The battery on that site lists that battery size as  140 x 80 x4, so it's smaller dimension than the regular maxi sys battery. At least if the connector is the same , you know it will fit with room to spare. if you are able to post a you tube video on how to remove the maxi sys battery  you will help other people  .What about the voltage regulator part that drops the charging voltage to 5 volts, does it work?

Support Thanks for answering a ton of questions. I really do hope that safe suitable economical DIY battery replacements will be made  available soon to avoid unnecessary downtime and expense and  keep Maxi Sys platforms working way longer than 2 or 3 years with out having to purchase another head for $900-$1500. I've been wanting to upgrade from a DS 708 for awhile but have a external 12V lith battery velcroed to back and see a non serviceable internal battery becoming an issue of a costly future liability. I bought my wife a tablet a few years ago and  the battery is failing already but replacement batteries for it can be ordered on line pretty cheap.

         If the tablet still works fine with the AC adapter ,then leave a (non shorted)  internal battery alone. To get by till a suitable economical internal replacement becomes available,   Velcro one or two of these Chinese Bricks of C-4 to the back of your Maxi Sys and that might be all you need, granted your Tablet likely have the girth of the original Strapon Mobis . LOL, when the internal voltage regulator finally craps out a year or two later and the screen goes black you will have kicked the $900-$1500 Proverbial  Can down the road then have justification to either replace the head unit  , or upgrade to the Latest Disposable Flash n the Pan that will be out by then... LMFAO,
  Note I would just play it safe and shut any unattended suspect tablet down , turn off and disconnect any external Lith Ion  battery piggy backed on it. Also avoid running any USB powered devices off  the MaxiSys because the MaxiSys internal Voltage regulator will already be taxed , working overtime , and could just go Poof and you could have a Black faced  Red headed Stepchild you'll have to hit with  a fire extinguisher.
 
http://www.ebay.com/itm/DC-12V-20000mah-Super-Rechargeable-Li-ion-Battery-EU-Plug-Pack-for-CCTV-Camera/262094636355?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D35006%26meid%3Dcbdc6f9481924e12ad1cd2af606a3e86%26pid%3D100005%26rk%3D4%26rkt%3D6%26sd%3D171867425580

http://www.ebay.com/itm/DC-12V-20000mAh-Super-Rechargeable-Portable-Lithium-ion-Battery-Pack-NEW-/171867425580