Yes you can use them both on any federal tax liability ( not SE taxes or other penalties) however the EV credit is used first because the unused portion cannot be carried forward like the solar credit can. If you have other non refundable credits those will also be taken into consideration as well so it can get a bit interesting. If your tax bill will not be enough to use up the credits in full then planning a way to increase your income is a wise decision ... like converting a 401K or IRA to a roth.
