For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.
Battery from 13" MacBook pro are compatible. Try known good battery first. Also check if battery is fully recognized in OSX with charge cycles and battery status: normal.
Any suggestions as to a good source for original batteries? Will the system still lag without a battery in the system?
My seller for my stocked batteries has done well for me so far, the 2 air batteries I used and only unibody one have been top tier from what I can tell. Just this Amazon one has been crap.