of 80% charged. And Microsoft did the same recently for its Surface devices intended to be used as kiosk devices plugged in all the time by providing a UEFI firmware update allowing one to limit the charging of the built-in Li-ion devices on these expensive premium devices to 50% to help preserve battery lifespan. (even though they’re running on AC, they’re drawing their current through the battery and the AC is just constantly recharging the battery).

So how practical is only charging the Quattro charger and the Quattro HA’s to at most, only 80% (the case has gross % charge LED light display for both the charger battery itself and the HA’s). Don’t know how linear % charge really is in terms of daily battery use but if 100% charge for the Quattro’s is 30 hours, 80% charge should be ~24 hours of battery, more than enough to get through a 16-hour waking day. If the Quattro charger case fully charged provides 3 full charges, 80% charged it should provide ~2.4 full charges to my Quattro HA’s.

So if ReSound expects with full normal charging the HA’s should last at least 3 years (since that’s the typical warranty time), I hope to make my rechargeable Quattro’s last at least 6 years (doubling the expected battery life by not charging above 80%).

Since the new Phonak Marvel premium product only offers at most (with no streaming) a 24-hour battery life, for the sake of experimenting I am simply reducing my Quattro’s to the performance level of a Phonak Marvel. And if all works out as planned, I might be saving a bunch of money along the way until the next big thing in HA’s comes along. What do they say? Idleness is the Devil’s plaything?!

What is missing from my scheme is some metric provided by ReSound to evaluate the current mWh capacity of the batteries involved. For example, my Nikon DLSR in the settings has Battery Info and the camera will display a report from the battery chip as to where the battery stands in its lifespan. Running at an Admin Command Prompt in Windows 10 the command “powercfg /batteryreport” (without the quote) will give you an HTML file on your battery characteristics for your battery-powered device including original stated battery capacity, current battery capacity, and equivalent number of full charge cycles your device has been through, which might help you figure out how much battery lifespan your device has left. I seem to remember that somewhere in iPhone settings on my wife’s iPhone she can get a report in iOS on battery lifespan remaining, too. Both Apple and Microsoft these days say that if you treat your device right, even if you charge it fully, you should be able to go through about 1200 complete charge cycles and have 80% capacity still left (at which point they hope you buy a new device!). So if ReSound did things right, they should also offer a way through the phone app to get a metric on remaining charger and HA battery lifespan.

At any rate, it’s going to take years to see how this scheme works and if it’s too onerous to just charge stuff to ~80% capacity, I may just give up along the way. But I like trying to cheat the battery life tax collector!

BTW, how do you keep track of this. “Alexa, set a 1-hour Quattro charging time.” When the hour is up, Alexa will keep yammering “Your Quattro charging timer is done” until you recognize the timer has expired and tell her “Alexa, cancel.” (Alexa is Amazon’s AI assistant living on Amazon Echo speaker devices and allowing you to have multiple named timers running simultaneously that will also show up in the Alexa app on your mobile device or your PC using the web browser version of Alexa). Alexa is great, also, for cooking timers.

How about a simpler approach? Phonak and Signia will let you send your hearing aids back just shy of 3 years and replace the batteries under warranty. I’m guessing Resound might too.

That’s what Dr. Cliff advised, too, in the comments section for his online YouTube review of the Quattro when I asked him if I knew anything about battery lifespan. My audiologist, when I asked her if the batteries were replaceable, etc., did not mention doing so under warranty except if they died under warranty, and otherwise told me that she thought I’d probably be charged the standard refurbishment fee of $279 per ear, I think she said. I’ll have to ask her to follow-up on that. And when I asked a TruHearing rep about battery replacement, he told me that the expected lifetime of the HA’s was 3 years and after the warranty was up, it would be time to buy new HA’s! (Ha!).

One thing you can’t escape is that even if you don’t use them, Li-ion batteries still age. They age faster the higher the temperature and the higher the percent charge you keep them at. My Surface Pro 2 is 5 years old. It’s only been through 260 charge cycles (I only really use it when I travel) and normally kept between 35% and 65% charge. I try to keep it below 80 deg F in storage at 40% to 50% charge. In 5 years, it’s lost 5% to 6% of its battery capacity. At $1400 a pop with its accessories, I don’t feel like just using it up and throwing it away. I use my laptop at home with the Li-ion battery removed, stored in a loosely wrapped plastic bag in a frig door compartment at 50% charge at ~45 deg F and run the laptop on an uninterruptible power supply (UPS, lead-acid battery backup), which your Li-ion battery effectively provides, too, but with the UPS, I can keep a couple of devices on, including my 27-inch monitor if power goes out.

