Too much voltage for the power inverter
10-15-2006, 08:30 PM
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Too much voltage for the power inverter
I have a 1500W power inverter that I just installed. It works fine when the truck is not running, but at an idle, the "fault" light turns on and the inverter shuts off. I found out that it is due to "high voltage" going into the inverter. I have 15V coming off of my system (battery) with the engine running. The inverter shuts down at 15v to protect itself. It is at 13.5v with the motor off. Is 15v normal? Seems a little high to me . . . . 14v sounds right. Any thoughts?
10-15-2006, 08:57 PM
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Your readings are high , a fully charged battery should be 12.75 , engine not running .
Engine running is a differant story , depends on the demand , what els is pulling power ? telling the regulator to step up its output , if you just started the enigine , its putting amp hrs. back into the battery , also the alt. is not going to put out max amps at idle , over 1,300 RPMs 14.25v-15v .
If you draw 1,500 watts off the starting batteries thats 125 amps [ 1500 watts devided by 12v = 125 amps ] thats going to draw down the volts in the batteries to the shut down voltage within seconds , thats may be why .
You should be using much larger deepcycle batteries to run that inverter .
Engine running is a differant story , depends on the demand , what els is pulling power ? telling the regulator to step up its output , if you just started the enigine , its putting amp hrs. back into the battery , also the alt. is not going to put out max amps at idle , over 1,300 RPMs 14.25v-15v .
If you draw 1,500 watts off the starting batteries thats 125 amps [ 1500 watts devided by 12v = 125 amps ] thats going to draw down the volts in the batteries to the shut down voltage within seconds , thats may be why .
You should be using much larger deepcycle batteries to run that inverter .
10-15-2006, 09:16 PM
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When I start the truck, the inverter isn't even on. I start it up, then turn the inverter on. I was only running my sons PS2 and a little LCD screen (maybe 250 watts total). Everything on the truck was off (lights, heated seats, A/C, etc.). I have 2 Gague cable running to the inverter from the battery (I have a 150amp inline fuse).
This same set-up worked great on my previous truck with no issues. However, on this truck, I didn't need about 5ft. of the 2 gague cable that I required on the other truck . . . . that extra 5 ft dropped the voltage I'm sure . . . .with the shorter cable, the voltage loss is less. I'm not sure what to do now.
This same set-up worked great on my previous truck with no issues. However, on this truck, I didn't need about 5ft. of the 2 gague cable that I required on the other truck . . . . that extra 5 ft dropped the voltage I'm sure . . . .with the shorter cable, the voltage loss is less. I'm not sure what to do now.
10-15-2006, 10:15 PM
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2ga cable? You really think there was a noticeable voltage drop on 2ga cable over 5ft? If there was a voltage drop I don't think it would be enough to cause any issue. Just think that tail lights have roughly 16ga wire with a run of over 20+ft and there is generally battery voltage back at these lights.
15V does seem high...normal is typically 14.4-14.7V. Just for giggles...try putting a multi meter on the battery with the engine running. Switch the multi meter to DC Volts and rev the engine above idle (say upwards of 1750-2000rpm) what does the DVOM say at this RPM? If it is the same then it isn't too bad...if you have a bum Voltage regulator then it will be even higher than 15V.
15V does seem high...normal is typically 14.4-14.7V. Just for giggles...try putting a multi meter on the battery with the engine running. Switch the multi meter to DC Volts and rev the engine above idle (say upwards of 1750-2000rpm) what does the DVOM say at this RPM? If it is the same then it isn't too bad...if you have a bum Voltage regulator then it will be even higher than 15V.
10-16-2006, 01:25 AM
#7
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Put an external regulator on it, do a search to find out how to set it up. These trucks charge too high. You might also try unplugging the heat sensor from the bottom of one of the battery boxes, should be the drivers side. It may be bad causing the charging to think it is real cold outside.
The external regulator will be somewhere between 13.8 and 14.3 generally about 14 even.
