power loss (electrical)

RiceRocket · 12-19-2003, 09:22 PM

Simple question.

When I turn on the lights or fan (yay I got it working!) or anything that uses big power, the engine strains and runs kinda funny. Revs drop alittle and it idles erractically (sp?). Is it time for a new battery?

wolfman · 12-20-2003, 03:23 AM

Most folks will probably chime in and immeadiately try to condemn the alternator. Truth be told, it probably IS just time for a new battery. Your car gets it's electrical power from the BATTERY at all times engine running or not, the alternator is only there to keep the battery alive. If turning on electrical componants strains the battery's output enough to put the alternator in to full charge mode, (the strain you feel) and the BATT light is not coming on, your BATTERY is on it's way out, and the alternator is just trying to keep it alive as long as possible. DON'T GO CHEAP ON A BATTERY! Get the largest CCA (cold cranking amp) battery that will actually fit in the car. You won't be sorry.

**Ssicarman** · 12-20-2003, 03:55 AM

I differ some with Wolfman on what the battery and alt do in the car but he is right in saying that it is not nessecarily the alt that is at fault. If there is a problem with the battery (internal short) it may be taking all of the alternators output and not leaving enough to run the systems onthe car properly. Get the charging sysytem and battery checked out.

The way I look at it the battery is an electrical storage device to allow the start to get the engine started. Once the engine is running the alt is able to begin charging. Once charging it is able to recharge the battery to the proper level and provide the current that the cars electrical systems need to operate. Further the battery acts as a buffer for electrical surges or draws. Two different opinions but the same conclusion, if you run high draw items and it affects the engine adversly (beyond a slight slow down in the RPM's as the alt puts more strain on the engine) then you have a problem.

RiceRocket · 12-20-2003, 05:27 PM

In response to the last part of what Ssicarman said: The strain almost the same as turning on the a/c.

I noticed most people in the pics are running optima batterys.....I'm assuming that's what I should get.

I seriously doubt that the alternator is going after only 34k. The car doesn't have a hard time starting, though....that's kinda weird if it was the battery....

Could the battery just not be charging enough? Most of my trips are under 5 miles of city driving.

wolfman · 12-21-2003, 01:09 AM

Generally speaking, a battery needs 2 CCA (cold cranking amps) per CI (cubic inch) of displacement to start an engine. Your Saturn is 119CI (+/-) so 119X2=238 CCA to crank and start it. Needless to say, your battery is probably more like 350CCA Minimum (listed on battery top label) so you see, it is possible to have enough to consistantly crank the engine, but once it starts, the alternator will still try to charge it up to it's full capacity whether it will accept it or not. Think of an aged battery as a bucket with a hole in the side, and your alternator as a open faucet tap. While it can eventually fill the bucket up, it has to consistantly work harder and more often to do so, and when it's not being "filled" the bucket will just drain down to the level of the hole in the side, but not empty completely, so that the alternator has to fill that space right back up as soon as things are running again.

RiceRocket · 12-21-2003, 01:52 AM

Quote:

Originally Posted by wolfman

Generally speaking, a battery needs 2 CCA (cold cranking amps) per CI (cubic inch) of displacement to start an engine. Your Saturn is 119CI (+/-) so 119X2=238 CCA to crank and start it. Needless to say, your battery is probably more like 350CCA Minimum (listed on battery top label) so you see, it is possible to have enough to consistantly crank the engine, but once it starts, the alternator will still try to charge it up to it's full capacity whether it will accept it or not. Think of an aged battery as a bucket with a hole in the side, and your alternator as a open faucet tap. While it can eventually fill the bucket up, it has to consistantly work harder and more often to do so, and when it's not being "filled" the bucket will just drain down to the level of the hole in the side, but not empty completely, so that the alternator has to fill that space right back up as soon as things are running again.

That's a good way to put it for an idiot like me. Thanx for the help