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I don't think one can blame the battery; if a capacitor or charging circuit went, then maybe the battery could be the culprit, but not if a flash tube goes.
I wouldn't say it's your fault, either. Sometimes tubes just blow. Age, a sharp blow during shipping, a manufacturing defect, etc. can all be issues that can cause a fault. That's why every wedding pro carries back-ups. Glad to hear you did, too.