No no, just when you're looking at batteries, look at the ones specified for the diesel. They're generally a lot more heavy duty to be able to crank over a diesel when it's stone cold. Mine gets left for weeks at a time and there's still no problems starting when I come to it. (I suppose I must be fortunate too in that I don't suffer from the BeCM being woken up by spurious signals received by the fob radio receiver. Either that or it was upgraded to the new one. Never had it out to check).
Anyways, with batteries, you get what you pay for. Also look for a three year warranty too.