Stoffel Vandoorne stands next to his broken down McLaren on the main straight of the Circuit de Catalunya. Picture: Llius Gene / AFP

Barcelona, Spain - Renault has blamed faulty batteries for electrical problems suffered in testing by McLaren and Red Bull, both teams who use its engines.

McLaren had two electrical-related problems on Tuesday, the first day of the final pre-season test in Barcelona, while Red Bull's Max Verstappen also brought out a red flag when his car stopped on track. Renault's works team had no problems but technical head Bob Bell said it was nothing to do with the way the batteries were installed.

"What we do ahead of (the season opener in) Melbourne is that we try and shake down all of the battery systems to make sure all of the stock that are going racing are in good shape," he said. "That's why we test them here. We revolve them around the customer teams and ourselves to make sure they are all tested ahead of Melbourne, so it's not unusual to find issues."

McLaren has switched to Renault in 2018 after terminating its difficult three-year relationship with Honda. Now, however, Honda's new partner Toro Rosso, owned by Red Bull, has now done many more laps than McLaren, whose first week of testing in Barcelona was hit by mechanical niggles.

Potential title contender

Stoffel Vandoorne lost power in the car early on Tuesday but was able to coast back to the pits. He then suffered the same issues when he went out again and stopped on track. The team then changed the battery, but his day's testing was finally cut short by an hydraulic leak.

McLaren, which last won a race in 2012, are hoping to get back on the podium in 2018 while Red Bull, which won three races in 2017, is seen as a potential title contender again.

Bell said of Tuesday's issues: "Those problems could have affected any of the three teams, so of course it's an issue for us. But the reason we do this testing of those components before going to Melbourne is to find the ones that have got problems.

"It's the right thing to do, we have found some that are not fit for purpose and that's great."

Each driver is allocated two 'energy stores' per season under the regulations.

"That's a pretty heavy duty cycle for them," Bell explained, "and the importance of making sure they are completely fault-free is critical, which is why we test them ahead of Melbourne."

The season will start in Australia on 25 March