Strange charging (1 Viewer)

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Joined
Jul 9, 2009
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4
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Location
the netherlands
HDJ80 with 2 batteries (yellow top). Batteries were pretty empty, around 11 volts, started anyhow. Went for a 400 kms drive; figured alternator would top batteries up. However, volts didn't come above 12,5 with incidental 11,9, charging light went out, batteries didn't drain empty.
That was new to me, would expect 14,5 volts and batteries full by the time I got home. On the other hand; power didn't go away, just stayed around 12 volts.
Came home, put car on charger and next morning I had 13,5 volts, started the car and I got 14,5!!!

Now I'm baffled. Does the alternator need more power to go up to normal volts and if low, then not?

Anybody any ideas?
 
Check wires attaching to alternator? Had a 22RE which was finally traced down to a bad charge wire, it was hard to troubleshoot since it was intermittent.
 
Couple of things, 400 kms is nothing for two very flat batteries. When you tested the voltage had the batteries been disconnected from each other and from the vehicle and left standing for 8 hours or more?

A flat battery adds a higher load on the altetnator, so slipping belts, harmonic balancer slipping, voltage regulator getting hot, all reduce available voltage and amps to the battery.

Need more information.

Regards

Dave
 
Batteries were still in car and connected. Didn't wait for 8 hours. So I need to test further? Or just start using the bloody thing, because she's been sitting in the barn for ages. Yellow tops are new anyway.
 
Try an external charger and let it go through the whole cycle.
 
Two batteries connected will give a false reading, i.e. if one battery is bad and one is good, you will get a mean figure.

I see the batteries are new but since Johnson took production to Mexico Optima's have never been the same.

Charge batteries fully and find soneone with a decent battery test meter, not a volt meter and test the batteries individualy, that is the ONLY way to be sure.

Once batteries are called good, fit and start the motor, turn all electrics on, AC, HRW, fan blower, headlights ect, then check voltage at the battery the alternator charge cable is connected to, you are looking for 13.8v or more, you may need to lift the idle a little, if ok then check the second battery, it should be the same or within a couple of tenths of the first battery.

Anything less than 13.8v you have a problem, belts, connections, alternator..........


Regards

Dave
 
OK, thanks. Will do just that.
 
I had a similar issue with my FJ 40, thought it was a bad diode in the alternator, however my clever mechanic noticed my battery dash light was not lighting up. Found a broken wire, connected it and immediately the charging voltage went up above 13.3
 

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