EDIT - have purchsed the XTAR batteries with the XTAR LC4 charger.
Hi All, I'm not the most electronically knowledgeable person, but I know I need some 1.5v rechargable AA's to power one of my audio devices correctly.
I've seen XTAR batteries get good reviews but unsure about compatibilty with my charger and Chat GPT is telling me Hixon 1.5V Lithium are compatible with the UM4.
Can anyone confirm, deny or recommend some 1.5v batteries that will worth with my charger?
Thanks!
I think that is the actual question , please recommend rechargeable aa batteries (lithium?) that output 1.5v nominal, not 1.2v ~ 1.3v you get with nimh.
thanks! I had no idea my qustion would cause such confusion.
yes, I need a 1.5v AA batteries. I have a nitecore UM4 charger. I don't really want to buy a new charger. I'm not sure if there is a lot of false advertising or nuances around 1.5v batteries. came for some recommendations.
More info needed.
What you are asking for does not really exist. So lets look at what you actually need. What exactly is the requirement?
Primary cells are 1.5V nominal, not rechargables.
@bargaino: I guess you should tell that to all the manufacturers who are selling 1.5v rechargeable batteries.
@buckerooni: When you make a sarcastic comment like that, we can't tell if referring to the li-ion cells with 1.5v buck converters built in, or to NiMH, or whether you understand the difference.
Out of curiosity, why are you asking here?
Probably because OzBargainer is the foremost eneloop website in Australia.
Yeah, it's not just all ADAGCHS.
1.5V AA/AAA lithium rechargeables are readily available in a number of brands.
They use a lithium cell, with a small IC that converts its 3-4V output down to 1.5V output.
They are available to either be charged with a charger, or directly charged with a charging cable that plugs into a socket in the top of the battery.
But while their output is a 1.5V from fully charged right down to flat, when output suddenly drops to 0V, they have to be charged with 5V. And the IC strictly limits both the charging rate and output current. So they are only suitable for light loads.
And whether your charger can understand what voltage it is supposed to supply, you'll have to look at its specs and compatibility.
thanks, soooooo, any recommendations?
Sorry, there a number of brands of 1.5V constant voltage lithium ion rechargeables, and they all seem to work the same, and have similar reputations. I bought TPOWER, and they work as claimed, with the exception of one that seems to run out of charge earlier than it should.
I understand how they work in use. The IC in the top regulates the 3-4V from the cell down to a constant 1.5V. But I have no idea how it works if you put them in a charger. I know there are chargers specifically for them. Without understand more how the charging process works, I wouldn't dare put them in something like a UM4 charger that's not designed for their sort of battery. I'd be afraid I'd fry the IC.
I bought mine in packs of four. Each pack contains a charging cable which goes into a PC USB-A socket at one end and has four microUSB connectors at the other end that plug into sockets on four of the batteries at a time. So I don't use a charger as such. I don't need one. You just leave them plugged into USB charging until the LED on the top stops flashing. That version of the batteries with the socket for direct USB charging has a bit smaller capacity than the other version that doesn't have a socket and requires a charger.
The core challenge here lies in the intricacies of voltage regulation and compatibility with chargers like your Nitecore UM4. Lithium-based 1.5V AA rechargeable batteries operate on a fundamentally different principle than traditional NiMH or alkaline cells. As GordonD astutely noted, these batteries utilize an internal DC-DC converter (likely a buck converter) to step down the nominal 3.7V of the lithium-ion core to a steady 1.5V.
Now, this raises a few interesting points of inquiry:
Voltage Hysteresis and Converter Efficiency: The internal converter typically has a limited efficiency range (around 85–92%). This means that for higher current draws, the battery might not provide the necessary peak power for devices that require instantaneous surges—like audio equipment. You’d need to account for this in your device’s power profile.
UM4 Charger Profile Compliance: The Nitecore UM4 charger is primarily designed for cells like Li-ion (3.6V/3.7V), NiMH/NiCd (1.2V), and LiFePO4 (3.2V). While it might physically charge lithium-based AA cells with an integrated voltage regulator, the charging current and termination voltage must align precisely with the IC's firmware logic. Any deviation here could cause overcharging, undercharging, or trigger a fail-safe cutoff, rendering the batteries unusable.
Pulse Current Demands and IC Tolerance: Many 1.5V lithium rechargeable AA batteries are engineered with a nominal discharge capacity designed for low-to-moderate load devices, such as remote controls or LED lights. Audio equipment, depending on its impedance load and gain settings, may cause micro-spikes in demand, which the internal regulation IC might interpret as a fault condition, thus shutting off abruptly.
Thermal Runaway Considerations: Since these batteries rely on an onboard IC, prolonged exposure to high current draw combined with passive heat dissipation inefficiencies could lead to thermal throttling. This results in reduced performance until the IC recalibrates—assuming it’s programmed with adaptive throttling firmware (which may vary by manufacturer).
Charging Circuit Impedance Matching: Without knowing the precise impedance characteristics of the UM4’s charging bays and the specific dynamic impedance response of your target battery's protection circuit, predicting compatibility is speculative at best.
So, while it's technically feasible to use these batteries with your UM4, the interplay between the charger’s algorithm, the battery’s internal IC, and your device’s power requirements is highly nuanced. It would be prudent to deep-dive into each component's datasheet to fully ascertain their interoperability.
I hope this clears everything up for you!
ok thanks for that detailed info, yep that is the detail and nuance that I am unfamilair with! ended up just getting the XTAR batteries with the bundled charger.
Are they AA or does it run in 14500’s?
If they are AA, and you are seriously asking on an Eneloop forum, what battery to buy? Also consider Laada from IKEA, I’ve had a good run out of them in the past.
The issue you my strike is that alkaline type AA batteries are 1.5~1.6v where NiMH type rechargeables are typically under this (1.2~1.4v), and in some devices, they may give the indication that the device will report the batteries as being flat and need replacing even though they are fully charged.