It looks like HI needs a new battery. I was back out at the airfield yesterday to do a couple of touch and goes, maybe make use of the lovely crisp day to go for a bimble out west. I pulled HI out of the hangar and up to the bowser - why does the bowser have to be up a hill - to top up the tanks. Unfortunately when I finally got around to starting her - nothing. Well, not nothing but certainly not enough to start a cold O-200.
It looks like my engineering guru was right, charging wasn't enough.
If you're interested, I found this useful info on www.batterystuff.com and there's plenty more there:
" Battery life and performance - Average battery life has become shorter as energy requirements have increased. Two phrases I hear most often are "my battery won't take a charge, and my battery won't hold a charge". Only 30% of batteries sold today reach the 48-month mark. In fact 80% of all battery failure is related to sulfation build-up. This build up occurs when the sulfur molecules in the electrolyte (battery acid) become so deeply discharged that they begin to coat the battery's lead plates. Before long the plates become so coated that the battery dies. The causes of sulfation are numerous. Let me list some for you.
- Batteries sit too long between charges. As little as 24 hours in hot weather and several days in cooler weather.
- Battery is stored without some type of energy input.
- "Deep cycling" an engine starting battery. Remember these batteries can't stand deep discharge.
- Undercharging of a battery to only 90% of capacity will allow sulfation of the battery using the 10% of battery chemistry not reactivated by the incompleted charging cycle.
- Low electrolyte level - battery plates exposed to air will immediately sulfate.
- Incorrect charging levels and settings. Most cheap battery chargers can do more harm than good. See the section on battery charging.
- Cold weather is also hard on the battery. The chemistry does not make the same amount of energy as a warm battery. A deeply discharged battery can freeze solid in sub zero weather."