My neighbor has a f-150 302 with a external voltage regulator only seems to charge 13.50 volts.Also when he unplugs one of the batt. cables the engine dies.Alternator checked at advance auto charging fine.Can anyone tell me what could be the problem?Thanks For All Replys.Bobby
Charging at 13.5v without a 'load' on it, is just fine.
The problem? Here is the cause:
The solution?....Don't do that! lol
Dave S(Texas)
Amps charge lead-acid batteries.
Voltage charges small batteries like ni-cads for cordless drills.
A lead-acid battery should charge fine at 13.5 volts as long as the alternator is putting out enough amps.
However a 9.6 volt ni-cad may require 18 volts to charge, but at a constant 100 milliamps.
Some common charging problems.
Bad battery, dirty terminals, loose connection at terminals, negative battery cable loose at engine. negative or positive battery cable gone bad.
Don't disconnect the battery while the engine is running. If you're lucky all that will happen is the engine dies.
Thanks for all the advice,I was thinking I never unplug my battery for fear of blowing the alt..mine charges about 14.50 no load,.but he insists it should keep running with the batt.cable unpluged..that was true on the older vechiles with generators.Just wanted a second opinion..Thanks Bobby
Last week a guy at work did the same thing. His battery was died in his Saturn car. He jumped it off and disconnected a battery cable to quote "Test the alternator".
The engine immediately died.
He reconnected the battery cable and jumped it off again, it immediately began idling rough and missing horribly.
Either jumping it off, disconnecting the battery, or the combination of both screwed something up.
This should not be done because of the computer. When the power is lost to the computer the RAM is lost. RAM is where the 'history' and the computers ability to 'learn' and adapt is kept. Losing that memory makes everything revert to the factory default settings and the computer has to re-learn all over again. Factory defaults are when everything (systems/sensors/etc.) was brand-new out of the factory. Through the course of time, things with the engine systems/sensors change and the RAM adapts to the newer parameters it has to deal with in order to keep the engine running as best as possible.
Bottom Line: don't disconnect the battery.
Dave S(Texas)
Sorry his truck 1986 F-150 4x4 302 Mex.doesn't have a computer.Mine is a
1986 F-1504x2 4.9 Canada does have computer.Don't know exactly what the difference is except 2 seperate locations.Thanks Bobby
No? OK! Well, I saw it had a EEC but maybe that doesn't have any RAM/learning abilities. When I'm wrong, I'm wrong! Keep in mind what my post was saying anyway, don't disconnect power to the ECM on any computer usin' vehicle. The resulting engine performance will be less than satisfying until the controller re-learns/adjusts to the new sensor data.
Dave S(Texas)
On Sat, 29 May 2004 08:25:46 -0500, put rearranged some electrons to form:
It's more than that... the voltage spike that occurs when you remove the battery from the charging circuit while the engine is running can easily fry non-computerized electrical items as well (such as the alternator rectifier diodes).
Your neighbors vehicle should continue to run with the battery cables disconnected from the battery. A charging system when operating properly runs the vehicle, not the battery. I agree that the newer systems suffer when disconnecting batteries while running, but the specific vehicle you are referring to should not.
Spdloader
On Sat, 29 May 2004 21:23:24 +0000, Spdloader rearranged some electrons to form:
I hate to disagree, but the voltage spike that is introduced when a cable carrying a large current is disconnected, can easily fry stuff.
Voltage on an inductive load = L(di/dt) L = inductance, di/dt = rate of change of current, which would be quite high when the cable is disconnected while the alternator is charging the battery.
I'm not gonna unplug my batt.cable while the truck is running either...neighbor got his alternator at the junk yard...I told him he should have got a regulator also... he cleaned the one he had said the wires were really coroded... get my electrical parts at auto zone.I'll keep yall up to date on what he finds out to be the problem.Thanks Bobby
Actually, you're not disagreeing David, I just didn't make myself clear.
The vehicle in question is an older Ford, with an EEC-IV type ignition. A properly operating charging system doesn't need the battery to stay running, just to start the vehicle, and supply power when the vehicle isn't running for radio presets, clock, etc. On newer vehicles it obviously does more, but that's not the question.
I don't condone disconnecting the battery while the vehicle is running, but if it is done, and the vehicle shuts down, it was clearly running on battery power and the alternator or voltage regulator was not doing it's job. It's done quite often at the lake, with boats, dead battery, borrowing another battery to get started, unhook it and then reconnect your own to get it charged.
Later,
Spdloader
David M wrote:
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