Battery Issue/Question - High Output Alternator Installed

[LordX2]

I have a 200AMP High Output Alternator in my 2004 Impala 3.4L.

As with many of these units, when the car is at idle (stoplights etc) the output drops.

I have had a regular battery in the car for 2+ years, and I believe it is close to the end of its life.

When I replace this battery - I want to put a battery in that is designed for this type of situation.

One that is designed for charge/discharge many times, and perhaps one that is able to put out more volts?

Because with the lowered output at stoplights - all the internal electronics slow down or dim (wipers/air blower/lights).

Or should I just get a regular battery with some type of capacitor that will kick in during stoplights and prevent the battery from being drained.

Any suggestions are greatly appreciated.

[Tech II]

Have you had your old battery tested?

Batteries don't put out more voltage...they all put out the same voltage.....12.6 volts.....what the larger batteries do is put out more current......

Basically, batteries serve two purposes.......to crank the vehicle, and when load on the alternator exceeds it's output, then the battery supplies power to the car.....basically, after the car starts, the output of the alternator is higher than a battery at about 14+ volts......this helps to recharge the battery, which discharges by just being in the vehicle(approx 25ma is the current flowing when the vehcile is off), which discharges when it is cranking the vehicle, which discharges when accessories are left on when the vehicle isn't running, which discharges with a parasitic draw, etc.


EVERY car's alternator output drops as it warms up, due to the fact that rpm's are higher on a cold vehicle, and lower on a warm vehicle.......

Have you had your alternator output checked? There have been some TSB's for this problem, some involving ground bolts to the alternator.....

If a vehicle is warm, you have your headlights on, you heater blower on high, your rear defogger is on, maybe the radio is blaring, and you you come to a stop, and now your brake lights are on.....this is a huge load on the charging system, and could cause your lights to dim somewhat......but as soon as you step on the gas and increase rpm's alternator output increases and the lights are bright again......so in some cases, this is considered normal....

Some of the newer vehicles monitor current flow(load) and increase engine rpms to compensate.....