Montana Owners Club - Keystone Montana 5th Wheel Forum - View Single Post

trukdoc · 08-18-2007, 12:34 PM

Steve hit it pretty close. As a general rule one can assume with a diesel rig that the altenator is at a minimum 100 amp. To start your engine the starter peaks at better than 800 amps and settles at about 350 amps as the engine gets turning. So the first function when the engine starts is to replenish the battery. On a good battery, starting and charging system. that is done within 20 minutes. A battery likely will not use more than 60 amps to do this and the closer the batteries come to full charge the amperage tapers off. Phones, PDA's, GPS and most accessories do not use very much power. A 12VDC coffee pot will draw about 15 amps. This is pretty high. A large power inverter can use a LOT of power when using a microwave or try to power a AC. With all this said, Heat is a killer to batteries and altenators. The problem with running an altenator close to capacity is heat buildup. In the summer with a lot of accessories going with the AC it is more of an issue than in the winter. Our TV's are designed to operate with a trailer and the batteries and lights are figured into the load. So not to worry. It is when a lot of extras are used at once that use big power 15+ amps that will cause problems. As for adding lights. If you insist on a lot of running lights consider Diode lights. They use a fraction of power incandescant lights use. And when it comes time to replace batteries DO NOT BUY CHEAP BATTERIES this cannot be stressed enough. The most common battery sold is Exide. I would not use one in my lawnmower. And keep battery connections clean. Not on the outside of the terminal but on the post where it counts.

08-18-2007, 12:34 PM	#5
trukdoc Montana Master Join Date: Oct 2004 Location: Sulphur Springs Posts: 748 M.O.C. #2220	Steve hit it pretty close. As a general rule one can assume with a diesel rig that the altenator is at a minimum 100 amp. To start your engine the starter peaks at better than 800 amps and settles at about 350 amps as the engine gets turning. So the first function when the engine starts is to replenish the battery. On a good battery, starting and charging system. that is done within 20 minutes. A battery likely will not use more than 60 amps to do this and the closer the batteries come to full charge the amperage tapers off. Phones, PDA's, GPS and most accessories do not use very much power. A 12VDC coffee pot will draw about 15 amps. This is pretty high. A large power inverter can use a LOT of power when using a microwave or try to power a AC. With all this said, Heat is a killer to batteries and altenators. The problem with running an altenator close to capacity is heat buildup. In the summer with a lot of accessories going with the AC it is more of an issue than in the winter. Our TV's are designed to operate with a trailer and the batteries and lights are figured into the load. So not to worry. It is when a lot of extras are used at once that use big power 15+ amps that will cause problems. As for adding lights. If you insist on a lot of running lights consider Diode lights. They use a fraction of power incandescant lights use. And when it comes time to replace batteries DO NOT BUY CHEAP BATTERIES this cannot be stressed enough. The most common battery sold is Exide. I would not use one in my lawnmower. And keep battery connections clean. Not on the outside of the terminal but on the post where it counts.