View Single Post
Old 02-08-2015, 10:20 AM   #11
BlueYonder
Senior Member
 
City: MD
Vessel Name: Blue Yonder
Vessel Model: 37
Join Date: Mar 2013
Posts: 346
I've been researching inverters for some time as I would like to be able to run some ac loads while on the hook without running the genset. When determining the battery bank size and inverter size, you need to do a calculation of dc amp requirements.

An AC fridge that takes 1.2 amps at 120v would convert to about 13 amps dc. If the refrigerator runs 50% of the time, that would be a draw of about 6.5 ah or 78 amps over 12 hours. A brand new group 27 deep cycle battery probably has somewhere around a 100 ah capacity. If you ran the inverter for 12 hours while on the hook, the refrigerator alone would use up 78 of the available 200 amp hours. You will have to calculate other dc loads, (lights, pumps, etc) to determine the total dc amp requirement. Most would recommend that you don't exceed 50% of your battery capacity between charges.

This applies whether you use an inverter to power your fridge or use an ac/dc fridge.

Are you considering a modified sine wave or pure sine wave inverter? Running some ac motors on a modified sine wave inverter can cause it to overheat and run less efficiently.
BlueYonder is offline   Reply With Quote