Life time of battery is hard to judge, since most users of the Phonak Select send the device back due to lack of performance - before battery ever runs out.
Don’t know what the right term is for it - some of the more technical folks on the forum might know - but you want the “resting voltage” of the battery, not the voltage just when you’re done charging, which will invariably be a bit higher. And as to something like a li-ion battery being “3.7 volt,” that may well be what the actual voltage of the battery will be, at least on average, when delivering current under some sort of load. You can often find a technical data sheet on the Internet with voltage discharge curves under various loads (and past posts on this forum have given examples for zinc-air and li-ion batteries, showing for example that zinc-air are extremely flat voltage curves over a range of charged states from fully charged to almost discharged. Since battery chemistry within a type, like li-ion, lead acid, etc., can vary a bit, leading to variation in the exact shape of the discharge curve (vs. applied load, too), the best thing is to find some examples for your exact type of battery and the load (or resting state) of the battery. As an example, here’s a series of voltage discharge curves under different loads for the type of Samsung Li-ion battery that is more or less in my EGO string trimmer (for any parallel battery circuit, ~14 of them in series to give the 56 v the device operates under): See the section of the page that has the heading Doing some capacity tests on the Samsung 25R5 (green) Notice with how little discharge the battery voltage drops from 4.2 to ~4v (as soon as you start going above 4 v on charging, it’s supposed to have a big effect of the long-term lifespan of a Li-ion battery-so you have to ask yourself, if that extra 0.2 v to top off the charge is really worth it?!).
1 Like
The Select is designed to last at least 5 years with “normal use”. The answer to how long the battery will last in reality is a boring one: it depends. As has been already brought up in this thread the longevity of Li-Po batteries is affected by numerous factors like operating temperatures, average voltage, number of charge cycles etc. One of the worst things you can expose a Li-Po battery to is heat and a high average voltage, so leaving it connected to the charger for several months in a cupboard with other heat sources is probably close to worst case. Another no-no is to leave it discharged for long periods which can lead to deep-discharge of the battery. There are protection circuits that will shut off the battery when the voltage gets below a certain threshold, but even the protection circuit consumes a tiny bit of current, and the battery will have a certain amount of self-discharge, so after several months the battery may be damaged beyond rescue.
Defining end of life for a battery is also difficult as it depends on your needs as a user. Let’s say that you are a heavy user that use Select for phone calls 5h/day. If we assume a capacity loss of 20% per year, the battery wouldn’t last long enough to handle 5h of use after 3 years if we assume 8h of operating time when new. But for someone only using it a couple of hours at a time for the occasional dinner with friends it might have an acceptable operating time even after 10 years.
The battery in Select can be replaced during repair.
4 Likes
@RogerPM thanks for confirming ability to replace battery 
@jim_lewis don’t you think such measurement is overkill? I mean, going through all that to get several dozen of hours more of potential lifetime, and that’s assuming that you keep it in the perfect environment during whole lifetime (eg it probably won’t matter if you carefully charge it to titer around 50% for half a year if you leave it out for hours on hot sun 
)
By all means, if you have time and energy to spend into such optimisations, go for it. I just think it is not generally feasible, and definitely not worth it for me.
This surprises me. Everyone on this forum who has it is very very satisfied (afair), me included and I never saw someone being disappointed and returning it. (assuming the program was properly done for each person).
If I’m sure about something is how versatile and useful I find this select in. With HAs I’m in the process of thinking it over, for various models, but select was literally love on the first sight, no doubts that I’m buying it and I haven’t changed my mind in several months I’ve owned it. I still haven’t paid it so I can change my mind.
But I guess it depends what’s your quicksin score / needed snr. I guess that for people for who aids are already sufficient, they probably would not see much effect from any mic anyway (discarding the distance, just focusing on hearing people around one table).
For me HAs alone in any noise just don’t cut it. Like relatively quiet radio and switching between two people speaking with a kid running around.
I can, but I also need a ton of effort, lip reading, concentration and whatnot. With select I stay in the loop almost effortlessly (compared to without it) and I can even look around away from the table.
Did you have bad experience then?
