Rechargeable batteries

Lestratcaster

Do they have a lifespan? Have had some Duracell 2400mAh 1.2v batteries for about 5 years now and not had any issues. They're used for a Line 6 Relay G50 wireless transmitter. I read somewhere they react differently with rechargeable batteries as opposed to normal alkaline ones, but I saved a lot of money by using rechargeable ones. Also have read the size of them are different to normal AA ones which mean they don't seat in the compartment properly leading to dropouts in some cases.

Is it time to just get a new set of rechargeables for another 5 years?

Modellista

Maybe try a more advanced charger which can test the batteries' remaining capacity. 

I got one off Amazon for about 20 quid - has a number of different modes and a display for each battery. One mode is a total drain and charge, and the display shows how much charge the battery has taken. 

Invaluable for checking the state of one's cells. 

Lestratcaster

I'm currently using this at the moment to charge it, let's me know when its charged with 3 bars but not how long its got left as in lifespan

https://www.amazon.co.uk/Energizer-Universal-Charger-Pack-1/dp/B018IE3UM4/ref=sr_1_1?ie=UTF8&qid=1529579265&sr=8-1&keywords=battery+charger+energizer