You don't need anything like the size of a car battery. The 4x basically uses 1Amp every 5hrs.

I had one of those sealed hobby batteries with spade connectors (7a/hr) from Supercheap and it never dropped below 50% even after a full weekend on the Hobie. Not much bigger than a standard block of ground coffee and easly fits into a waterproof bag.

 Yep, I have the same. You don't need cranking amps, so these small sealed batteries work well. Solar works fine with them too. Have you explored charging from your outboard? Most motors will have that option somewhere.

I have a little 390 explorer and went with an n50 12v battery setup as this allowed me to fit nav lights, amfm radio, bilge pump and sounder, no charging off the little 15 suzi and have no dramas with having enough power. I'm also going to run strip lights under the gunnels for night fishing, so fitting a 12v car battery has allowed me a few more options.

 I have a small battery to run the Combo, radio & bilge pump in the tinny.

A small solar panel on top of the battery box (about the same size), keeps it charged all day & no need to charge off the motor.

Maybe worth a thought....

 I do charge mine from the lighting circuit off the motor, haven't had a need for a external charger yet.

 Get a 12v 22 or 36 ah dry cell deep cycle. They r sealed so can't spill. Lots of golfers use them to push their buggies also run small leccy outboards anything on yr dinghy. Should cost you between  $80 to $140. As stated above grab a small solar panel to maintain it.

 get your self an oddesy battery  not cheap but are brilliant batterys , hold a charge 12 months , you can run them flat and they will recover , we used them in our nav aids when i was in the marine whsp i convinced rio tinto to buy in a hundred of them to replace the old centery marine 400s  they worked well , just ask all my mates in karratha that ended up with them in their harleys haha , coruption at its best got a trip to a afl  game in vic for that deal from the  the supplier

 thanks guys. Actually went out and bougt a little 9amp/h battery and a waterproof box. Works a dream and will last more than I need inbetween charges. Probaly turn the little box into a complete charging box and also buy a solar set up for longer camping trips.

 thanks guys. Actually went out and bougt a little 9amp/h battery and a waterproof box. Works a dream and will last more than I need inbetween charges. Probaly turn the little box into a complete charging box and also buy a solar set up for longer camping trips.