How long to idle to charge battery?

cycledude said:

i am confident that your wings battery was fully charged within the first couple of minutes at idle

if u hook up the battery tender to your wing in the next few days it will show fully charged within a couple of minutes, if not i would suspect there is something wrong

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I'm with cycledude on this. Considering you probably only crank the starter motor for a few seconds to start it, it will only take a minute or so to replace that amount of charge.

Just supposing for the sake of argument it takes 120 amps to run the starter motor, cranking it for 5 seconds consumes only about 1/6th of an Amp/hour capacity (120Amps*5seconds/60seconds/60minutes=0.16667Amp/hours). If the alternator can put out about 120 watts extra at idle as stated in the previous posts then it has just over 10 amps of charging current capacity (120watts/12volts=10Amps). Most of the charge has actually been returned within the first minute after the engine started in this example. (10Amps*60seconds/60seconds/60minutes=0.16667Amp/hours)

Depending on how many amps it really takes to run the starter motor and how long you actually crank, I would say it's a safe bet that your battery has almost certainly been fully charged back up within the first couple minutes, as cycledude stated above.