Comments (27)

• 6

  DocOnes - March 30, 2020

  OMG, thank you. I’ve only bought energizer and cheap rechargeables. I hated them every time. Somewhat anecdotally, half of my energizer batteries would have half the lifespan on video game controllers after only 15-20 cycles. I never felt I could trust them for emergency scenarios. With this info, I can now have the kit I want and feel confident it will keep up with my, somewhat minimal, expectations. Thank you. Stay safe, keep up the good work.

   
• 6

  Frank San Diego - August 18, 2020

  How well does the NiMH batteries hold up to hot environments such as the glove compartments of my cars. I try to keep flashlights in each of my cars and nothing is more frustrating than needing a flashlight in an emergency situation and the batteries are dead. I have been using LiOn (18650 rechargables) for this situation and pulling them out for a recharge every couple of months. Would NIMH batteries be better suited to this application?

   
  • 2

    Gideon ParkerStaff - July 5, 2021

    Hi Frank, 

    According to Energizer:

    • NiMH batteries are best stored in temperatures from 0 to 30°C (32-86F) although storage for limited periods of time at higher temperatures is feasible. 
    • NiMH batteries will typically retain approximately 50% to 80% of their capacity after 12 months of storage. NiMH batteries that are stored at high temperatures will self discharge faster due to the increased reaction rates caused by the elevated temperature.

    The eneloop batteries state that they will hold 70% of their charge for 10 years. So it looks like eneloops are able to withstand self discharge better than Energizers. 

    I would do some testing for your particular circumstance. Buy a set of batteries and use a multi meter to test the voltage when you place it in the car, after 1 month, 3 months, and 6 months to see what the discharge rate is for your batteries and temperature. Maybe you do need to top them off once a year.

    One more note, do not store NiMH batteries in a waterproof/airtight battery case, they do need some airflow in order to vent off gases, but a glove compartment should not be that airtight to worry about.

    I don’t have any hard facts and statistics, but from the bit of research I have done, it looks like NiMH batteries are a bit more temperature resilient than lithium ions.

     
  • 2

    Lowell - July 5, 2021

    I’m glad I read this about storing NiMH in waterproof cases! To be clear, this means it is a bad idea to put them in a “dry bag” with my other electronics, yeah? What’s the risk here? Pressure build up and explosion??

     
  • 2

    Gideon ParkerStaff - July 5, 2021

    Going back to that Energizer study, it says: 

    Some of these factors do include battery capacity, temperature, depth of discharge, design materials, charge and discharge current, exposure to overcharge and over discharge, storage conditions, and age. Some of these factors can cause gas generation within the battery which can lead to activation of the safety vent and subsequent permanent deterioration of the battery.

    also

    The nickel-metal hydride battery is designed so the oxygen recombination cycle described earlier is capable of recombining gases formed during overcharge under normal operating conditions, thus maintaining pressure equilibrium within the battery. However, in cases of extended overcharge or incompatible battery/charger combinations for the operating environment, it is possible that oxygen, and hydrogen, will be generated faster than it can be recombined. In such cases the safety vent will open to reduce the pressure and prevent battery rupture. The vent reseals once the pressure is relieved. The expulsion of gas thru the resealable vent can carry electrolyte, which may form crystals or rust once outside the can

    To me, the biggest threat is overcharging for extended periods of time or using a charger not meant for charging them correctly. It would be interesting to place a battery in a deflated balloon and tie the end and see if it would inflate at all from the creation of hydrogen gas. I don’t think these are actively creating gases constantly but if exposed to unsuitable conditions for long periods of time could allow the battery to vent off that extra gas to prevent it from bursting. 

     
  • 2

    Frank San Diego - July 5, 2021

    Gideon, Thank you for your response. I have adapted the strategy of using lithium ions (18650) flashlights and I recharge every 2 months. This had ensured that my flashlights are ready to use when needed. This tact has worked for me so far. I use NiMH (Eneloops) for all my inside use. I may add the NiMH to the car flashlights in the future, if that strategy does not work out. Thank you for everything on your website. It is a great resource.

     
  • 1

    Gideon ParkerStaff - July 5, 2021

    Same here, I have a lithium ion 18650 in my flashlight and top it off every two months or so, even if I don’t use it that often just to keep it fresh and that I know it’s always going to be ready for me.

     
• 2

  Lowell - July 4, 2021

  Will you please share the specific data you used to make your decision of recommending Eneloops over other options, like Amazon Basics and EBL’s AAAs?

   
  • 1

    Frank San Diego - July 5, 2021

    Did you read the main article that this post was associated? It should explain it all.

