amp hours
Posted: Tue Dec 08, 2009 12:08 amThe way I see it, your gonna need about 75 watts or more (because your inverter won't be 100% effecient) out of your battery (a SWAG for sure but in the ballpark).
At a nominal voltage of 12 volts thats about 6 amps. More or less. A general rule of thumb is that you can get about 50% of the amp hour rating of your battery out of it before you need to recharge it. So, I don't know the specs of your battery but if you had a 100 amp hour deep cycle battery you might get maybe 8 hours out of it before it needed to be recharged. I doubt that your starting battery is anywhere close to a 100 amp hour battery.
I wouldn't recommend using a starting battery as its not designed for this type of discharge and it's always such a pain to get a jump start! I once encountered a power boat (I was sailing) about 20 miles offshore and they had run down both their batteries with the bait pump. I removed one of my THREE batteries and let them use it to get their engine started. I always had three on board and charged, lived off one only, and kept two in reserve. You can't hand crank or "push" start a 40 hp diesel in a sailboat, ha!
Hope this helps.
Gus
At a nominal voltage of 12 volts thats about 6 amps. More or less. A general rule of thumb is that you can get about 50% of the amp hour rating of your battery out of it before you need to recharge it. So, I don't know the specs of your battery but if you had a 100 amp hour deep cycle battery you might get maybe 8 hours out of it before it needed to be recharged. I doubt that your starting battery is anywhere close to a 100 amp hour battery.
I wouldn't recommend using a starting battery as its not designed for this type of discharge and it's always such a pain to get a jump start! I once encountered a power boat (I was sailing) about 20 miles offshore and they had run down both their batteries with the bait pump. I removed one of my THREE batteries and let them use it to get their engine started. I always had three on board and charged, lived off one only, and kept two in reserve. You can't hand crank or "push" start a 40 hp diesel in a sailboat, ha!
Hope this helps.
Gus