Wednesday 20 July 2011

Really interesting stuff about Battery dimension tolerances..........

This issue came up with a couple of #312 fittings, in relation to the higher power demands of the latest hearing aids and their wire-less functionality. Looks like the aids are pushing the batteries to the limits of their performance. My current fitting regimen which includes offering the Phonak CROS system is susceptible, with batteries typically lasting three days only at a high enough voltage to run the CROS system.
This article/blog was culled from some Audiologists in Tucson, who appear to be running into the same kinds of issues:
An earlier post detailed our efforts to figure out why the newest, coolest hearing aids were turning themselves on and off at an alarming rate, serenading their wearers with a constant reboot song.  We tentatively concluded that there were some batches of batteries that were a bit skimpy.  We also reported that the issue was popping up across the hearing aid industry, which was relating it to introduction of new mercury-free batteries.  At that point, we asked for input from the manufacturers to help us alert and help our patients. We also asked for input from our patients.  All of those inputs to date are summarized below:
1)  Despite repeated requests, the only thing we’ve been able to get from any hearing aid manufacturer is that “the battery issue is being looked at by Switzerland.”  They are not opening their kimonos, so to speak!
2)  Rayovac contacted us immediately and gave us lots of helpful information.  The most important thing we were able to confirm is that even the smaller sized batteries that caused problems for our patients are within ANSI specs.  They don’t seem to work, but they aren’t out of line, which seems to put the ball back in the hearing aid manufacturers’ kimonos. 
3)  Another important thing we found out from Rayovac is that mercury-free may not be the only choice down the road, as we’d reported.  The regulation appears to be state-specific (we’re still a bit unclear on that part) and mercury-free is not required in other countries.  But, it’s probably easier for the battery companies to make batteries that meet the most restrictive regulations, rather than make a bunch of different kinds, so we’re guessing that mercury-free is the way of the future.
4)  None of the size-challenged batteries we measured were Rayovacs, either anodyne-type or mercury-free.  We thought that was a good sign, so we asked the Rayovac guys where to direct our patients to their products.  It turns out that the private label batteries we have in our office are Rayovacs (who knew?) and all the batteries you get at Costco are Rayovacs.  So, there are two reliable places we know of for our patients to purchase batteries till this issue gets cleared up.
5)  We heard quite a bit from patients who read our post.  All were experiencing the boot-up problem recently, all came in and we gave them mercury-free Rayovac batteries to try, none have had any further complaints.  Right now, we’re concluding that the issue in the industry is not specific to mercury-free, but something else having to do with slight variations in size coupled with capacity variations. We can’t measure the latter and all we can say with any assurance is that Rayovac doesn’t seem to be capacity challenged.
Here are some of the comments we received by email from our patients.  We mentioned that our patients are fiesty, but did we mention that they are witty too?
1) ”Thanks for the info, I thought I was hearing angels.”  pt LDLT
2)  The Blame Game.  I read your latest newsletter and blog with great interest….  I appreciate your forthrightness in telling the world that others are having the same problems that I continue to have.    I looked up the specs for 312 batteries.  They’re supposed to be 7.9mm x 3.4 mm and 1.35-1.45 volts.  Publishing industrial specs is by no means limited to hearing aids. …   But any product that falls within these tolerances should work with any other product that is designed to use it.  So the question is really quite straightforward:  Is the (hearing aid) model … designed to accept 312 batteries within industry-standard tolerances for 312 batteries?  Since battery manufacturers and hearing aid makers alike are supposed to adhere to these tolerances, it is impossible that they are not readily available to all industry participants.    The next question, of course, is whether Duracell, Rayovac, Energizer, etc., are routinely marketing 312 batteries that are off spec…. Your efforts with the micrometer and caret scale are a good way to research the situation, assuming you are comparing your measurements to published standards and tolerances. Common sense … suggests that major battery manufacturers with a huge investment in brand quality reputation would do everything in their power to prevent defective units from getting into the marketplace.  The fact that 312 batteries in the past contained mercury is irrelevant. The fact that major, trusted battery manufacturers have distribution through drug stores, supermarkets, discount superstores and the internet is irrelevant.  Nobody told us that when you buy this (manufacturer’s hearing aid) that you must only use old-style mercury batteries or it won’t work right.  Nobody told us that we must buy only unbranded batteries from one specialty outlet in a city hundreds of miles from our home, or it won’t work right. I think you and I must now seriously raise the question;  Has ___ produced a unit that is defectively designed…or have they released into the market a batch of units that were defectively manufactured?  Or both?  I’ll let you and Sharon continue to research it, … but it’s pretty clear to me that ____ has a problem and they are not being as forthright as you.  This leaves you holding the bag.  Your clients, too.”  pt HC
3)  “…I thought it was something in battery.  Only when I got your e-mail did I realize there might be a fit problem which caused intermittent loss of contact … but it doesn’t happen frequently enough to be to be intolerable.”  pt HM
4)  “After replacing the batteries for the third time today, I am electing to deliver these  devices to (go to the) “hospital” …It is difficult to express the frustration these devices have created with me. Though I retain max confidence in you both, you may feel free to tell (the hearing aid manufacturer) that (aside from some semi-whacko girlfriends) these devices are the most expensive “nuisances” with which I have ever been associated. … let (them) know that I am not a very good walking, talking, lip-reading advertisement for their company.”  pt JM
5)  “Holly and Sharon,  I read your news letter twice to make sure not to miss anything.  I didn’t realize hearing aids were so complicated and am happy that you are both so smart to know what to do to take care of the problems.  I hope this doesn’t happen to me.”  pt FR
Wow, what a month!  Hope those manufacturers open their kimonos soon! 
Submitted for your reading pleasure/consternation by your (nerdy but faithful) Tucson Audiologists,
Holly Hosford-Dunn PhD FAAA
Sharon K Hopkins MA FAAA

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