Self Charging Batteries!

[Jim Cassedy]

Ok, I know the subject line is somewhat misleading, but it got your attention, right?

I got these AA batteries with built in USB charging ports on Amazon last week.
I haven't had a chance to do a complete load-&-lifespan test yet, but so far
they are working just fine in an AM/FM/SW portable radio I use a lot at home.
USB_Battery1.jpg

USB_Battery2.jpg

They came with an octopus charging cable that plugs into a
standard USB wall-wart power cube. (Technically, I guess it's
actually a 'quadropus', since there's only 4 output leads)
The top each cell has an LED built in to indicate charging status.
USB_Battery3.jpg

Jim C

[Carsten Kurz]

I saw them in an add today, and looked up the datasheet. They seem to offer 1000mAh in AA size, that is a lot less than conventional NiMH rechargeable cells. However, they probably offer constant 1.5V voltage, which probably makes up for the smaller capacity.
I also just checked a larger radio shack, and they seem to offer similar batteries with higher capacities (at a higher price, of course).

These mWh numbers are unusual for rechargeable cells, but they compensate for the different output voltage between these and the 1.2V of NiCd or NiMH cells.

They probably contain a conventional Li Polymer battery with a 3.7-4.1 volts cell voltage, plus a charging circuit, and a small DC/DC converter to create 1.5V from the higher native cell voltage. Wondering what their max output current is, as that is limited by the current capabilities of the DC/DC converter.

As DC/DC converters often create RF-Noise, a radio may not be the best usage scenario, but, maybe the case is metal and offers enough shielding?

What did you pay for the set of four?

[Jim Cassedy]

[Edited]They probably contain a conventional Li Polymer
battery with a 3.7-4.1 volts cell voltage, plus a charging circuit, and a small DC/DC converter
to create 1.5V from the higher native cell voltage. Wondering what their max output current is
as that is limited by the current capabilities of the DC/DC converter.
As DC/DC converters often create RF-Noise, a radio may not be the best usage scenario,
but, maybe the case is metal and offers enough shielding? What did you pay for the set of four?

According to product page on Amazon, they are Lithium-Ion batteries, and have a conventional 1.5V
output. This seems to be verified in the customer reviews by people who've done measurements,
although I haven't had a chance to do voltage & current readings myself. - They've got a 4.6★ rating
and the customer reviews I read were mostly positive. As I mentioned, I'm using and testing them in
a portable Grundig AM/FM/SW radio and I haven't noticed the batteries producing any RF noise.
I see there are also 9V batteries with built-in USB-C charging ports on Amazon. I'm darn curious
how they're doing that- - although obviously they must have some sort of DC-DC conversion circuitry
inside. The price was $25(US) for the 4 USB cells + cable I got, although you can buy them in
several different quantities and mAh ratings.

[Harold Hallikainen]

If they have a switching dc to dc converter, they probably need an FCC and CE declaration of conformity

[Frank Angel]

And how much space does that converter take up? Given even the most space=efficient surface mount components, I would guess the area that it needs has to be enough to compromise power storage capacity. Even the USB-c port itself, given the limited physical space of that AA body would be eating up a good percentage of area available for NiCd or NiMH material.

[Ryan Gallagher]

If you deal with a lot of batteries, I’d personally rather have bank charging, instead of the inevitable tangle of charging cables. But these have real utility in-situ portable devices, since many people already carry suitable chargers.

What would sell me is if they were ALSO compatible with bank chargers TOO. I’ve not tried that, but most modern charging banks can handle all kinds of cell chemistry, but maybe not these.

[Tj Hopland]

I have seen similar products on the market for many years now so the concept isn't new. I never tired em or got too deep into research. I suppose it really depends on the product you are using them in and how often you are using it plus things like when its off is it off or is there some sort of constant drain.

Initially I was thinking that the higher and able to maintain the higher voltage thing someone mentioned would be really cool but then I wonder how many devices that run on this type of battery is that actually a problem? Seems like battery stuff that has that low of a current draw would have button cells? But I suppose something like a TV remote ? I don't think those have any standby draws so no problem there and your only using a slight amount of power in short bursts so maybe that's an ideal application?

I wonder if they have any sort of protection to prevent bad things from happening if you did stick them in a more conventional nicad or nimh charger? This strikes me as the sort of product that was developed or requested for a specific user and where cost wasn't a factor so they could also design custom chips and other components making them maybe sell for say over $100 each. Then like many things these days someone else says we can make something that looks like that and may or may not understand or care what they are copying.

[Leo Enticknap]

I like the idea of an AA rechargeable that actually gives you 1.5V (I have several devices that won't work with 1.2V NiMH rechargeables, in which I have to use one-time batteries), but not having to mess around with cords and wall warts. Will these things also charge in a regular charger such as this one, or only via USB-C?

[Jim Cassedy]

<Edited> Will these things also charge in a regular charger or only via USB-C?

I've been wondering the same thing, but have not actually tried that yet. Since there's some 'extra'
circuitry in the battery, I'm not sure how a regular stand-alone charger would react. It may not even
'see' the device as a battery. While the tiny instruction sheet that came with the batteries doesn't
specifically say "no", one precaution reads: It is strictly forbidden to use non-designated chargers
to charge this battery" If I'm feeling adventurous tonight when I get home, maybe I'll give it a try!

[Ryan Gallagher]

I've been wondering the same thing, but have not actually tried that yet. Since there's some 'extra'
circuitry in the battery, I'm not sure how a regular stand-alone charger would react. It may not even
'see' the device as a battery. While the tiny instruction sheet that came with the batteries doesn't
specifically say "no", one precaution reads: It is strictly forbidden to use non-designated chargers
to charge this battery" If I'm feeling adventurous tonight when I get home, maybe I'll give it a try!

