Yes, that could happen. You might not be able to use both credits if your tax liability isn't big enough, since both credits are non-refundable and you cannot carry unused part of the credits toward future years. However, the solar tax credit might not be available at all starting next year, therefore to use part of that might be better than nothing. I would also recommend you to check your electric vehicle manufacture here:
https://fueleconomy.gov/feg/taxevb.shtml
