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Smart $ said:
That's an indication of this problem waiting to happen. Why? Because that's the input voltage that the inverter is rated 1000W on. When voltage is less than that, which is common during vehicle operation, the inverter tries to put out the same wattage at lower input voltage and thus overheats. (FWIW, I've burnt up audio amps for the very same reason.)

If you replace the inverter with a brand new one, it'll likely work for awhile... then the same thing will likely happen. Try getting a 1.5 or 2kW inverter....
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I don't think it was all that clear if 14.8 volts was nameplate rating of the unit or what was actually measured.

If 14.8 was measured it presumably was with vehicle charging system running, otherwise voltage should have been closer to 12 volts.

We also don't know (if it was measured voltage) if that was loaded or unloaded.

As iceworm pointed out 1000 watts at 12 volts is around 80 amps. One may want to look into what is there for a supply circuit and see if there is any problem with handling that kind of power over whatever distance it is connected to.

If it once worked fine but now doesn't there could be a failing connection somewhere limiting the current when it reaches certain levels, I've had this kind of troubles before with too small of conductors on only 300 watt units - they worked fine at low load levels but not at higher load levels.
 
kwired said:
I don't think it was all that clear if 14.8 volts was nameplate rating of the unit or what was actually measured.

If 14.8 was measured it presumably was with vehicle charging system running, otherwise voltage should have been closer to 12 volts.

We also don't know (if it was measured voltage) if that was loaded or unloaded.

As iceworm pointed out 1000 watts at 12 volts is around 80 amps. One may want to look into what is there for a supply circuit and see if there is any problem with handling that kind of power over whatever distance it is connected to.

If it once worked fine but now doesn't there could be a failing connection somewhere limiting the current when it reaches certain levels, I've had this kind of troubles before with too small of conductors on only 300 watt units - they worked fine at low load levels but not at higher load levels.
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The inverter spec's are not anywhere near regulated as NRTL listed equipment, but there are some standards to which a manufacturer can ascribe to. There isn't necessarily a nameplate, though. As I recall, Gus said website spec's.

The thing about some automotive standards is, they let manufacturers rate equipment for a 14V system. True it is not a common system for consumer vehicles, but there are many audio competition fanatics that convert their "rides" over to 14V... simply because they can get a little more power out of their audio system... so it has become somewhat a standard voltage in DC power equipment ratings.

Having explained that, let's look at the spec's in that respect. 1000W at 14.8VDC is ~68A. If we try to get the same 1000W out of that inverter powering it with 12V, the amperes have to go up to ~83. The electronics were not built to handle 83A on the front end. This is how the units burn up on usage.

Technically, most of a 12VDC to 120VAC inverter is the same as a mono block subwoofer amp. The main difference is the inverter's front end is fed a constant 60Hz signal. From there, it is just a question of how low the impedance can be and still have a stable output.
 
Smart $ said:
The inverter spec's are not anywhere near regulated as NRTL listed equipment, but there are some standards to which a manufacturer can ascribe to. There isn't necessarily a nameplate, though. As I recall, Gus said website spec's.

The thing about some automotive standards is, they let manufacturers rate equipment for a 14V system. True it is not a common system for consumer vehicles, but there are many audio competition fanatics that convert their "rides" over to 14V... simply because they can get a little more power out of their audio system... so it has become somewhat a standard voltage in DC power equipment ratings.

Having explained that, let's look at the spec's in that respect. 1000W at 14.8VDC is ~68A. If we try to get the same 1000W out of that inverter powering it with 12V, the amperes have to go up to ~83. The electronics were not built to handle 83A on the front end. This is how the units burn up on usage.

Technically, most of a 12VDC to 120VAC inverter is the same as a mono block subwoofer amp. The main difference is the inverter's front end is fed a constant 60Hz signal. From there, it is just a question of how low the impedance can be and still have a stable output.
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Not disagreeing with you but am trying to go with simpler issues first. Unless a heavier conductor was custom installed to this inverter, it is likely plugged into a cigaratte lighter or power plug of similar design. Such device is not designed or has heavy enough supply conductor to handle 60-80 amps (whatever corresponds to actual voltage) and something in this circuit may be compromised causing the issues encountered. I have had similar experiences even with only a 3-400 watt inverter.
 
kwired said:
Not disagreeing with you but am trying to go with simpler issues first. Unless a heavier conductor was custom installed to this inverter, it is likely plugged into a cigaratte lighter or power plug of similar design. Such device is not designed or has heavy enough supply conductor to handle 60-80 amps (whatever corresponds to actual voltage) and something in this circuit may be compromised causing the issues encountered. I have had similar experiences even with only a 3-400 watt inverter.
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I would seriously question the 1000W rating if it is just plugged into the cigarette lighter. :happyyes:
 
Smart $ said:
I would seriously question the 1000W rating if it is just plugged into the cigarette lighter. :happyyes:
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So would I, but for no longer then the printer would draw high current to heat the fuser, it probably never is long enough duration to blow the fuse, but that don't mean there isn't an undersized adapter plugged into it that has taken some damage or some other weak link in the circuit after some time has passed. Such a high wattage inverter (for a vehicle application) about needs direct wiring to the battery as nothing existing in the vehicle is designed for that kind of load.

