Primarily for general aviation discussion, but other aviation topics are also welcome.
By flyingdoug
#1890430
rdfb wrote:For example, the "battery low" alert will be accurate (instead of getting 30 seconds warning as you might with rechargeables when the electronics is designed to predict remaining battery life using the alkaline discharge curve), you'll get the advertised battery life, and when any battery runs low the equipment will start to malfunction (requiring a reset).


As I understand it, that's the main reason for avoiding rechargeables - nothing to do with causing damage. With an alkaline (where voltage degrades slowly), the 'low battery' warning will give you plenty time to do something about it. With a rechargeable (voltage drops off a cliff when it runs out), you might not even get a warning before it shuts off. As with most inconveniences in aviation, that's guaranteed to be at the least opportune moment!
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By Rob P
#1890432
flyingdoug wrote:you might not even get a warning before it shuts off.


The low battery warning on the Lightspeeds certainly does work as advertised, though I know not for how long as I have only ever seen it when shutting down. Who looks at their headset box in flight?

Rob P
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By Paul_Sengupta
FLYER Club Member  FLYER Club Member
#1890433
flyingdoug wrote:With a rechargeable (voltage drops off a cliff when it runs out), you might not even get a warning before it shuts off.


Though depending on how it's set, it might be the opposite - you may get the low voltage warning for very many hours before it finally shuts off...indeed, if 1.2V per cell is considered a low voltage for that particular use, it may come on after a very short time and stay like that with no further warning when the batteries are about to give up the ghost.

And regarding Ikea food, the lamb shank in red wine sauce they're doing at the moment looks rather nice - except I don't really like lamb!
By PA28
#1892819
Smartoools Lithium Ion 1.5V rechargeable AA batteries have arrived.
They come ready charged with a USB C charging cable. I measured the voltage of each one. They were between 1.50V and 1.53V which is almost exactly the same as a brand new alkaline AA.
They are supposed to be 1700mAh.
I will let you know how I get on with them A20.
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By Rob P
#1892824
Why 1.5v?

Your standard AA are 1.2v. Does this difference not matter?

Following Paul's advice I sent off for a set of the IKEA 2450mAh, AA rechargeables, alleged to be Eneloops in another wrapper. They seem to put out 1.4v when charged (According to my meter 1.399v). These are not intended for my headset, primarily for my Speedlite, and the trailcam.

Electric stuff always confuses me.

Rob P
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By timjenner
FLYER Club Member  FLYER Club Member
#1892837
PA28 wrote:Smartoools Lithium Ion 1.5V rechargeable AA batteries have arrived.
They come ready charged with a USB C charging cable. I measured the voltage of each one. They were between 1.50V and 1.53V which is almost exactly the same as a brand new alkaline AA.
They are supposed to be 1700mAh.
I will let you know how I get on with them A20.


Be a bit careful with these. Like the concept but have veered away as I'm guessing they are 3.7v lithium cells with an integrated voltage regulator to drop it to 1.5v. One potential problem is it'll maintain 1.5v all the way until it's flat and then stop with no warning. The other potential issue is that the regulator is probably a switch-mode type which can generate high frequency noise which may be audible through the audio panel, headset or radio.

Personally I use low self-discharge ni-mh cells (Eneloop type) in my Bose X. Have many from Lidl and use them in lots of devices, they're in at the moment in both AA and AAA sizes!

Cheers,
Tim
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By VRB_20kt
FLYER Club Member  FLYER Club Member
#1892838
Non-rechargeable AA batteries generally deliver 1.5V whilst NiCd quickly drop to 1.2V for much of their “charged” life. Typically they’re used in fours so instead of getting 6V only 4.8V is available which in some instances is insufficient. Rechargeable technology that delivers 1.5V was available as rechargeable alkaline but hard to find. The relatively new Lithium Ion batteries show promise.
By SteveX
#1892848
Such devastating 1st world problems this one. 4 pages about a headset losing power, and the, oh so awful prospect of a) having to change batteries, b) just accept the increased noise for the remaining flight. Is it really that hard to start the day with fully charged batteries that will always (unless you are flying more than say 4 hours), get you through the day?
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By Rob P
#1892878
@SteveX

Steve. Nice rant but totally missing the point.

The question I asked was in regard to dire warnings within a headset instruction manual on rechargeable batteries 'damaging' headsets.

Writing off a £1,000 headset is 'an awful prospect' and would be heading towards 'devastating' if it had been done from lack of knowledge that could easily be gleaned here.

Thread drift? It just happens.

VRB_20kt wrote:... whilst NiCd quickly drop to 1.2V for much of their “charged” life.

Did you mean NiCd, not NiMh? I am confused enough already.

Rob P
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By VRB_20kt
FLYER Club Member  FLYER Club Member
#1892887
Rob P wrote:Did you mean NiCd, not NiMh?


Both NiCd and NiMH have a nominal cell voltage of 1.2V. The latter have a better energy density and last about 3x longer than the equivalent-sized NiCd.
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By Genghis the Engineer
FLYER Club Member  FLYER Club Member
#1892974
For the record, the pair of freshly charged Kratax batteries I put in my SEHT ANR headset have so far done about 7hrs without any trouble.

Early days of course, but it's a good start.

G
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By PeteSpencer
FLYER Club Member  FLYER Club Member
#1892977
My son bought me shed loads of AA and AAA NiMH rechargeable batteries from Maplins Sale when they closed down.

Trouble is they never seem to be fully charged when I need them so i just shove Duracells in.

If I have a charging blitz, and stick them in the drawer, they're always flat when I need 'em.......................... :roll:
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By Rob P
#1892979
PeteSpencer wrote: they're always flat when I need 'em


That's the USP of Eneloops and their ilk. They are supposed to (and seem to) hold their charge longer when not in use. I have no idea if Paul's IKEA specials perform as well. I will report back if I ever discover.

And reading @Dino 's link, I see NiMh self discharge can be slowed by keeping them refrigerated.

Rob P
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By Paul_Sengupta
FLYER Club Member  FLYER Club Member
#1893004
There are rechargeable NiMHs and rechargeable NiMHs. It's been mentioned on here before. The new generation come as "pre-charged". What this means is that they are the newer generation of low self discharge NiMHs and can be used in clocks, etc, and will last a year or more. The older, standard, ones will self discharge when left in a drawer or in something which takes little current. It's best they are used fresh out of the charger. The "pre-charged" ones you can keep charged ready for use, though after a couple of months I'd probably give them a quick top up before using them if I wanted to get the maximum life out of them.
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