Hi Ajax
I would be very suspicious of your first charger as it took out the fuses !!
if you have access to an amp meter it might pay to check the charge current
It may be that the first charger was indeed faulty and that is the reason the blade fuses blew.
I strongly believe that a good charger is essential if you are going to get long life and good reliability from your battery pack.
As the source of all the power you use from the battery comes from the charger initialy, and the battery is just (!!!) a convenient and portable package to keep it in until you use it, its no good having an expensive battery if the charger is not up to the job of looking after the battery and is going to knacker it in no time!
Cheers, Mark.