We haven't been told how this thing was powered from the vehicle yet, and that may be a contributing factor to the problem encountered.
 
kwired said:
So would I, but for no longer then the printer would draw high current to heat the fuser, it probably never is long enough duration to blow the fuse, but that don't mean there isn't an undersized adapter plugged into it that has taken some damage or some other weak link in the circuit after some time has passed. Such a high wattage inverter (for a vehicle application) about needs direct wiring to the battery as nothing existing in the vehicle is designed for that kind of load.

We haven't been told how this thing was powered from the vehicle yet, and that may be a contributing factor to the problem encountered.
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IMO it would be long enough and at high enough current to blow the fuse. Laser printers take longer than just a couple cycles to warm up the fuser(s).

I am not saying Gus should in any way discount simpler problems and remedies... but I'm leaning toward having an undersized inverter from the get go.
 
Smart $ said:
IMO it would be long enough and at high enough current to blow the fuse. Laser printers take longer than just a couple cycles to warm up the fuser(s).

I am not saying Gus should in any way discount simpler problems and remedies... but I'm leaning toward having an undersized inverter from the get go.
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We also don't know if the stated 1000 watts is continuous rating or a surge rating of his inverter.
 
[h=1]BESTEK 2 AC Outlets 1000W Power Inverter [/h]Rated Power: 1000W, Max Power: 1200W, Peak Power: 2400W
• Input Voltage: DC 12V, Output Voltage: AC 110-120V
• Output Waveforms: Short-Wave, Switching Power: 85% above, Circuit Mode: P.W.M

connected to the vehicle battery thru a 100 amp fuse with 1/0 DLO
 
I'm looking at these amperage numbers being posted. Most automobile alternators do not put out 80A.

I also don't see where anyone factored in the (lack of) efficiency of the inverter which pushes numbers even higher.

I'm going to again suggest OP look at getting a printer intended to operate in a mobile environment.

Edit: I see augie just posted model # and specs.
 
mgookin said:
Most automobile alternators do not put out 80A.
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But the battery will, but only for so long, and the alternator can then restore the lost charge at it's own rate.

As long as he isn't printing hundreds of pages at a time it can probably handle this.
 
Does the fact that my Fluke multimeter measures 98v indicate an inverter problem or is that just a result of the type output ?
I can't recall what reading I had when it was working well.
 
151205-1555 EST

I have not read back thru all the posts since I last posted, but I did skim.

I have run a test on a Whistler PP300AC inverter. Not much of a label, but it states 300 W continuous (not VA) and 600 W peak. No indication of input voltage. Thus, I assume 14 V.

I used a 25 W incandescent as a nominal 120 V load. An adjustable DC supply for the input via a Variac for adjustment.

095 V reading on a Simpson 270 in AC position and using the Output input terminal. Full wave rectified, average reading (0.636 * Vpeak, scaled up by 0.707/0.636 = 1.112)

094.6 V on a Fluke 27. Same as Simpson, it is average reading. Fluke always has an input capacitor in AC mode.

116.5 V RMS on a Beckman 4410 true RMS meter.

164 V peak (116.5 * 1.414 = 164.7, good correlation) measured via a 1N5625 (400 V diode) and a 1 mfd capacitor and read on DC on the Fluke 27.

This inverter is not close to a sine wave output, but has been designed to provide the same peak voltage and RMS voltage as the designed for sine wave would.

augie47 are you using an average reading meter or a true RMS meter?

Does the printer not work at all on the inverter? Or does it print, but not fuse correctly? Or are there data errors?

When the inverter is running and has the printer load what is the DC input voltage at the inverter.

.
 
Whatever type of meter you have, the change in reading from an unloaded to a fully loaded condition will give you an idea of the health of the inverter, wiring, and battery.
Does the printer work any better with the engine running?
 
151205-2054 EST

augie47:

If your meter is a true RMS meter, then your output voltage reading is low and indicates a problem with the inverter, or the wiring to the inverter, or the voltage source in the engine compartment.

My LaserJet 5MP when not connected to a computer and with an input of 123.6 V, and after a short warmup reads 0.08 A, 4.7 W, 10.5 VA, and 0.44 PF. This would be a very low load on your inverter, and I expect your printer is not much different.

The voltage and power for the electronics in your printer is probably dependent upon the peak voltage of the AC source, and the heating capability of the fuser is dependent upon the RMS voltage of the AC source.

.
 
151206-1450 EST

I looked at my inverter output waveform. It consists of +/- 164 V pulses. Using my previous peak measurement for the value. The on and off times are approximately equal.

OFF for about 2.5 mS,
ON +164 for about 5 ms,
OFF for about 5 mS,
ON -164 V for about 5 mS, and
OFF for about 2.5 mS.

This waveform will produce a 164 V peak voltage, an 82 V full wave rectified average voltage (a reading of 91 on my Simpson 270 in AC), and 116 V RMS.

Good correlation with my actual measurements except the Simpson actual reading was 4 V higher. Also there may be some differences in the on and off times.

Vrms = sq-root ( 164^2/2). The divide by 2 is for the 50% on time.

The average DC current to a 25 W lamp load is very low. This implies an output transformer coupling, or good pulse balancing to avoid a DC component.

This is a low cost way to get an approximation to a sine wave, and useful for many applications. But, high in harmonic content.

.
 
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