Which battery do I buy? :)
10-24-2016, 12:18 AM
#16
[QUOTE=Jeff928S4;13687073
I have been playing around with my voltage meter and have got my battery up to a 12.70 area when "fully charged" (after leaving it on my Genuis charger for about 2 hours)....but as Im reading that number (immediately after removing the charger), it literally drops from 12.70 to 12.69 to 12.68, etc. right before my eyes (with hatch open/interior lights on). "Maybe there is a drain?????", I thought.
I started the car last night around 9:00 p.m. - went for a drive of about 15 minutes total (but stopping every 5 minutes - so three short drives). I check the meter and it says 12.45. Seems like a lot of drop for 3 car starts/doors being open for a minute or two, no?
Figuring there is a drain of some sort, I went out this morning and put the meter on it right away....still reads 12.45??? Huh?
Drive to work (3 minutes of driving), check again - still 12.45. Drove 3 minutes home from work, still 12.45.
Put it on the charger again, and this time it only took 20 minutes to charge fully - reading 12.85 now.
Maybe if I just stay on it every day, I can keep the battery voltage between 12.45-12.8ish - that seems to be a good amount for goods starts, etc.
[/QUOTE]
Is the current one an AGM or lead acid? This sounds like typical surface charge behavior for a battery that is on the way out.
You will very likely be installing a new one before this winter is over. Might as well do it when you are not stranded and the weather is not harsh!
If it has died that many times in the course of a year and was in fact new as the previous owner indicated, they either did not fully charge it when it was installed, it is also faulty or you have something else amiss.
The properly sized batteries for these cars should last 5-7 years. Before ruining another new battery:
1. Test for a parasitic drain when the vehicle is off... the easiest way would probably be to use a cheap ($20) DC power meter for RC or solar cell metering. I would not advise cranking the starter or running the engine with it hooked up unless you use one with sufficient current handling and appropriately sized wires/shunt and know how to set it up correctly. You just need to hook it up simply and let it sit for a while to measure how many amp-hours might be possibly draining while parked. Do you have any aftermarket accessories installed like stereo components, etc.?
2. Test your alternator thoroughly. It may not be putting out enough voltage or current. Despite short drives you should not have to be charging that often. It could also be the source of a parasitic drain.
I have been playing around with my voltage meter and have got my battery up to a 12.70 area when "fully charged" (after leaving it on my Genuis charger for about 2 hours)....but as Im reading that number (immediately after removing the charger), it literally drops from 12.70 to 12.69 to 12.68, etc. right before my eyes (with hatch open/interior lights on). "Maybe there is a drain?????", I thought.
I started the car last night around 9:00 p.m. - went for a drive of about 15 minutes total (but stopping every 5 minutes - so three short drives). I check the meter and it says 12.45. Seems like a lot of drop for 3 car starts/doors being open for a minute or two, no?
Figuring there is a drain of some sort, I went out this morning and put the meter on it right away....still reads 12.45??? Huh?
Drive to work (3 minutes of driving), check again - still 12.45. Drove 3 minutes home from work, still 12.45.
Put it on the charger again, and this time it only took 20 minutes to charge fully - reading 12.85 now.
Maybe if I just stay on it every day, I can keep the battery voltage between 12.45-12.8ish - that seems to be a good amount for goods starts, etc.
[/QUOTE]
Is the current one an AGM or lead acid? This sounds like typical surface charge behavior for a battery that is on the way out.
You will very likely be installing a new one before this winter is over. Might as well do it when you are not stranded and the weather is not harsh!
If it has died that many times in the course of a year and was in fact new as the previous owner indicated, they either did not fully charge it when it was installed, it is also faulty or you have something else amiss.
The properly sized batteries for these cars should last 5-7 years. Before ruining another new battery:
1. Test for a parasitic drain when the vehicle is off... the easiest way would probably be to use a cheap ($20) DC power meter for RC or solar cell metering. I would not advise cranking the starter or running the engine with it hooked up unless you use one with sufficient current handling and appropriately sized wires/shunt and know how to set it up correctly. You just need to hook it up simply and let it sit for a while to measure how many amp-hours might be possibly draining while parked. Do you have any aftermarket accessories installed like stereo components, etc.?
