Running a cordless phone on alkalines instead of NiMH?

magellan

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I had a question for the battery experts here.

I recently replaced all the AAA and AA batteries in all the remotes and other devices around the house with NiMH rechargeable cells. I did this after an alkaleak almost ruined an expensive remote, probably the fifth or sixth time I've seen one leak in the past 5 years. So I got sick of the alkaleaks and replaced all of them. Now I have about 75 of these alkalines, most of which are at 70 to 100% of capacity that I don't know what to do with.

We have an older Panasonic cordless phone with five handsets, and I don't care if it gets ruined as I'll just buy a new one at Costco. So I installed the alkaleaks. They work fine, but the handsets came with Panasonic NiMH AAA batteries which are now doing other duty.

So here's my question. The charge indicator on the handset says the phone is only 25% charged. I was surprised by this since alkalines are 1.5V and NiMH are only 1.2V. The handsets work fine with the alkaleaks (I wasn't worried about the extra 0.3V stressing the circuitry) and as long as I don't forget and put one of the handsets back in its charging cradle and try to recharge a primary all should be well. I just don't understand the state of charge indicator only showing 25% since they were all replaced with alkalines showing 90% to 100% capacity.
 
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WalkIntoTheLight

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I had a question for the battery experts here.

I recently replaced all the AAA and AA batteries in all the remotes and other devices around the house with NiMH rechargeable cells. I did this after an alkaleak almost ruined an expensive remote, probably the fifth or sixth time I've seen one leak in the past 5 years. So I got sick of the alkaleaks and replaced all of them. Now I have about 75 of these alkalines, most of which are at 70 to 100% of capacity that I don't know what to do with.

We have an older Panasonic cordless phone with five handsets, and I don't care if it gets ruined as I'll just buy a new one at Costco. So I installed the alkaleaks. They work fine, but the handsets came with Panasonic NiMH AAA batteries which are now doing other duty.

So here's my question. The charge indicator on the handset says the phone is only 25% charged. I was surprised by this since alkalines are 1.5V and NiMH are only 1.2V. The handsets work fine with the alkaleaks (I wasn't worried about the extra 0.3V stressing the circuitry) and as long as I don't forget and put one of the handsets back in its charging cradle and try to recharge a primary all should be well. I just don't understand the state of charge indicator only showing 25% since they were all replaced with alkalines showing 90% to 100% capacity.

If it's like my Panasonic cordless handsets (that take AAA's), the charge indicator doesn't appear to be based on the voltage level of the batteries. The handset seems to estimate the charge based on how long the phone is in use. Also, the phone assumes that any replacement batteries put in the phone are dead, and wants to do a full charge on them.

Whatever the mechanism it uses to estimate charge level, alkalines must confuse it.

Unplug your charging cradles, to make sure you don't accidentally try to charge them, or they will probably leak. Alkalines will take a small charge (about 20% by my estimates, if you charge them before they get low), but it greatly increases their chance of leaking shortly afterwards.
 

magellan

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Thanks WITL, for the info, that makes sense. I also already unplugged the cradles so I don't accidently make a mistake.

Had read here somewhere about someone using a really low trickle charge on alkalines but for me it's not worth the trouble. I seem to recall they said the number of cycles was pretty limited too.
 

WalkIntoTheLight

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Had read here somewhere about someone using a really low trickle charge on alkalines but for me it's not worth the trouble. I seem to recall they said the number of cycles was pretty limited too.

I've played around with recharging alkalines. I usually use a slow-charger, that charges at 250mA. It does work, but you have to charge them before they get too low. If you charge them when they're half-full, you'll generally get about 20% more charge in them. But, I'm sure this goes down for every cycle. I've cycled some alkalines a few times, but never so many that they don't respond at all. I've never had one explode when charging, but that might be a risk. I have had several leak within a few days after charging, especially when they are charged when nearly empty.
 

Lynx_Arc

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First off nimh voltage isn't rated like alkaline voltage nimh off the charger is about 1.4v and after they sit for a day or so they drop to about 1.35v or so and at 1.2v they are over half discharged the 1.2v is nominal voltage under load while alkalines aren't rated under load. A cordless phone probably loads down alkalines sagging their voltage way below 1.5v in use that is why you are probably getting 1/4 charged is because the voltage sag is showing. I'm guessing that the alkalines will probably give you a lot shorter runtime as compared to nimh alkalines shine on light loads while nimh blow them away on heavy load use.
As far as trickle charging alkalines from what I have gleaned and experienced the more you discharge them the less charge they can take and also recharging them greatly increases chance of leakage. On very light load use devices perhaps recharging alkalines would work but the low drain levels would have you only recharging them on a yearly basis in devices and not checking batteries for months at a time with alkalines... can leave you finding a leaker.
 

