Need to reduce Fed Withholding as Close to Zero as possible without claiming exempt

[RichTR11]

I just realized I will not have enough Fed tax liability at the end of this year to claim my $7500 EV tax credit without reducing my fed withholding to about zero the rest of this year on my job withholding. Can I claim 50  dependents (besides my 2 qualifying children under age 17) on my W2 without raising issues? I have a bi weekly deduction of about $870 for fed withholding and only have 6 paychecks left to increase my tax liability (based on my estimates I would only owe $2.5K at the end of the year currently) and need another $5K to claim the full $7500. 

Or should I write in the amount for above the $27,700 standard deduction by X $'s to get the extra $5K liability?

The problem is I do not know how much either of these actions reduce the fed withholding each month.

[RichTR11]

Sorry Meant to say: The problem is I do not know how much either of these actions reduce the fed withholding each month  on each bi-weekly paycheck. Any W4 feedback will help. Thank you.

[TurboTaxBrenda]

You will need to contact TurboTax Community on the US side for assistance this is the Canadian side. 

Thank you for choosing TurboTax.