Off-Grid Charging System For AA-AAA Batteries, Plus USB


Off-grid charging for the AA or AAA battery and other consumer batteries can be accomplished with a combination of the right portable solar panel and battery charger to get the job done.

When might this be useful? While off-grid, camping, hiking, a remote location, or simply for your own preparedness.

  • Communications devices
  • Portable radios
  • Flashlights
  • Handheld GPS
  • Etc..

While on the go, out in the field or backpacking, the following off-grid charging equipment will charge the most popular size consumer batteries (AA, AAA).

There is also a recommendation for a solar charger for USB devices (see below).

(UPDATED 2020 for latest practical solar panel and charger to get the job done)

Off-grid Charging System For AA, AAA Batteries

Did you know that the AA size battery is the most common consumer battery?

The following off-grid charging system includes two components:

A solar panel
A complimentary battery charger

Note that this will only charge “rechargeable” batteries (had to say it…).

I also want to mention the following all-in-one solar battery charger for AA – AAA – C – D batteries. It’s not nearly as powerful, but it works. It does not charge nearly as fast and it’s not a “smart” charger, however I wrote an article about it a while ago which may be of interest:

[ Read: A Good Solar Power Battery Charger from C.Crane ]

The following off-grid charging system will charge faster and will “smart” charge today’s NiMH rechargeable batteries.

How To Charge AA Batteries With A Solar Panel

You will need a “smart” charger and a solar panel.

AA – AAA Battery Smart Charger For Use With Solar Panel that has USB Output Power

This “smart” charger is unique.

Tenergy 4-Bay AA/AAA Charger with USB Input
(view on amzn)

It has a micro-USB input which will connect with the solar panel shown below.

A benefit of this charger is that you do not need to insert batteries in pairs.

Each battery slot is independently monitored and uniquely charged according to the state-of-charge of each battery.

Smart chargers also have more sophisticated charging and sensing circuits improving charge quality and promoting longer battery life.

Portable Folding Solar Panel For Use With AA / AAA Battery Charger

21-Watt Folding Solar Panel with USB output
(view on amzn)

21 watt solar panel

Solar panels come in many sizes, shapes, and various electrical specifications.

This 21 watt solar panel is portable, folds up, and provides the correct output operating voltage and minimum current requirements to power the charger listed above.

Since it has USB output, it can be used to charge your cell phone too.

In addition to charging USB devices straight away, this panel is also popularly used with many of the various USB External Batteries. I have been using one of the “Anker” external batteries for many years with great success. The current most popular model is this one:

Anker PowerCore 10000
(view on amzn)

Note that solar panel specifications are under ideal direct sunlight conditions.

[ Read: How To Keep Your Cell Phone Charged During A Power Outage ]

[ Read: Best AA Rechargeable Battery ]

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  1. Our off grid setup is simple. A deep cycle battery, a 1000 watt inverter, and a 7 watt solar panel to charge the deep cycle. Works good to recharge our Energizer AA & AAA, cell phone, and portable dvd player.

  2. What would you recommend for semi portable. I have a cpap that keeps me from hunting as far into the back country as I would like. I am ok with space in the pack and weight to include the cpap and battery up to 10 lbs. I was considering a 12v 4×6 battery an inverter and a solar cell.

    I’ve tested the battery over night at home and it will drop to 10 volts with the machine running 6 hours. I am hoping the solar cell could charge the battery to 12v with 8 hrs of sun. Issue is I don’t know the math to determine what size solar cell to purchase.

    The cpap pulls 35 watts per hr continuous and .3 amps at max per hour.

    Any suggestions are appreciated.

    1. @Rwt, Your problem is going to be weight. Here’s why…

      If I interpreted your power requirements correctly, your cpap draws 36 watts (120 volts AC x 0.3 amps).

      With a 12 volt DC battery via an inverter, the current draw will be 3 Amps (36 watts / 12 volts).

      To operate the cpap for say, 7 hours, will require 21 Amp Hours capacity (7 hours x 3 Amps).

      The capacity requirement for your 12VDC battery will need to be within the vicinity of 42 AH (Amp Hours) if you allow it to discharge 50% over the period of operation. At maximum, don’t discharge beyond 80% or your will risk killing your battery. In your case, a 26 AH battery will operate your cpap but will discharge the battery by 80%.

