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That usually indicates a problem with either the charging or the batteries or both. Check the fluid level in the batteries first. See if the cables need cleaning, especially the ground lead to the chassis frame. If the batteries are over 3 years old they may be ready for a change. The charging can be checked with a small digital multimeter like you can find at most automotive or hardware stores. About $20 or so and I can direct you in the testing. Let me know what you find and we can go from there. All follow ups are included in our fee.
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