The major difference between aircraft and auto batteries is the plate design. (among other things like robust construction and longer shelf life)
You see cars tend to do frequent starts and short recharge times (down the corner shop for a pint of milk) but don't need to run very long if the alternator dies. Airplanes start less frequently and generally run for a good while when they do but absolutely need the best life if the alternator fails. In the July'09 Kitplanes this is described in detail. Aircraft batteries have thick plates for sustained current draw (0.1") but may suffer in the cranking department. Auto batteries have larger, thinner plates (0.05") for massive cranking current but suffer in the long draw department Therefore aircraft batteries have relatively higher Amp-Hour (AH) rating Auto batteries have a relatively higher cranking current rating. This is not to say not to use auto batteries but please understand the benefits and limitations. IFR or highly electric planes should really use an aircraft battery or at least have a backup (as I will be doing) Aircraft that use predominantly steam gauges, gravity fed fuel and magnetos can get away with an auto battery. Paul Smith Brisbane, AUSTRALIA pk.sm...@bigpond.net.au http://kr2spacemodulator.blogspot.com/ -----Original Message----- Does anyone have strong opinions as to why an aircraft battery is better for our application than an automobile one?
