Choosing the Right NiMH Batteries for the Right Application

[Cardnyl]

I've been put to task by the other half to come up with a solution to the household's battery demands. I've read through a number of posts on analyzing chargers and batteries in general (both LSD and non-LSD). The part I'm struggling with is whether or not given the devices in question am I better off with LSD vs. non-LSD batteries.

Some of the devices are easy enough to select. For example we have a ton of 9 LED 3xAAA flashlights from harbor freight that are used as a temporary light source during a power outage until we can fire up the generator. Since they primarily sit idle 99.9% and their use is temporary our concern is that they device works when needed as opposed to run time. I think for such a use case the LSD batteries are well suited.

On the other end of the spectrum I have a 2 different flashlights that I keep in my pocket for every-day use. Fenix LD12 and a Klarus XT2A. I've dug through the forums a bit and found some reviews that go into specifics on the emitter used, and power draw at each of the various brightness levels. Since these lights double as a self-defense tool its more important to me that when I turn them on, they are blinding bright. I think what I want here is either a non-LSD battery with a high mAH rating or a LSD battery that operates well in the 1 amp draw range because run-time at a given power level (turbo/high) is more important. Does this sound reasonable?

Where it gets a bit muddy for me are devices that fit into one of the following use scenarios:

• Device sees constant use but the draw is relatively low. (e.g Thermostats, smoke detectors, wireless keyboards and mice, LED headlamps)
• Devices that use a fair bit of standby current due to poor design but need to work in a pinch (e.g Eotech 517 holographic weapon sight)

I can provide a full list of the devices to power, battery sizes/quantities, charger and batteries I have my eye on, and some of the power draw information for the devices I was able to find or can easily test if necessary.

Thanks in advance

 

[StorminMatt]

You don't necessarily need HSD batteries for a light that you want blindingly bright when you first turn it on. Unless that light draws SO much current that it needs high draw batteries like Elites (which are NOT LSD), ordinary LSD batteries like Eneloops will give you as much juice as any HSD battery. And a one amp draw is actually quite low (and VERY doable) for ANY NiMH AA battery. With this said, HSD batteries are best used in applications which are routinely used (like a work light used every day or a light you use while walking the dog every day). Or applications where you want the longest possible runtime, and want to carry the least number of spare batteries possible (or none). A good example of this would be a situation where you want to go on a long night hike, and don't want to carry extra batteries. But if you don't use your lights in these kinds of ways, LSD batteries will work fine for you. They can also work in the aforementioned 'heavy use high drain' situations if you don't mind carrying more batteries and changing them more often.

 

[Grijon]

LSD will be great for everything you describe, Cardnyl (and :welcome.

I would recommend that you go with high-quality LSD NiMH (Eneloops!) for all your needs. For your daily users you could get Eneloop Pro/XX (2400mAh) that truly give you the best of both worlds, and regular Eneloops for everything else.

Duracell Ion Core AA's would be perfect, as we believe they're rebranded Eneloop Pros - for $11 per four-pack at your local Walmart. At that pricing, you could go all Duracell Ion Core and have everything loaded with high-capacity, true LSD, quality batteries!

 

[Chicken Drumstick]

I've been put to task by the other half to come up with a solution to the household's battery demands. I've read through a number of posts on analyzing chargers and batteries in general (both LSD and non-LSD). The part I'm struggling with is whether or not given the devices in question am I better off with LSD vs. non-LSD batteries.

Some of the devices are easy enough to select. For example we have a ton of 9 LED 3xAAA flashlights from harbor freight that are used as a temporary light source during a power outage until we can fire up the generator. Since they primarily sit idle 99.9% and their use is temporary our concern is that they device works when needed as opposed to run time. I think for such a use case the LSD batteries are well suited.

On the other end of the spectrum I have a 2 different flashlights that I keep in my pocket for every-day use. Fenix LD12 and a Klarus XT2A. I've dug through the forums a bit and found some reviews that go into specifics on the emitter used, and power draw at each of the various brightness levels. Since these lights double as a self-defense tool its more important to me that when I turn them on, they are blinding bright. I think what I want here is either a non-LSD battery with a high mAH rating or a LSD battery that operates well in the 1 amp draw range because run-time at a given power level (turbo/high) is more important. Does this sound reasonable?