      In any event, the battery you would need will be heavy. For example, a “Universal 12v 35 AH Deep Cycle Sealed AGM Battery” (a good compromise in AH) apparently weighs 22 pounds. And we haven’t begun figuring the rest (an inverter, the solar panel(s) which would be necessary to sufficiently recharge, the charger, etc..).

      Unless you’re hauling this stuff on an ATV, it might be a bit difficult…

      By the way, you mentioned that your 12 volt battery went down to 10 volts. It’s probably now a boat anchor…

      Here’s a battery ‘state of charge’ chart which may help.

      Hope this helped.

      Note: Although VERY expensive, a ‘Lithium Ion’ 12-volt battery (35AH) weighs 10 pounds, but costs $450!!

  3. Solar power generation for recharging is great, but what about, and this may be off topic, the use of a crank-style miniature generator, which as an added benefit doesn’t have to worry if the clouds are out or if you’re on the move and can’t keep reorienting your panels? A stator/rotor setup with neodymium magnets or something of that sort, with a diode? I’m no electrician, but PV seems not only expensive, but only works at certain times and latitudes…

      1. If you live near running water, or water that can be made to move with a small expenditure of labor you could use micro hydro. Wiki it.

  4. BT-C3400 Universal battery charger for Li-ion NiMH NiCd rechargeable batteries. Check your batteries for actual capacity measurement.Features four independent channels, like having four chargers in one. Program each slot individually or all at once. Easy to setup and simple to use.Back lighted LCD display Digitally displays capacity, voltage, time elapsed and current for each battery charging channel.Charge, Discharge, Refresh , Test. Even test internal resistance. This charger does it all with ease.NiMH/NiCd sizes: AAAA, AAA, AA, A, C and SubC. Li-ion sizes: 10440, 14500, 14650, RCR123A (17340), 17500, 17670, 18350, 18500, 18650, 19670 (protected 18650), 25500, 26500, 26650

    1. Looks like a good charger. The fact that it also charges Lithium Ion is a plus.

      FYI, regarding ‘home’ chargers (that plug in to ordinary 120VAC home wall outlets), the one that I’m currently using is:
      Maha Powerex MH-C808M 8 Cell Multi-Charger for AA/AAA/C/D

      I’ve had it for 2 years so far and it has operated very well. It does not charge Li-ion, but that’s not an issue for me since I’m stocked up with lots of Ni-MH (eneloop).
      Panasonic eneloop AA New 2100 Cycle Ni-MH Rechargeable Batteries

        1. Steve, I just loaded up the charger with eight AA eneloop batteries (partially drained) and am using the fast-charge mode (draws a bit more power than ‘slow charge’).

          I measured the power with my handy-dandy ‘Kill A Watt’ meter which indicates a pulsating fluctuation between 30 and 35 watts (@120 VAC) while oddly the measured current fluctuates between .42 and .46 amps (which translates to a slightly higher wattage, 55 watts). Not sure why the discrepancy.

          Suffice it to say it’s somewhere between 35 and 55 watts with a full load of 8 AA’s.

          I will check the power with ‘slow charge’ when these are finished charging and I load up some more…

          UPDATE: I just ran a batch in ‘Soft Charge’ mode. Apparently the max power requirement is the same. However the difference is in the charging profile. I can see it pulsing through three different current readings (whereas the normal or fast charge mode ‘pulses’ through two different current readings).

          1. thanks for the reply Ken. How long is it taking to charge at that 35-55 watts?

          2. @steve, That will depend on the ‘state of charge’ of the battery or batteries, so there is no one correct answer. If they are nearly depleted then it will take longer than if they’re somewhere in between. Additionally, this charger has a fast charge mode (the default) and a ‘soft charge’ which takes longer. Next time I charge some depleted batteries I will try and remember to approximate the time and update this comment…

            By the way, to be clear, this particular charger that we’re talking about in this comment-thread does not include a DC-adapter, and is only powered by 120 VAC.

  5. This is a very good post my son has been using a similar system for over a year for an off grid camper he lives in .Now it has one flaw when it is in heavy use. Cigar plugs DO NOT hold up well we found they fail after repeated use. WE use one cigar plug and added a 2 wire slip plug to the end .These hold up to heavy use. His system is a jump pack and 55 watts in panels. Mp3 player, DVD player, radio, cell phone, lights. Never a problem .