1 Like
@hold4triple where did you come up with that? Do you have any data to back up this claim. That has not been the impression I get from reading the forum or from my audi (whom I trust)
1 Like
I’m not sure about your math, Blacky. It’s said if you don’t charge over 80%, you double the lifespan of a Li-ion battery. According to Phonak, the Roger Select lasts up to 8 hours on a full charge. Assume 300 lifetime recharge cycles. That’s 8 x 300, or 2400 total lifetime hours of use with no battery-saving measures. Just not going above 80%, you get an extra 2400 hours of use, not “a few dozen” as you claim.
But the claim for Li-ion batteries is that if you stay within the 30% to 60% charge range or so, that you can quadruple or quintuple battery lifespan. That would be up to an extra 9600 hours of use. If you stay within a 10% charge range, you can supposedly increase total usage hours by almost a factor of 10, roughly an extra 22,000 hours of use, i.e., the device’s battery ~never dies.
For a number of years now, there has been talk of wirelessly recharging devices over-the-air. Apple has supposedly been working on it for the iPhone (I can hardly wait to get exposed to all the in-air electromagnetic radiation from everyone’s OTA chargers!). If that ever comes to pass, you could have a little on-board intelligence and a Li-ion device could manage its charge status the way electric cars do right now to make the most of the lifespan of their super-expensive batteries (~$20K).
And did we talk about price? Roger Select ~ $1,000 U.S. Double the lifespan. Save $1,000. Quintuple the lifespan, save $4,000.
On the effort to save battery life doesn’t prevent you from hapless accidents. Yeah, same philosophy for cars. Always buy a junker, never a BMW or Mercedes because as soon as you hit the road, some idiot is likely to broadside you and total your $60K investment.
I totally agree if time is precious, it’s not worth the effort to maximize one’s Li-ion battery life. But if you have no pressing need for a device (I can hear well enough to get by totally without my HA’s), rather just running up a bill wearing out Li-ion devices, it’s economical to get the maximum lifespan you can out of them that fits with your lifestyle, rather than just throwing away money on devices with planned obsolescence built into the battery. Particularly for poorer countries of the world, it makes sense to optimize battery lifespan. The rest of us can live as if we’re in California (gee, it seems hot and smoky around here - maybe a little more management would have helped?).
Edit_Update: BTW, as an aside to this post, relative to the question “To be or not to be?!,” since I mentioned management relative to CA in passing, the NY Times as an excellent in-depth review on where CA’s development policies and climate change have led it. I have created a Social Topic thread on the article here: NY Times Article of Why California Is Ground-Zero for Climate Change Disasters
1 Like
I’ll see if can get access to the NY Times article later, but a couple of points. It’s not just California that’s having a horrible fire season: Oregon and Washington are also having a bad time. Regarding forest management. It’s the US government who manages US Forests (most of the fires) and they have not been big on funding forest management. I think our fire issues are complex. Better management could help, but climate change is also having a big impact. Following a fire close to me I hadn’t realized how important humidity levels, both of the air and the fuel is to how fire behaves.
1 Like
Off topic…
Here in Texas we try to not burn unless humidity is greater than 40%, temperature below 60 F and wind is below 8 mph.
This is a A&M guideline.
1 Like
@jim_lewis
https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
Check table 2.
Tell me if I got it now correctly.
If I read correctly, when it says dod 100% that means full charge and full discharge. And that gives 600 cycles. Let’s assume 1 full battery gives us 10h of work for simplified calculations.
That means that you’ll get 600 cycles * 10h = 6000 working hours of that battery.
However, dod 10% means you’ll get just 10% of the battery working for you(simplified), so 1h of work, so total 15000h. Also, you should cycle between 90% of battery and 100%. Since cycle is always to the full.
So, table
Dod 10% 1h x15000 = 15000h (full battery when 90%)
Dod 20% 2h x9000 = 18000
Dod 40% 4h x3000 = 12000
Dod 60% 6h x1500 = 9000 (fill bat when reaches 40% left)
Dod 80% 8h x900 = 7200
Dod 100% 10h x600 = 6000 (fill when empty)
So this means that the best would be to fill battery to the full once it shows 80 % left.
