charged battery w/ 10amp charger while conn in bus. killed

[1thomas]

Hello guys,
I just charged my dead battery with the positive and negative cables still connected in the bus. Now the red alternator light doesn't go out, and the alternator is not charging the battery (reads 12.14v while running at battery).
I usually take the battery out to charge, but was trying to save some time.
I just ordered a new voltage regulator just in case it's that... but is charging the battery with a smart charger (at 10amps) something that will kill the alternator?

I haven't checked any fuses yet... don't really know what else it could be. Any suggestions as to what this might have blown? (I did notice in the last few years the red light stayed on until I gave it a little gas, but it always went off before.... but it would be insanely coincidental if anything else except charging it like this caused the issue... What is strange though, is that the light did go out when I first started it to warm it up. I then shut it off (i didn't notice the light at this time if it was on or off during a 5 minute warm up). It was on the next start that the light never went out.

I cleaned up the terminal connections, but it made no difference.

14 years ago I blew the original alternator by hooking a friend's charger up backwards to it for just a few seconds (cable colors were reversed). I remember it being a frustrating job to replace the alternator with the motor in the bus if that's what I have to do...

What problem could I cause by charging the battery while connected inside the bus?

[Wildthings]

Buses came with either a generator or an alternator depending on the year, plus some early buses that came with generators have been upgraded to alternators. It would help if we knew what year your bus is and if it is stock or modified.

Buses often have the wrong colors for the cables so it is easy to get them reversed if you don't carefully check which is ground and which is hot.

[timvw7476]

There are three wires that share a common block, they plug into the
regulator, plus a blue wire that "rides alone" going into a plastic sleeve,
I had a bus with a loose wire in that black block, every once in a awhile,
after I plugged the block into the regulator, I had to check that one wire was
also shoved home all the way, or my battery light remained on.

[1967250s]

If your battery was dead, you might have a dead cell. You can measure the voltage between the cells and see if it is the same voltage between each one.
_________________
'72 Elm Green Deluxe

[Tom Powell]

[SGKent]

you can have 14 V at the alternator but it needs to be DC. Make sure that the diodes in the alternator aren't putting out AC now.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[telford dorr]

Charging with a "smart charger" (assuming that it's working correctly) should not damage the alternator. Charging with a dumb (brute force) charger very well could.

The alternator is sensitive to two things: (1) over-voltage, and (2) polarity reversal. Over-voltage can happen when the battery is dead or failing. A good battery will limit the maximum voltage from a charger by absorbing all of its available current. A bad battery won't - its terminal voltage can easily exceed 18 volts. What's the maximum voltage the alternator will take? Don't know. Only way to find out is to increase voltage until it fails...

Polarity reversal will destroy an alternator pretty much instantly. No second chances.

The way to find out if your charger will play nice with the alternator is to charge the battery with it disconnected and monitor the voltage with a meter. Any readings above 14.5 volts and the charger loses its gold star certification.

If you have a solid-state regulator, it too is sensitive to over-voltage and polarity reversal. The mechanical types have more ability to take a joke (as long as it doesn't last too long...)

Rule of Thumb: when in doubt, disconnect the battery before charging.
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
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