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

Steve and Brenda · 10-10-2006, 04:16 AM

Hi all, I'm new to Montanas but have pulled RVs for some time now. I'm going to apologize in advance but electronic engineering is my discipline and I get wordy.

The goal of any wilderness camper is to manage your battery capacity and charging during daylight hours. The preferred battery is a marine battery because they deliver constant current before draining. Auto batteries drop in voltage and are not linear. Golf cart batteries are 6 volt cells which take up extra space in order to create a 12 volt circuit. The first modification I'm doing on my 3475RL Montana is to add a second deep cycle battery in parallel with the original battery and if that battery is not a good deep cycle battery I'll replace it. Batteries in parallel gives you more available current at the same voltage, in this case 12 volts DC.

The method to figure out what you need for a wilderness camp is called amp-hours. The larger the amp-hour rating the longer you'll have light and heat at night.

There are several ways you can reduce the draw on your batteries. One popular way is to change your 12 volt incandescent lamps in the RV with equivalent LED lamps. The original lamps, part number 921, range from 20 to 27 watts. Using the formula Amps = Watts/Volts you can see that a candelabra with three lamps pulls almost 7 amps from the battery. Similar LED lamps using the same wedge based 921 connection draw 30 milliamps (thousandths of an amp) for the same light. The drain on the battery goes down to less than 3/4 of an amp!!! http://superbrightleds.com/specs/T13_specs.htm gives you samples of lighting options using the 921 base LED lamp. LEDs are a little bit more in cost as compared to the original lamps but since they will last for years, are so shock resistant and do not suck power they are a must.

Keeping everything as DC as possible is another way to save power. You never get something for nothing as the story goes and the same thing is true for converting DC to AC. Power inverters draw more DC power to give you a relatively small amount of AC power. A small DC powered TV will last longer than the same size TV using a power inverter.

I used solar chargers in my former rig, IPC Solar has the chargers and voltage control regulators to prevent gassing and overcharge as said in previous posts. The solar chargers should exceed your expected daily amp-hour drain to ensure full power at night.

10-10-2006, 04:16 AM	#58
Steve and Brenda Montana Master Join Date: Oct 2006 Location: Choctaw Posts: 530 M.O.C. #6364	Hi all, I'm new to Montanas but have pulled RVs for some time now. I'm going to apologize in advance but electronic engineering is my discipline and I get wordy. The goal of any wilderness camper is to manage your battery capacity and charging during daylight hours. The preferred battery is a marine battery because they deliver constant current before draining. Auto batteries drop in voltage and are not linear. Golf cart batteries are 6 volt cells which take up extra space in order to create a 12 volt circuit. The first modification I'm doing on my 3475RL Montana is to add a second deep cycle battery in parallel with the original battery and if that battery is not a good deep cycle battery I'll replace it. Batteries in parallel gives you more available current at the same voltage, in this case 12 volts DC. The method to figure out what you need for a wilderness camp is called amp-hours. The larger the amp-hour rating the longer you'll have light and heat at night. There are several ways you can reduce the draw on your batteries. One popular way is to change your 12 volt incandescent lamps in the RV with equivalent LED lamps. The original lamps, part number 921, range from 20 to 27 watts. Using the formula Amps = Watts/Volts you can see that a candelabra with three lamps pulls almost 7 amps from the battery. Similar LED lamps using the same wedge based 921 connection draw 30 milliamps (thousandths of an amp) for the same light. The drain on the battery goes down to less than 3/4 of an amp!!! http://superbrightleds.com/specs/T13_specs.htm gives you samples of lighting options using the 921 base LED lamp. LEDs are a little bit more in cost as compared to the original lamps but since they will last for years, are so shock resistant and do not suck power they are a must. Keeping everything as DC as possible is another way to save power. You never get something for nothing as the story goes and the same thing is true for converting DC to AC. Power inverters draw more DC power to give you a relatively small amount of AC power. A small DC powered TV will last longer than the same size TV using a power inverter. I used solar chargers in my former rig, IPC Solar has the chargers and voltage control regulators to prevent gassing and overcharge as said in previous posts. The solar chargers should exceed your expected daily amp-hour drain to ensure full power at night.