Using DC to DC charger to run AC ???

[Rbertalotto]

Is this possible. Rather than using an outboard generator to run the AC unit on my travel trailer, can I run it off a 40A Renogy DC to DC converter running off my trucks alternator. The AC unit on the travel trailer will run on a single Honda E2000i Inverter Generator.

Here is what I have:

200Ah of AGM deep cycle battery (100Ah usable) Soon to be replaced with 300Ah of Lithium .....
2000w Inverter
220Amp alternator in truck
Renogy 40A DC to DC Charger

Running the truck is much quieter than running the Honda generator. (The Honda generator can not run in the quieter ECO mode and run the AC)
Will the 40amps the Dc to DC converter is putting into the battery, keep up with the discharge of the battery by the inverter.

Thanks in advance

 

[Bud Martin]

How much power does the Aircon needs to run and the startup surge it needs to startup?

"220Amp alternator in truck" what is the rating at idling?

 

[Rbertalotto]

I never measured the current needed. But it runs on a Honda 2000. I installed a sofisticated "soft start" device on it so it can run on a single 2000 generator. Works great! But running off the truck would be much better. The new Ford F150 hybred has a feature that allows exactly what I'm trying to do.
The truck I have has a new "smart" alternator and will out put whatever is needed at any RPM up to 220 amps.

 

[Bud Martin]

Renogy 40A DC to DC Charger is about 500W of power (for 12V system), so if the Aircon uses more than that then it will also draw power from battery to keep up with the demand, so if you use more than the charger can provide to keep the batteries charged up then you will drain the batteries, that is why you need to find out how much power your Aircon uses.

 

[tazmann]

Without the Dc to Dc charger, going direct to AGM's maybe . but if your limited to the 40amps @12volt and running standard rv roof air you will be out of battery within a couple hours

 

[Rbertalotto]

Thank you! Looks like I'll keep running the generator...

 

[noenegdod]

From an efficiency perspective this is insane. The truck engine all on its own just idling and doing nothing will consume somewhere around .5 gallons of fuel each hour or more, adding 500 Watts of load to that will increase consumption.

A Honda 2200 on 1/4 load which is 450 watts will run for 8 hrs on .95 gallons.

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The Honda EU2200i super quiet inverter generator offers 2200 watts of power. Extremely quiet and fuel efficient, this portable generator is ideal for camping & RV use.

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If you do this a couple days a month, who cares. If you do it every day it makes no sense.

 

[Rbertalotto]

Understood. Only would be used on very hot days for a couple hours. I'm never in the camper during the day. I use my toy hauler as a means to an end. Motorcycling during the day or shooting cowboy action. When I get back to the camper at 4pm it might be hot enough that it needs a couple hours of cool down. The extra gas matters not.

 

[noenegdod]

The other nice thing about running the truck instead of the generator is the fact that the exhaust goes through a catalyst and even though you are burning at least 4x as much fuel the exhaust is far less smelly.

 

[Smokin]

" find out how much power your Aircon uses."
VA power not watts.
You see the motor is a big inductor. The power lags in inductors. In a Capacitive circuit the power leads. You can add a Capicator to the line at the load to balance out the PF. A fan Capicator is what I use. 370 volt at 10uF.

Say I'm running a well pump on 125 volts ac off a generator with a 100 wire run to the pump.. The pump motor struggles to start and pops the breaker on the 3kw genset. . By adding a Cap at the well pump the solves the issue of the well pump not starting and pulling the breaker on the generator.

Volts x Amps = VA. AC has real power and reactance power requirements. Simply looking at the watts and power factor will show VA. Reactance power usually is provided free of charge from the power Co. On a Generator you are the power Co and if you are making the reactance power.

A simple truth.

The distance between the truck and trailer will limit the current all by it self. If you run a wire from the truck battery to the battery in the camper you will not be able to push alot of amps anyway. So you may not need to do anything more than calculate you wire run to satisfy you loads. The alternator is regulating itself at the post at the back of the alternator. It sees 14.5 volts cold and 13.8 hot. When you run 50 feet of wire off this post to a battery you will NEVER be able to push 220 amps. 50' of wire is 25' of wire x 2. Yeah Baby it's all good. Hook it up.

I don't know but maybe the 40 amp DC to DC uses a Boost converter topo to pump the 40 amps. IDK.