You could have a problem in the pcm causing it or a bad alternator doing it, not unlikely. Try attaching a better ground to the alternator, run a wire from the alternator straight to the pcm. If the ground is weak, the sensing would be poor.
the cure is the external, no more problems at all. If you are really charging at 15, get ready for a battery to blow up. They like to do that and they do make a mess out of the compartment. Mine boiled the batteries constantly until I installed the external.
The external regulator will be somewhere between 13.8 and 14.3 generally about 14 even.
You could have a problem in the pcm causing it or a bad alternator doing it, not unlikely. Try attaching a better ground to the alternator, run a wire from the alternator straight to the pcm. If the ground is weak, the sensing would be poor.
the cure is the external, no more problems at all. If you are really charging at 15, get ready for a battery to blow up. They like to do that and they do make a mess out of the compartment. Mine boiled the batteries constantly until I installed the external.
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10-16-2006, 08:28 PM
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Thanks for the tips . . . I think I have it figured out now. I got a better meter, and I'm getting 12.75 off of the battery with the motor off, 14.4 with the motor running. I don't really have any power loss through the 2ga wire going into the inverter (14.4). When I shut the "appliance" off, there is a spike of voltage for a split second that hits 15v or slightly higher . . . that shuts the inverter off. I only have .6v to play with before the inverter shuts down to protect itself from high voltage.
As some suggested, I will look into a voltage regulator that can hold it at 12v or so.
As some suggested, I will look into a voltage regulator that can hold it at 12v or so.
10-16-2006, 08:46 PM
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Put an external regulator on it, do a search to find out how to set it up. These trucks charge too high. You might also try unplugging the heat sensor from the bottom of one of the battery boxes, should be the drivers side. It may be bad causing the charging to think it is real cold outside.
The external regulator will be somewhere between 13.8 and 14.3 generally about 14 even.
You could have a problem in the pcm causing it or a bad alternator doing it, not unlikely. Try attaching a better ground to the alternator, run a wire from the alternator straight to the pcm. If the ground is weak, the sensing would be poor.
the cure is the external, no more problems at all. If you are really charging at 15, get ready for a battery to blow up. They like to do that and they do make a mess out of the compartment. Mine boiled the batteries constantly until I installed the external.
The external regulator will be somewhere between 13.8 and 14.3 generally about 14 even.
You could have a problem in the pcm causing it or a bad alternator doing it, not unlikely. Try attaching a better ground to the alternator, run a wire from the alternator straight to the pcm. If the ground is weak, the sensing would be poor.
the cure is the external, no more problems at all. If you are really charging at 15, get ready for a battery to blow up. They like to do that and they do make a mess out of the compartment. Mine boiled the batteries constantly until I installed the external.
10-18-2006, 01:24 AM
#10
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10-18-2006, 04:37 PM
#11
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If you draw 1,500 watts off the starting batteries thats 125 amps [ 1500 watts devided by 12v = 125 amps ] thats going to draw down the volts in the batteries to the shut down voltage within seconds , thats may be why .
You should be using much larger deepcycle batteries to run that inverter .
You should be using much larger deepcycle batteries to run that inverter .
10-18-2006, 08:50 PM
#12
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Yeah but how much load are you using. The previous post had it right. Of course big enough batteries and you can. Most of the time the microwave in on for a few minutes at what, 1500 watts max? What would you use 5000 for? Air conditioning? It would take some battery bank. If your 5000 watt inverter is only running a tv and a few lights it will run endlessy on a good battery bank. Use the 5000 and it won't.
10-18-2006, 09:20 PM
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10-19-2006, 06:32 PM
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I can't figure this thing out. Currently have about 10ft of 2ga. Went today and got a pair of jumper cables (4ga @ 20ft) . . . even with the added resistance, it still causes an overvoltage situation. I'm going to call the inverter company tomorrow. Given that the overvoltage protection kicks in at 15v, and the truck produces 14.4v when running, that doesn't leave much room for error if the voltage surges when you shut the appliance off. Crazy!