Ch. 5: Electrical supply for the SquareDrop Camper.
SquareDrop Camper ELECTRICAL: AC/DC
Official Disclaimer: I am not an electrician. All your work should be inspected by a person that knows something about the movement of electrons; hopefully contained within the insulated wire in which they are meant to travel.
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| Image 1 |
One of the AC circuit breakers is for the Air Conditioning plug/ USB chargers in the front of the cabin with the other breaker supplying power to one plug in the storage box (for the 12 volt battery charger) and an additional plug in the back for the kitchen (hot plate/Instant Pot/water warmer, etc.). The "shore" power plug is probably being supplied by a 20 amp breaker, so we don't have 30 amps of power available. We need to be careful not to overload the shore plug by having the Air Conditioner on while we are using a high power drain at the kitchen; like a hot plate. I periodically inspect the shore power plug for abnormal heat gain during use.
A deep-cell 12 volt car battery provides two circuits of 12 volt DC power. One circuit is dedicated to the Fan-Tastic Fan. An additional circuit provides power to the LED lights (interior, exterior, reading lights, using a triple switch at the head of the cabin - see below) and to the SirrusXM radio/ DC USBs chargers (by way of the dual USB charger/voltmeter that also mounted at the head of the cabin - see below). Just like the AC power, circuit fuses for the two DC circuits need to be added inline as soon as they leave the POSITIVE (+) 12 volt connection in the battery box. If you go with the low voltage disconnect this is where the fuses will be placed (see image 4). No power source should be unprotected (without a circuit breaker/or fuse) outside of this aluminum tongue storage box.
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| Image 2: Dual USB charger/voltmeter and thee pole light switch |
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| Image 3: Battery charger, solar controller, 110 volt AC outlet with sub-panel, red battery source switch |
The battery can be recharged by two sources, AC (shore power through a battery charger) and solar controller. Pictured above: Attached on top of the sub panel is a red battery selector switch. Normally these types of battery selectors are used with two batteries going to one circuit or load. Here we are using it to supply charger or solar power to the 12 volt battery. The main reason for the "source" selector switch is to minimize having the solar power controller connected to the battery while the battery charger is also attached and supplying power. This condition is damaging to the solar controller. In the picture the switch is in the up position that prevents either source from connecting. On some older 12 volt chargers, if power is not being supplied and the connected unit is off, some discharge will occur through the resistance of the unit. Therefore it is better to disconnect both supply sources from the battery. The only problem using the switch in this manner is that one can position the switch 180 degrees to the "both" position and risk damaging the solar controller. The good thing is this unit only cost about $15.00. I found out about the negative effects of having both attached to the first one.
To power the solar controller, we elected to use a portable solar panel as opposed to one permanently mounted to the top of the trailer. Mainly because we try to find shade for the trailer, or use the Coleman instant canopy for cover if no trees are available. With a portable unit we can move the solar panel and position it to provide the greatest juice the Sun can provide. The solar controller will not charge a battery that has reached a voltage below 10.7 volts. To prevent the condition of running the battery down below what the solar supply can recover, we added a low voltage battery disconnect. This allows us to use the battery while to a predetermined minimum above the non recoverable 10.7 volts. We have selected 11.0 volts as the battery disconnect. Once the controller (or charger) sufficiently raises the voltage above the 11.0 volts, the battery circuit is closed and your back in business. This is not a problem when shore power is available as the charger easily keeps up with maximum use; fan on high, all lights on, and charging phones.
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| Image 4: 12 Volt car/boat/rv battery with low voltage disconnect |
More detail on the products mentioned above is below.
This is a ton of information to cover, so if you need better pictures or clarification, please contact me at squaredropcamper@gmail.com.
Bill
Aluminum Tongue Mounted Storage Box: This box is made of good quality, thick aluminum. It has a key to secure the equipment. Granted, a big enough pry bar can open anything, but I am satisfied with this container. It fit perfectly on the tongue of the trailer; the appearance of custom design for the project.
AC Plug with USB chargers: These are very handy when you are plugged into shore power. Can you have to many USB outlets?
Battery Charger/Maintainer - 12 volt 3 amp/15 amp: Light weight and easy to use. Hit the on button once to see the voltage and percent of charge, then again to begin charging. Once charge the unit automatically switches to maintenance. It can be left in this condition indefinitely.
