A 93 flhs loosing charge in less than 2 hour

Battery needs charging. Not enough volts to make the spark and not enough amps to beat the compression of the motor. Get the battery load tested. Any Interstate Battery outlet does it for free in 2 minutes. You get a paper readout voltage plus stated battery CCA amps to actual amps.

Depends on what battery. car battery I charge with i 10 means with a current 1 / 10 of the capacity in Ampere hours for 14 hours. So a 80 Ah battery with 8 A for 14 hours.
A camera battery in the charger I got with the camera. Or a good universal charger from GP. A NiMH AA or AAA battery, with a quick charger that at least needs 2 hours to charge. The quick chargers I have that can charge in less than 2 hours (one can manage in 15 minutes) all kill batteries after a few charge cycles. Hope this helps.

To recharge the current taken out of the battery during start up requires at least 10 -15 miles driving. Driving less than that, progressively drains the battery available power until it has not enough power for another start. Such a battery "resting" for more than 10 minute might regain enough power for a start but is inherently flat. Put it on a battery charger for at least 12 hours or go on a 2 hour or more drive. It should be OK for quite a number of starts even when doing short distance driving. If it is showing the same symptoms directly after to 12 hour charge/drive get the battery tested at a garage or battery dealer who will be able to tell if the battery needs replacement. If the battery test OK there might be bigger problems like a blown top gasket or problems with the starter motor.

Not recommended. The case would have to be modified to accommodate more cells, the circuit board inside the battery casing may not function properly, and unless you have a commercial dual pulse welder working with Li-ion could ignite. Save time and money and pick up an extended battery such as this one : http://tinyurl.com/pxcpqv9

If the cell phone battery is more than 3 - 4 years old then the battery could be worn out.Rechargeable batteries have a finite number of charge and discharge cycles andwill lose their charge capacity over time, i.e. won't charge to 100% and graduallythe charge reduces until the battery won't charge up at all. OR The batteryshows a 100% charge but when the adapter is disconnected the battery drops offto zero capacity in a very short time. If the battery drops to an unacceptablecharge level then the battery needs to be replaced.

A new battery should have approx 12.62 fully charged
It could be slightly more
If you ever see 13 volts, on an old battery, it is gone

You need a min of 12.5, to do any testing of your vehicle, or you charge it
It should hold 12.5 or more for 3 or 4 weeks,then charge, if you let the truck sit
unused.

Up to 9 hours of battery life after fully charge.

I think the normal talk time is around 6 to 8 hrs if your battery is holding less you probably have a unit with a faulty battery
how old is your headset