Hello John & Welcome to Just Answer,
Sorry to hear of the issue you are having with your phone system.
May I ask:
1) The AGE of the system?
2) The TOTAL number of handsets you have with this system?
3) How long is the "short time" you waited for the handset to charge?
To answer your questions about how long to charge and getting a replacement battery:
It is recommended that the battery be charged for AT LEAST an hour for you to be able to use the handset - for a "short time".
But for a FULL charge, 11 hours are recommended (such as overnight).
As for a replacement battery, no, you do NOT have to go to Radio Shack. You should be able to get one of those batteries at almost any store that sells a lot of Vtech phone systems. These could be electronics stores, office supply, and even some department stores.
And if you have a "battery store" in your area, that would be a good place to look too.
If there is a limited supply locally, they can be found online - at places like Amazon. I have a link to the search results for this battery below.
CS6719 Battery Search Results (Amazon).http://amzn.to/1ghOVGo
Please let me know what you find or if you have any more questions.
Thanks, ***** *****
I see it has been a few days and I just wanted to follow up to see if you have any more questions concerning this issue or if the issue was resolved.
I look forward to any further questions or results that you may have.