The other goal in all this is to live frugally. More consumption, more energy to produce replacements, more CO2 in the air. So until the planet is running on more renewable energy, running through stuff, more consumption, just leads to faster global warming. One can say, to heck with that, nobody’s doing nothing, why should I shortchange myself when nobody else is… We only consume 1/2 the energy of “energy-conscious” neighbors, according to our utility statistics, and 1/3 the energy of people who are average users and not particularly energy conscious, e.g. cooling house to 70 deg F when it’s 105 deg F out . So making devices last longer is just part of my wife’s and my goal to conserve-and help save the planet a very teeny bit. And since our gas furnace/AC condenser units and outside AC compressor would cost at least $20,000 in toto to replace, we are selfishly trying, also, to economize on AC/heating unit replacement costs as well as feel better about not contributing so much to global warming.


One thing you’re assuming is that the mfg didn’t factor in the 20% buffer that you’re planning to factor in, while they might have already factored this in themselves… In which case your effort would be moot.

I can see how with computer and cell phone companies, they want to maximize the usage time because the possibility of running out of battery juice in a day is real. So they wouldn’t want to play the buffer game. But if the Quattro can give 30 hours of charge which is almost 2 full day of use, and there’s a very high probability of people charging every night, then they really don’t need to charge up to 100% and might have opted to limit their charge to 80% of the real capacity already, even if they show you that the real 80% is being displayed as 100% for you to see.

I’ve heard that electric car makers already buffer their charging to prolong battery longevity because they need to provide a much longer warranty on their battery than the computer and cell phone industry does.

You make good points.

Even if the manufacturer limited the charging capacity to 80% having some sort of indicator that told you how you’re doing on projected battery lifespan would be nice. If nothing else, it would give you an indication of how fast a battery was heading south. Otherwise, I guess you can guesstimate by how many hours you can go on a charge as time goes by - not as nice as if the phone app just gave you some info, like I think my wife’s iPhone does (she and the iPhone are in Hong Kong right now so it’s kinda hard to check - I’m at home with the cat! She’s visiting her 97-year old father.)

I guess the Quattro battery terminals are inaccessible as it’s probably inductively charged but otherwise by reading the voltage across the battery terminals when “fully” charged, one might determine if a battery was charged to some limit less than 100%. According to AccuBattery, it’s even better to charge to a lesser percent charge. The app claims from Li-ion battery research that if you only charge to 60%, you can extend the lifespan of a Li-ion battery by a factor of 5. So if ReSound has already set a charging limit to 80% of full charge and you get 30 hours of battery life, if I charge to 0.8 of 80% or 64% of full charge, I will be extending the life of my Quattro’s even more while still getting 24 hours of battery life. So it’s just a game for me to see how long, if I follow my scheme, the dang things actually last.

I’ve heard that NASA has extracted up to 10,000 cycles out of Li-ion batteries by incrementally charging and also with help from the very cold environment of space, where you actually have to heat the batteries to avoid freezing (batteries on space vehicles are the ultimate form of the “irreplaceable” battery so NASA wants to max out lifespan).

I’ve heard the same about electric car charging, too, and it’s too bad that computer and cell phone companies don’t let consumer implement such strategies. Especially with wireless charging coming along where you might have a charging pad or charging stand that you just rest your phone on when you’re not using it, no wires to plug in or unplug, it shouldn’t be hard to incrementally charge your phone throughout the day at work or home. I think I read that American telco’s were backing a different charging standard than the Qi charging standard and that’s why there hasn’t been one standard up 'til now that would allow charging pads a whole bunch of different places so it would be easier to incrementally charge your device on the go, too, with no electrical outlets for a curious kid to zap himself/herself with by fooling around. Maybe now that Apple is offering wireless charging by the Qi standard that will carry the day and the other standard will be history, if it isn’t already.

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I’m definitely inconsistent in my attempts to live frugally. We do a pretty good job at reducing electricity usage by going to what some would consider extreme measures to save on heating and cooling. But I haven’t been willing to do much to work on battery life. I could retab my zinc air batteries every night, but the gains seem pretty minimal. Heck, I could just do without hearing aids and my life wouldn’t be terribly impacted. I guess it’s all a balance and best if one’s efforts to save energy/money can be seen as a game rather than a burden.


