Holds 15 3800mah samsund SDI, Batteries are found in many laptops and chromebooks.the Dellpack 5R9DD is an example. battery interrnally has an LGUH6FB60 (3800MAH) or samsung SDI ICP596080A (3700mah). Each battery has a built in fuse, so no need for fuse wire.In total at 1s15P gives you about 57000mah at 4.2v depending on how you wire it.I plan on stacking 7 of these to make a 7S15P 29.4V for use with a 24V inverter.