     
  • 3

    Gideon ParkerStaff - July 5, 2021

    Hi Lowell, 

    As stated in the article, the eneloops lead the market for a high number of charge/discharge cycles without sacrificing too much in capacity. We recommend going for a smaller amount batteries which have a higher charge cycle amount (longer lifespan) than a larger supply of batteries that don’t last as long, especially if needing to bug out.

    There isn’t many other contenders on the market that offer as high of a lifespan as eneloops. The PowerEX batteries are our second recommendation after the eneloops but have fewer recharge cycles.

    Under the section of the article titled How we picked the best rechargeable batteries for preppers it goes into a bit more detail on how we came to the decision that we did:

    Emergency preparedness has special needs. So we picked the winners based on:

    1. Number of charge/discharge cycles, that way a single battery can be used repeatedly for the longest possible time in a long-term crisis.
    2. How well they retain a charge when sitting in storage, so they’re good to go whenever you rarely and suddenly need them.
    3. No special maintenance needs for long-term storage, like keeping the batteries cold or topping them off.
    4. Available in common sizes and able to be fit into less common sizes using adapters.

    NiMH LSD AA/AAA batteries were the clear winner here, nailing all of the above prepper-specific criteria. There isn’t even a close second.

    Does this answer your question?

     
  • 2

    Lowell - July 5, 2021

    Hi both! Thank you very much for taking the time to respond, and doing so so quickly! This doesn’t quite answer my question, because I didn’t see any specific quantitative comparison in cycle lifetime against competitors. I ask this because both the EBL & Amazon Basics AA/AAAs claim to be LSD, but I didn’t see something like a tabular comparison in the article. I also didn’t see that y’all ran independent testing, which is unusual for TP articles that almost always take manufacturer-reported claims with a grain of salt.

    I’d be happy to help with whipping up a quick tabular comparison to show what I mean — I’ll try and do that today! However, that’d still be based off manufacturer claims, and I’m not sure I’d be up for verifying the thousands of cycles! Though I don’t think I’d be game for most of the rigor y’all demonstrate in your articles, so perhaps this would be an opportunity to step outside of my comfort zone!

     
  • 3

    Gideon ParkerStaff - July 5, 2021

    We would love to see your results. A table of the different lifecycles and max Mah’s of each battery is a great idea to quickly differentiate between what batteries you want to go with.

    And yes, testing out the thousands of cycles of batteries would take a very long time to constantly monitor through draining and recharging. I think that taking the manufacturer’s word for it is probably your best bet because the alternative would take months to complete.

     
  • 4

    Lowell - July 5, 2021

    Here’s an example of that table I’d described, which says ultimately the same as what you & Jon have stated, but makes it even more striking to me how much the Eneloops dominate in terms of recharge cycles and retention while not in use.

    Feel free to embed this in the article if you like! Whatever you think is best 🙂

    Thank you again for your time bud!!

     
  • 2

    Gideon ParkerStaff - July 5, 2021

    Thank you for taking the time to create this chart, i’ll share it with the team! I do like that visualization of comparing all the various brands and how clearly eneloop dominates. 

     
  • 3

    Lowell - July 5, 2021

    The “retention” was less trivial to compare for me, do you have any suggestions there? I don’t know enough about the behavior of these batteries to, for example, normalize “70% after 10 years” with “85% after 1 year”

     
  • 1

    Gideon ParkerStaff - July 5, 2021

    That’s going to be a hard one to answer because as I mentioned in another comment up above Energizer said that their NiMH batteries will typically retain approximately 50% to 80% of their capacity after 12 months of storage where as eneloop is claiming 70% after 10 years. So each battery brand is going to be very different.

    If you have a multi meter or a little battery tester, I would check every few months and see what is true for your particular set of batteries.

     
• 3

  Lowell - July 5, 2021

  What maintenance schedule do y’all use for these batteries? The retention on the Eneloops is so long that I’m leaning towards topping them off perhaps every 2 years, because doing so more frequently doesn’t seem worth the reduction in overall lifespan.

   
  • 2

    Gideon ParkerStaff - July 5, 2021

    I like keeping my batteries topped off as much as possible so they are just ready to go at a moments notice. Inferior battery types that drain to unusable levels after a few months of storage really bother me. 