If you do it at 40% left you’ll get 1.5 times longer life, or double life if you don’t allow your battery to go below 60%…
But when you fill the battery you should go to the full, this table is only about how low it can get.
Did i understand the numbers correctly now?
I think I’ve inverted something in my mind earlier.
I think the following is the sort of lifetime performance curve I’m thinking of for HA or HA accessory Li-ion batteries. It seems to show that the more charge you take out during one usage cycle (1.0 C vs 0.2 C) the shorter the total number of full-equivalent discharge cycles you get out of the battery (from why-does-the-lithium-battery-capacity-decrease
(bad things happen to Li-ion battery electrodes in the fully charged state or in the completely discharged state so it’s supposedly better to take partial discharges out of somewhere in the middle of the battery charge/discharge voltage curve - which is NOT the graph shown above)
I actually have more experience killing Li-ion batteries than I have so far extending their useful lifetime, e.g. running laptops with removable Li-ion battery in hot device always being charged to 100% while laptop runs on AC power and, also, charging smartphone continually on window sill exposed to direct hot sunlight! 
And whether one uses one’s HA’s or accessories or not, a Li-ion battery is going to age just sitting around, no matter what. At least 1% capacity loss at year even if stored an near-ideal room temperature conditions and ~50% charge. So that alone places an upper-limit on how long might my Quattro’s and ReSound accessories might last on the shelf someday as my backup hearing aids.
Yeah, from this link I’ve linked I’m not sure if they’re saying it’s ‘full cycle equivalent’ or ‘this short cycles’. I think it’s the latter. Because it just seems crazy to get 15000 full cycle equivalent lifetime if you keep your battery between 90% and 100% full 
I do try not to leave it to die, so if I notice at 20% or less, it’ll definitely go into the charger.
But it’s just that numbers are easy to track on phone if you want to be battery-mindful, but for roger select you have just 3 colors or you’d have to time it.
Yes, they’re not cheap devices, but I mean, nothing today is made to last forever anyway 
I somehow take that into the account when I’m buying something in the first place. And ability to change battery for select definitely sounds better than for other mics where I’ve heard official exchange isn’t possible.
Biggest portion of the select price is R&D anyway + profit of your seller, not hardware, so I wouldn’t expect that battery would cost me nowhere near 1000 eur like new device costs.
But, interesting things I’ve learned here, thanks 
1 Like
I personally wouldn’t recommend any Roger Select owner keep the device between 90% and 100% charged. Microsoft provided a good example of why not to do this. They tried to promote Surface devices as the “brains” behind kiosks. The devices were set to run on AC, charging the Li-ion battery to 100% all the time. The devices did not hold up so well. So Microsoft introduced a firmware update intended to be applied to kiosk usage devices. It keeps the device at 50% charged when running on AC and the Li-ion battery lifespan lasts longer. At 100% charged and 4.2 volts applied, you get oxidation of the anode much more rapidly and much more rapid deterioration of the long-term lifespan of the battery. It would probably be far better, if possible, to let a device like Roger Select cycle through some part of its full discharge cycle rather than keeping it close to 100% or letting it discharge fully until the red light comes on.
One difficulty in discussing this topic is there are a number of slightly different Li battery chemistries and it’s never clear exactly what type of battery is in what device or exactly what type of battery a particular performance curve applies to and how much the phenomena observed apply to somewhat different Li battery chemistries. Hopefully, the tremendous push to build electric cars is going to bring new battery chemistries that benefit HA users indirectly so OEM’s like Phonak cannot only recover their development and production costs in an expensive relatively low-market saturation device like Roger Select but also reward the users who choose such a great device with a long, long battery lifespan without having to worry about replacement options.
My simplified “grasp” of this matter is that Lithium ion batteries of assorted chemistries will likely last the longest if kept between 50-80% charge. However, what if the manufacturer has already set it to top out at 80% charge, knowing it will last longer? I think Tesla has a couple of different charge levels–one for day to day to use and one for max range. It’s nice to be able to use the full battery capacity if one needs it, but it does make sense to prolong the life of the battery if it can be made simple.
