Power Inverter
#1
07-07-2011, 09:53 PM
Power Inverter
I have 2 inverters. The first is compact with one outlet plug and a small LED indicator. The second is a larger unit with 2 outlet plugs, an LED indicator and a switch that lights up when flipped on.
My question does either of these drain the battery (when the ignition is off) if they are plugged into any of the truck's 12V power sources but nothing actually plugged into the inverter?
I should mention that the LED indicator remains on when the inverters are plugged into any of the trucks 3 power supplies and the engine is not running.
Hope this all made some kind of sense.
My question does either of these drain the battery (when the ignition is off) if they are plugged into any of the truck's 12V power sources but nothing actually plugged into the inverter?
I should mention that the LED indicator remains on when the inverters are plugged into any of the trucks 3 power supplies and the engine is not running.
Hope this all made some kind of sense.
Last edited by Formula jg; 07-08-2011 at 10:56 AM.
#2
07-08-2011, 12:12 AM
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Made perfect sense.
While measuring the no-load current draw of your actual inverter is the only way to know for sure, I think the answer would generally be "Yes, there will be some 12V current draw even if nothing is plugged in to the inverter output, which will eventually drain your battery."
These inverters typically work by using a DC-to-DC converter to first boost the 12V input to about 140V DC. Then they use a series of power transistors to connect the 140V to the output for 1/240th of a second, then 0 volts for 1/240th of a second, then the 140V "backwards" (i.e. -140V) for 1/240th of a second, then 0 volts for the final 1/240th of a second, then repeat. That sequence of voltage changes approximates a 120V, 60 Hz AC sine wave, which is "close enough" for most household power equipment. (Some equipment doesn't tolerate that sort of approximated spiky wave very well; for those pieces of equipment you need to buy a more-expensive "true sine wave" inverter.)
Anyhow, generating that 140V DC and piping it through the power transistors in sequence will consume power from the 12V DC input even if nothing's drawing power from the output outlets.
While measuring the no-load current draw of your actual inverter is the only way to know for sure, I think the answer would generally be "Yes, there will be some 12V current draw even if nothing is plugged in to the inverter output, which will eventually drain your battery."
These inverters typically work by using a DC-to-DC converter to first boost the 12V input to about 140V DC. Then they use a series of power transistors to connect the 140V to the output for 1/240th of a second, then 0 volts for 1/240th of a second, then the 140V "backwards" (i.e. -140V) for 1/240th of a second, then 0 volts for the final 1/240th of a second, then repeat. That sequence of voltage changes approximates a 120V, 60 Hz AC sine wave, which is "close enough" for most household power equipment. (Some equipment doesn't tolerate that sort of approximated spiky wave very well; for those pieces of equipment you need to buy a more-expensive "true sine wave" inverter.)
Anyhow, generating that 140V DC and piping it through the power transistors in sequence will consume power from the 12V DC input even if nothing's drawing power from the output outlets.
#3
07-08-2011, 12:47 AM
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Made perfect sense.
While measuring the no-load current draw of your actual inverter is the only way to know for sure, I think the answer would generally be "Yes, there will be some 12V current draw even if nothing is plugged in to the inverter output, which will eventually drain your battery."
These inverters typically work by using a DC-to-DC converter to first boost the 12V input to about 140V DC. Then they use a series of power transistors to connect the 140V to the output for 1/240th of a second, then 0 volts for 1/240th of a second, then the 140V "backwards" (i.e. -140V) for 1/240th of a second, then 0 volts for the final 1/240th of a second, then repeat. That sequence of voltage changes approximates a 120V, 60 Hz AC sine wave, which is "close enough" for most household power equipment. (Some equipment doesn't tolerate that sort of approximated spiky wave very well; for those pieces of equipment you need to buy a more-expensive "true sine wave" inverter.)
Anyhow, generating that 140V DC and piping it through the power transistors in sequence will consume power from the 12V DC input even if nothing's drawing power from the output outlets.
While measuring the no-load current draw of your actual inverter is the only way to know for sure, I think the answer would generally be "Yes, there will be some 12V current draw even if nothing is plugged in to the inverter output, which will eventually drain your battery."
