Tag Archives: Batteries

Steve searches for a USB-powered battery charger for solar recharging

Many thanks to SWLing Post contributor, Steven Crawford, who writes with the following inquiry:

[I’m searching for] good quality USB powered battery chargers for AA and D size rechargeable batteries.

Wall outlet chargers are common but quality USB powered battery chargers appear much less common…less common than the packable solar panels with USB ports such as Anker’s, that could be used to power them. Ideally the charger should handle Nicad’s, NIMH and Ii-on but have standardized on AA, AA + D adapter sleeves, and D batteries for my storm supplies.

If I understand correctly, you’re searching for a good qualityUSB-powered battery charger that supports multiple battery chemistries (nickel-cadmium, NIMH and lithium ion) so you can recharge AA, AAA and D batteries with a portable solar panel.

I’m hoping SWLing Post readers can offer some suggestions.

I’ve also looked into this type of charger for both Ears To Our World and my own personal use when off-grid in the summer. I’ve never found one that truly supports all of the battery chemistries you mentioned. The one I’ve used (an EBL) works quite well, but only supports NiMH AA and AAA batteries. As you mentioned, you can use D cell sleeves with the AAs.

EBL makes a number of USB chargers that can be found by searching Amazon. This one–an EBL Quick Charger (affiliate link)–can recharge NiMH batteries within 40 minutes and I’ve personally used one. I’ve been pleased with EBL batteries as well.

I never use nickel cadmium rechargeable batteries at this point, so really don’t know what’s available on the market.

I have found that there are a number of USB-powered lithium battery chargers, but typically for specific lithium cell configurations like 18650, 16340, 14500, 26650, etc. Some of these inexpensive chargers have magnetic contacts that can fit almost any battery type and on Amazon and eBay they claim to recharge multiple battery chemistries, but frankly I’m quite skeptical. These $9 devices don’t seem to have a way of detecting battery chemistry, thus I’m not sure how they would adjust the charging cycle accordingly. Perhaps I’m incorrect in this assumption?

Other than using Powerfilm solar NiMH battery chargers (I can recommend these) which are incorporated in their folding panels, I’ve never charged batteries directly from a solar panel. Typically I have a 9ah or larger 12V battery floating between the PV panel and the charger.

I’ve found that using a 12VDC charger–like this–that’s pulling power from a 12V battery is simply a little more efficient, faster and reliable than charging directly from a small PV panel. Since I always have 12V batteries on hand when off grid, it’s a simple solution for for my system.

Post readers: do you have any USB-powered battery charging suggestions for Steven? Please comment!

Guest Post: Battery Testers–Don’t Get Caught Without One!

Many thanks to SWLing Post contributor, Mario Filippi (N2HUN), who shares the following guest post:

Battery Testers; Don’t Get Caught Without One!

by Mario Filippi, N2HUN

(All photos by author)

Ever consider what life today would be like without the humble dry cell battery? Old timers know the term “dry cell” as opposed to “wet cell.” The dry cell is your garden variety battery for sale composed of a semi-dry composite or paste of chemicals designed to make electrons flow when the circuit is complete, such as in flashlights, radios, remotes, watches, etc. “Wet cells” on the other hand have fluids, such as sulfuric acid that work in conjunction with lead plates. But let’s stay with dry cells for now. Walk into any house and you’ll find some form of battery powering a plethora of devices that contribute to the quality of daily life. In short, life without the humble battery would be unfathomable.

Electronic Menagerie: Radios, Timepieces, Flashlights, Remotes, Test equipment, Mouse.

Batteries, like humans, unfortunately expire due to age or use. True, they toil tirelessly while out of sight and mind, hidden behind plastic compartment panels somewhere in the bowels of a device and for the most part are ignored or taken for granted. That is until the device they are powering ceases to function. We’ve all been there and done that countless times in our lives with an array of consumer products. Most instances of battery failure tend to occur at the most inconvenient times, that is when the device they are powering is needed most (a corollary of Murphy’s Law hi hi). A good example is the toolbox flashlight. It can sit amongst the tools quietly and ready to go (at least in our minds) until we switch it on while working in some dark, cramped location. Or late at night when under the covers and the bedside shortwave radio starts spewing out distorted audio. To boot, the radio’s convenient dial light is too weak to determine where you are in the shortwave spectrum.

Motley Crew of Cells in Author’s Armamentarium Awaiting Call to Duty.

