amp draw?

[JHardwick]

1,237 miles, LOL

Need to make it home for T-Day, hehe

 

[DPellegrin]

The real question here is: Does the alternator have sufficient output to maintain the batteries at an acceptable state of charge with an additional 100 amp load?

The way to test this would be to use a volt-ohm-meter (VOM) and a carbonpile. With good batteries start the engine and allow it to idle for about 10 minutes to allow the charging voltage to stablize. Using the VOM measure the charging voltage at the battery posts. At 70 degreesF the charging voltage will be 13. 9-14. 0V. At colder temperatures the charging voltages will be higher. Now connect the carbonpile across the battery and dial in a 100 amp load. With the engine still at idle check the charging voltage, if is still at 13. 9 this means the alternator is keeping up with the 100 amp load. If the charging voltage drops speed up the engine to see if the charging voltage will increase back to the stabilized charging voltage (13. 9-14. 0V). If the voltage increases then at least the alternator will supply enough current at increased engine speed.



There is no question that the additional 100 amp load will reduce alternator life- my guess is that it will be substational.



Good luck with your test.

 

[steved]

Watts= volts x amps

1500w/12V = 125A

Wouldn't that be 1500w/13. 8V = 108. 7A???? Or, when running (and temperature dependent), 1500w/14. 4V = 104. 2A? However, you got to take in account the additional amperage used by the truck itself...



A 1500 watt heater... what are you driving it with?



steved

 

[K5IP]

The 15 to 20% duty cycle indicates that this is the period of transmit time, it has nothing to do with modulation factors, If you are pulling 100A (about right for 1500w PEP) with a 20% duty cycle, thats an average draw of only 20Amps. When you are not transmitting, the finals are biased at cutoff and draw very little current.

There should be no technical problem doing this as long as you don't do it very long with the engine off. We ham guys run 1500W PEP all the time (legally).

K5IP

Rog

 

[Skydiver]

The ford ambulances in our town run 2 alternators and will automaticly idle up .

I would not run a heavy load on my alt. TOO much heat generated.

When ever possible I try to cut back on the electrical load that our firetrucks pull while we are on a call. I have noticed the volt meters dropping down to 12 volts .

 

[JHardwick]

The 15 to 20% duty cycle indicates that this is the period of transmit time, it has nothing to do with modulation factors, If you are pulling 100A (about right for 1500w PEP) with a 20% duty cycle, thats an average draw of only 20Amps. When you are not transmitting, the finals are biased at cutoff and draw very little current.

There should be no technical problem doing this as long as you don't do it very long with the engine off. We ham guys run 1500W PEP all the time (legally).

K5IP

Rog

Good answer, LOL ... ... ... ... . I stepped down to an 85amp 1x4 anyway, LOL.

 

[Hitec.Redneck]

If you are running this on AM, when you are keyed down you will draw @ 100 amps. If you use this on SSB, the current will fluctuate with your voice peaks. I have a friend and fellow HAM that runs @ 1500 watts in his car using a 200 amp alternator and a single battery. Under max power out he sees less than a 2 volt drop in the battery voltage. I hope you are running a good antenna and some good coax so you don't start smoking antennas.

 

[jwinnie]

High Ouput alternator

This might be an option for you;



http://www.mean-green.com/products/alternator.html



Never seen one but 300% more juice sounds good!



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