Will a Battery Tender Junior charge a flat car battery?

[mousejunks]

One trick I use is to connect a good battery in parallel with the bad battery to trick the charger into putting out current. Then I would disconnect the good battery and let the charger continue. Works ok to get some extra life out of it but a battery sitting flat for months has already sulfated and the chance of it being reusable is low.

[Stig / Major Tom]

After 36hrs battery Tender Jr. is showing solid red light...which apparently means it's charging.
Info on the tender says if blinking red light...it is "not charging".
Will check again tomorrow.
Stig