Were it me I would do, in the following order (testing after each step to see if the problem is fixed):
1: Verify battery cable size as Tim mentioned. Replace if necessary.
2: Clean the battery cable ends (pay special attention to the ground cable).
3: Load test the battery. Replace if bad (the more CCA the better).
4: Test starter. Rebuild or replace if bad.
If you don't have it fixed by then you have larger problems.
Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.
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