F1t said:
“We have clearly identified a problem that we could not fix this morning, but we are working to ensure that the teams, especially Red Bull and Toro Rosso are able to take to the track at 9am. It's a sequential problem resulting from the integration of all systems".
Taffin further said the problem is to do with hardware only, and while spare parts are available at the track, they do not have enough of them to get all teams running again. Therefore, parts from Viry will be flown over to the circuit to resolve the issue for all three customer teams available at the Jerez test.
The issue is to do with the control system of the batteries, and different packaging within the different cars makes fixing it all the more difficult. He said "sometimes it's easy, but due to the design of cars, sometimes we first have to remove a lot of parts before being able to access the batteries".
It is not surprising that the Renault customer cars suffer from an integration problem. Merc and Ferrari designed the whole package with one set of engineers and their customers took their clues for the main design decisions from them. Renault customer have three different solutions to battery packaging and it makes it so much harder to solve the problems. People were right about the advantage of an integrated manufacturer package at least for speedy prototype testing. It may not make a difference later in the season but the manufacturer jobs are obviously less of a mess to sort out.