I have a Toshiba M400 Tablet PC that has overall been an excellent system for me. Small, light, and powerful, I have had it for two years now without many issues. Given that it is a tablet, it is more useful while free from electric cords than a normal (non-tablet) laptop. Portability is key with such a device.
In order to extend the battery life beyond the advertised time of 4 hours with the standard built-in battery, Toshiba offers a "Slice" battery (http://www.toshibadirect.com/td/b2c/adet.to?seg=HHO&poid=321977). This attaches to be bottom of the notebook and extends side to side, and takes about 1/2 of the bottom surface. It is called a slice because it is made such that it looks like a slice of pie from the side. This does offer the advantage of elevating the back of the notebook when in normal laptop mode, so that typing is a bit easier.
When in tablet mode, it makes it easy to hold the device in one hand and write with the other. It does not add a lot of weight, or maybe I have gotten used to it; when removed it feels lighter in a significant way. The only other disadvantage is that it covers the expansion port on the bottom of the M400, which makes it unable to connect to the docking station. This means that it will not be charged when docked like the internal battery is.
Given all of that, I like the slice battery. But it is a battery, so it needs to give power, right? It does this, but not to the extent that Toshiba advertises; in fact it is not even close. Toshiba's online store states two numbers:
- It adds 4.85 hours to the primary battery
- That when combined with the primary battery, it will have 9.96 hours!
Wow - that second number really leaps at you. That is more than one day of work. I could start at 8:00am and go until 5:00pm on one charge? Not so fast.
My experience using standard power settings (and normal office worker usage) gives me about 3 hours or a little more with the primary battery. Additionally I get about 2-2.5 hours additional time with the slice battery. All of this adds up to about 5.5 hours of battery life at max. So I can start at 8:00am and go to a little after 1:00pm working. That is not nearly what is advertised.
Very disappointing. So, while helpful, the buyer should beware.