Fan-Tastic Fan: I mentioned this in an earlier post, but we do love this unit. The electrically modulated lid opening and closing is over kill, but impressive (probably only impressive to geeks like me). Good volume of air moved makes for a comfortable setup. While boondocking, use sparingly as energy consumption for these types of fans is high when compared to LED lighting. Remember that the dial needs to be turned to zero (0) for the unit to be off and in this position the lid cannot be lowered or raised. If the dial is on a fan speed of 1,2,or 3 then a red led light will illuminate to indicate the unit is on and relying on the thermostat to power.
Interior Lumitronics Designer Double LED Dome Light: These are very bright and attractive lights. The switch in the middle of the light is off when centered and one side comes on when thrown one direction, both sides are on when the switch is thrown the other direction. We elected to control the light with a switch from the Triple SPST at the head of the cabin. This makes for an easy location to turn on the dome light while in the dark. Another of these units is in the kitchen area and it too has a light switch, but could have easily been hard wired to the battery and the on-board switch used; sometimes I over kill things, or over think it. Remember to swap connections at the light if they do not come on; the LED thing.
Exterior Kohree LED RV Exterior Porch Light: This model has a switch at the bottom and it is the unit that we use, however we use the Triple SPST to turn control them; both on or both off. I like lighting up the world around the camper from the inside. These have all the light you will need, as a matter of fact your close neighbors will want you to turn them off during the night.
Reading Lamps: An added nice touch to the interior of the cabin. They come out of the box very bright, which is not bad, but I had to tone it down a bit and got bulbs a little less bright. Good product. We use the on-board switch to control them individually, so they are directly attached to the battery through the fuse supplying the lights.
Triple Switch SPST: The triple single pole/single throw is used for the blue accent lights under the squaredrop camper, the interior lights in the cabin, and the two exterior lights on each side above the windows. Basic deal where one wire comes from the (+) battery and is connected to all three switches on one side of the unit then the other side of each switch goes to the consumer components. Sometimes if LEDs are in parrallel they will not work. Switch the polarity to one of them and that should work. The diode ( the "D" in LED) does not like electrons going the wrong way; or something like that.
Cllena Dual USB Socket Charger: We use the large 12 volt accessory to power the SirrusXM radio and the USBs to charge the phones. Having a voltmeter inside is very handy on determining the condition of the battery as you use the consumer items. The on/off switch powers down all the outlets and the voltage readout. We usually have it off when not in use. I mounted this in a two plug outdoor electrical box, the same box that was used for the Air Conditioning outlet. Not exactly a perfect fit, but with some modifications, it worked.
Solar Controller: This is the second controller that I have purchased. The first one was rated for 20 amps and cost $20. As I eluded to earlier, it met it's demise by me applying the 12 volt battery charger to the battery while the solar controller was also attached. Electrons need to travel in the direction of their intended route and not backwards. This new controller appeared to be exactly the same, but rated for 30 amps and cost $15. Easy decision there.
Red Battery Switch/Dewhel Dual Battery Selector: The controller is really meant to be a switch for something like a boat that has two batteries; one for starting the motor and one for the trolling motor. It has a "both" position to charge both batteries while the boat is underway. Here I am using it as a source switch and was attracted to the low cost. Yes, if we turn the knob south I will once again be applying electrons in the wrong direction to the solar controller, but the way I have the selector positions marked this should eliminate the urge to turn it down under.
Portable Solar Panel: This is a slick item here. It is light weight and folds to the width of a couple of towels. We store this under my mattress at the foot of the bed and I do not no it is there. On a sunny day it really brings in the juice. The only hesitation about this model is that it states it is not water proof, which may be an issue if we leave it out in the rain. Time will tell. To assist in the positioning we also got a 50 foot cord which you will cut in the middle, as 25' is the limit of extension that is advised. The 50 footer comes with a male at one end and a female at the other. Cut the wire in half and attach the severed ends to the controller. Be sure to get the polarity correct by back tracking from the solar panel through the connected extension to the correct + and - on the controller. Check it twice as this is Very important. Nothing will blow up, but you do not want to compromise the controller or the panel.
Low Voltage Battery Disconnect: Saves you from damaging the battery by not letting the voltage get below a user selected minimum. Heavy duty red wire attaches to the positive terminal on the battery with a small black wire going to the negative terminal. A red "load" wire comes out of the unit and goes to the positive wire of your consumers. To adjust the voltage minimum a small slot driver is used; simply turn to the desired voltage minimum. As you can see in the picture of the battery the two circuits are splice off the "load" wire from the unit with inline fuses.
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