I just posted a new page on the consistency of the SRM power meter. Consistency seems to be very good, and I’m planning on exploring this a bit more in the future also.
Computing watts for an ascent
If you don’t have power meter on your bike, you can still compute nominal wattage for a climb (assuming reasonable steepness so that air resistance is not a major factor).
Nominal power output can be computed with the following simplified formula, which does not take air resistance or drive-train losses or other power losses into account.
Add about 16% to the nominal watts to account for friction and other losses.
Watts = 9.8 * WeightInKg * AscentInMeters / seconds
Watts = 1.3549 * WeightInPounds * AscentInFeet / seconds
Naturally weight must be the total riding weight: rider + clothing, water, bike, etc, since that’s the load you’re carrying uphill.