Bog Roll ::

It's Not Magic, It's Work!

13 Oct 2010

What Were They Doing II?

This spring we moved into a new house. We now have some more energy use data.

EnergyAprilMay JuneJuly AugustSeptember
Gas-9-96-93-78+408+306
Electric-83-86+4+2-2-82
Combined-38-91-74-56+39-68
Our energy use as a percentage of the previous owner's.
In Summary, a 62% overall energy reduction, made up of a 73% electricity and a 51% gas reduction.

In no way is it a strict comparison, and though I have continued to take regular meter readings they are not all used and power company does tend to average out previous years. On the power companies own figures it's an estimated 5.6 tonnes CO2 reduction on last year if we continue at our current energy use rate for the year.


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...