  6. OK. I am a novice to portable solar battery charging, etc.
    The Opus BT-C2400 comes with power inputs of 110ac and the automobile adapter as well. The portable solar panels that I see have only the USB plugs to deliver power. I am confused, how is that connection made from solar panel to this battery charger unit. (I need to charge only AA /AAA batteries.) is there an adapter connection that I need to have or purchase.
    I don’t understand the connection, litteraly. any help appreciated.

    1. @ Keith,

      The PowerFilm solar panels that are pictured (and linked) in this particular article come with an RA-2 accessory (12V female Cigarette Lighter Adapter). This will accommodate a battery charger which itself includes a 12-volt car adapter. Unfortunately the PowerFilm fold-able panels are fairly expensive. If anyone out there finds a less expensive portable fold-able panel (at least 10 watts or better, with a 12-volt car adapter), leave a comment and let the rest of us know…

      If you find other panels with only USB connectors, they are for charging cell phones, etc., and only output 5 volts for that purpose. I believe I’ve seen (online) some AA/AAA chargers which will connect via a USB connection – but am unfamiliar with their practical functionality, reliability, etc..

      1. Thanks Ken
        Would this work: Instapark® NEW All Black 10W Mono-crystalline Solar Panel with 12V Solar Charge Controller.
        Seems to be a flood of new, better(?), and different setups for portable panels.

  7. Great article – exactly what I was looking for! Thinking eneloops also – I saw the 10W Instapark on Amazon for $50, would it be worth it to go for the 27W at $115? Cost/watt goes down, but would the extra watts be used? The 27W version has 2 USB out puts as well at a 12V output – so you could charge your phone etc and the batteries right? Would it make sense – could you – set up a few of the chargers on the bigger Solar pack?

    1. @Banzai83, The 27 Watt Instapark Solar Battery Charger looks like an intriguing product.

      Adequate power to adapt its 12-volt DC output to an external ‘smart charger’ (as shown above) for AA’s, AAA’s etc by way of a 12-volt (fem) car adapter that apparently will connect to the Instapark 12-volt cable.

      Plus there’s the added benefit of 5-volt USB charge ports for other devices…

      Thanks for pointing out this product, which is a better price-point.

  8. Ken will the BT-C3400 Battery Charger Analyzer also work in this configuration with the PowerFilm F15-600 thanks

  9. Ken I guess I jumped the gun I went back and read the comments and seen the opus BT-C3400 Battery Charger Analyzer had been discussed. the only issue I have is why it comes with a 12 volt car adapter? or did I miss something

  10. I’m very new w/solar battery chargers. Can brand batteries such as Duracell/Enegizer AA AAA be used instead of AA AAA NiMH as I have a large quantity of them.

  11. I have ordered but yet to receive my instaspark mercury 27 solar panel. i currently have the bt-c3400 charger with both wall and car adapter. Works great plugged into 110. will this charger plug directly into the instaspark female car socket or does the power need to be regulated somehow? I’m electrically ignorant.

    1. Hi, kind of new to this stuff myself but I believe you have to have a controller that’s not too expensive to decrease the panel from 16 volts to 12.

      1. I’m not an expert on this stuff but have used panels to run the electrical systems on my sailboat. It is usual to have panel with higher output to charge lower voltage batteries. A charge controller takes the 16 volts and steps it down to a lesser voltage. A fully charged 12 volt battery has more than 12 volts in it.

        Also just noted, 3 vote away from #5!

  12. I have a wind and weather station which is mounted outside and runs of 4x AA Lithium or Alkaline batteries, I would like to replace these batteries with rechargeable and fit a solar panel to do the recharging. where can I get a controller for 6V and must the solar panel have a lower open circuit output (21V)

  13. Of the correct gender orientation! You mean plugs and sockets don’t get to choose? ROFL

    1. Those plugs and sockets have no choice – they’re stuck with the way they are!

      But wait, upon further thought, I do have a soldering iron and the ability to use it… and I suppose I could put them through an orientation replacement procedure and reverse them…

      1. In theory we dont get to chose either but now due to people wanting to play God some think they can change it to whatever,,,
        What the hell is wrong with our world now, its mental!

