Alternator Regulator going bad?
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Alternator Regulator going bad?
I just installed a 50 watt 2-meter Amateur radio in my 1994 Mazda Navajo and have been noticing large voltage fluctuations. The radio has a “DC IN” feature where you can watch the voltage. I am seeing a high voltage of 14.8 VDC and watching it drop to 12.8 VDC with the rear defrost on. Now this radio is currently drawing power via the cigarette lighter line (no cig liter plug, direct connection via a relay).
This weekend I will tap directly to the battery (via a relay, fused of course), but am wondering if I should start to worry about my alternator’s regulator?<o =""></o>
Can you replace a regulator only on a Ford alternator?<o =""></o>
<o =""></o>Thanks for the input,
<o =""></o>Andy-<o =""></o>
This weekend I will tap directly to the battery (via a relay, fused of course), but am wondering if I should start to worry about my alternator’s regulator?<o =""></o>
Can you replace a regulator only on a Ford alternator?<o =""></o>
<o =""></o>Thanks for the input,
<o =""></o>Andy-<o =""></o>
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Joined: Apr 2004
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From: NJ where fun comes to die
I am not familiar with the Mazda, but all my newer Fords, from the 90s & up have been one unit. The older were seperate. I don't know what year they actually changed. You can take it off and have it tested at AZ or PEP Boys etc. Good luck.
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From: Pauline, South Carolina
50 watts is only like 4½ amps. If that and your rear defrost are pulling down to 12.8 volts, then yes there is a problem. The '94 definitely has an internal voltage regulator. It can be replaced, but it would involve rebuilding the alternator (I'm guessing you don't want to do that) and getting the parts may be difficult. Regarding the battery, it only supplies starting voltage to the alternator so once the alternator is working, the battery shouldn't be able to drop the voltage unless there's a severe failure. If you have a weak or older battery, then an alternator that is swinging can cause the battery to fail. Either way, you should be able to get the alternator tested and the battery load tested at a local parts store. However, if it is intermittent, the alternator could test good and still be bad. Usually though they will fail under a high load test if they have problems.
Good luck................
Good luck................
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Originally Posted by JerrySimm
50 watts is only like 4½ amps.
8 amps @13.8VDC at 50W, 6 amps @13.8VDC at 25W, 3 amps @13.8VDC at 10W and 2 amps @13.8VDC at 5W.
Well I am going to connect directly to the batery and see what voltage I am getting there.
Thanks for the advice, I will let yall know what I find.
Andy-
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From: Pauline, South Carolina
I realize that there is an effeciency factor (but I really thought it would be better than 45%) but regardless the point is your alternator should be rated for at least 60 amps (probably more) and your ham + defroster grid shouldn't pull anywhere near the rated load. When your engine is running the alternator should be putting out between 14 to 16 volts. If the load is near capacity for the alternator, the engine RPM may very well have to be increased above idle to maintain output voltage.