Where it gets a bit muddy for me are devices that fit into one of the following use scenarios:

• Device sees constant use but the draw is relatively low. (e.g Thermostats, smoke detectors, wireless keyboards and mice, LED headlamps)
• Devices that use a fair bit of standby current due to poor design but need to work in a pinch (e.g Eotech 517 holographic weapon sight)

I can provide a full list of the devices to power, battery sizes/quantities, charger and batteries I have my eye on, and some of the power draw information for the devices I was able to find or can easily test if necessary.

Thanks in advance

Keep it simple, stick with Eneloops. They work.

Non LSD generally only have marginally more capacity and can go flat within a week of not being used.

 

[MidnightDistortions]

If you use up all the power in one day HSD cells might be for you, but otherwise like others have said if you only need to recharge say once a week, or at least every 3-4 days LSD is the best. Eneloops and Duracell would be my first two selections. Energizer and AmazonBasics are also good LSD brands, though i have ran into needing to refresh Energizers every couple of years (in storage) but one full discharge a year should be needed if you plan to keep them storaged.

Usually i will reserve crap batteries (under 80% of full capacity) for tv remotes, clocks, and other low drain devices. With clocks, the batteries do have to have good LSD qualities and have at least 500mAh, at least for me to at least so i don't have to worry about resetting the clocks time but it's not a huge deal if it happens so that's really up to the user, some people prefer to stick with Alkalines as they will last longer. For smoke detectors, i still use alkalines for that as well as i haven't tested them out yet but you'll want to use a good LSD NiMH cell and check/test weekly and maybe recharge every 3-5 months. I think some people mention you can get by 8 months but it would depend on how much milliamps a smoke detector draws. I don't recommend that people do use rechargeables in smoke detectors but it's really up to you, i think as long as you do weekly tests and check the voltage and try to keep it above 1.25 volts (maybe higher) then test the battery out every year or every other year to make sure it's still got good capacity and maintains voltage. Discharging them at a high rate will give you a pretty good indication. Some rechargeables will produce a good amount of milliamps but the voltage drops lower than normal. It's usually from overcharging or overdischarging though so if you got a good charger and don't overdischarge the battery there should be no issue there.

 

[WalkIntoTheLight]

I don't recommend that people do use rechargeables in smoke detectors but it's really up to you, i think as long as you do weekly tests and check the voltage and try to keep it above 1.25 volts (maybe higher) then test the battery out every year or every other year to make sure it's still got good capacity and maintains voltage.

I think you're overstating the risks of using rechargeables in smoke detectors. Weekly tests is probably a good idea regardless of any kind of battery type you're using. Press the "test" button on the smoke detector... it takes 5 seconds. If you don't have 5 seconds to waste every week, do it monthly.

I hear local news stories every month about people dying in a house fire, because they took the batteries out of their smoke detector and never replaced them. That's the real risk. When your batteries die, either replace them (alkaline) or recharge them (NiMH). Unfortunately, people that don't have 5 seconds to waste testing their smoke detector, are unlikely to waste 5 minutes replacing batteries.

 

[MidnightDistortions]

I think you're overstating the risks of using rechargeables in smoke detectors. Weekly tests is probably a good idea regardless of any kind of battery type you're using. Press the "test" button on the smoke detector... it takes 5 seconds. If you don't have 5 seconds to waste every week, do it monthly.

I hear local news stories every month about people dying in a house fire, because they took the batteries out of their smoke detector and never replaced them. That's the real risk. When your batteries die, either replace them (alkaline) or recharge them (NiMH). Unfortunately, people that don't have 5 seconds to waste testing their smoke detector, are unlikely to waste 5 minutes replacing batteries.

Your right, provided that you do regular tests and i do recommend checking the voltage as well to make sure the battery is charged around the mid range. Disposable alkalines you really only need to hit the test, but can also check the voltage to see where the battery is at. The only reason though i overstate the risks is because it's pretty much like not replacing the battery as with this topic here unless you religiously check your batteries and charge them on a timely basis when they need to be it's not recommended to use rechargeables. Chances are if they don't replace the dying battery or don't bother to test their smoke detectors it would be recommended that they just stick to disposable. I'm typically one of those people but since i had some charged alkalines i later on threw those in so i have a working detector.