I agree. Maybe energy savings could be like carbon credits. If you save a lot in one area, maybe one shouldn’t worry too much about a little indulgence elsewhere.

One thing I look out for a bit is that plugged in power adapters/chargers with transformers consume a small amount of energy even when not being used. So I try to unplug or have them on a surge protector or power strip that I turn off when not in use.

I’m a big fan of ambient AI and home automation. But most of the ambient AI speaker devices scattered around our house and the IoT devices with Wi-Fi in thermostats, video doorbell, light switches, etc., are consuming electricity 24x7. Maybe we can forgive ourselves that as we’re still 1/3 the average power use in our neighborhood. But having stuff that could go into really deep sleep when not being used would help save every little bit of unnecessary CO2.

I read somewhere that it would only take the amount of solar energy falling on a country the size of Spain to power all the world’s current energy needs. Hope the tech and economic and social/cultural stars all align to help us grab all the solar power we need and store it when the sun don’t shine (hydrogen!).

I just got the Quattro rechargeable. I had and have misgivings for the exact reasons listed. I like having backup hearing aids. I still have my 2007 Phonaks and my 2014 Oticons. I have used them zero since getting newer aids.

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Being a newbie to HA’s I wonder how many audiologists have a “loaner” in case one of your HA’s breaks under warranty but you have to send it away for evaluation and either warranty repair or replacement. Since my Quattro’s will be my first HA’s, I don’t have any old HA’s myself to use as backups. Just for the fun of it, I’m going to try to make my Quattro’s last as long as possible - someone else somewhere else in the forum said that with care, one ought to be able to make a set of HA’s last at least 6 to 8 years and advised not to be driven by marketing pressure to renew unless something truly better comes along. There is the concern that you can’t store a rechargeable HA for years as a backup device but my experience with storing my Nikon Li-ion camera batteries and preserving their excellent status belies that worry: GN Hearing introduces ReSound LiNX Quattro

Some people get 6-8 years, but I’m guessing 3-5 is more typical. At least 2 different schools of thought: 1) Buy top of the line and keep it “forever.” 2) Buy less expensive ones (Costco, perhaps?) and replace more often. The second aid in the number 2 approach will likely give you a better aid than with the first approach. (And there’s approach #3 ala PVC: Buy used and get a new aid every year or two. Certainly the most economical and keeps pretty current tech.)

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Thanks for the tips! Tip #3 sounds like a good source for backup HA’s if I get so used to my HA’s that I don’t want to go without some if either of my new ones have to go back to the factory for evaluation, service, or replacement and my audiologist doesn’t do loaners.

Aiding my controlled, incremental charging scheme to get the most out of my expensive Quattro Li-ion batteries is the fact that when the HA’s are in their charging case charging, the ReSound Smart 3D app on my phone can be used via BT to read the charging state of each HA separately in 20% increments. This is handy because the charging case itself only indicates the % charge of the least charged HA of the two and also 10 seconds after inserting the HA’s to be charged, the LED indicator on the charger times out and one has to remove the HA’s from the charger case then to access the charging state of their batteries via the case LED display, whereas the Smart 3D phone app allows continuous monitoring of the charging state of each battery separately.

I’ve discovered a few funky things about charging my rechargeable ReSound LiNX Quattro 9 61’s that anyone else with the HA’s might find useful to know or might find behaves differently and want to contrast their experience.

First of all, the behavior of the bank of 5 charging LED’s for the HA itself, represented in the Smart 3D app and on the front of the charger case for charging the HA’s. Discharging the number of lit green circles seems to represent the state of charge you’d expect. 5 circles lit, fully charged. 2 circles of 5 lit, 40% charged, etc. But in charging ReSound seems to have switched the logic. You start out at 2 of 5 circles lit, you charge to just over 3 LED circles lit and the 4th has just started to flash. So you think, OK, based on the way things went down during discharge, you’ve charged to just over 3 circles lit (>60% lit) and you’re working on the 4th charge state (80%) being reached (it’s flashing) but you’re not there yet, because otherwise it would be solidly lit. (This is following charging of each HA in the Smart 3D app). But what happens at this state when you remove the HA’s from the charger and look in the app, you see, according to my interpretation of how the app display % charge when not charging, that you’ve actually charged the HA’s to >80% charge. Apparently, going up in charge, an LED up the charging scale starts flashing ONLY WHEN YOU’VE PAST THAT DEGREE OF CHARGING. I’d rather have a particular LED in the hierarchy only light and stay solidly lit when you’ve passed that level of charge and have the next level light start flashing to indicate that you’re just beginning to work on that level.

