There are several choice reviews about certain kinds of batteries; batteries for solar power storage, toy and device batteries and appliance batteries. I am interested in other possible uses of batteries and in the general questions of deciding which type fits a given purpose and how to determine value for money.
Let’s start with a case study and move on to generalities later. I need a battery to supply a fair whack of power away from the grid, 12V would do fine and such are commonly available, although you can get other voltages. My purpose is to provide power for a CPAP machine while camping or similar situations. You can buy ready-built systems for this but as observed in another thread anything to do with CPAP (rather like weddings) in this country is unaccountably expensive. My sums using the power consumption of the device and the duration required arrive at a capacity of some 30-40 Ah. I need a long slow discharge (deep cycle) not a high current discharge.
You can get lithium and other exotic batteries in that range, this is what the pre-packaged systems are built on. They are much lighter than lead but also much more expensive, even if just buying a battery and not paying the CPAP tax.
OTOH lead batteries seem to have come a long way. A lead battery in that capacity range is commonly used to power golf buggies, mobility scooters etc. They are readily available in a sealed package that does not require water top-up and is unlikely to leak unless grossly abused even if operated sideways. These are much cheaper than lithium but also heavier. Within this type there is a range technologies and of prices and weights for the same capacity.
My criteria for such a battery are; safety, reliability over a long useful life and cost effectiveness. I have been told that for lead batteries the heavier it is (for a given charge capacity) the better the quality. I have no idea if that is true.
So my primary question is: for this application how do I work out which is the best battery for me?
A secondary question is how do you make sense of the competing claims and warnings about how to charge, discharge, store and speak nicely to various kinds of batteries? How do you determine the best technology for a given purpose? An authoritative source for this kind of advice would seem valuable given the ever-growing number of machines that need batteries today.