It actually wouldn't be a bad idea to have extra smoke detectors for my case anyway that way i can see for myself whether NiMHs are ideal plus since i already check all or most of my NiMH cells, i most likely would check the ones in the smoke detector. For those non hobbyists though they won't check the voltage, a button click won't make much of a difference if the cells die off quicker than the smoke detector can warn you within a week or worse a month. If you are at home 80% of the time, chances are you'll hear the low battery warning but if your out for most of the day and the thing only beeps at you for 4 hours before the cells die you wouldn't know until you test the smoke detector the week after. It might also vary from different makes and models so one might work fine with some Eneloops but for others they might work better with alkalines. The main idea is hobbyists will be able to figure out how their smoke detector behaves and most likely know when the low battery warning starts up and the time it takes for the battery to fully discharge through the low warning indicator. Again it's probably overstating them but an inexperienced person who only knows to buy new batteries when their device stops working and they figure that's the only way to fix things doesn't know to check voltages and keeps tabs on all their battery operated devices.

I myself would not risk putting Eneloops in my smoke detector without running some tests first to see whether they are adequate enough to power the low battery indicator long enough for someone to notice it . I would most likely test the voltage anyway but the low voltage indicator is actually quite important as well. Battery level indicators should be mandatory on these devices and would give a better heads up of when it's time to recharge/replace batteries and not just an annoying chirp.

 

[Cardnyl]

Just wanted to say thanks to everyone who took time out to weigh in and educate me on my battery situation.

Had a follow up question I wanted to run past the forums that falls into the same theme of "right battery for the right job". Is anyone aware of any attempts to compile average weight of a particular brand/generation of battery for weight sensitive applications? Just curious if there is a stick/informative post I missed or if I'm better off looking up spec sheets from the manufacturers.

 

[InHisName]

Yes, it helps 'prove' more evidence that two brands are made at same factory. Along with weight, positive button style, shape, vent hole shape / count also helps that proof along with other aspects.

 

[more_vampires]

For smoke alarms, I prefer lithium primaries. They seem to last longer before draining and do not have leak failures. I've quite a few smoke alarms to change out and alkalines are worthless. They leak (50%-50% chance) before completing their proper runtime, they corrode the contacts, and if you don't clean them the alarm may not work though the battery is fresh. Lithium primaries (Energizer Ultimate) don't leak. Some will grumble about the cost, but don't forget that this is a safety device that can safe your life. I ride motorcycles and won't buy a cheap helmet. I view it like that.

For emergency lights, rarely used, lithium primaries or low self discharge nimh would be my choice. About once a month or two, I round up my rechargables and top them up. I basically never, ever drain a cell in actual use because of this. I'm always loaded.

For everything else (for me,) there's Eneloops. I hide them everywhere... remote controls, radios, this that the other. If the S did H the F, I've got a fat stack of cells with no need to recharge during the outage... but I have the capability to do so.

Still shopping for a solar setup. Oh well. 21st century, gotta love it!

Disposable lithium primaries go in BOBs (bug-out-bags)

 

[WalkIntoTheLight]

For smoke alarms, I prefer lithium primaries. They seem to last longer before draining and do not have leak failures.

I'm currently using low-self-discharge NiMH in my smoke detectors. However, someone pointed out to me that smoke detectors take advantage of an alkaline's discharge curve to give you plenty of warning before they die. That's not the case for NiMH (so I have to test the smoke detectors to make sure the batteries are still charged), and may not be the case for lithium primaries either. I'm not sure if that's true, but something to consider if you're using lithiums because you have safety concerns.

 

[more_vampires]

I was just reflecting on the 1.2v nimh vs the 1.5v lithium primary. Both of these values exceed the minimum, but when the annoying chirp starts is a good question. Annoying chirp runtime is an extremely important question.

Heh. Looking at the calendar it's time to go test again. We'll see if we can test beep still. No test = no safety. Testing is the important part, probably less so than what battery.

 

[tandem]

For more than 14 years I've been doing victim assistance work for our fire department and have attended hundreds of scenes. My duties see me interacting with the fire investigation team and of course evacuees. For personal and professional interest I'm always interested in causes of fire and how it was detected and whether smoke detectors played a role in alerting occupants.

For the events I've been able to collect information from, to date every smoke detector that failed to warn has been because the occupants (and in a few distressing cases, their landlords) disabled the detector (wired or primary battery powered), usually because of false alarms due to cooking (they should invest in more convenient detectors). In all these years I've run into zero cases of alkaline 9V batteries causing a failure due to leaking and detector damage.

