Using radio while engine is idling same power drain as if engine off?

Loppysaurusrex

Loppysaurusrex

Well-Known Member
205
65
I'm curious as to when the alternator is active.

I thought it was only active if the car is in gear, does anyone know more?
 
On a similar note, my mechanic made a point to tell me I probably need a new battery (car is more than 3 years old now, still using factory battery). He went on to explain that any car that uses the A/C at all kills their battery in as little as 3 years. I found this odd and had never heard that before. Does anyone have any input on his observation?

Sent from my SAMSUNG-SM-N910A using Tapatalk
 
PainlessCandy said:
On a similar note, my mechanic made a point to tell me I probably need a new battery (car is more than 3 years old now, still using factory battery). He went on to explain that any car that uses the A/C at all kills their battery in as little as 3 years. I found this odd and had never heard that before. Does anyone have any input on his observation?

Sent from my SAMSUNG-SM-N910A using Tapatalk
Click to expand...

I have to say, I've been working on cars professionally for 16 years and have never heard this. Ever. The only caveat is what I mentioned above. The Cadillac STS for example uses a generator module to control voltage shed. So at idle it will not produce full charging voltage and extensive idling will actually drain the battery instead of charging it. Actually had a few customers get mad at me for this. It will only produce a proper full charge voltage at about 1500 RPMS on up. Realistically ANY system that has a high draw will likely put some strain on the battery, but to put such a fine point on it seems premature. I have customer cars over 9 years old and more modules than the space shuttle still on the original battery. His info seems anecdotal at best.
 
Gixxerfool said:
I have to say, I've been working on cars professionally for 16 years and have never heard this. Ever. The only caveat is what I mentioned above. The Cadillac STS for example uses a generator module to control voltage shed. So at idle it will not produce full charging voltage and extensive idling will actually drain the battery instead of charging it. Actually had a few customers get mad at me for this. It will only produce a proper full charge voltage at about 1500 RPMS on up. Realistically ANY system that has a high draw will likely put some strain on the battery, but to put such a fine point on it seems premature. I have customer cars over 9 years old and more modules than the space shuttle still on the original battery. His info seems anecdotal at best.
Click to expand...
Yeah it seemed odd to me, but could also make sense depending on how the charge is being divvyed since the compressor is constantly turning on and off. I just always thought the compressor was being run by the serpentine belt and not purely on electricity. The constant switching of high draw from the compressor to normal draw all while a constant charge is being applied is not healthy for any battery, really. He also has a lot of experience, both as a general mechanic and as a member of a racing team doing all sorts of aftermarket upgrades, so I have more reason to trust him than not.

Based on how many people drove their cars (idling a lot), I'm surprised any manufacturer would design a charging system to not apply a full charge at idle. That's crazy; You learn something new every day, lol.

Sent from my SAMSUNG-SM-N910A using Tapatalk
 
PainlessCandy said:
Yeah it seemed odd to me, but could also make sense depending on how the charge is being divvyed since the compressor is constantly turning on and off. I just always thought the compressor was being run by the serpentine belt and not purely on electricity. The constant switching of high draw from the compressor to normal draw all while a constant charge is being applied is not healthy for any battery, really. He also has a lot of experience, both as a general mechanic and as a member of a racing team doing all sorts of aftermarket upgrades, so I have more reason to trust him than not.

Based on how many people drove their cars (idling a lot), I'm surprised any manufacturer would design a charging system to not apply a full charge at idle. That's crazy; You learn something new every day, lol.

Sent from my SAMSUNG-SM-N910A using Tapatalk
Click to expand...

The Compressor isn't the electrical load. Although it will compromise some voltage output due to the mechanical load slowing down the alternator. The blower motor is a high draw. Especially since high speed is actually full voltage and the lower speeds are shed by resistance. Even more load and wasted energy.

While I don't doubt his pedigree, and while I agree to his assessment somewhat, the three year mark is what I question. I've seen more than my share of batteries last well beyond that in some really adverse conditions.

Any sort of discharge situation will create calcification on a lead acid battery, this is what will ultimately make most batteries unusable. As the calcification builds, the calcified section can no longer store energy. Your best bet is to be mindful for leaks, try not to stress the battery too much and keep the system in proper working order.
 
I will say I personally am not a fan of Honda batteries. I have purchased 2 vehicles that both came with brand new Honda batteries (3yr warranty). The first one went bad 1 month outside of the 3 year warranty period. The other battery I just had to replace and I have only had the car for just over 2 years.
 
Flightmaster127 said:
I will say I personally am not a fan of Honda batteries. I have purchased 2 vehicles that both came with brand new Honda batteries (3yr warranty). The first one went bad 1 month outside of the 3 year warranty period. The other battery I just had to replace and I have only had the car for just over 2 years.
Click to expand...

I've gathered they aren't great. What did you replace yours with?
 
Gixxerfool said:
I've gathered they aren't great. What did you replace yours with?
Click to expand...
1st time I replaced with a standard replacement from advance auto since I needed a battery that day. That battery lasted 4 years and then it got replaced with a optima yellow top since the car its in sits for long periods of time between use. Most recent battery also got replaced with a yellow top as well since I know a guy and at the price he could get me it was only about 10 bucks more expensive than the regular battery.
 
Flightmaster127 said:
1st time I replaced with a standard replacement from advance auto since I needed a battery that day. That battery lasted 4 years and then it got replaced with a optima yellow top since the car its in sits for long periods of time between use. Most recent battery also got replaced with a yellow top as well since I know a guy and at the price he could get me it was only about 10 bucks more expensive than the regular battery.
Click to expand...

I stopped buying Optimas. I've had too many issues with them crapping out for the money.
 
Flightmaster127 said:
I will say I personally am not a fan of Honda batteries. I have purchased 2 vehicles that both came with brand new Honda batteries (3yr warranty). The first one went bad 1 month outside of the 3 year warranty period. The other battery I just had to replace and I have only had the car for just over 2 years.
Click to expand...
I was going to turn this into a new thread since I'm going to buy a new one anyways. I've noticed in particular that the batteries in our Si's are incredibly weak - literally just powerful enough to turn over the engine on a warm day. Is it possible to replace the factory battery with one that is slightly larger, thus alleviating this problem? I don't see why not as long as it's not hugely oversized.

Sent from my SAMSUNG-SM-N910A using Tapatalk
 
PainlessCandy said:
I was going to turn this into a new thread since I'm going to buy a new one anyways. I've noticed in particular that the batteries in our Si's are incredibly weak - literally just powerful enough to turn over the engine on a warm day. Is it possible to replace the factory battery with one that is slightly larger, thus alleviating this problem? I don't see why not as long as it's not hugely oversized.

Sent from my SAMSUNG-SM-N910A using Tapatalk
Click to expand...

It won't be an issue as long as it fits in the car physically.
 
PainlessCandy said:
I was going to turn this into a new thread since I'm going to buy a new one anyways. I've noticed in particular that the batteries in our Si's are incredibly weak - literally just powerful enough to turn over the engine on a warm day. Is it possible to replace the factory battery with one that is slightly larger, thus alleviating this problem? I don't see why not as long as it's not hugely oversized.

Sent from my SAMSUNG-SM-N910A using Tapatalk
Click to expand...
The only limiting factor your going to run into would be the size of the battery tray itself. As long as it fits in the tray and you can get the hold down over it to secure it you should be good to go.
 
I personally use an XS power battery in my civic and has enough juice for my stereo no problems at all

Sent from my ONEPLUS A3000 using Tapatalk
 
You must log in or register to reply here.
Back
Top