"It is such a long-tailed story in terms of consumer adoption, we see a hard time sort of arguing for the payback here in the near term and many, many investors … sort of need that confidence in order to invest today," he said in an interview with "Closing Bell."
He also called the timing of the anticipated merger "suspect," saying his big question on solar is about valuation.
"The why now, the why use Tesla equity if you do believe, in fact, it's incredibly discounted to the opportunity in the long term, that argues that you are paying even more for SolarCity," said Albertine.
On Friday, Tesla CEO Elon Musk, who is also the chairman of SolarCity, dismissed critics who say it's too early for Tesla to acquire the solar company. He contended it will streamline the ability to secure big contracts.
"I think the timing is just right, if not, I mean frankly, we may be a little late. I wouldn't say that we're early. It is really an accident of history that the companies are even separate," Musk told CNBC in an interview Friday.
To billionaire investor Ron Baron, Tesla is perhaps the most interesting company he's ever invested in over his 46-year career. He owns about 1.5 million shares of Tesla, valued around $300 million.
"I think in this investment from here in the next 15 years, we can make 30 to 50 times our money," Baron told "Squawk Box" on Friday.
The proposed merger also got a boost Friday from Institutional Shareholder Services. The influential advisory firm recommended shareholders of both companies vote for the merger on Nov. 17.
Albertine believes the odds are that the two companies will merge, and therefore there will have to be a better understanding on net metering — which credits solar energy system owners for the electricity they add to the grid — as well as what states allow and the consumer adoption curve.
"We're very comfortable being equal weight on the solar side while getting up to the curve and seeing how the synergies play out over time."
He currently has an overweight rating on Tesla.
—CNBC's Robert Ferris and Matt Belvedere contributed to this report.