Things we've learned from FE testing

HEADLINE-GRABBER ABT KEEPS ITS POWDER DRY

Such was the pace of team-mates Daniel Abt and Lucas di Grassi in the second test at Donington Park that the Audi Sport Abt outfit had a deliberately low-key final outing before preparing to ship its Abt Schaeffler FE01s to China.

Both drivers lowered the previous unofficial lap record in the second test, with di Grassi's 1m29.920s the first sub-1m30s lap for the series at the track, and phrases like "a step ahead" and "everything is under control" dominated the debriefs.

But the street track set to greet the championship in Beijing, the first round, is a very different prospect to Donington's sweeping curves.

"There are three pillars: performance, reliability and efficiency," says di Grassi. "If you take these three pillars it collapses.

"To be quickest at Donington really doesn't prove anything. You have to be quick at street tracks. That's our focus."

The e.dams Renault outfit was very satisfied to have worked through the entirety of its programme, and apparently cured the gearbox problems that briefly plagued its Renault Z.E.15 in the second test.

Not quite on Abt's pace in terms of raw laptime - though Sebastien Buemi was keen to point out with a clean lap his theoretical best suggested he was there or thereabouts - but looking very strong on longer runs and at a lower energy output, the e.dams team and DS Virgin Racing operation look equally as competitive.

The peaks weren't as high as Abt's, but they matter less at Donington. In Beijing, expect both to be in the mix.

THE TWO-TEAM POWERTRAIN APPROACH IS WORKING

Gamely seeking a steer on who's looking hot and who's not, AUTOSPORT put the question to several paddock figures. The usual names cropped up: Abt, e.dams Renault, DS Virgin. But one or two were quick to point out the pace of the Dragon Racing cars of Loic Duval and Jerome d'Ambrosio.

And where there are two (four, technically) Venturi VM200-FE-01s, there are four (eight, technically). That's because Dragon is the championship's only customer of season-two powertrains, having struck an alliance with the manufacturer Venturi operation.

Venturi's modus operandi is electric vehicles, and while that's not a concrete validation of its credentials as a Formula E manufacturer, it's a step in the right direction. Beyond that, the benefits of this tie-up are quite clear.

The EV land-speed record holder's powertrain - an uncomplicated single-motor, four-geared system that packs increased torque and a broader rev range - got double the running in testing, which means double the data.

The lead Venturi-powered car was within more or less a second off the benchmark throughout testing, so it's in the ballpark at least, but that's not what was most impressive about its pre-season.

Venturi comfortably topped the 'laps completed' chart at all three pre-season tests, logging 235, 302 and 274 laps respectively.

That's an incredible tally given we're approaching a season set to be defined by the performance of the new and different technologies, a season in which reliability and consistency will prove key.

"You don't know if others are hiding a little bit or not, but I think we are in the game and that's all we can ask for," said Dragon team boss Oriol Servia. "But we're a thousand miles ahead of where we were last year, so I'm pretty pleased."

CHAMPION PIQUET'S TEAM HAS WORK TO DO

The Campos-run Team China Racing entry has work to do heading to Beijing.

Whether it was the gloomy weather or the trade of a Global Rallycross car for the troubled NEXTEV TCR 001, champion Nelson Piquet Jr cut a frustrated figure at the final test.

Having lost any meaningful running at the first test to technical problems, Piquet and Briton Oliver Turvey (all-but-confirmed in the second entry) have been playing catch-up since.

It's thought the twin-motor system it has gone for with its single-gear package has made the rear end quite heavy, and that has left it slightly off the pace, though it does seem to have cracked the reliability issues that blighted the early running.

"Our system is probably quite radical and there's a lot still to get on top of," admits Turvey. "That's why every day is important. Reliability with making such big changes is a challenge, and there are some areas we need to get on top of before we go racing."

TRULLI HAS STUCK...

Call it determination, perseverance, pig-headedness or commercial pressure - whatever your view, cynic or fan, Trulli is sticking with its own powertrain for the 2015/16 season.

Given the level of investment that has gone into the new technology, it's probably no surprise. But, equally, the car has completed no timed laps in testing, and even the few installation laps managed on the final day were problematic.

The upshot of it all is ex-Formula 1 driver Jarno Trulli's outfit continuing with the Motomatica JT-01 for season-two drivers Vitantonio Liuzzi and Salvador Duran.

A parts-supply delay meant the team missed the first four days of testing, and while the car was fired up within its Donington base it also failed to appear for the first day of the final test.

Liuzzi emerged on Tuesday morning for an installation lap, although hardware problems caused the Italian to bring out two red flags during further runs, the car stopping on the exit of the pitlane on one occasion and at the final corner on the other.

Its single-motored, four-geared concept is here to stay though, with the team opting to avoid following Andretti Autosport's lead in reverting to the season-one Spark SRT_01E (keep reading).

The other lesson learned from testing is that Trulli's out of the driving seat, though this was pre-planned, with the Italian only driving in season one because the team had nobody else to field in its second entry.

...BUT ANDRETTI HAS TWISTED

While Trulli and Motomatica are committed to their powertrain, Andretti Autosport has opted for the safe (and probably sensible) option of going back to the season-one package.

The American outfit formed Andretti Technologies to develop its own motor and inverter for the ATEC-01, which uses a revised four-speed Hewland gearbox, but it has had a disastrous pre-season with it and racked up no timed laps.