2. Test your alternator thoroughly. It may not be putting out enough voltage or current. Despite short drives you should not have to be charging that often. It could also be the source of a parasitic drain.
10-24-2016, 11:39 AM
#17
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Thanks for the tips..... 
I left the car on the charger over night and when I removed it from the charger, it read 13.00 - highest I ever have seen it.
Now, here is the thing - all last winter, I would charge the car while at work. Usually for 4-5 hours. The charger I have will blink at "25%" (red light) at the start, then will turn solid and move up to the "50" red light and blink, etc. Once it hits the Green light, it is fully charged. It always starts at 25%, but the more charge the battery has, the faster the lights stop blinking and move up to the next level. I've seen it blink at 25% for only like 10 times, then move on to the 50% (on fully charges batteries); other times, I've seen it take an hour of blinking before it moved up to 50%.
But.....I had never seen it go solid green...just blinking green - and most of the time the battery would read 12.25-12.35 after charging it. It wasn't until the other night when I took the charger off of the 928 that I noticed the light on the charger was a solid green (the charger has been still on the 928 in "AGM/COLD mode" most of the summer (has a Yellow Top in it) - just didn't see it I guess).
So, this morning, after charging the 955 all night, I see the solid green and the "13.00" on the meter. Mind you, that number seems to drop down and settle at a 12.80 area. After driving to work (one start), I checked again and it read 12.49 (but because the interior lights are on, it should be around 12.70). When I read it this morning, no interior lights are on because I charge from the rear hatch area and flip the hatch striker to the closed position, so when I open the hatch to unhook the charger, no lights come on - that is probably why I get the higher reading immediately after removing the charger. The lights being on makes the meter dip down from say 12.80 to 12.60.
Another thing to note is the charger has two 12V modes - "Normal" and "AGM/Cold". I have been charging it on Normal lately (seems faster), but during the winter I use the "AGM/Cold" option.
The charger I use is below....
As for drains when the car is off......it seems it hold a number over night. If it reads 12.50 before I go in for the night, it still reads 12.50 in the morning.
One thing I did notice was I accidentally hit the stereo button the other night when getting out of the car and was in the store for 10 minutes. When I came out, the car was playing a CD and saying the "ignition off use of radio limited....blah blah". So, the CD was playing for ten minutes with the car off. That made the reading go from a 12.60 down to a 12.00. Really zapped the battery.
Another really odd thing I've noticed, but have found ZERO other people with the same problem when searching google/Rennlist, etc. is that if I am playing a CD (MP3 homemade kind) and just shut the car off; when I get back in the car, the CD will be playing at a later point.....like it just kept on playing. If I am listening to a song at the 1:00 minute mark and and shut off the car and go somewhere for 4 minutes, when I start the car again, the CD will be playing at the 5:00 minute mark. It seem to do this up to around a 20 minute max....like if I leave overnight, it will be playing 20+ minutes into a song (I listen to a lot of 1 hour pre-mixed radio shows, so I can see how long it skips ahead).
Anyone out there with a MP3 compatible CD player want to try this for me? Put a CD in, start it, shut car off (noting where CD was playing), wait a couple minutes, start car and check if CD starts at later point. Obviously my CD player is still going when the car is shut off (for at least 20 minutes, that is).
Now, if you change the stereo back to "radio" before shutting the car off, this seems to stop the CD from playing (and playing further with the car shut down). Odd, eh?
I left the car on the charger over night and when I removed it from the charger, it read 13.00 - highest I ever have seen it.
Now, here is the thing - all last winter, I would charge the car while at work. Usually for 4-5 hours. The charger I have will blink at "25%" (red light) at the start, then will turn solid and move up to the "50" red light and blink, etc. Once it hits the Green light, it is fully charged. It always starts at 25%, but the more charge the battery has, the faster the lights stop blinking and move up to the next level. I've seen it blink at 25% for only like 10 times, then move on to the 50% (on fully charges batteries); other times, I've seen it take an hour of blinking before it moved up to 50%.