The other possibility is that it would "kinda" work, until the lithium starts delivering 1.5v again due to the voltage regulator, and then the standard charger would think the battery is full.

I'm gonna lay my money on the regular charger not recognizing them at all... or always claiming they are full already.

Also how do you know they are topped off? any status LED built into the charging cap?

[Jim Cassedy]

<edited> how do you know they are topped off? any status LED built
into the charging cap?

Yes. There's a tiny LED in the top of the battery. During charging,
it flashes green. When it turns solid green, it's at full charge.

[Ed Gordon]

It looks like it might be problematic to use any charger for lithium ion batteries. Amazon does sell chargers that will work.

Charging Requirements for Lithium-Ion Batteries

Do You Need a Special Charger?

Lithium-ion batteries typically require a charger specifically designed for their chemistry. While some lithium batteries can be charged with standard lead-acid chargers, this is not recommended for optimal performance and longevity.

Why a Dedicated Charger is Important

• Voltage Requirements: Lithium batteries operate at higher voltages (14.4 to 14.6 volts) compared to lead-acid batteries. A standard charger may not fully charge a lithium battery, leaving it at 80-90% capacity.
• Charging Profile: Lithium batteries use a constant current/constant voltage (CC/CV) charging method. This differs from the three-stage process used by lead-acid batteries, which includes bulk, absorption, and float stages.
• Battery Management System (BMS): Lithium batteries have a BMS that manages charging and discharging. Using an incompatible charger can confuse the BMS, potentially leading to errors or damage.

Risks of Using the Wrong Charger

• Undercharging: A non-lithium charger may not fully charge the battery, reducing its capacity over time.
• Overcharging: Some chargers may apply voltages that exceed safe limits for lithium batteries, risking damage.
• Insurance Issues: Using an incorrect charger could void warranties or insurance claims if damage occurs.

In summary, while some lithium batteries can work with standard chargers, using a dedicated lithium charger is highly recommended to ensure safety, efficiency, and longevity.

[Jim Cassedy]

<edited>
It looks like it might be problematic to use any charger for lithium ion batteries. \

Generally speaking, that is 100% good advice, especially if you've seen any of the
numerous scary videos on U-Tube of Lithium-Ion batteries bursting into flame while
being recharged. However, these particular batteries have their own built in charging
circuitry of some sort, and all their documentation states they can be be recharged with
'any' standard 5V USB power source.

<edited> Will these things also charge in a regular charger?

Just for fun, last night, I tried putting one of these batteries into a 'smart charger' that I have
which can automatically detect the type of battery (ni-cad, Li-io, etc) and adjust the charging
parameters accordingly for each type.
> The charger correctly identified the battery I inserted as a Lithium-Ion cell. However, it did
not attempt to charge it, even though I had run the battery down enough for it to need a charge.
After a few seconds of analyzing the battery, LCD display on the charger simply began to flash
on-and-off, which for this particular charger indicates that it has gone into an "error" mode and
then it shut down for safety. I'm sure this is at least partly because the charger 'sees' the charging
circuit that's built into the battery, and detects it as an error or fault of some sort.

It would be fun to send a couple of these cells to Big Clive for him to dissect and reverse
engineer to see whatever tiny circuitry they've got inside

We are semi-shut down for the next week or two for installation of all new seats and carpets,
so I may stick a couple of these into one of the wireless microphones to see how they perform.
(Although, generally speaking, I'm against using rechargeable batteries in wireless microphones,
and, in fact, I've worked at several large conventions, trade shows, and film festivals, where it
was expressly forbidden to use rechargeables in the microphone systems)

[Ed Gordon]

... I'm against using rechargeable batteries in wireless microphones,
and, in fact, I've worked at several large conventions, trade shows, and film festivals, where it
was expressly forbidden to use rechargeables in the microphone systems)[/I]

I had never heard of there being issues with using rechargeable batteries in wireless microphones, so I googled it and found this from Shure:

By knowing the current draw of the wireless transmitter along with the capacity of the battery, it is possible to know the life of the battery. Wireless transmitters that use AA batteries, rechargeables and alkalines both perform well. For older transmitters that use 9 volt batteries, it is easy to show that rechargeable 9 volt Ni-Cd and Ni-MH batteries have a much shorter life than standard alkaline types. For this reason, 9 volt Ni-Cd and Ni-MH rechargeables are typically not well suited for wireless transmitter applications. Therefore, 9 volt alkaline batteries are the best choice because of their performance for the cost. If an application does require rechargeable batteries, use the 9 volt version of the rechargeable Li+ batteries.

The full article on batteries can be found at: https://service.shure.com/s/article/...S&region=en-US

[Leo Enticknap]

Me too. I'm guessing that these bans are in place because there are just too many reliability variables with them: what capacity are they (and have they degraded from the original mAH spec?), is there any memory effect, is a mismatched set dragging down the overall voltage output, etc. etc. I have a pair of walkies that I use in some install situations where cell reception is not reliable to co-ordinate things like doing convergence and testing things in good locations. A good condition, fully charged set of 2,000 mAH NiCD AAs gives them around two hours. A set of Durahells (so called for their propensity to burst and vomit alkaline goo throughout your device's battery compartment) or Sodomizers (so called for their cost) easily gives them 6 to 7. I suspect that this is why theaters, conference venues, sports stadia and other workplaces that use radio mics and walkies go through staggering quantities of one-time AAs. I worked one festival in which the tech director had a cast iron rule that a fresh set of lithium, one-time Energizers (that cost around $2.50 per individual battery) be installed in all devices at the start of each day, regardless of whether they had been used at all the previous day!