The other funky thing is the bank of three LED’s displaying the state of the charging case Li-ion battery that serves as a power pack to charge the rechargeable HA’s. I got the charger case from the audi on Wednesday, 10/24/18, fully charged. The charger case supposedly holds 3 complete charges for both HA’s. Since Wed. at 30 hours of use per full charge, I estimate I have done the equivalent of fully charge my HA’s 1.5x to 2x, yet the LED’s on the charger case still show all 3 LED’s fully lit when I insert or remove the HA’s Theoretically, at least one of the 3 LED’s should have gone out by now as I should have used at least one full charge from the case (I haven’t charged anything on AC yet myself).

So I’m a sample of one. If you just charge your HA’s every night, maybe none of this makes any difference because you’ll charge both your charger case and the HA’s fully but if you need a quick charge and want to know where you’ve actually charged to as the HA’s are being recharged in their case, knowing about the funky behavior that I describe about the 5 HA LED charge indicators might make a difference. Also, if you’re counting on the 3 charger case LED’s to accurately reflect the charger state of charge when used as a power pack, you might go out the door with the charger case with 3 circles lit thinking it’s full of reserve charging capacity when it’s not if you haven’t fully charged both HA’s and the charger case overnight.

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Ok, now read this and relate it to your experience in charging and displayed charge level. :crazy_face: :joy:

Battery University is a techno-weenie geek fun house!

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Oops! MY BAD! I am an RYFM type, Big Time. The LED indicators for the HA’s do not indicate a level beyond which you are past. The LED indicators indicate a RANGE. So even if all 5 HA LED charge indicators are lit, that only means your HA’s are somewhere in the range of 80% to 100% charged, NOT 100% CHARGED.

So charging past 3 fully lit LED charge indicators with the 4th flashing, then having four HA charge indicators fully lit when I’m done, according to the declared ReSound behavior, means that I’ve achieved a charging level of 60% to 80% charged, which is exactly what I expected. And starting to charge from 2 of 5 LED’s lit doesn’t mean that I started above 40% charge. It means my HA’s were somewhere in the 20% to 40% charge state. So that’s good to know if you go out the door thinking your HA’s have >40% charge (2 of 5 LED’s lit) but they actually are just above 20% lit (and one green light means 0 to 20% charge!).

From the Quattro 9 61 manual:

Also, here’s the Quattro 9 61 chart for the charger case itself. The LED light indicates a RANGE, not a charging level past - but I still think that I’ve used more than 1 of the charges in the case and only 2 of the 3 LED’s on the case should now be lit after 5 days of HA use and charging only from the case.


Yes, I’ve followed Battery University for years and that’s in good part where I’ve derived my Li-ion battery use and storage “protocols” from. Apple also has good advice on the expected lifetime and device storage for their Li-ion battery-powered devices. And I’ve skimmed through various research papers on Li-ion batteries (the Android app AccuBattery is based on one particular research paper).

The catch with all this stuff is, how current is the knowledge expressed in any article, website, and what the heck type of battery exactly is in my particular device. Some of the advice on the Battery University site seems kinda old and I think they do claim in general that the general chemistry/behavior is the same across all Li-ion powered devices whether it’s truly Li-ion slush or Li-ion polymer, etc.

The advance in Li-ion battery chemistry that I’d most like to hear is that it’s now safe to charge below 55 deg F. The Quattro’s claim from the manual is: " If the hearing aid temperature is below 0 °C (32 °F), it will not charge immediately. Charging must take place between 0 °C (32 °F) and 40 °C (104 °F) ."

I’d like to know how “safe” the high and low temperatures of the charging/operating range are or what kind of price you really pay on the lifespan of your device for operating at the stated extremes. Unfortunately, HA manufacturers seem to follow the KISS principle to the extreme, perhaps both not to reveal potential weakness of their devices relative to their competitors and not to confound old folks who don’t like new complexity injected into life.

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BTW, Tim, if one just skips most of the article and goes straight to the Summary and Guidelines at the end, there is some simple, straightforward advice on dealing with Li-ion batteries in easy-to-understand language. I recommend reading that part and skipping the rest!

Ok, sorry, but I’m going to have to ask you to turn in your geek card.

Summaries are never enough for me, I want the down and dirty complete intimate details.