Before 9V alkaline batteries fail to the point of leaking outside the casing their voltage has dropped to the point where the detector is going to complain (some designs set this at ~ 7.5V). As most folks aren't keen to live with a beeping detector, they pull the cell before damage is done. Hopefully they also replace the cell... but experience shows some do not. Could there be outliers that fail at voltages > 7.5V? Assume so and don't rely on one detector.

I've zero concerns about putting in alkaline 9V batteries into our wired (as backup power) and stand-alone detectors, but I always use fresh batteries that have years before their expiry date is due, and we swap them twice a year when clocks roll forward and back. If you are in a jurisdiction where the time zone doesn't change, pick some other obvious dates. Detectors also have a life span; check the replace-by date when swapping batteries.

Immediately after my first fire I went out and purchased four more detectors for our home. Later, when doing a home reno, we pulled cable to all floors in our home to support wired in + interconnected detectors; we still have a few standalone battery powered units. When it comes to detectors truly one is none, two is one...

 

[more_vampires]

We had a trash can fire in my shop and the smoke alarm had alkaleaked. We noticed by the smoke and that's not good at all. 3 fire extinguishers later, the fire fighters showed up.

All in all, it was a bad night and influenced my decision to stop using alkalines for this role.

AC power + interconnects are far superior to stand alone battery. Unfortunately, the alarm in question was a stand alone and not one of the ones hooked to the security system.

The crowning irony: We had one of those "jiffy pop" popcorn one-time-use disposable aluminum pans hanging above the trash can that caught fire. A humorous label had been applied to the popcorn pan stating "Redneck fire alarm." After the fire was out, I noted with sad irony that not one kernel had popped.

The old chinese method of putting packs of firecrackers around has got to be better than that!

 

[WalkIntoTheLight]

I've zero concerns about putting in alkaline 9V batteries into our wired (as backup power) and stand-alone detectors, but I always use fresh batteries that have years before their expiry date is due, and we swap them twice a year when clocks roll forward and back. If you are in a jurisdiction where the time zone doesn't change, pick some other obvious dates. Detectors also have a life span; check the replace-by date when swapping batteries.

All that is good advice, but seriously, what percentage of occupants actually do that? My guess is less than 10%.

At best, most people might replace batteries once a year, and not check their detectors at all in-between. Typically, many people won't replace the batteries until they start to chirp, and then they're more likely to rip them out and leave them out until they can be bothered buying some batteries.

 

[more_vampires]

I've moved into apartments with battery-less smoke alarms before. There was zero protection until I decided to check.

"Oh, I'll get around to it later." I'm sure someone thought that.

 

[tandem]

WalkIntoTheLight: Glad it wasn't worse!

more_vampires: Apartment buildings, condos, joined town-homes and duplexes leave me feeling uneasy because one's safety can be compromised by the actions of other residents so easily. Even detached homes are at risk from their neighbours but at least you have some time working on your side for evacuation.

If one day we sell our house I won't move into anything but a full on concrete building with a sprinkler system. Sprinklers make a mess but improve life-safety and save the structure. There'll be no wooden three story walk-ups in my kid's future when they move out... I will insist upon it (or equip it with 100's of detectors LOL).

While fires can happen anywhere, in our large city (by Canadian standards) they happen disproportionately on one side of town. Socio-economic and cultural factors play a role in that stat.

 

[MidnightDistortions]

I'm confused on how smoke detectors can expire. I have electronics older than i am that works fine. I've seen some apartments that have the smoke detector designed to be wired into the electricity that wasn't hooked up to anything.

 

[more_vampires]

I'm confused on how smoke detectors can expire. I have electronics older than i am that works fine. I've seen some apartments that have the smoke detector designed to be wired into the electricity that wasn't hooked up to anything.

The smoke alarm designs I'm aware of contain a very small amount of radioactives. (Americium, IIRC) Half-life means it's decayed into something else and the circuit goes out of parameters.

...at least that's my understanding. I'm not a smoke alarm engineer, unfortunately.

 

[MidnightDistortions]

The smoke alarm designs I'm aware of contain a very small amount of radioactives. (Americium, IIRC) Half-life means it's decayed into something else and the circuit goes out of parameters.

...at least that's my understanding.

Oh thanks, well the nice thing is about the one i have is it has a beep pattern that tells you need to replace the alarm.