The numbers don't add up (?)...

[Mike Banks]

If you have any fluoro lights, get rid of them. Replace with LED's.

Also--put your hand on the engine alternator. If it is warm, your alternator isolation relay (or diode) is not functioning, and your battery is feeding into current the alternator.

Similarly it may also be back-feeding the solar array at night.

If you have a Lectrasan or some other battery powered chlorine generator aboard, look no further. They will draw a LOT of current when operating.

Another source of big power drain is an electric water heater or anti-freeze electric element.