NorCalSteve
Senior Member
I have added a computer to my Hawk camper, which gathers camper data. Every 5 minutes it records inside temp, outside temp, refrigerator temp, freezer temp, HW heater temp, refrigerator condenser temp, and battery voltage. I also put a GPS up in the fan area and gather location and speed data as well. I do have the solar panel option. This was a good decision for me.
While on my last adventure from Northern California to Texas and other places, I started getting low on Propane. Since I am still learning how long I can go on a tank of propane, I started getting nervous and decided to switch the refrigerator to DC for a day of driving, which I did a while before leaving the campsite. As I was driving down the road, I realized that the graph of my DC power showed the battery voltage jumping from about 12 volts to about 11.5 volts. This occurred about 6 times in a two hour period. It "seems like", after the battery charged a little, this cycling went away. The voltage measurement is taken pretty much at the refrigerator and not at the battery. More on that later. My "guess" is that the breaker under the hood of the truck for the camper must have been tripping. After the batteries in the camper charged some, it stopped tripping and things were fine. If I learn more about this, I will post it. For now, I will make sure the batteries are charged before I put the refrigerator on DC and add another 12 amps or more to the pull on the alternator. If the breaker is cycling, I figure this is not a good thing. It was also a warm day so the breaker was probably pretty warm under the hood. If I see this happening again, I plan to jumper the breaker long enough to see if it goes away by doing that.
While on the subject of using the refrigerator on DC, I decided to beef up the wiring to the refrigerator. With the refrigerator on and car off, I measured the voltage at the battery (12.6 volts) and at the refrigerator (11.7 volts). So I was loosing 0.9 volts in the wiring, breaker, fuses, etc.. This also means, the coolant heater in the refrigerator was running at 233 watts, instead of 250 watts or more. I ran 8 gauge wire directly from the battery to the refrigerator. Currently it is connected without a fuse (little dangerous), but I plan to add a fuse at the battery.
After the change, the battery was at 12.3 volts and the refrigerator was at 12.1 volts. This means the coolant heater was running at about 152 watts (with the engine off). I am not sure why the battery dropped from 12.6 volts, before to 12.3 volts after but I did like only seeing a 0.2 volt drop between the battery and the refrigerator. I have not tried driving anyplace with the refrigerator on DC but I think it is going to be an improvement. I have a short camping trip planned for this weekend. I will post anything I learn.
Steve
While on my last adventure from Northern California to Texas and other places, I started getting low on Propane. Since I am still learning how long I can go on a tank of propane, I started getting nervous and decided to switch the refrigerator to DC for a day of driving, which I did a while before leaving the campsite. As I was driving down the road, I realized that the graph of my DC power showed the battery voltage jumping from about 12 volts to about 11.5 volts. This occurred about 6 times in a two hour period. It "seems like", after the battery charged a little, this cycling went away. The voltage measurement is taken pretty much at the refrigerator and not at the battery. More on that later. My "guess" is that the breaker under the hood of the truck for the camper must have been tripping. After the batteries in the camper charged some, it stopped tripping and things were fine. If I learn more about this, I will post it. For now, I will make sure the batteries are charged before I put the refrigerator on DC and add another 12 amps or more to the pull on the alternator. If the breaker is cycling, I figure this is not a good thing. It was also a warm day so the breaker was probably pretty warm under the hood. If I see this happening again, I plan to jumper the breaker long enough to see if it goes away by doing that.
While on the subject of using the refrigerator on DC, I decided to beef up the wiring to the refrigerator. With the refrigerator on and car off, I measured the voltage at the battery (12.6 volts) and at the refrigerator (11.7 volts). So I was loosing 0.9 volts in the wiring, breaker, fuses, etc.. This also means, the coolant heater in the refrigerator was running at 233 watts, instead of 250 watts or more. I ran 8 gauge wire directly from the battery to the refrigerator. Currently it is connected without a fuse (little dangerous), but I plan to add a fuse at the battery.
After the change, the battery was at 12.3 volts and the refrigerator was at 12.1 volts. This means the coolant heater was running at about 152 watts (with the engine off). I am not sure why the battery dropped from 12.6 volts, before to 12.3 volts after but I did like only seeing a 0.2 volt drop between the battery and the refrigerator. I have not tried driving anyplace with the refrigerator on DC but I think it is going to be an improvement. I have a short camping trip planned for this weekend. I will post anything I learn.
Steve