MX5 Batteries

[mxdi]

Last week, I left my side lights on by accident when I got into work (8am)
By 1pm the battery was so flat the engine would not even turn and the alarm would not set.
Good old dad came and jump started me and since then its been fine.

But...
sidelights left on for 5 hours draining battery that much???? Is this normal?

[lotusnobles]

Di, Put the battery on charge then see how it goes, ought to last longer than 5hrs though if the battery takes full charge, if it doesnt then best to buy a new one