x2A good JetWorks gel battery or a high quality AGM should last long enough for most anyone. The new digital TL units use less current than the old analog systems. If you properly charge the battery with a smart charger designed for the battery you choose then you should be ok. Parasitic loads that completely discharge the battery will shorten its life. Batteries do not like to be run completely dead especially if they sit discharged for any length of time. The biggest problems with TL systems seem to be failures from bad connections or water intrusion due to poor setup techniques.
Another good idea would be getting two good batteries, keep them properly maintained and switch them in between the rides if needed. Even the analog TL should last you for at least a day.