73 Challenger not charging battery • The Dodge Challenger Message Board

by **screamin 340** » 20 May 2008 20:14

I'm having a charging problem with the battery. It's new, the alternater is new. I've checked the voltage at the voltage regulator. It's 14 volts, I've checked it at the ballast resistor it's also 14V. When I check across the battery while the car is running I'm only getting 12V. I thought that the amp meter was bad so I jumped it out and it didn't help my problem. Does anyone have any suggestions where to look next? Any help would be appreciated! Thanks. :roll:

by **dave-r** » 20 May 2008 20:42

This is a strange one. You can't have 14 volts at the regulator and only 12 volts at the battery. Where would the extra 2 volts come from? The regulator is connected to the battery. So it will be getting the same voltage as connecting over the battery.
How did you measure the 14 volts?

by **dave-r** » 20 May 2008 20:43

Did you measure the 14 volts without the engine running and the battery fully charged?

by **screamin 340** » 20 May 2008 20:50

I made all the checks while the car was running. I measured 14V at the ballast resistor to ground on the engine. I checked across the battery terminals and got 12V.

by **screamin 340** » 20 May 2008 20:52

I made all the checks while the car was running. I measured 14V at the ballast resistor to ground on the engine. I checked across the battery terminals and got 12V.

by **dave-r** » 20 May 2008 21:05

Well that has me stumped.

The voltage regulator gets its voltage between the +ve side of the battery and ground.

The only thing I can think of is somehow a bad gound connection is effecting your measurements.

I will think some more about this one.....

by **Eddie** » 20 May 2008 21:13

Either the alternator is bad or the connections to it are in need of a good looking over.

by **drewcrane** » 20 May 2008 21:21

disconnect the positive cable and put your meter one on the terminal one on the wire and see if you have a draw?

by **screamin 340** » 21 May 2008 0:57

Under further investigation I found that the blue wire to the alternator was not making contact to the spade connection all the time. I need to replace the connector, that should take care of it. I also did a test on the alternator where you ground the spade connection to the green wire which gives max out put of the voltage regulator and it put out 16 volts where I read it at the battery. Thank for all the help. WE need the Challenger at top performance for Saturday at the Flashlight drags.

by **Moparman1972** » 21 May 2008 1:00

Clean the terminals? My battery had blackened terminals and the alternator gauge showed it was charging (well, not charging the battery because of the terminals) way towards the positive side, like 15 volts. I dont know the wiring side of it, so Dave will probably tell you this is wrong, but maybe this will show 14 through the rest of the system? Simple thing to try, at least.

by **screamin 340** » 21 May 2008 1:00

Under further investigation I found that the blue wire to the alternator was not making contact to the spade connection all the time. I need to replace the connector, that should take care of it. I also did a test on the alternator where you ground the spade connection to the green wire which gives max out put of the voltage regulator and it put out 16 volts where I read it at the battery. Thank for all the help. WE need the Challenger at top performance for Saturday at the Flashlight drags.