A retail installment contract is slightly different from a loan. Both are ways to obtain a solar system and battery storage by agreeing to make payments over time.
A solar RIC is an extension of credit by a seller, typically your installer, to a consumer for purchasing solar panels and other items related to the system. Once you sign the RIC agreement, the seller will immediately assign that RIC to a third-party finance company, like EverBright.
A solar loan is a transaction between you and a lender (not a seller) for money, and you use that money to purchase the solar system and agree to repay the cost of the solar panels and equipment plus interest.
Functionally, a consumer will see little to no differences between a RIC and a solar loan. The consumer will still receive the solar system installment from the seller and pay for the financing. The financing company and the seller more substantively feel the differences between RICs and loans. The seller has little involvement in the underwriting decision and administration of payments.