TrailManor Owner's Forum - View Single Post

09-10-2002, 07:30 AM

:-[

;D

Batteries & inverters could be discussed in length, but the short of it is - think of the battery/batteries as a glass full of water which you cannot use the bottom 20%.  So if you have a standard battery that has 120 amp/hour capacity, you have a MAXIMUM of 96 amp/hour to use. (NOTE: on a standard deep cycle/marine battery, you should only use 50% in order to obtain the typical 30 life cycles)

DO NOT use heavy current drain devices such as coffee makers, hair dryers, etc. for any length of time or your batteries will be discharged very quickly.

EXAMPLE:  Hair dryer for 10 minutes = 1500 watt = 12.5 amps @ 120 volt = 125 amps @ 12 volt = 20.8 amp hours - You now have left 96-20.8=75 amp hours

EXAMPLE:  13" color television W/VCR for 2 hour movie = 70 watts = .58 amps @ 120 volt = 5.8 amps @ 12 volt = 11.6 amp hours - you now have left 96-11.6=84.4

Any device that is designed to turn electricity into heat is generally a higher wattage device (curling irons do not blow air & keep thier heet very concetrated).

Look at the wattage rating & divide by 12 volts - this yields the amperage - Note the amount of time that the device will be used as a portion of an hour & multiple the amperage by this fraction to get the AMP/HOUR.  This AMP/HOUR figure can then be subtracted from your glass of water example showing you how long your batery should last.

Again, do not expect to drain a normal battery more than 50% before recharging it.

The next logical topic would be the inverter.  Size the inverter to be 50% over the maximum wattage of any device you intend to use.  In the case of any device having a motor in it (blender, drill, etc.), you will be best off doubling the size of the inverter over the listed wattage of that device.

A good size to handle most items is a CONTINUOUS 2000 watt inverter.  Do not expect to be able to plug this into the 12Volt socket (or most inverters) because the fuse for that socket will blow.

I wired a 2000 watt inverter under the pull out bed next to the front wall & ran the heavy gauge wires through the floor & connected them directly to the batteries.  I also wired a 120 volt outlet from the inverter along side the refrigerator so that I could plug any devices into it very easily.  With a slight movement of the pull out bed, I can reach my arm down & turn on the inverter when I want to use it & turn it off when I am through.

For good batteries I use 2 Trojan J305H 6 volt 330 amp hour batteries in series with heavy cables connecting them.  This gives me a usable 12 volt with 264 amp hour & will get me & my family through most 4 or 5 day camping trips with (movies).  These batteries have a life cycle of over 800 times compared to typical 15 to 30.  The capacity is also realistic.  

I tested several deep cycle/marine batteries on the market & found thier capacity to actually be less than half of what the manufactuer posted.  The various manufactuers reluctantly stated that they tested the batteries only after controlling the temperature & cycling the batteries through have of thier life to get thier questionable (ONCE IN THE BATTERIES LIFETIME) rating.

09-10-2002, 07:30 AM	#10
Guest Posts: n/a	Re: Inverters and Batteries :-[ ;D Batteries & inverters could be discussed in length, but the short of it is - think of the battery/batteries as a glass full of water which you cannot use the bottom 20%.  So if you have a standard battery that has 120 amp/hour capacity, you have a MAXIMUM of 96 amp/hour to use. (NOTE: on a standard deep cycle/marine battery, you should only use 50% in order to obtain the typical 30 life cycles) DO NOT use heavy current drain devices such as coffee makers, hair dryers, etc. for any length of time or your batteries will be discharged very quickly. EXAMPLE:  Hair dryer for 10 minutes = 1500 watt = 12.5 amps @ 120 volt = 125 amps @ 12 volt = 20.8 amp hours - You now have left 96-20.8=75 amp hours EXAMPLE:  13" color television W/VCR for 2 hour movie = 70 watts = .58 amps @ 120 volt = 5.8 amps @ 12 volt = 11.6 amp hours - you now have left 96-11.6=84.4 Any device that is designed to turn electricity into heat is generally a higher wattage device (curling irons do not blow air & keep thier heet very concetrated). Look at the wattage rating & divide by 12 volts - this yields the amperage - Note the amount of time that the device will be used as a portion of an hour & multiple the amperage by this fraction to get the AMP/HOUR.  This AMP/HOUR figure can then be subtracted from your glass of water example showing you how long your batery should last. Again, do not expect to drain a normal battery more than 50% before recharging it. The next logical topic would be the inverter.  Size the inverter to be 50% over the maximum wattage of any device you intend to use.  In the case of any device having a motor in it (blender, drill, etc.), you will be best off doubling the size of the inverter over the listed wattage of that device. A good size to handle most items is a CONTINUOUS 2000 watt inverter.  Do not expect to be able to plug this into the 12Volt socket (or most inverters) because the fuse for that socket will blow. I wired a 2000 watt inverter under the pull out bed next to the front wall & ran the heavy gauge wires through the floor & connected them directly to the batteries.  I also wired a 120 volt outlet from the inverter along side the refrigerator so that I could plug any devices into it very easily.  With a slight movement of the pull out bed, I can reach my arm down & turn on the inverter when I want to use it & turn it off when I am through. For good batteries I use 2 Trojan J305H 6 volt 330 amp hour batteries in series with heavy cables connecting them.  This gives me a usable 12 volt with 264 amp hour & will get me & my family through most 4 or 5 day camping trips with (movies).  These batteries have a life cycle of over 800 times compared to typical 15 to 30.  The capacity is also realistic.   I tested several deep cycle/marine batteries on the market & found thier capacity to actually be less than half of what the manufactuer posted.  The various manufactuers reluctantly stated that they tested the batteries only after controlling the temperature & cycling the batteries through have of thier life to get thier questionable (ONCE IN THE BATTERIES LIFETIME) rating.