My Tailgate Inverter Setup powering my trailer

[timjcarter9]

I built a quick tailgating power system. I got a trailer plug that goes into the wiring harness.

Then I cut the clamps off of an old 300 watt inverter power cables. I wired these in to the hot and ground on the trailer plug, Now I just plug into my trucks wiring harness to get 110 volts out back. In the GM trucks it is always hot.



Just for laughs I tried powering up my trailer using shore power cord. Turned off converter, microwave and A/C at the breaker panel. Plugged it in. All trailer plugs reading 117 volts.

Plugged in my 22 inch LCD TV (65 watts) and DVD player and works great. Fan didn't even go on on the inverter.

I have a plastic box that it goes in under the trick to keep the weather out. Just run an extension into the hole in the side to plug
items in (or RV)

Now I will not be using the trailer batteries to power the inverter. This became problematic when the furnace kicked in. (Alarm or powered out).

Just running off my truck battery now. Don't run much except charging phones and the TV / DVD.

Now the big question. With a 300 watt inverter, maybe drawing 90 watts at a time, how long before I have to be concerned about the truck not starting? Probably only 2 - 3 hours of use per day.

I can install a dual battery setup in this vehicle which I may do.

[Longtrace]

timjcarter9 wrote:
Yeah that is what I thought. I have dual battery capability so will add the deep cycle to the truck. Would only be running max two hours before using the vehicle again to go out and do whatever we do.

Even with a diode or relay battery isolator, running a dual battery system on your truck that way will result in short battery life.

First, you want a deep cycle for the inverter, but a starting battery for the truck. Not a good idea to charge two different types of batteries from the same changer.

Second, even with identical batteries, if they are discharged differently but charge together, neither one will be charged correctly. Usually what happens is the fuller battery is overcharged an "cooks" off "water".

There is no reason why you shouldn't be able to run that same inverter powered from the trailer batteries. That's what I would aim for.

That said, I like your modification. Makes it quick and easy to get 120 VAC for all those other tasks that happen near a tailgate

[Gdetrailer]

timjcarter9 wrote:
Yeah that is what I thought. I have dual battery capability so will add the deep cycle to the truck. Would only be running max two hours before using the vehicle again to go out and do whatever we do.

As I said above the inverter tends to alarm when the water pump or furnace goes on. Only 2 six volts so want the AC separate. No room for mor batteries on the trailer tongue.

You have some wiring issues.

I RUN a home fridge from a 1250W inverter using a pair of 6V GC batts, I have no problems with the inverter going into alarm when the furnace kicks on or even if I run a bunch of lights.

Have you tried hooking the inverter DIRECTLY to the batteries?

If you have been using the trailer wiring to run the inverter that is the problem. The trailer wiring is not robust enough and is causing a large voltage sag when other high current 12V devices are being used.

Large and short wires are your friend for inverters, 10Ga for a couple of feet is fine but your trailer will have 20 or more feet of 14 or 12 ga wire if you use the cig plugs in the trailer.

I also feel that using your tow vehicle battery(ies) is a very bad thing to do in the name of entertainment.

As far as charging cell phones, skip the inverter and buy purpose made 12V chargers for your cell phones. Saves a lot of battery since you do not need to run the inverter.

[RoyB]

I always go by the rule to not mess with the truck starting battery. This is the only way I can get back home hehe...

Having 200Ah battery capacity from the trailer is alot of power to run your 300WATT Inverters... What most folks do is direct connect the small inverters directly to the trailer batteries and run their home entertainment system from this source.

Your inverter should be connected as close to the battery terminals as you can get them (Typical around 5-feet) and still be inside the trailer. Then you can run the 120VAC extension cords almost any length you need to get to where you want the 120VAC to be at.

This is a typical trailer hookup showing this...


I also would be very cautious what you plug into a MODIFIED SINE WAVE type Inverter. The home entertainment electronic items work best using PURE SINE WAVE Inverters. A lot of dollars are most likely invested in your home entertainment items that might go up in BLUE SMOKE using the MSW type inverters. ALot of others use the cheaper MSW Inverters but I only use PSW TYPE Inverters so that I don't have to worry about things blowing up on me...

Just my thoughts only...
Roy ken

[tvman44]

A dual battery set up with an isolator so you do not run down the cranking battery. 🙂

[timjcarter9]

Yeah that is what I thought. I have dual battery capability so will add the deep cycle to the truck. Would only be running max two hours before using the vehicle again to go out and do whatever we do.

As I said above the inverter tends to alarm when the water pump or furnace goes on. Only 2 six volts so want the AC separate. No room for mor batteries on the trailer tongue.

[KD4UPL]

That's a near trick. I've done similar things to run accessory's off my trailer plug. I love that GM leaves it hot all the time.
I don't quite understand why you would want to power your TV from the truck batteries instead of the camper batteries.
Starting batteries aren't designed to be used like that. You risk the truck not starting and you shorten the overall life of your starting batteries by subjecting them to deep discharges. I would power the inverter from the camper batteries or from a separate deep cycle battery.

[naturist]

First question, how many amp-hours is your truck's starting battery? As a guess, probably no more than 70 Amp Hours. 90 watts is going to be 7.5 amps at 12 volts. So in something like 9 hours you'd exhaust that battery totally. Of course, it won't get that much because the rated capacity is calculated on a 20 hour discharge time, so maybe you'd get 6 hours to total discharge. A little less if the battery is not new, even less if it isn't fully charged, which automotive systems rarely do anyway.

Now there's no way a nearly fully discharged battery is going to be able to crank your starter. MAYBE a 50% discharged battery could do that, Maybe not. That says at best, you might get 3 hours before you couldn't start your truck, but there's one more factor to consider here: starting batteries are not designed to be discharged that deep. Running that inverter for anything like 3 hours is going to completely kill your battery long before it would otherwise die.

So I'm going to make a suggestion to ya: buy a deep-cycle marine battery just for this purpose, and charge it up on a battery charger in the house before you go tailgating. It'll run your stuff longer, will deal with deeper draw-downs without killing the battery, and you'll never have to worry about being able to start your transportation.