Another charging question

How did you start it up?

The last alternator I bought and the 'big green' (maybe the name) one my old tenant bought both say the warranty is void if you start them up on a dead battery.

A new alternator cannot take that amp surge until the brushes wear in a bit, they just arc out all to crap. Arcing out means heat....

That is why some shops refuse to put a new alternator in with an old or dead battery. The battery needs a charge to break in an alternator.

Mike

JimG wrote:

Well I found this link and it says the alternator is not a charger.... wow! So I am charging the batteries now and will test later.

Hi Mike,

I started it on the primary battery,,, it was about 11.8 V. The secondary was at 9v (I am not sure about it's quality now). Once it started I switched to both batteries. Do you think I damaged the new alternator? I only ran it for about 3 minutes till I noticed the overheating.

JimG

Maybe you just took a couple years off the life of the brushes.

Hopefully you didn't arc out the rings they ride on. That can pit them bad and it will then just chew up the brushes.

A charged battery and a restart will tell you fast. If it stays hot, then it might be damaged.

The ring is round and the brushes come with a square end on them. The square end on the brushes needs to wear a bit to give a nice connection to the ring, it can arc all over the place drawing high amps to charge a battery with a 1/32" contact vs the full width of the brush, close to

11.8 V with no load is a really dead battery. Mine was just 12.2 and wouldn't start it, it dropped to 10 with a load so I replaced it.

I put a new alternator in, but I was sure to charge the battery first.

Mike

JimG wrote:

In an effort to bring closure to a thread (as an earlier poster suggested)... I ran the Jeep this morning after charging the batteries all night, and all seems fine, the alternator runs cool. As you said Mike, I may taken some of the life out of it though. Thanks for the help.

JimG