[mg2969]

Not an electrical expert
(failed Navy Nuclear B - double E - Basic electricity and electronics).
However.
Off the top a few distinct issues come to mind.
1. Battery amperage, for a standard 12V brick it seems kinda low
2. Color Screens use more juice
3. GPS can tend to use more juice
4. Combo units since they are processing 2 signals (sonar & GPS) use more juice
5. Max Peak power out is 2400 Watts unlike a cuda 245 which is only 1500W peak, I think that means you'll get a better picture sonar wise but like every thing else it will use more juice to get it

Quality batteries that are maintenance free types shouldn't go bad

There may be some issue with sulfurication due to constant deep discharge though. Basically the plates inside the battery develop a layer of sulfur and causes an inability to fully charge (?), not 100 % sure of the info though. Its also for more long term like 3-5 years rather then just 5 months.

Just my 2 cents and some random thoughts on the subject