Enginer has now begun offering  4Kwh or 8kwh systems for the Nissan Leaf.

There’s some discussion about it on the MyNissanLeaf web site.

Initially there were reports of there being a 12kwh option, but Enginer confirmed that it is not true. While electrically possible, it would be a challenge space-wise.

The 4kwh system fits under the rear deck. The 8kwh system protrudes about 6″ above the rear deck into the cabin.