These inverters typically work by using a DC-to-DC converter to first boost the 12V input to about 140V DC. Then they use a series of power transistors to connect the 140V to the output for 1/240th of a second, then 0 volts for 1/240th of a second, then the 140V "backwards" (i.e. -140V) for 1/240th of a second, then 0 volts for the final 1/240th of a second, then repeat. That sequence of voltage changes approximates a 120V, 60 Hz AC sine wave, which is "close enough" for most household power equipment. (Some equipment doesn't tolerate that sort of approximated spiky wave very well; for those pieces of equipment you need to buy a more-expensive "true sine wave" inverter.)
Anyhow, generating that 140V DC and piping it through the power transistors in sequence will consume power from the 12V DC input even if nothing's drawing power from the output outlets.
Could have just said yes
But the drain is minimal.
#4
07-08-2011, 08:12 AM
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Inverters - in general there are three types ; square wave , modified sine wave , and pure sine wave. As mentioned certain things like amateur radio gear , computers , want pure sine wave .For that use square wave is terrible . Inverters also are about 90 % efficient .
Generators are similar .For the electronics get something like Honda's series that has a pure sine wave.
Generators are similar .For the electronics get something like Honda's series that has a pure sine wave.
#5
07-08-2011, 11:07 AM
#6
07-09-2011, 09:46 AM
I have a 400W PSW inverter installed under my back seat. It has a ON/OFF switch on it but I usually find it ON most of the time. It hasnt run my battery down yet just sitting there.
These are handy things to have aboard... Always something you want to use it for. I use it grind my fresh coffee beans when RV camping off the power grid. Great for charging up things like my hand drill.
The 400W inverter really tears up my ham radio junk RF wise especially on the HF bands (3-30mHz).
The big guys (1500W-2000W models) really have to be installed as close to the battery terminals as possible. They draw some serious amps from the battery when being used. I have a 1500W PSW model in my RV POPUP trailer that has a 175AMP fuse installed in the 12VDC side and the spec says with a no load it will draw 1.45 amps which will run down your battery if left on over night in your truck.. I suspect my 400W inverter in my truck draws around 1/2 AMP or less just sitting there connected with no load. If that was left on for several days (around a week) might run down your battery.
I always try to keep it turned off but every now and then I go to use it and it is already on haha This circuit is hardwired to the battery for my two-way radio junk so the truck wont turn this off after 10minutes like everything else is controlled.
These are handy things to have aboard... Always something you want to use it for. I use it grind my fresh coffee beans when RV camping off the power grid. Great for charging up things like my hand drill.
The 400W inverter really tears up my ham radio junk RF wise especially on the HF bands (3-30mHz).
The big guys (1500W-2000W models) really have to be installed as close to the battery terminals as possible. They draw some serious amps from the battery when being used. I have a 1500W PSW model in my RV POPUP trailer that has a 175AMP fuse installed in the 12VDC side and the spec says with a no load it will draw 1.45 amps which will run down your battery if left on over night in your truck.. I suspect my 400W inverter in my truck draws around 1/2 AMP or less just sitting there connected with no load. If that was left on for several days (around a week) might run down your battery.
I always try to keep it turned off but every now and then I go to use it and it is already on haha This circuit is hardwired to the battery for my two-way radio junk so the truck wont turn this off after 10minutes like everything else is controlled.
Last edited by Roy Braddy; 07-09-2011 at 09:50 AM.
#7
07-10-2011, 09:56 PM
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Well, of course. But usually the next question is then, "Why is that?" It's not necessarily obvious that even without anything plugged in to the outlets, there's still a lot happening within the circuitry.
For a 400W inverter and up, the drain can be high enough to suck one's battery, within a few days, down to the point where you'll get only a "click" out of the starter. I've seen it happen. Reminds me of the phrase "for only pennies a day...."
It's not necessarily obvious that even without anything plugged in to the outlets, there's still a lot happening within the circuitry.For a 400W inverter and up, the drain can be high enough to suck one's battery, within a few days, down to the point where you'll get only a "click" out of the starter. I've seen it happen. Reminds me of the phrase "for only pennies a day...."