Shaty, your watt hours will not compute with a motorcycle battery unless you are running engine.
I have one of those chargers and it works great although it does appear to take much longer to charge than my P3P wall charger, so I would think the amp output is low. One other thing I noticed with this charger is, it felt warm, not hot but good and warm after a charge, I went to look at maybe putting a fan unit over the vent holes, ONLY to find there is no holes where the vent holes appear to be located. It's a fake indention.