  14. Holy Christmas! I actually thought of something before you posted about it! LOL All kidding aside, a good friend of mine suggested this about a month ago and I’ve been looking at some on Google and Amazon to see what’s most affordable but still reliable. There’s mostly crap stuff out there but hey, that’s why we have people like yourself to take the time to wade through the junk out there and give us honest reviews of what works and what doesn’t! Thank you for that!

    1. Glad to be of help. Bear in mind that any charging system with solar panels will not work well (if at all) under persistently cloudy conditions. Fortunately though, the sun eventually comes out!

      1. Agreed! And sadly the friggin Annie song popped into my head when I read that last part….thaaaaat’s gonna be stuck there all day…friggin earworms LOL

  15. I still just use my Goal Zero setup, works reasonably well, my main use was for charging AAA batteries for my head lamp and it works for that, will also charge cell phone though and can plug other chargers into it with some home made adapters

  16. That smart charger is exactly what I have been wanting. One of the most frustrating things for me is that one of my chargers will only do 2 AAA batteries at a time, no more, no less. My other charger will only do 4 AAA batteries at a time, no more, no less. Between DH and myself, we have 5 headlamps​ that all require 3 AAA batteries. Recharging the batteries has been a juggling act. I can’t even put into words how excited I am that I will be able to charge 3 batteries!!! The other thing is that one of my chargers​ plugs into the wall, the other into the solar panel. To have one that can do both is brilliant!

    As far as portable panels go, I have had excellent experiences with Goal Zero. I love the way that it clips to my backpack or my boat for river trips. It’s​been great for recharging batteries for lights, GPS, etc., and phone/camera on long backcountry trips. Mine isn’t, but all of the new models are chainable. That feature would be especially cool when traveling with friends who also have portable panels, which seems to be the case more and more.

    One thing that DH and I have been discussing is a generator for power outages. We have pretty much decided to go with a solar one instead of a gas one. We are saving our pennies and hope to get the Goal Zero Yeti 1250 with chained GZ Boulder panels and chained AGM sealed batteries. The whole setup would be stored in a Faraday cage. Yes, it will take many pretty pennies to get a setup like this, but it will be silent and we wouldn’t have to store gas. I would love to hear some feedback on this, as I know there is a wealth of experience amongst you…

    1. I had one that could do 2 AAA’s and 2 AA’s. With a bit of fiddling I could get it to do 4 AAA’s at one time. Unfortunately I cannibalized it for another project…

    2. The guide 10 plus will charge 1-4 batteries but you have to have 4 in it, dont all need to be dead though, its just how the paralell loop works, i believe they equalize and charge together.

      1. Nailbanger, I did that with “non-dead” batteries to complete the loop and they got really hot. I haven’t done it since, because I was afraid they might catch fire from overcharging. This wasn’t born out of scientific knowledge, but from all of the stories of batteries catching fire and how hot they were. Does anyone have any data one way or the other?

  17. What I have, I feel like a Salesman.

    NITECORE i4 Intellicharge Universal Smart 4 slot Battery Charger

    Bundle with 12V DC Cable, EdisonBright BBX3 Battery Box, 2 X EdisonBright AA to D type Battery Spacer/Converters

    Able to charge over twice as many types of batteries as its previous model
    Automatic current selection chooses optimal current based on battery’s capacity
    Capable of setting the charging voltage of each bay individually
    Active Current Distribution (ACD) technology ensures optimal dispersal of charging current amongst installed batteries from 1 to 4
    Automatically detects non-rechargeable batteries and notifies user
    Overcharge protection automatically stops charging after 20 hours to prevent overheating
    Reverse Polarity Protection prevents damage to both batteries and charger
    Special charging setting specific for IMR batteries

    Compatible with batteries:
    Li-ion / IMR / LiFePO4: 26650, 26500, 25500, 22650, 22500, 21700, 20700, 18700, 18650, 18500, 18490, 18350, 17670, 17650, 17500, 17350, 16650, 16340 (RCR123A), 16500, 14650, 14500, 14430, 14350, 13650, 13500, 13450, 12650, 12500, 12340, 10500, 10440, 10350, 10340
    Ni-MH / Ni-Cd: AA, AAA, AAAA, C, D

    1. It looks like it allows you to use AA batteries in a device that normally requires D. Is this true? If so, is there any noticeable difference in power? I’m thinking about my large maglight…

      1. You don’t want to substitue anything for a real ‘D’ battery. There are adapters that simply utilize a smaller battery to be inserted into a ‘D’ size form factor. Nowhere near (not even close) enough equivalent power to properly operate whatever device takes the D-cell.

