R4i and charger for NDSi ver. 1.3u

Hi, I'm a newbie here in this forum, and I would like to ask some help about my DSi. It's been sitting around in my cabinet for three years now, having been played only 4 or 5 times, if I remember correctly. Anyways, I looked up in the internet and discovered that I could play downloaded games using the R4i flashcard and a micro SD, so I thought that I might as well give it a shot. I've placed an order for an R4i flashcard which is to be claimed next week, August 17. Questions: my DSi's version is 1.3u. Is it still compatible? Is the R4i flashcard safe to use? What is the difference between the R4i flashcard and the Acekard 2i?

The other thing is that here in the Philippines, we commonly have 220v outlets, rarely 110. So when charging my DSi, I use a transformer, but the instruction manual discourages the use of transformers when charging. Any suggestions as to charging the DSi? I forgot to mention that I accidentally plugged the charger into a 220v wall outlet and even if I charge my DSi with a transformer, it still worked fine. Also, are there available usb chargers for the DSi?

Hoping for your replies. Thanks.