Pale Blue is a battery/project on Kickstarter that is a recharge-via-USB AA-Sized and AAA-sized LiPo battery. Claims by the manufacturer are one battery will save up to 1000 conventional batteries per unit and thus far in testing I have not had reason to doubt.
A couple of years ago I was introduced to my first recharge-via-USB AA battery. The concept was novel, the execution was not particularly noteworthy as performance was not what I’d expect for in something trying to replace conventional alkaline.
Pale Blue now has an offering that while not a new product, seem to be (so far,) as advertised. A micro-USB rechargeable lithium polymer battery that can be reused an estimated 1000 times before it degrades significantly.
I’m going to compare a 4 pack of AA sized Pale Blue to a pack of Duracell here because that’s what I’ve got. The current cost of the Duracell, best price is $0.64 a battery that I can locate. The current cost of a single Pale Blue AA is expected to be about $7.50 with charging hydra dongle included.
That puts the Pale Blue at about 11.7 times the cost of initial purchase, but factor in the recharging and you would be seeing about $640 vs $11.7 over the estimated life of the product.
If it lasts 12 recharges you broke even.
There are also no chargers to buy (although you are expected to have a USB-A standard charger, which we all do these days,) and you can recharge with any Micro USB cable, or use the 4-headed Micro USB cable they include with any standard USB socket to charge four at a time.
I’ve had my doubts about this type of battery. My experience with the Green ones (different company,) that I didn’t bother to write about two years ago and what I’m guessing is a faulty 14500 that came with the very expensive flashlight have me distrusting this style, but so far at least there’ve been no issues.
What’s better is I can recharge things like flashlights wherever I’m at now. My car, work, at an airport. All I need is a cable. Now, if I want to recharge four at a shot I might want to have their 4-pronged recharge cable in tow, but it’s cool.
Charging time for a AA is a little under two hours from dead, as long as you’ve got a two amp charger you can charge four at a time in that timeframe. Lower amp chargers will take longer.
But I had some questions
how long from a charge until these have discharged half their life without being used? Is this known? How does that compare with traditional?
I think the question relates to ‘self-discharge’, which is how long the battery would last without being connected, just with internal consumption. Firstly we should recognise that the Pale Blue battery is an electronics assembly of a power pack (the chemistry part = Lithium Ion or Polymer) and secondly the Electronics part (PCBA with a power regulator and safety management circuit). This is different to a traditional battery, which is purely chemical, there is no electronic circuit inside. The Electronic circuit in Pale Blue allows the battery to efficiently and safely control the charge / discharge, hence the rapid charge time and very stable 1.5V discharge. This does however mean there is some small load on the cell, even when the battery is not connected or in use, due to the internal circuit drawing some small current. As such the Pale Blue is a battery which ‘wants’ to be used, the more its charged / discharged the more useful it is. It’s not a battery which is designed to be charged and stored for a very long time. It’s not ideal for ‘Domesday prepper’ type applications. Pure chemical batteries will sit on the shelf longer, holding the chemical potential energy internally. Pale Blue self-discharge would fully drain a fully charged battery, stored in the plastic case (not inserted into a device) in 18 months. But we really recommend the battery is moved around, in different applications, or seasonal type products, where it’s in more regular use, or at least give the battery a top up charge after ~6-9 months of no use. This will also gain the maximum return from the investment in a recharging solution.
Can you use a normal recharging station like for the old style rechargeables or would they blow up?
No, a traditional recharging dock can’t be used with Pale Blue. There are a few reasons why, not least as normal rechargers are designed to be used with NiMh batteries, which only recharge at 1.2V, and Pale Blue recharges at ~4v (hence the faster recharge). However, if a user does put them in an old recharging dock, basically nothing will happen. The battery cannot draw current in from the external terminals, only from the microUSB connector.
Is there any mechanism with these to indicate if the voltage they’re putting out is inconsistent? Can they shut down? What happens when they’re overloaded? Is there a max chain of batteries you can use these in (EG 8xAA)
The battery will always put out 1.5V, until the power pack inside is drained. The circuit is designed to put out 1.5V, and as long as it’s powered by the cell inside, that’s what it will run at. This is different to Alkaline or NiMh batteries. As mentioned above, those other type of batteries are purely Chemical assemblies, there are no electronic controls inside the batteries. The output voltage is purely coming from the internal chemical reactions generating a voltage potential. They start at 1.5V (alkaline) and 1.2V (NiMh), but actually as the battery drains the voltage drops off quickly, and they end up running at around 1V. Pale Blue will put out 1.5V continuously, until the battery cell is fully depleted. The circuit has a protection IC (PMU), and this allows a max current drain. If the current drain is too high, for example the battery is shorted out with a wire connecting +/-, excessive current will flow and that would overheat the PMU circuit. The PMU will shutdown the battery in this case to protect both the cell and the circuit. This is part of the safety design. After the cell and PCBA have rested the cell will return to normal function. Depending on the ambient conditions (say at 25 degrees C), this might happen with high current drain, like 3A or above, continuously. Very few portable applications using AA or AAA type batteries will draw 3A continuously, mainly as the small size battery would be depleted very quickly at high current drain, so it’s not a good application. Products like home power tools (drills etc) draw this kind of current, but they typically have their own specially designed power packs for this reason, they don’t use AA type cells. So in normal household, toys or outdoors applications, the max current drain is typically <2A, and Pale Blue will support this comfortably. There is no effective maximum chain, but I can’t think of many normal applications where more than 4 / 6 / 8 AA cells would be designed into the product. The current flow running through the batteries is constant in a circuit. Batteries are connected in sets to increase the Voltage (which adds up, so 4 x AA = 6V), but the current doesn’t ‘add up’ as the current flowing in any circuit is a constant.
What’s the oldest living test unit of these batteries and how does it compare?
We have cells around 18 months old from very early samples. We have made several improvements since then in the fit of the battery, the robustness of the casing etc. For example, note that current Pale Blue AA’s are built with a metal cannister that fully encloses the Lithium power call ‘pot’. This makes it much more robust and stronger. These are the types of improvements that support our claim to have the ‘best’ AA / AAA rechargeable on the market!
Do you manufacture these yourselves or are they rebranded?
These are manufactured specifically for Pale Blue to our design and test specifications. We have made various R&D / DFM type improvements which are only incorporated into our batteries. We also have additional sizes of batteries, with similar custom improvements coming to the market this year.
In my testing they’ve performed near to what I expect a standard battery would. I’m not really set up for battery drain testing on AA and AAA units, but the Pale Blue AA vs a 6-year-old have thus far been on par with traditional.
I will be updating if these fail in the future, however to go through 1000 normal discharges to see whether they last that or the full 18 months would take several months.