Electrical Schematic Flow Chart

[cdnred]

I recently purchased a small Teardrop that has a 4 pin plug. It came with a 12v battery for supplying power to a cabin light, a kitchen light and a 12v plug in the kitchen area. My TV has a 7 pin plug and I'd like to change my current 4 pin over to a 7 pin to match my TV. The 7 pin would be required to allow for recharging the battery when traveling down the road. The battery currently needs to get recharged manually after each use. I'm planning to install a 30A shore power plug in the side for powering a 8 plug power bar which I feel would satisfy my power needs both in the kitchen and in the cabin. My travels mainly would involve fully serviced campgrounds the majority of the time so I'd be relying mostly on the 110v for power..

I also own a Champion 2000w Inverter Generator for supplying power when boon-docking or where allowed. I'd like to be able to recharge my battery while traveling. I'd also like be able to convert the 110v to 12v for powering the cabin/kitchen lights. Rather then converting the 12v setup, it may be easier just to wire in 110v for lighting..?

I'm not all that up on wiring the trailer's electrical or what's required. Would anyone have a flowchart pointing out how and what's needed to wire this up especially what's needed to recharge the battery when on the road..? Both a wiring schematic and showing what extra equipment I'd need to wire in to make it work, fuses needed. Since the current 12v system only supplies power for the lights, might be easier to just wire in a solar setup to recharge the battery rather then charging from the TV..? Thanks

[Tom&Shelly]

I'm not all that up on wiring the trailer's electrical or what's required. Would anyone have a flowchart pointing out how and what's needed to wire this up especially what's needed to recharge the battery when on the road..? Both a wiring schematic and showing what extra equipment I'd need to wire in to make it work, fuses needed. Since the current 12v system only supplies power for the lights, might be easier to just wire in a solar setup to recharge the battery rather then charging from the TV..? Thanks

Afraid I don't have a good schematic (mine was drawn on paper, not a computer), but there are many posted on here. We used a PD4045 converter, as did many others, so you might search for that in the forum. The PD4045 is a combination of converter (takes 120vac--shore power, and converts to charge a 12 volt lead acid battery), electrical box to hold several 120 vac circuit breakers, and a fuse box for 12 vdc fuses. Might be more than you are looking for, to do what you want.

The key word is "converter" to convert the shore power to 12 volts for charging. Also, you'll want to make sure the device works with your type of battery (lead acid, sealed lead acid or AGM, or lithium). Lithium batteries require quite a bit of electronics to charge correctly.

Incidently, the device that takes 12 vdc and makes 120 vac is called an "inverter." You didn't mention wanting to go in that direction, and I only mention it for completness. There are issues. Often when folks want something that runs on 120 vac, the power requirements are too much for a reasonable 12 vdc system to supply.

If you have a lead acid battery (sealed or otherwise), you can just connect the auxilery power output from the 7 pin connector to your battery, with a 10 guage wire, and that will work to charge the battery from the tow vehicle's alternator. Lot's of stuff on the interwebs about using dc to dc converters to up the voltage slightly at the battery, and that's fine. We didn't do that, and it takes a longish drive (5 hours or so) to fully charge the teardrop battery that way. That's simply because the voltage from the 7 pin connnector isn't quite as much as our sealed lead acid battery wants to see.

We also charge from the PD4045 when we are at a camp with shore power. At home, we keep it in a garage without power, and we use a 100 watt solar panel, which works best of all (here in sunny New Mexico). For that, we have a PWM charge controller. If you spring for an MPPT charge controller, that will also act as a dc to dc converter to help with the tow vehicle charging.

We chose to use all 12 volt lights exclusively.

We don't have a generator, but you should be able to plug a converter into yours to charge the battery.

Sorry for a longish and potentially confusing post. Hopefully it'll give you some things you can google on and find some answers for your particular situation.

Tom

[bdosborn]

I've attached a PDF of the electrical one-line diagram I drew by hand in 2004. I never bothered to do a nice Bluebeam version like I have for the van. Hope this helps...
Bruce

[cdnred]

I'm thinking that with the limited use of the 12v now that it maybe simplier to just leave the setup as it is now for short term use. Install a 30A shore power connection on the outside of the teardrop and run a separate 110v circuit inside. With limited 12v usage and limited draw, the battery should hold a charge a long time. I could install or hookup a small solar charging system to keep the battery chargered up. A small solar charging setup to recharge the battery shouldn't be that expensive. I'll either be using full service campgrounds or connecting to my generator so the majority of time I'll be hooked up using 110v. With running everything off the surge protected power bar I'm thinking that fuses may not be required..?

I'm looking to go with the easiest fix without getting too elaborate. The more that's added to the circuit, the more that can potentially go wrong..