WalkIntoTheLight

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First off nimh voltage isn't rated like alkaline voltage nimh off the charger is about 1.4v and after they sit for a day or so they drop to about 1.35v or so and at 1.2v they are over half discharged

At a resting voltage of 1.2v, NiMH cells are almost completely discharged. You might get a few more percent out of them, but the resting voltage will rapidly decline after going below 1.2v. Half full is about 1.26v resting voltage, depending on the brand and how heavily they are discharged.

A cordless phone probably loads down alkalines sagging their voltage way below 1.5v in use that is why you are probably getting 1/4 charged is because the voltage sag is showing. I'm guessing that the alkalines will probably give you a lot shorter runtime as compared to nimh alkalines shine on light loads while nimh blow them away on heavy load use.

I think for most modern cordless phones, load should be acceptable even for alkalines. Mine lists a talk-time of 10 hours, based on the included 650mAh AAA batteries. That's only 65mA current draw. Even for alkaline AAA's, that's pretty low, and a good AAA alkaline should outlast the rechargeables. (Standby time is over 10 days, so definitely favours alkalines.)
 

magellan

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Thanks for the info, all.

Just a quick update. After putting two Eneloop black XX's that were at 25% back in the cradle and doing a full charge, now when I put the same two alkalines back in they show fully charged instead of 20%.

It appears to just assume the same two batteries are in the handset. But the alkalines are at almost 100%. Of course if I put a couple of discharged NiMH back in it would show a low charge and initiate a charge. I just tried two alkalines that were at 10% and those registered as depleted. So sometimes it gets it right and sometimes not. But it does seem like the alkalines confuse the charger cradle like WITL said.

This really doesn't matter as long as the alkalines can power the headset.
 

magellan

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First off nimh voltage isn't rated like alkaline voltage nimh off the charger is about 1.4v and after they sit for a day or so they drop to about 1.35v or so and at 1.2v they are over half discharged the 1.2v is nominal voltage under load while alkalines aren't rated under load. A cordless phone probably loads down alkalines sagging their voltage way below 1.5v in use that is why you are probably getting 1/4 charged is because the voltage sag is showing. I'm guessing that the alkalines will probably give you a lot shorter runtime as compared to nimh alkalines shine on light loads while nimh blow them away on heavy load use.
As far as trickle charging alkalines from what I have gleaned and experienced the more you discharge them the less charge they can take and also recharging them greatly increases chance of leakage. On very light load use devices perhaps recharging alkalines would work but the low drain levels would have you only recharging them on a yearly basis in devices and not checking batteries for months at a time with alkalines... can leave you finding a leaker.


Great info, thanks.

I didn't know that alkalines aren't rated under load. Interesting.
 

magellan

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At a resting voltage of 1.2v, NiMH cells are almost completely discharged. You might get a few more percent out of them, but the resting voltage will rapidly decline after going below 1.2v. Half full is about 1.26v resting voltage, depending on the brand and how heavily they are discharged.



I think for most modern cordless phones, load should be acceptable even for alkalines. Mine lists a talk-time of 10 hours, based on the included 650mAh AAA batteries. That's only 65mA current draw. Even for alkaline AAA's, that's pretty low, and a good AAA alkaline should outlast the rechargeables. (Standby time is over 10 days, so definitely favours alkalines.)

More great info, thanks!
 

Kurt_Woloch

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Great info, thanks.

I didn't know that alkalines aren't rated under load. Interesting.

Not even that... even the no-load voltage will be below 1.5 V for most of the discharge. At the end of the discharge, some modern alkalines come close to 1.3 V (1.28-1.29) of no-load voltage while some will show way below that, down to 1.0 V or so. In contrast to that, a NiCd or NiMh battery will stay above their rated voltage of 1.2 V for most of the discharge for no load and light loads... how long depends on the battery, but Eneloops typically have a strong point here.
 

more_vampires

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Agree, Kurt. Cheap direct drive lights like alkalines since the voltage sags so quickly that the makers can be much sloppier with resistance value. The batteries themselves limit the system on many of the bottom of the barrel lights.

You'll never see a good hot rod light powered by alkalines. At least one that won't get smoked by even an NiMH light, all else equal.
 

WalkIntoTheLight

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You'll never see a good hot rod light powered by alkalines. At least one that won't get smoked by even an NiMH light, all else equal.

