Seven F1 cars will run KERS in Bahrain Grand Prix

It is believed that up to seven Formula One cars will be fitted with active Kinetic Energy Recovery Systems in practice for the Bahrain Grand Prix.

A dwindling three drivers took to the Shanghai grid a week ago with the controversial energy re-use technology, as the benefits of the 82 bhp power bursts comes under scrutiny.

McLaren's duo Lewis Hamilton and Heikki Kovalainen have used Mercedes' KERS consistently this year.

"This is one of the circuits where KERS can give you the most time, because there are three very long straights," Spanish test driver Pedro de la Rosa said.

Ferrari took KERS off both cars in China for reliability and safety reasons, but will reinstate the system on Felipe Massa's F60 in Shanghai.

"I don’t use it tomorrow," Kimi Raikkonen said. "The other car (Massa) will run it and then we will make the decision which way we go. We either take it and use it if we don’t have any issues with it and we will put it also in my car but really we want to look a little bit and compare the two cars with and without and see a little difference. That’s our main thing tomorrow."

Due to Raikkonen's additional weight, Ferrari's KERS is seemingly of less value to the Finn.

"It should be a significant advantage here.

A great deal of work at the factory has gone into working on the KERS system since Sepang so I am hopeful it can help us," said Massa.

Nick Heidfeld has used KERS all season so far, but his much heavier BMW Sauber team-mate Robert Kubica - although sometimes testing the system in practices - has not. The Pole, who qualified a dismal 18th in qualifying in China, will again test KERS on Friday in Bahrain. "Yeah, I will use KERS tomorrow," Kubica confirmed at the circuit today. "The plan is to run it through all the weekend."

It is clear that Renault is also assessing KERS on a circuit-by-circuit basis, with Fernando Alonso and Nelson Piquet's cars likely to test the system on Friday.

"I think it will a decision we will make race by race and at the last moment, maybe on Friday night," Alonso told reporters.