Bog Roll ::

It's Not Magic, It's Work!

01 Oct 2010

Rechargeable Batteries

I've got lots of electrical devices and I'm also careful with money. That means I don't buy lots of disposable batteries but carefully select rechargeable ones and recharge them saving money and the environment.

Early NiCd batteries were okay, but their typical charge for a R6/AA/U11 size cell is only 0.5-0.6Ah, less than a non-rechargeable zinc-carbon cell at 1.1Ah. Additional they suffer from the memory effect and are made from toxic metals.

Eventually NiMH became available, they have much higher capacity for the same size, 1.3Ah in early models, rising to around 3Ah for the current top of the range. They aren't full of toxic ingredients and don't suffer from the memory effect that gradually ruin NiCd. Their problem is that though they hold a similar charge to alkaline or lithium batteries, they very rapidly discharge on their own, so they need constantly topping up to be of any use and you can't use them in low discharge long term applications, e.g. clocks or torches.

Today I got a batch of Sanyo eneloop batteries. They don't have the highest charge capacity possible for NiMH batteries at only 1.9Ah, but their ultra low internal discharge means that they can be treated like ordinary zinc-carbon/alkaline batteries. This should solve several problems...