Hi Everyone, Sorry for the dumbish question. I read several threads and still don't have any good answers for my questions. Just bought my 08 prius a few weeks ago. When I went to test drive the car it was almost fully discharged. The sales person had the car on and running before we got there and said it needed a few minutes prior to driving it. This was well before I knew about the differences between a typical car 12v and the prius 12v. So very quickly after getting on PC I started reading all of these threads bout the 12v, it's relative short life and all of the problems that can be attributed to it. When I tested my battery using the internal check recommended on other threads it did appear my battery is on the lower side of things. When I first tested it was giving me 11.8v on the first testing reading. I figured that the battery had a bit of time left on it but I'd rather replace with the Optima then wait until the OEM dies on me at an inconvenient time. So with the recent amazing deal on the Optima I just bought one. The more I read about the battery health/life of the Prius 12v the more often I am testing my battery. The weather is getting warmer here to and I have been driving the vehicle more and more, so a few days ago my initial reading was 12.1 and this morning 12.3. All of these readings are in the morning after the car has been sitting overnight. I am not that mechanical but think I am going to take a stab at installing the optima myself. However it might be a while before I get around to that, especially as it seems my current battery is healthier than I thought it was. So I would like to get a battery tender/charger to keep the Optima healthy as it sits on the shelf and to get it up to a full charge before installing it. I would also like to use one to take my current OEM battery up to full charge and drive it for a week or so after that to see how it is doing. I was hoping for suggestions on battery tenders/chargers. Is the battery tender junior that some recommend good enough for my needs? http://www.amazon.com/dp/product/B000CITK8S?tag=priuschatcom-20 about something like this that I can pick up easily at my local Advance Auto Parts? http://www.amazon.com/dp/product/B0009IBJAS?tag=priuschatcom-20 question is kind of the dumb one. I live in a condo and don't have access to a 120V AC plug where I park my car. Do all of these battery chargers/tenders need to be plugged into the wall while charging or can they be charged up and then taken out to the car where I would hook them up to the current battery to get it up to a full charge? After I install the Optima I plan to maintain it by bringing it up to a full charge once a month or so to compensate for my frequent short trips. Thanks.