Well, all is not lost my fellow hobbyists; it is time to do some cell (dry cell that is) soul searching and plan for future failures. I propose a useful acquisition for the home, shack, Go-Bag (or what have you) that won’t break the bank; a simple battery tester that’ll be the end to your power problems.

At this QTH an AMPROBE BAT-200 was purchased a few years back from Amazon and has proved its worth and utility many times over. This simple tool, which ironically needs no batteries, will test many of the common batteries around the shack and home such as AAA, AA, C, D, 9V, and button batteries.

Pocket-size BAT-200. A Snap to Use.

Since purchasing the BAT-200, life in the battery cosmos has become a lot less complicated. Armed with one of these, you can immediately rule out battery failure when troubleshooting myriad devices. You can also test outdated batteries to determine their status.

Flashlight, Magnifying Light, and Head Lamp…

…Test meter…

…And Various Remotes Use A, AA or Button Batteries.

AA Battery from Remote Tests “Good.”

An item such as the BAT-200 can be found for less than five dollars if you shop around, and will pay for itself by taking the guesswork out of the bad battery scenarios. You’ll wonder how you ever did without one!

Thank you very much for sharing this post, Mario!  

At the SWLing Post HQ, we keep all of our loose batteries in a “battery box.” All new cells stay in the packaging where we mark the date purchased (although many alkaline cells now have a “best by” date). We recently pulled all of the loose/orphan batteries out of the box–there must have been 40+–and tested the voltage of each one. I used the test meter from my toolbox to do this, but I’ve just ordered one of the BAT-200 chargers from Amazon and will now keep this in the battery box permanently.

Thanks for enabling me, Mario! Ha ha!

Click here to check out the BAT-200 in Amazon.com (affiliate link).

Anil’s hack: Using a smart phone battery bank to power portable receivers

Many thanks to SWLing Post contributor, Anil Raj, who writes:

I wanted to share a small but useful hack with your readers.

I use a common garden variety smartphone “Powerbank” 10,000 mAH Li Ion pack to power my Sony 7600GR which is perfectly happy with the 5V which the pack supplies. [See photo above.] I see no reason why this won’t work with other radios which require a 6V supply.

As you can imagine, the setup typically lasts for many weeks of extended daily listening and recharges in a jiffy. However, one needs to sacrifice a USB cable by soldering a DC plug at the other end. Haven’t bought AA batteries in a long time…

Thank you, Anil! What a simple but useful hack. The best part is, battery packs/banks are  very inexpensive these days and, I for one, have a number of USB cables I could sacrifice for the job!

Off-Grid Radio: Portable power recommendations?

Elecraft-KX3This year, I have a lot of portable radio play in mind as I travel across the continent. At some point, I even plan to spend several days in an off-grid cabin on the coast.

In the past, I’ve powered my 12 VDC ham radio transceivers with a system comprised of three PowerFilm solar 5 watt foldable PV panels (see below), a Micro M+ charge controller and several gel cell type sealed batteries (a couple 7 Ah and one 20 Ah).Powerfilm-Solar-Panel

The system works well, but the batteries are a little heavy and unhandy when I want to hike into a remote site or play radio on the beach, for example.


In terms of receivers, my portables (like the Sony ICF-SW7600GR, Tecsun PL-660, etc.) simply use AA batteries which I charge with PowerFilm AA PV chargers (see above). My CommRadio CR-1a has an internal battery that will power it for hours at a time.

Power is much less of an issue with receivers because they’re quite resource efficient.

I mainly need a system to power my QRP ham radio gear, and that’s where I could use your experience!

Wish list

Charge controller

I need a new charge controller since my Micro M+ (no longer produced) is now being used to power a remote antenna tuner.

Of course, I’ll need an inexpensive charge controller that doesn’t produce RFI (radio interference).

It would be an added bonus if the charge controller could also charge my batteries when grid power is available.

12 VDC Battery packs

I’d like something relatively lightweight and safe.

Note: LiPo packs worry me, especially since I had one (an early GoalZero model) quite literally melt down and burn up on my bed only a few hours after bringing it back from an eight hour flight a few years ago. Scary!

Pure Sine Wave Inverter


I’d also like a small, efficient pure sine wave inverter that I I could connect to my largest battery and power my laptop for extended SDR spectrum recording sessions while off-grid.

I’d love a recommendation from someone who uses one and can confirm a model that doesn’t create radio interference while operating.


Post readers: Please comment with your recommendations and include model numbers and links if possible. Thank you in advance!