This is going to require group input, likely a step at a time. Mine is don't replace the battery and then the alternator, charge the battery first and see if the alternator is working, if not then consider another alternator. Charge the battery fully, see if it holds a charge for a couple of days. If not, most batteries are dated by month and year, see how old yours is, if it's around 3 years or so might just get a new one for that reason. If you don't need it now you'll need it soon. If the battery seems like it should have some virtue but is not holding well for a couple of days, disconnect the closest battery cable and leave it off for a couple of days then see if it acts like it should when you replace the cable. If it does, you have drain while the battery is off and that's another story, come back to the list for the answer to that one. Les Michael Pike wrote: > Secondly.... after starting the car and backing it out > for a nice 200 mile drive (now that i can see how much > gas i have), i happened to glance over at my battery > meter.. it was almost to 0.... like the alternator > wasnt working..... it was fine before... i am > wondering if maybe i screwed something up putting the > tankzilla in???? When the needle goes down to the > bottom like that, does it mean the battery, or, worse, > i need to get an alternator???? I am going to > disconnect the tanzilla tommorow and see if that > helps.. if it does maybe its grounding somewhere, if > not... i guess i'll buy the battery and if that doesnt > work, head for the alternator...