Can Belt tensioner cause poor charging

[gdubya]

When I had my 97 Conti in for service, they told me that the belt tensioner had poor tension and should be replaced soon. Originally I brought it in because it wouldn't start and they told me I had a bad battery giving improper voltage to the computer which prevented it from starting. New battery and it worked great for a couple of weeks.

Again now it wouldn't start and when I threw the battery tender on it, it seemed to charge for a quite a while indicating that the battery was again low. Once charged, it fired right up. Could the belt tensioner be causing the alternator to slip just enough that it is not fully charging the battery and maybe that is what killed my battery in the first place?

Do I need to look at the alternator itself and have it and/or the voltage regulator replaced when they are in there? It is quite a tight squeeze in the engine compartment so I am inclined to have the shop do it, but don't want to pay for the labor getting around in that tight space twice.

 

[chris2523]

if it slipped that badly all the time, the heat generated would probably burn up the belt very quickly..
i would be checking with the alternator itself.

 

[gdubya]

Is there a way the shop can easily test the alternator?

 

[chris2523]

auto zone and the like should be able to test it.

 

[bradyelich]

Test it yourself with a volt meter from the bolt on wire to ground should be 13.5 to 15 volts. If you are having problems it is more likely to be the regulator which contains the whole charging circuit. It is easily replaced after removing the alternator. On reman alternators, check that a new regulator is installed before purchasing - they seem to not replace the regulator.

If the tensioner/belt is not squealing it has good tension. Make sure you start with a new battery with clean posts and clamps.

 

[gdubya]

Had alternator tested and voltage is good, but putting out about half the amps it should be. This would explain the eventual draw down of the battery, and why the last one failed after a while. Unfortulately with highs in single digits F, and lows of -15 to -20 with no heated garage, I'm gonna have to have the shop put it in which is not cheap.

On the plus side, this shop said no need for belt tensioner, belt or pulleys at this time. They seemed to know what they are doing a little better than that last place, so I am more inclined to believe this is true.