    If you do end up getting eneloops, I would test at 6 months, 1 year, 1.5, and 2 years. If you notice them getting below 75% during any of those times I would know that is your limit and you need to charge them before that duration occurs again. I see your point about not topping off too often in fear of reducing the overall lifespan, but with those mighty eneloops you probably don’t have to worry about that with the 2000+ lifecycles. One top off a year won’t make a dent in that huge number. And if there are any buildup of gases (which I don’t think will happen if stored in mild temps inside) then that will allow that gas to dissipate more frequently if checked more than every 2 years.

    Around winter time I tend to go through all my preps to top off batteries, eat old rations in the BOB, rotate water containers, and just do my annual prep review when the weather is too nasty to go do anything outside in and I’m bored inside. Then preps and camping gear are all ready come spring time to have some fun with.

     
  • 2

    Lowell - July 5, 2021

    Roger all this bud, thank u! Also real solid thinking with the winter timing of your prep review. Perhaps even more ideal to do it before it gets *too* nasty so you can be sure your car can handle whatever winter throws at it~

     
• 2

  Popsicle - August 19, 2021

  Just thought I would share: per a customer service chat I just had at fenixlighting.com, those CR123A-equivalent rechargeables cannot be stacked, though I could not find any mention of this on their site (nor fenixlight.com). I was hoping to find a rechargeable alternative to put in a Streamlight ProTac 2L I already own. It takes two CR123As in series.

   
  • 1

    Gideon ParkerStaff - August 19, 2021

    That is some good intel, thank you for looking into that and sharing it here. I called Streamlight to see if I could help you out in your quest, and they said that the Streamlight ProTac 2L is not designed for multi-fuel use. Which means they don’t recommend using a rechargeable, and to only stick to lithium single use batteries with this particular model.

    Kind of a bummer right? I personally wouldn’t use my flashlight as much as I would like to if I had to keep buying expensive single use batteries. Having a rechargeable option allows me to feel comfortable whipping it out whenever I want and not worrying about how much power I use because I can just charge and top it off when I get home.

    If… you are interested in buying a new flashlight in the future or something to add to the Christmas wish list, a forum member named matthew shared their experience on testing out a few flashlights that might aid you in your search.

     
  • 2

    Popsicle - August 19, 2021

    Gideon, thank you for looking into that. I admit, I’m already updating our lights and lanterns, and I have a Fenix TK16 V2.0 coming in the mail. (The one-touch strobe activation on the tail won my spouse over for the after-dark dog walks.) Just looking also to extend the usefulness of stuff we already have rather than throwing out or relegating to the junk drawer abyss.

     
  • 1

    Gideon ParkerStaff - August 19, 2021

    A one-touch strobe is a nice feature for the nightly dog walk. I’ll have to look into that, so thank you for the recommendation.

    Also, good job on trying to give some more life to your old flashlights. I have an ancient AA battery Fenix that I probably bought in 2008 that now lives by the front door for those occasional times you need to look out the window at night after hearing a strange noise.

     
• 2

  Gideon ParkerStaff - November 19, 2021

  I thought this review video was interesting. It tests the capacity of batteries after sitting on a shelf for a year, and another set after one year of discharging and recharging every day.

  The main takeaway for me is that Chinese made batteries performed worse than Japanese made ones.

   
• 3

  Felix Hunziker - March 24, 2022

  Hello,

  I enjoyed and learned a lot from this article. A couple things I didn’t see covered and would appreciate feedback on:

  1) how do you recharge these batteries if there’s no grid power? Can a small solar panel, such as those you’ve reviewed in other articles, connect to the Eneloop charger? What size panel would one need?

  2) I’ve read elsewhere that NiMH batteries have slightly lower voltage and might make a ham HT like the recommended Yaesu FT-60r think it has to transmit at low power (<5W) when using the AA battery pack. I’ve also read other posts saying this was not a problem. Can you shed any light on this issue?

  Thanks,

  Felix

   
  • 1

    Robert LarsonContributor - April 8, 2022

    The Prepared has two companion articles that will help answer your first question. Small solar panels, and one on battery chargers. The small portable solar panels will have no trouble charging batteries, but the charger will need to have USB capability.

    The only time I’ve had my rechargeable batteries not be recognized by a device is when using some of the cheaper and lower end ones in a Nintendo Wii controller, and those were old batteries that were nearing the end of their life. Once I moved to higher capacity and quality rechargeable ones they worked well. You shouldn’t have any trouble with Eneloops.

     
• 1

  Jay ValenciaContributor - May 19, 2022

  I saw an ad for rechargeable batteries by a company called paleblue. They are expensive at $30/4 AA batteries, but they claim to charge 5X faster than other rechargeables, last over 1000 charges, and have a built in charging port on the side of the battery.