      2. Skibum
        the adapters I received with the charger hit the bottom drawer real fast, only in an absolutely “Gee that was STUPID NRP”, would I use them. But in a pinch, what the heck, 30 minuets of flash light is better than none…..
        And a flashlight designed with a xyz LED that run’s on AA and a flashlight that run’s on the same LED with D size batteries, will it still not run as long as the AA flashlight? Same draw from the LED bulb, correct? So carrying some AA’s AND some D’s, maybe that adapter is not such a bad idea considering weight? Or just get the smaller AA Flashlight to begin with and toss out those adapters….. :-)
        Just saying.

  18. Thank you! Like someone else said, exactly what I’ve been thinking about. Anyone have titles for good, fairly simple, books on this kind of lower end solar rigging?

  19. A few years back I got a battery charger at the fancy gadgets store at the airport during a layover. It also charges alkaline batteries. I strictly use it for D size batteries. (Cue the safety Nazis).
    I can charge 4 at a time. I have charged 10 since yesterday and have 4 in now. The 4 in the charger have been charged 9 times. This will make 10 charges if they take the charge. The 120 ac plug reduces to a 12 volt 1 amp rating . These batteries go in the old school flashlights that I have placed all around the property. I keep the chargers on a piece of cement board on top of a metal rolling table just in case.
    I also have solar charger that clips on a backpack and a small panel I hooked up to trickle charge a 12 volt battery that I can use to charge all types of equipment.
    I use rechargeable AA/AAA for headlamps and led flashlights…

    1. Bill J H
      Ya know when I was a kid 900 years ago, my Dad would charge Alkaline batteries all the time with no problems, I wonder what changed? Besides now a battery cost 10 times as much.

      1. Nothing changed except the company needed to sell more batteries so they started telling everyone it wasn’t safe. In my (recent) experience the alkaline batteries will charge with no problems but they tend to heat up faster so they can’t be left IN the charger after they’re fully charged. They will start to leak after being recharged a couple times (average seems to be about six recharges) so watch carefully for any sign of bulging. Quality also matters–the batteries from the dollar store will start to fail after one or two recharges.

        I have never had a battery explode, although some have heated to the point that I couldn’t touch them to get them out and had to unplug the charger. Yes, I’ve had some leak but after a while the rechargeables leak as well. And after a while the rechargeables get hot in the charger. It just takes a little more time.

        The main difference between the rechargeable batteries and the alkaline seems to be that the alkaline reaches their minimum faster–the point where the battery will no longer hold a significant charge and should be discarded. Eventually all batteries get to that point.

  20. Superb article!! With solar panels are they in danger of being fried from EMP? Thanks all!!

    1. @scprepper, Pretty much everything with electronic circuitry is vulnerable from EMP, depending of course on the factors of the EMP itself. Some people store away a few essential items in a Faraday cage, just in case. (A metal trash can with a lid – inside lined with something non-conductive)

  21. Can I recommend Olight rechargeable flashlights. They are CR123R based system that are rechargeable by induction pad that is USB cable voltage feed. I got two of them and they are as bright as any Surefire. I got a head lamp based and a hand held version. I have yet to wear the batteries out so I do not have real info on charge times.

  22. I checked Amazon and both devices had plenty of one and two star reviews which is kind of scaring me away from these two devices. Are yours older, maybe? Have you bought more since then? I see posts are 5 yrs old, so maybe these devices now have quality control issues?

    1. SSH
      my go to for charging AA and AAA batteries is the Goal Zero Guide 10.
      is a little expensive but after 5 years it still works good. I also use a Panasonic Eneloop charger that plugs into the wall, but have an inverter that i can run it off a car battery connected to a 50w solar panel or plug into my truck.

    2. SSH,
      I just checked each of the product links in the article. They all have nearly 5 star ratings. So I don’t know what you’re referring too exactly?

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