[Tom&Shelly]

I'm thinking that with the limited use of the 12v now that it maybe simplier to just leave the setup as it is now for short term use. Install a 30A shore power connection on the outside of the teardrop and run a separate 110v circuit inside. With limited 12v usage and limited draw, the battery should hold a charge a long time. I could install or hookup a small solar charging system to keep the battery chargered up. A small solar charging setup to recharge the battery shouldn't be that expensive. I'll either be using full service campgrounds or connecting to my generator so the majority of time I'll be hooked up using 110v. I'm thinking that with using a surge protected power bar that fuses may not be required..?.

I'm looking to go with the easiest fix without getting too elaborate. The more that's added to the circuit, the more that can potentially go wrong..

Excellent points! You obviously know what you need for your camping style. Your ideas should work just fine.

Tom

[bdosborn]

I'm thinking that with the limited use of the 12v now that it maybe simplier to just leave the setup as it is now for short term use. Install a 30A shore power connection on the outside of the teardrop and run a separate 110v circuit inside. With limited 12v usage and limited draw, the battery should hold a charge a long time.

Ditch the 30A plug and go with a 20A; they're much more common and you've got one in your garage. Here's a thread that might be usefull:
Super Simple Electrical System

Bruce

[cdnred]

@bdosborn Good point, would save me the hassle of having to pull out the heavy 30A cord to plug in when home..

[cdnred]

Decided to order me a 15A plug with a 18" extension. Easier solution for wiring up. Just plug my power bar directly into the extension and good to go. Picked up a 30A male/15A female RV adapter for plugging into campground service..

15A Plug.JPG (81.12 KiB) Viewed 245 times

[troubleScottie]

On the charging while driving front:

There are nice chargers that cover a wide range of battery types.

REDARC Electronics Dual Input 40A in-Vehicle DC Battery Charger : about $400; a great product, could be used in conjunction with a solar setup (two inputs)

Renogy 12V 60A DC to DC On-Board Battery Charger : about $200 on Amazon; supports multiple battery types, only a single input. You could use switches to select more than one source.

You would really have to add wiring (10 gauge or smaller (bigger diameter) depending on distance), solenoid, fuses, Anderson connectors, more wiring, glands from the vehicle battery to the trailer to make everything work. Think high power car audio system (do people still do that?) The 12V power wire on a 7 pin connector is not rated to carry high current (40-60 amps) -- more like minor charging like an electric brake battery charger.

I would not skimp on this part of your build.


To your simple system:

You need to address what are your needs are.

Fortunately there are LED lights which produce good (bright) light with little power draw.

Just to list a few items that you might power:
lights (interior, higher power exterior)
fan
usb charging ports
refrigerator/freezer (12VDC, dual power frigs- 120VAC/12VDC)
monitors (CO2, CO, smoke, fire)
computers -- laptops, tablets, DVD players
routers & signal boosters
heater (propane/natural gas/diesel heater with ignition system and fan)
water pump
radio - AM/FM, satellite, ham, weather
TV

There are other things like
CPAP machine
heater -- 120VAC
microwaves -- 120AC
blenders -- 120AC
coffee machines/grinders
electric blankets
air conditioner

Granted I am getting pretty over the top with possible usages. However fans and refrigeration are often on the "I need them" list. Both have large draws.

The general idea is you need to compute your Amp-hours. Generally speaking a lead acid battery, one can use half of its listed capacity. Lithium you can use 80% or so.

You than need to compute how many Amp-hours you will be needing per day.

For each 12V appliance, you can multiple their draw in Amp by the number of hour per day you use it. LED lights can have very low draws -- 0.2 to 0.6 amps per hour. So run for 2 hours is 0.4 - 1.2 Ah. From above list, one of the bigger draws is a ceiling fan or refrigerator. Bigger fans like MaxxAir or Fantastic Fan have relatively large draws and are often run for long periods. The big MaxxAir 7000 is rated at 5 Amp. So it can only run 16 hour(2 nights) on high and you burn through quite a bit of power

Inverters can be computed the similar way but you have to multiply by 10 in the USA eg 120V @ 1 Amp = 12 V @ 10 Amps. Of course that requires 100% conversion. Most invertors have lower efficiencies. So you are consuming even more amps. That is why you want to use direct connections for phones or computers, to eliminate the conversion to 120VAC then back to 12VDC and the loses that has. Most computers do have connectors that plug directly into a 12VDC socket though it is an extra accessory. There are DC TVs.

All of this means you need to plan what you want to do. If all electrical needs is a single LED light run for a couple hours, you are great. If you have all of the above, you need to find a way to recharge while you are traveling/camping be it solar, shore power, generator or from the towing vehicle or some combination.