power Inverter question

[rustytoolss]

Just learning some about Power Inverters. Got a question. The inverter I'm thinking of is HF 1500W. It has 2 outlets. My question is (because I don't know much about this)... can the power inverter output power be wired directly into my standard AC power supply ? I'm sure that this would not be the thing to do. But if it would be possible , I could use the current wiring AC outlets in my system. Instead of using an extension cord from the inverter, to my item needing power.
Also how bad of an idea is it to use a standard car battery (mounted outside), in place of an AGM battery ?

[bobwhite215]

A standard car battery is designed to produce a lot of amps for a very short time. What you want is a deep cycle battery, which puts out lower amps for a long period.

AGM is just a way that the battery is built. It is sealed, and you don't need to worry about orientation. You can use a traditional liquid lead acid deep cycle battery with no problems outside. Just need to mount it upright, and make sure it's vented. Also should make sure it is accessible for service.

Sent from my XT1080 using Tapatalk

[GuitarPhotog]

What is your "standard AC Power Supply"?

Are you using a converter/charger like a PD4045 or WFCO? Or??

A 1500 W inverter will draw down a battery very quickly. If your battery is rated at 100 AH, that's only 1200 total WH, so you can't run your inverter at full capacity for more than about 20 minutes before you need to recharge the battery.

<Chas>

[Cosmo]

You can try and calculate what you need. I use the watts to convert from one voltage to another.


AMPS X VOLTS = WATTS and WATTS / VOLTS = AMPS

A device that draws 2 amps on 120 voltage = 240 watts (amps times volts equals watts)
240 watts divided by 12 volts = 20 amps on 12 volts power. (watts divided by volts equals amps).
I add in a percentage for conversion losses,

As GuitarPhotog pointed out an AC appliance that draws more than a few amps will require a very large battery to satisfy the inverter. A 10 amp AC draw will require about 100 amps from a 12 volt battery. CHECK YOU APPLIANCE AMP OR WATT needs and convert for an idea of what you need before you build your system and keep in mind your systems limitations.

I carry a small 150 watt inverter for small devices like a laptop or electric shaver for short periods of time. However I also stick with 12 volt for everything else. The 150 watt inverter draws 10 amps out of my battery to supply 1.25 amps AC.



-Cosmo

[swoody126]

the inverter you mentioned, 1500w, needs to be attached to a good deep cycle battery and only used when the battery is being charged by the TV or you will drain the coach battery in short order

the connection from the TV to the coach battery needs protection to keep the inverter from drawing off the TV battery when the engine is not running(actively charging) or you will draw the TV battery down to a point where you can't start the TV engine

i used a similar inverter on my OTR big truck which had an automatic starting system that would start the truck engine when the battery bank(several BIG batteries) when the voltage dropped to a predetermined level

running the microwave in the sleeper would cause the truck engine to start almost immediately

charging my computer battery wasn't so draining

IMHO some re-thinking is in order

sw

[lfhoward]

In order to have an inverter feed to the same 120V AC household power outlets that the shore power connects to, you will need a transfer switch. A transfer switch will isolate your inverter from shore power, effectively tying it in only when the shore power is unavailable. It's the same kind of switch that lets a generator power a house, but that automatically disconnects the generator from the house grid when the utility power comes back on.

Here is an example of a transfer switch:
http://www.progressivedyn.com/pd5110010.html

[rustytoolss]

the inverter you mentioned, 1500w, needs to be attached to a good deep cycle battery and only used when the battery is being charged by the TV or you will drain the coach battery in short order

the connection from the TV to the coach battery needs protection to keep the inverter from drawing off the TV battery when the engine is not running(actively charging) or you will draw the TV battery down to a point where you can't start the TV engine

i used a similar inverter on my OTR big truck which had an automatic starting system that would start the truck engine when the battery bank(several BIG batteries) when the voltage dropped to a predetermined level

running the microwave in the sleeper would cause the truck engine to start almost immediately

charging my computer battery wasn't so draining

IMHO some re-thinking is in order

sw

Thanks for that information, The whole inverter thing has just been an after thought . What's you view on things like 12 volt appliance's .. Like flat screen TV's , coffee makers ? Not even sure ,that will even happen

[Shadow Catcher]

I have a 30A DPDT switch that cuts out the power to the converter and shunts the power from our 300W Morningstar inverter to the 120AC outlets. Any thing that uses resistance heat is a no no i.e. your coffee maker. It will however work for the TV however.

[bdosborn]

But if it would be possible , I could use the current wiring AC outlets in my system. Instead of using an extension cord from the inverter, to my item needing power.

I assume you have a shore power inlet that you use to plug your trailer into 120 power. You could use an extension cord to connect you inverter to the shore power inlet. Then you don't have to mess with a transfer switch. Just make sure and unplug you battery charger when you do it (assuming you have a battery charger connected to your 120V system in the trailer).

There isn't really much difference in battery life between a wet cell battery and an AGM, it depends on what you plug into the inverter. Microwave, AC, electric skillet = *minutes* of battery life. Cell phone charger, radio, camera battery charger = hours of battery life.

Bruce

[absolutsnwbrdr]

Hey guys, I'm working on a wiring diagram that is based on a PD4045, and will include an inverter and automatic transfer switch to provide AC power to the system when not plugged into shore power. I keep getting stuck in a loop though. Doesn't the automatic transfer switch only alternate either from shore power to inverter power?

How do I keep inverter output (120VAC) from automatically driving the PD4045 charging circuit, generating 12V power to the batteries, which then powers the inverter input?

It seems like I need a DC disconnect switch on the 12V primary wire between the PD4045 and the Master Disconnect. But then its not all automatic.

Or am I missing some sort of magical device?

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[lfhoward]

Hi Zach,

Couldn't you have the PD4045 branch off of the main 120VAC power line upstream of the transfer switch? When plugged into shore power, the PD would be powered by AC, but not when boondocking. What is missing in the diagram is a line from the Transfer Switch to some 120VAC 3 prong outlets. You could run your AC gadgets from those, regardless of where the 120VAC power is coming from (shore or inverter).

[absolutsnwbrdr]

In the previous diagram I was trying to feed the PD4045 from the inverter so that all 120VAC circuits protected by the PD4045 would be hot on inverter power. But with the PD4045 hot on inverter power, then that cycle starts.

I had given a little thought to the configuration you mention (I think). When boondocking, I think that leaves me with only one branch circuit from the PD4045 that uses inverter power. All other circuits from the PD4045 will be dead.

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When on shore power, all circuits would be hot and protected, by way of PD4045 and the transfer switch.

If that's the way it has to be, then it is what it is. Ideally, one would like to have all circuits able to be used while on inverter power.

Maybe I'm asking for too much.

[aggie79]

Zach,
How about the use of a relay that "makes" and "breaks" the DC battery charge line between the convertor and batteries? If the relay detects 120 VAC power between the shore power inlet and transfer switch, then it "makes" the connection. If there is no shore power then it disconnects the hot DC line to the batteries.
Tom

[absolutsnwbrdr]

Are you referring to my first diagram or the second one?

I wonder if that would prevent the PD4045 from providing power to all the 12V stuff. Some people have claimed that the power center will not produce 12V without sensing a battery. I cant confirm that though.