The higher a rechargeable battery’s capacity, the longer it should last per charge. But are ‘ultra-high’ capacity batteries really worth hunting down? And do you bother looking at the capacity anyway?
Before I got involved in battery testing at Which? I had no idea what to look out for when choosing rechargeable batteries. I’d probably have chosen the cheapest I could find from a brand I’d heard of.
Now, having just written my third battery article for the magazine, I am a little wiser in the world of batteries, and know that if you don’t have our Best Buy battery information to hand, then looking at the stated capacity (‘mAh’ number) on rechargeable batteries is your best bet for predicting how long they’ll last per charge.
But I also know from our lab test results that you don’t always get quite what you’re expecting…
‘Ultra-high’ capacity batteries
In our latest batch of rechargeable batteries, we tested the highest capacity AA rechargeable batteries I’ve seen – the Ansmann Digital 2850mAh. Our test lab suggested them and we had high hopes that these batteries could smash battery lifetime records.
But it wasn’t to be. While these batteries certainly didn’t do badly overall (see our full rechargeable battery test results for details) we didn’t achieve anywhere near the 2850mAh we were hoping for.
When we charged them up in our generic smart charger – representing everyday use – they only achieved 2225mAh on average. This is just 78% of their claimed capacity and is lower than some of the other batteries on test.
Do you look at battery capacity?
Ansmann told us that its batteries achieved 2,723mAh when they tested them according to the EU Directive and claims that under its ‘normal’ conditions they have achieved over 2800mAh.
But this got me thinking – are these ultra-high capacities achievable in real-life situations? Plus, how many people look at claimed capacities when choosing rechargeable batteries anyway?
We recently noticed that Asda, Sainsbury’s and Waitrose weren’t displaying the capacity information when selling batteries online – and have asked them to sort this out. But even when they do, is this the type of info you’ll look out for when battery shopping?