A few weeks ago, I got the
Battery
/Generator warning on the dash. I first checked the blinkers and other lights, because I had gotten this warning before when a turn signal bulb went out. But all my lights were good and I wasn’t getting any issues.
I got a code reader (
Foxwell NT530
) and saw I had the P1699 code - “Communication with generator interrupted”.
I tried a couple things but kept getting the code:
Cleared the code and restarted the car, but would get the warning again almost immediately.
Checked the battery after the car had sat overnight - everything looked good 12v, 14.5v with the car running, and 13.7-13.9v with everything on.
Measured the voltage at the alternator- 12v then 14.1 with the car running
When searching forums for this error code, I saw some suggestions to check the ground point behind the rear passenger wheel and was going to try cleaning the positive battery lead mentioned in a recent post.
In prepping to clean the lead, I disconnected the battery. I found the lead to be pretty clean and reconnected the battery.
When I started the car, I got some erroneous errors from disconnecting the battery (PSM failure, etc), but after a short drive to clear those errors, the original P1699 error did not return. I went for another drive this evening and still didn’t get the error.
Just wanted to share some info that might save someone else some time.
TLDR- if you get the Battery/Generator Warning, check your lights, check the battery, then try disconnecting and reconnecting the battery. If all else fails, then start checking the alternator.
FYI, 12.0v on a
battery
means it's half charged (
AGM
)... I'm not sure if that's what you're reading, or how, but I'd say you need to replace the
battery
if you're getting all these weird issues and have a 12.0v
battery
level.
Secondly, voltage measurements are not very accurate for reading the health of a
battery
. You need a load test, at least. Yes, leaving it overnight helps improve accuracy, but it's still not ideal...
Oh. The
battery
should be 24V? What should it be with the engine running?
While
AGM
is better than plain old flooded cell, I don't think the
987.2
came with
AGM
from the factory. So you could save some money using flooded. There are some benefits for
AGM
, and they tend to last longer. But since the 987 charging profile is not optimal for
AGM
. you won't get the full benefit. That said, I have been using
AGM
for many years.
Another thing to consider is the
battery
size group. OEM 987 come with an H6
battery
. However the larger (in both size, cranking AMPs, and reserve capacity) H8 will fit by adjusting the position of the hold-down bracket. So the car is designed for either size. It turns out there is very little difference in price between them.
It turns out the
battery
brand is not critical and there are only a few actual manufacturers. So I look at convenience, price, and warranty. Most auto parts stores will install it for free, or you can DIY.
Costco sells well regarded
Interstate batteries
at a good price. Assuming you are a member and you have a Costco nearby, the only downside is the warranty (36 mon) is prorated based on how many months you've owned it. Last week I returned a failed 23 month old H6 to Costco and had to pay $120 for the replacement. This wasn't the
Porsche
's
battery
.
Yesterday I decided to put a new
battery
in my MB, and I decided convenience and warranty was a priority so I went to Advanced Auto and bought a Platinum Die Hard
AGM
H8 with a 48 month free replacement warranty. Since a trip to Costco was 45 minutes each direction and their weaker warranty made the Die Hard worth the extra $$$. Ymmv.
I should of mentioned weight differences between H8 and H6. I realize that some of us are concerned about additional weight - mostly for tracking and handling. In my Die Hard example above the H8
AGM
weighs 58.7lb and the H6 weighs only 45.6. I would expect a similar weight differential for other brands between H8 and H6 of the same chemistry. Obviously Li batteries would be much lighter (and $$$), but that introduces other issues with charging including charge profile and use in freezing climates.
I replaced my
battery
after work today.
I went with an
AGM
H8, which is what was already in there.
I'm not concerned about the additional weight. I'm not tracking the car or trying to set smoke anyone at a red light 🤷♂️
Plus, I honestly like a little extra weight up front. The front floats less when I have something in the frunk so it doesn't concern me.
Thanks for all the information!
I checked my
battery
after the car had been sitting for a day and it was 12.56v.
Is this something I should be concerned about?
I have a
dash cam
in that has a parking mode, maybe that's draining
battery
. I'm really not sure.
Not sure exactly what parking mode does, but I suspect it leaves some sensors active to trigger video capture if the vehicle is disturbed. This would show up as a form of parasitic drain. If you don't drive the car every day it could cause an issue. If possible, let it set for a few days. One day isn't long enough to tell what the
dash cam
cost to the
battery
is. The car's factory electronics take a while to shut down, after which the normal parasitic drain should stabilize.
So 12.56 volts after one day isn't necessarily a problem. If after a week it gets down to 12.0, that would be an issue.
Is the car locked overnight? I believe that locking affects the system's drainage.
I have the parking harness kit installed on my
Garmin
Mini 2 but it senses the
battery
drain and will disable itself if the
battery
voltage drops below a set level. Not sure if other cameras with the parking mode have that feature programmed into them.
I will need to double check but I think my parking mode takes really low framerate video in it's current setting. I believe I can change it to only take video when motion is detected. I may try that if I find the other mode is draining too much.
I drive the car roughly every other day, if not every day. I can probably let it sit for a few days (if I can keep myself from driving it just for fun lol).
The car is locked overnight
I don't think mine has any autoshutoff feature like that, but I will read through the settings and information again to confirm.
