On this page:

• Do you need a rechargeable lithium battery?
• Why is voltage important?
• What's in the Tenavolts kit?
• How do Tenavolts batteries perform?

Do you need a rechargeable lithium battery?

If used well, rechargeable batteries are an undeniably better environmental option compared to single-use alkaline batteries. But the inability for traditional NiMH (nickel metal hydride) batteries to reach the voltage of a single-use alkaline battery at 1.5V or even maintain their 1.2V level for the operating life of the battery is an issue for some, particularly if you’re powering devices that house four or more AA or AAA batteries. 

Tenavolts AA lithium rechargeable batteries deliver 1.5V from the moment you put them in the device until they stop, and they can then be recharged to full capacity in just under two hours.

Why is voltage important?

The two most important things to consider in a battery are voltage (volts) and current (amps). A simple analogy to understand the two components is to imagine water moving through a pipe. 

Think of voltage as the water pressure supplied to the pipe while the current (measured in amps or mAh) is the flow rate. If the battery can maintain a consistent voltage, then the current or flow rate remains the same for the life of the battery.  

If the voltage for a single battery drops during operation, which can happen for most alkaline and NiMH rechargeable batteries, then the aggregated effect can lead to an inability to power the device even if there’s still energy left in the batteries. 

For example, if a toy requires a certain amount of current to operate and the toy needs four or more batteries, then any drop from the 1.5V you can get from a single-use alkaline battery to the 1.2V you can get from a rechargeable NiMH battery leads to a quick drop in your ability to power the toy.

What’s in the Tenavolts kit?

The package includes four lithium rechargeable AA batteries, a charger cradle and a micro USB cable that can be connected to your laptop or smart device power supply. The cable is quite short, but you can also use a longer micro USB cable if you have one that came with a smartphone, speaker or other smart device. 

It’s important to note that this charge cradle should not be used with any of the NiMH batteries you may already have at home. Keep the Tenavolts system away from your other rechargeable batteries and you’ll have an ideal option for the devices that really need that extra boost. 

The front of the cradle shows a blue LED to indicate the charge condition of the battery when it’s in the charger, and the LED turns off when the battery is fully charged.

How do Tenavolts batteries perform?

Tenavolts batteries consist of a 3.7V/2.8Wh lithium-ion cell, which would make them incompatible with standard AA batteries. However, a 3.7V to 1.5V voltage converter/voltage regulator circuit board allows the Tenavolts batteries to be used on devices that require standard AA batteries. The board is located within the battery cylinder under the negative terminal cap.

The Tenavolts AA high-capacity rechargeable batteries are pre-charged up to 2775mWh, and are fully charged in a bit less than two hours, which is faster than the traditional quick charge NiMH rechargeable batteries which need at least three hours to be fully charged.

The batteries deliver a consistent 1.5V from fully charged to completely spent, providing the voltage required for some devices that need the best possible performance in heavy load discharge. Our tester, Carl Mihailovich, found some small variance over the life of the battery, but no more than 0.02V, which wouldn’t be noticed in day-to-day use of the batteries.

The measured capacity of the batteries is 1825mAh at 1.5V, which compares favourably to the rated capacity of 2775mWh (1850mAh). The load current for this test was 0.35A, which was used as the load for the NiMH rechargeable (Eneloop) and single-use alkaline (Duracell) batteries.

Our tester noted that the overall capacity of the Tenavolts batteries compares well with the Eneloop rechargeable and single-use Duracell alkaline batteries. The impressive voltage regulation of the Tenavolts batteries also makes them more versatile over loads ranging from low (0.1A) to very high (2A).

While the battery voltage remained very stable at each load current, there was a slight reduction with increased load. At 2A load (heavy) the voltage was >1.27V.

If you want to keep your high-drain devices powered for longer or cut down on single-use batteries (without compromising on performance), consider introducing your toys and devices to some Tenavolts AA lithium batteries.

The post The rechargeable batteries that exceeded our expectations appeared first on ÌÇÐÄVlog.

Our expert testers

We’ve been reviewing batteries (rechargeable and single use) for over a decade and we’ve adjusted our test method over that time to keep it both rigorous and practical. Electronic tech has evolved over the years but the consumer’s need for good dependable AA and AAA batteries remains strong. 

While we test most products in our own labs, battery testing requires particular facilities and equipment that unfortunately we don’t have space for. So batteries are one of the few products we send to another expert lab, which tests them according to our requirements.

How we choose what we test

With so many to choose from, what makes us choose one battery to test over another? As with most of our product testing, our aim is to test the most popular brands and types on the market and what you’re most likely to see in shops.

We survey manufacturers to find out about their range of products, we check market sales information, and we also check for any member requests to test specific batteries. From this information we put together a final list that goes to our buyers, who then head out to retailers and purchase each product, just as a regular consumer would. We do this so we can be sure the batteries are the same as any consumer would find them and not ‘tweaked’ in any way.

How we test

Single-use or disposable battery testing

The batteries are tested in a rig and monitored by a computer. Each of the batteries is discharged into a fixed load – the load is 24 Ohms for the low discharge test, and 2 Ohms for the high discharge test. 

Four examples of each model are tested in each of the two tests, and the position in the test rig and models are randomly chosen to avoid systematic errors. The batteries are discharged until they reach a voltage of 0.7. The time and voltage of each battery is recorded during the test at approximately one-minute intervals.

Rechargeable batteries

Rechargeable batteries take a lot longer to test because – you guessed it – they have to be charged and recharged to determine their performance over time and with repeated use. The batteries are tested in a rig where each of the batteries is discharged into a fixed load. The load is 10 Ohms for the AA batteries, and 24 Ohms for the AAA batteries. Four examples of each model are tested with each position in the rig selected at random.

Test criteria explained

The overall score for single-use batteries is made up of:

• performance under high-drain conditions (25%)
• performance under low-drain conditions (20%)
• endurance under high-drain conditions (25%)
• endurance under low-drain conditions (20%)
• value score for high-drain devices (5%)
• value score for low-drain devices (5%).

The overall score for rechargeable batteries is made up of:

• endurance score (45%)
• consistency score (25%)
• self discharge score (20%)
• capacity score (10%).

Our test lab

We maintain our own lab that is up to date with the latest reference machines and calibrated measurement tools for our testers to bring you the right results.

For any testing required where we don’t have the necessary in-house skills or equipment, such as for batteries, we use an external expert lab.

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