hey are better? Well they are differnt! 6 volt batteries are normally wet cell and there fore need maintanance as well and the most upright place you can place them. They don''t do will if tip too far and the plates MUST remain flooded. You can get 12 volt batteries that don''t have these draw backs. Then again two 6 volt batteries will have more reserve power than the average 12 volt. If you install 6 volt put them there you can service them at least monthly. Make sure they stay upright and you never heal too far over. I am installing them on my boat because I need the deeper reserve. Good luck on your decision. Six volters aren''t for everyone on every applacation.