That prompted a last-minute move back to the Spark SRT_01E that uses a McLaren electronics system and five-speed Hewland gearbox.

Credit to the team for managing to convert two of its cars to the Spark specification overnight, which enabled Simona de Silvestro and Robin Frijns to rack up 70 laps between them on Tuesday morning, with ex-F1 test driver Frijns ending up 10th fastest.

Credit, also, should go to the team for holding its hands up and seeking an alternative solution. By taking on the build of its powertrain in-house, Andretti is the entity that loses out by reverting - there is no big commercial partner to satisfy in that regard.

The positives, as team principal Roger Griffiths explains, are obvious as well.

"The season-one package has proven to be very reliable and we've great confidence in the technology from McLaren and Spark, so it's the best way forward for the short term," he says.

"We've effectively lost five days of testing. We could have continued to fight through issues today, but if we then made the decision tonight to switch back we would have lost another day and our preparations for Beijing would have taken a further step back."

As Trulli has shown, Andretti is not the only manufacturer to have struggled with its own technologies - and those that have achieved good running are still finding gremlins, too.

VILLENEUVE IS ON THE PACE

One of the big additions to the 2015/16 Formula E season is undoubtedly 1997 F1 world champion Jacques Villeneuve.

Even though the Canadian hasn't won a mainstream race since the 2008 European Le Mans Series round at Spa-Francorchamps, his return to a full-time single-seater programme is one of the main stories.

There was an IndyCar outing last year in the Indianapolis 500 amid a disappointing and cut-short World Rallycross programme. Before that, his career had been a mix of stock car and sportscar outings since departing F1 midway through the 2006 season.

So, how's he fared? While the pre-season started with him being some way off the pace and ended with an off into the gravel in the wet, the majority of the middle bit has been solid.

After ending the first test around a second off team-mate Stephane Sarrazin - who, let's not forget, won the London finale on the road last season - he was then quicker in the second test.

Villeneuve didn't get near his own personal best in the final test, which was disrupted by rain, but the early indications are quite positive, probably more so than the naysayers would have initially expected.

WET-WEATHER RUNNING A BLESSING - REALLY

The hardy fans that ventured to Donington for the final pre-season test wouldn't have been thrilled to be rained on in both afternoons, but for the teams this provided a valuable opportunity to get some proper wet-weather running in.

Tuesday afternoon welcomed the heaviest rainfall, and it was mostly sustained as well. So whether it was fully wet or damp-but-drying, the teams and drivers finally had a chance to get a feel for the Michelin tyres that were massively underused last season.

With an April round in Paris now on the calendar, the likelihood of a wet race increases - so getting some running in was crucial, as Sebastien Buemi, whose e.dams Renault team was one of the busiest in the rain, explains.

"The problem you face basically is you never get to drive in the rain in Formula E, so you don't really know what kind of set-up adjustments you have to do to get the most out of this car and it's a bit of a guess.

"It was good to finally get some wet running and drive in those conditions. We now know what we have to do and what we shouldn't do."

WILLIAMS HAS HAD A LOT TO DO

Arguably one of the more underestimated parts of the Formula E cars is the battery designed by Williams Advanced Engineering - and the 'engine' will be crucial in season two.

More power (read on for more information) means more stress on the battery, and that's not something WAE will have taken lightly given it was being stretched last season at a lower level.

Williams wasn't first choice for the FE battery, and when it came round to producing the season-one model it was having to design and build a battery to fit a specific space.

Considering that building the car around the engine is one of the more basic principles of design and engineering, this is a severe compromise. But it extends beyond that.

While the first iteration of the battery was capable of processing 200kW of power over a qualifying lap, it was originally designed to accommodate a much lower race output.

The predicted average race output of 90kW in season one was some way off the 120kW average achieved, because the teams were achieving better power regeneration once they moved away from Donington and onto the world's streets.

Last week, Williams began to phase in an upgrade process, while it has also replaced the battery cells, as it feared the teams' differing usage of the batteries over the first season could make performance in the 2015/16 campaign uneven.

MORE POWER

Williams's efforts meant each of the 10 Formula E teams was afforded the opportunity to test with the planned new race power limit for the first time in the final test, a long overdue experience for the majority.

The draft regulations for its second season are expected soon, which will confirm teams can run at a maximum power output of 170kW in race trim instead of 150kW as used in season one (and should announce a super-pole session in qualifying, too).

Formula E has been evaluating an increased power output, but teams have not been able to try it on-track while they wait for the final version of the upgraded battery.

Some complained about the last-minute availability of the battery and the compromise this meant in terms of running at the increased power levels, but Vincent Gaillardot, Renault's Formula E programme manager, made a shrewd observation: "We've already run on the dyno because we've anticipated 170kW since day one."

EFFICIENCY THE GREAT UNKNOWN

As for the impact the power increase will have on racing, DS Virgin Racing chief technical officer Sylvain Filippi says it will be critical.

"It's significant," he says of the change. "If you were racing at the different levels you wouldn't stand a chance at 150kW."

This is because the amount of energy available to use is remaining the same, at 28kW/h, and so the emphasis on efficiency will be even greater.

Races last season, when Filippi says "even at 150kW we weren't flat-out all the time", were defined by who could manage their energy best. With a higher peak for 2015/16, that's exacerbated further.

"It's difficult to compare [efficiency] to last year," reckons Abt's di Grassi. "I don't think there is a massive step, but we have achieved better than last year.

"How much better it's hard to say. We'll only know in Beijing."