Maximum battery is 100 Wh, unless you have permission from the airline for up to 160 Wh
Batteries also need to meet certain standards ("batteries must be of a type that meets the requirements of the UN Manual of Tests and Criteria, Part III, subsection 38.3")
If your batteries are not marked up with the Wh rating then I doubt very much that they they'd meet the standards (or at least they wouldn't be accepted as such by security staff).
For reference, I've been stopped more than once with 96Wh batteries, been sung chapter and verse by security then had to patiently show them the documentation, regs and markings on the battery to prove that they were allowed and within the regs. I personally wouldn't bother trying if I wasn't able to justify it.