But.....I had never seen it go solid green...just blinking green - and most of the time the battery would read 12.25-12.35 after charging it. It wasn't until the other night when I took the charger off of the 928 that I noticed the light on the charger was a solid green (the charger has been still on the 928 in "AGM/COLD mode" most of the summer (has a Yellow Top in it) - just didn't see it I guess).
So, this morning, after charging the 955 all night, I see the solid green and the "13.00" on the meter. Mind you, that number seems to drop down and settle at a 12.80 area. After driving to work (one start), I checked again and it read 12.49 (but because the interior lights are on, it should be around 12.70). When I read it this morning, no interior lights are on because I charge from the rear hatch area and flip the hatch striker to the closed position, so when I open the hatch to unhook the charger, no lights come on - that is probably why I get the higher reading immediately after removing the charger. The lights being on makes the meter dip down from say 12.80 to 12.60.
Another thing to note is the charger has two 12V modes - "Normal" and "AGM/Cold". I have been charging it on Normal lately (seems faster), but during the winter I use the "AGM/Cold" option.
The charger I use is below....
As for drains when the car is off......it seems it hold a number over night. If it reads 12.50 before I go in for the night, it still reads 12.50 in the morning.
One thing I did notice was I accidentally hit the stereo button the other night when getting out of the car and was in the store for 10 minutes. When I came out, the car was playing a CD and saying the "ignition off use of radio limited....blah blah". So, the CD was playing for ten minutes with the car off. That made the reading go from a 12.60 down to a 12.00. Really zapped the battery.
Another really odd thing I've noticed, but have found ZERO other people with the same problem when searching google/Rennlist, etc. is that if I am playing a CD (MP3 homemade kind) and just shut the car off; when I get back in the car, the CD will be playing at a later point.....like it just kept on playing. If I am listening to a song at the 1:00 minute mark and and shut off the car and go somewhere for 4 minutes, when I start the car again, the CD will be playing at the 5:00 minute mark. It seem to do this up to around a 20 minute max....like if I leave overnight, it will be playing 20+ minutes into a song (I listen to a lot of 1 hour pre-mixed radio shows, so I can see how long it skips ahead).
Anyone out there with a MP3 compatible CD player want to try this for me? Put a CD in, start it, shut car off (noting where CD was playing), wait a couple minutes, start car and check if CD starts at later point. Obviously my CD player is still going when the car is shut off (for at least 20 minutes, that is).
Now, if you change the stereo back to "radio" before shutting the car off, this seems to stop the CD from playing (and playing further with the car shut down). Odd, eh?
10-24-2016, 11:55 AM
#18
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The reason the AGM setting takes longer to go to fully charged mode is - AGM has a slightly higher charging voltage than a standard wet cell. So - it takes longer to reach that voltage. Since your Cayenne probably has an AGM battery in it - that would be the correct one to use.
10-24-2016, 12:50 PM
#19
That thing sounds like it is barely holding on. A word of caution in that you could be pushing this battery too far and eventually cause it to leak or vent.
You are describing pretty extreme voltage sag for such a minimal load on a large battery. I stand by my previous post about testing your alternator and system for parasitic drain from the car over several nights and then just replacing with a new battery if all is fine. It is possible the previous owner installed a 'new' battery that had been sitting on the shelf for several years that had already suffered from sulfation.
I have an aftermarket stereo, so can't help you with testing your radio situation.
You are describing pretty extreme voltage sag for such a minimal load on a large battery. I stand by my previous post about testing your alternator and system for parasitic drain from the car over several nights and then just replacing with a new battery if all is fine. It is possible the previous owner installed a 'new' battery that had been sitting on the shelf for several years that had already suffered from sulfation.
I have an aftermarket stereo, so can't help you with testing your radio situation.