Forget the per cent readings on the charger, Get a multimeter for $20 and measure the voltage of the battery, or take battery to Oreillys or Autozone and have it tested. Try to get it close to full charge before you go. It's probably a bad battery or a bad charger.
Please don't use words like "nothing". Use "will not turn over" "not even clicking" "starter turns but won't start"......that type of specific verbage is useful.
The headlight test is always a great test to do in your case. Can be corroded or loose cables, all as Martin and Bill say.
Overnight charge and still 75% seems a red flag against the battery. But measuring it's voltage and a load test is best. If it shows 6.4V it can still have a bad cell and break down under the starters mega amp load.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
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