With the new Zebralight SC5 putting out over 500 lumens on a single AA Eneloop, while drawing 6 amps from it, I'd like to see any alkaline try to match that. I'm going to order that light; when I get it, I'm going to see how fast it kills an alkaline.
 

magellan

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With the new Zebralight SC5 putting out over 500 lumens on a single AA Eneloop, while drawing 6 amps from it, I'd like to see any alkaline try to match that. I'm going to order that light; when I get it, I'm going to see how fast it kills an alkaline.

500 lumens at 6A on an NiNH AA? Yowser. Wonder how long it lasts on high mode.
 

more_vampires

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With the new Zebralight SC5 putting out over 500 lumens on a single AA Eneloop, while drawing 6 amps from it, I'd like to see any alkaline try to match that. I'm going to order that light; when I get it, I'm going to see how fast it kills an alkaline.

I've got a current boosted light that can't even power on with new alkalines after the boost.

500 lumens at 6A on an NiNH AA? Yowser. Wonder how long it lasts on high mode.

14 minutes.
 

more_vampires

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A light modded to lion single cell direct drive and nichia 219 by vinh. E05SSvn. It's much like his CigVN and TisVN. It has no regulation and is a straight blaster. You sorta have to recharge after 2 minutes of playing with it as the output drops very sharply. :)

A single alky direct drive can't push a power led. Gotta have a boost driver. It's why the cheapy chinalights like to use AAAx3 so they can direct drive driverless.
 

WalkIntoTheLight

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I've got a current boosted light that can't even power on with new alkalines after the boost.

A light modded to lion single cell direct drive and nichia 219 by vinh. E05SSvn.

How do you power a lithium-ion light with alkalines? Are you using something like a 3xAAA to 18650-sized converter?

Also, what is the lumen-output of your modded light? I thought Nichia 219's couldn't be driven too hard. I know vinh likes to over-drive lights, but what can he do with a 219 that doesn't risk frying it?
 

more_vampires

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How do you power a lithium-ion light with alkalines? Are you using something like a 3xAAA to 18650-sized converter?

The E05ss, stock, takes alkies and does not support 10440 to my knowledge. The DD mod requires lithiums as there's no way to cram AAAx3 in there without a battery hack. I actually HAVE a couple of noname chinalights that take 18650 and/or an AAAx3 carrier. It works, but sure does kill the alkies FAST on high modes.

Also, what is the lumen-output of your modded light? I thought Nichia 219's couldn't be driven too hard. I know vinh likes to over-drive lights, but what can he do with a 219 that doesn't risk frying it?

IIRC, some estimates put it at 800-1200 lm OTF depending on the emitter and the cells, but only at turn on and the output immediately begins dropping like a rock. 2 minute bursts, 6 minutes runtime total. No safety net in a hard direct drive light, so newbies (not directed at WITL) take caution. You can easily overdraw a lion with this setup.

Hard direct drive lights will vary wildly depending on what current the cells can supply. Better cells give better zap. The light is a joke trying to run counterfeit house-on-fire 10440s. I use the Efest 10440 cells in it, nice little firecrackers. Beware, most chargers will charge these too fast and kill them. I have a 50 ma charger just for these Efest cells to feed my hot rod.

...and yes the 219 version is not as impressive as the other emitters Vinh offers. I think his top end is around 1200. Mine, being a Nichia, is far less. I did it for the tint! :) Guess I have the addictive need to get the XP-G2 version, but now I want to see what he can do with the XPL HI emitters in these tiny and ridiculously overdriven lights.

The light gets super hot, with heat limiting the 2 minute burst. There is no thermal stepdown and you can literally burn yourself with this light. Not for newbies, not for children, not for people who don't want to learn about lithium ion safety. Remember, these lights almost always have thermal mass and thermal path mods to go with the swap and direct drive.

Not really a lighting tool as much as an awesome toy. Wall of light. Beamshots are up in the Vinh forum.

http://www.candlepowerforums.com/vb/showthread.php?388109-E05SSvn-Best-Stainless-AAA
http://www.candlepowerforums.com/vb/showthread.php?396743-CigVN-AAA-Rustic
http://www.candlepowerforums.com/vb...VN-Brightest-amp-Most-Advanced-Keychain-Light

Vinh moved away from the E05SS host, trying to keep costs down. The CigVN and TisVN are basically the same deal, different host.

Hope I got everything right in this post. If not, it was a slip up on my part. Now, go check the beamshots! :)

Edit: found one slip up so far, meant to say 1200 lumens or so from a tiny keychain light. Obviously his big multi emitter lights are far more than that. Who can find the next slip up? :)

Edit 2: I prefer max brightness and dont draw lions as low as vinh does in testing. Your max brightness is hot off the charger, so I never let my 10440 get that low. I like the punch!

Edit 3: He offers these with drivers and modes as well. I've been talking about his (in)famous "Option D," direct drive super blaster.
 
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