My current buggy battery is 12 volt, 44ah, 360A

Is it ok to upgrade it to 12 volt, 44ah, 440A ?

Standard 1600 & standard engine ancillaries.

It will give you more starting power and will charge ok as long as it fits in the tray.

Thanks for the helpful reply. I've also seen another one rated at  12 volts,  45Ah; 400A. Would this also be OK to use? Both would fit into tray.

It would but unless your buggy has loads of electrics and seat heaters, massive stereo with amps n stuff you are only using lights and wipers when needed so the current draw is low. You need enough for cranking the motor over so any will do but you can end up paying for battery capacity you will not use.

there's 15 Ah ones with 500 cca, weighs only 6kg and is less than half the size of as a regular one.
look for odyssey racing battery

there's 15 Ah ones with 500 cca, weighs only 6kg and is less than half the size of as a regular one.
look for odyssey racing battery

Exactly what I have. Cost about £120.