Making an E1505 battery charger

I have a second battery for my e1505. I might as well have bought a brick. Why the heck would they make these without an external charging adapter? Did I miss something obvious? What an abuse of my hard earned money! When I needed it from a power outage, it was right there, dead as a, well, brick! I finally found a charger, but at over $50 for what looks like my ac adapter connected to a special head to connect it to the battery, it seems a little ridiculous. I think it would be a lot more economical to buy one of the ac adapters I find for under $30 and connect pins myself. Yet I do know enough to know I am really capable of making dumb mistakes, so would those of you that actually understand the intricacies of electronics out there tell me if I am on a solid track, and if so, do I "simply" need to identify positive and negative, hook'er up and let'er rip?

You can "rotate" the two batteries, charging them in your Laptop prior to planned "away" battery usage".

As for your plan…. hook'er up and let'er rip?, uhmmm, you already know the answer to that one!
Have you ever charged a simple rechargeable flashlight battery?
Did you notice how hot it gets?
You don't want that with a Litium Ion battery.

If you decide on an external battery charger, get a good one, and make sure it is rated for your machine's battery.
I believe that Dell makes the PA-12 Family battery charger and I think it's the one you need.
But check for yourself to be sure.

Spend the money.

Best Regards

do I "simply" need to identify positive and negative, hook'er up and let'er rip?

Sounds like a plan to me…

Actually you need to control the charge current. Try looking at a hobbyist site for battery-charger schematics.