battery size

[fab]

Ive never seen anyone post the exact specification of the original battery for the Williams. It's not in any service manual,parts catalogue Ive seen, and certainly not in an owners handbook.

50aH 540A which is what my battery rates and it cranks great from hot or cold, once fully charged.

Be mindful that the alternator may not be able to regulate the voltage or even charge an over-sized battery even though the manufacturer does list the silver as compatible.Also the starter motor may not be able to take it.

[fab]

50aH 420A was original spec from a source which sounds about right.

The Renault part number nowadays is

77 11 222 779
See here:http://www.autopartoo.com/oem/renault/7711222779.html

Another difference in going for larger aH batteries is the weight. They are likely to increase by 3 to 5kgs from a 50 to a 53.
So a 60ah is probably gonna put down around 6kgs in that corner.