What are the limits for carrying forward an unused EV tax credit for business purposes?

[SweetieJean]

 To the extent the vehicle is used in the purchaser’s business, a proportionate amount of the credit is treated as a general business credit and the unused business credit can be carried over to another tax year.

[mdemaster04]

Is there a limit to the number of years unused general business credits can be carried forward?  What if I report a loss on my business this year and next year, for example?