2 Likes
On the lifespan of Li-ion (and/or Li-polymer batteries) in Phonak Roger Select or any other such HA device, as I’ve previously mentioned, Apple seems to be one of the big companies most on the ball about TLC in charging and advising and caring for their customers to get the maximum usable lifespan out of (expensive!) Apple devices.
I happen to notice in upgrading my wife’s 2015 iPhone 6S to iOS 14.2 that if one goes to Settings, Battery, Battery Health, that down at the bottom of the Battery Health page there is a section and option that you can check on or not entitled “Optimized Battery Charging.” The feature came along with iOS 13 - but I never noticed 'til now in just starting to use an iPhone as an “iPod.”
From the Apple web page on optimized charging, here’s what it says
With iOS 13 and later, Optimized Battery Charging is designed to reduce the wear on your battery and improve its lifespan by reducing the time your iPhone spends fully charged. When the feature is enabled, your iPhone will delay charging past 80% in certain situations. Your iPhone uses on-device machine learning to learn your daily charging routine so that Optimized Battery Charging activates only when your iPhone predicts it will be connected to a charger for an extended period of time. The algorithm aims to ensure that your iPhone is still fully charged when unplugged.
Basically what this means is akin to the following. It only takes a few hours to fully charge your phone (even less if you use more recent USB-C Power Delivery options or similar for wireless charging). But why go to bed, say to sleep 10 hours, have the phone charge fully in 1 or 2 hours, and spend the rest of the night at 100% charge, being depleted slightly as it idles during the night, recharged continually around 100%, wearing out the battery through unnecessary constant mini-charge loops near 100%. Not good for Li-ion/-polymer batteries.
The following How to Geek article goes into detail relative to what’s at stake with charging Li-ion/-polymer batteries: https://www.howtogeek.com/423451/how-ios-13-will-protect-your-iphones-battery-by-charging-to-80/
From the article, here’s how Apple tries to extend your iOS device battery lifespan with Optimized Battery Charging:
In iOS 13, a new charging algorithm will keep your iPhone at 80% when charging overnight. That algorithm will determine when you typically wake up and start the day, and restart the charging sequence to give you a fully charged battery when you wake up.
Maybe someday makers of rechargeable HA devices and accessories will put some of the same smarts into their overnight charging schemes - or even if you want, allow you to set your own upper limit no matter what your schedule, i.e., specify that you just don’t need to charge over 80% - allowing you to go with your particular needs and desires rather than what the OEM figures the average gal/guy wants, no matter what.
I have used roger products for about 5 years, I am on my second table mic (though the first one still works), I have a roger pen and got a roger select 2 years ago.
Don’t do what I did…
My select has been in its cradle attached to my TV and continuously charging since I retired 18 months ago, and today the battery died.
It is like a bereavement.
Does anyone have any idea what kind of battery I need, and where I could get it changed? It is out of warranty.
Thank you!
Shari
Phonak can replace the battery, for a big fee, but-----
If you are only using it for the TV then just get a TV connect, better and cheaper.
Don’t older aids have similar device, under different name, tv link or something like that? 
Leaving a Li-ion battery continuously charging near 100% charge is not good for the long-term lifespan of the Li-ion battery. In the future, it would be better to pick a partial charge range with the average state of charge somewhere around 50%, say 30% to 70%. I’ve made numerous posts on the forum about this (including quite a few earlier in this thread!). It’s often not very practical since owners usually find it easiest just to charge their devices to 100%, use the charge until the battery is very run-down before recharging again and OEM’s love selling you new devices. Some manufacturers like Apple are very conscientious about helping the user get maximum battery lifespan and have excellent battery care advice on their support websites. Hopefully someday even devices like cell phones and hearing aids and their accessories will have the battery management smarts they put into electric vehicles, where a single battery can cost around $20,000. (price coming down and energy density, vehicle range going up - GM just in the news about this). About battery health management in Mac notebooks and earlier in this thread: What is the expected battery lifetime of Phonak Roger Select?
Just to point out, this select didn’t go to 0%, but was always fluctuating around 100% since it never left the cradle.
Best way to prolong lithium battery is charge it b/w 40 to 80 percent . It will double or triple the charge cycles
2 Likes