Battery Stabiliser Question

[Dynomax]

Just went to fit a battery stabiliser to my 2008 Bullitt. Rather than install a socket and hard wire it to the battery, I decided to use a universal plug and charge the battery via the “Power Outlet” socket located in the dash. I have checked that the socket is live with the key off (it is).


Here’s the situation:


Voltage at the battery = 12.44 volts

Voltage at the dash socket = 12.40 volts

Voltage at the battery stabiliser = 16.33 volts

I have continuity between the stabiliser plug and the dash socket.


The voltage at the battery with the stabiliser connected and on, is unchanged at 12.44 volts.


I have used 3 of these stabilisers before (including this one) and all worked great; I just never checked the output before.


Is there something in the S197 that prevents back feeding? Am I missing something? I recall that this stabiliser is voltage sensitive, so maybe it's already sensed a fully charged battery so is "dormant"? Like many S197's, this car will go flat after 3 weeks of inactivity.

 

[JeremyH]

It's probably a relay etc protected circuit. Preventing you from back feeding the rest of the fuse panel via the socket.

I always hook my tenders directly to the battery terminals.

Going flat after 3 weeks is pretty normal for these cars with a used battery. But you may want to do a parasitic draw test see if you have any gremlins.

 

[06 T-RED S/C GT]

Don't have any idea what you guys are referring to about back feeding the rest of the system? What I do know is this, during the past 8 years I've always maintained my batteries by plugging in the supplied 12v power accessory adapter into the 12v power outlet socket located in the dash. During those 8+years, my Motorcraft batteries have lasted 3 years+ with my "Battery Minder Plus" tender charger. Perhaps the 12v universal adapter plug you've been using for some reason just isn't compatible with your tender charger or you may have a short somewhere in the plug? Anyhow, at least from my personal experience, hooking the tender directly to the battery terminals isn't really necessary as the 12v power plug adapter which came included with my tender charger has kept my batteries well maintained with no issues whatsoever

 

[Juice]

Only 3 years out of a battery? I get 6-10 years out of batteries. Weather it be car, bike, jetski, or lawn eqipment. lol
I have 2 tenders I rotate between 10 batteries in total.

 

[JeremyH]

Back feeding in a fuse panel happens when you put power back on a always on load ie. hot circuit (it would only feed other always on circuits common to the panel). Key on or switch/relay is protected. Most of the time it's not an issue. Not every car has the 12v outlet always hot. Cant speak for my 07 as I deleted the 12v years ago when I repurposed the slot for a shift light.

If I neglect the battery about 4-5years. When I use the tender about double. When I cycle my winter/summer cars I disconnect the battery terminals as well then hook up the tender.

 

[06 T-RED S/C GT]

Only 3 years out of a battery? I get 6-10 years out of batteries. Weather it be car, bike, jetski, or lawn eqipment. lol
I have 2 tenders I rotate between 10 batteries in total.

I can only comment on the "OEM" Motorcraft batteries equipped on the 2005-09 S197 cars, as I've never come across any "OEM" Motorcraft battery last much beyond 3 years despite keeping a battery tender hooked up when the car is not in use. Prior to using battery tenders, my "OEM" battery would completely discharge after just sitting for 10-12 days. Needless to say, I was informed by Ford service techs that the keep alive memory (KAM) along with the Shaker 500 and active alarm systems are contributing factors behind discharging the battery if a battery tender is not being used to maintain the battery whenever the vehicle is not being ran beyond 7-10 day periods. Supposedly batteries such as Optima and Interstate have longer lifespans beyond 5-6 years, however from both my understanding and personal experience, my "OEM" Motorcraft batteries have not lasted much beyond 3 years despite having them connected to a battery tender. That being said, I'm currently on my third replacement battery at the present. As for lawn equipment, jetski and bike batteries are concerned, do they have electrical systems ran by computer ECM's along with active security systems in place? I think not. Therefore comparing electrical systems from lawn equipment, jetski and bikes to vehicles which all have advanced computer technology running their electrical systems is like comparing apples to oranges, rather than from apples to apples lol.

Back feeding in a fuse panel happens when you put power back on a always on load ie. hot circuit (it would only feed other always on circuits common to the panel). Key on or switch/relay is protected. Most of the time it's not an issue. Not every car has the 12v outlet always hot. Cant speak for my 07 as I deleted the 12v years ago when I repurposed the slot for a shift light.

If I neglect the battery about 4-5years. When I use the tender about double. When I cycle my winter/summer cars I disconnect the battery terminals as well then hook up the tender.

All I can say is using the 12v outlet has never been an issue during the past 8 years of connecting the battery tender to the 12v outlet port, but if in the event it ever does? then I'll start connecting the tender directly to the battery terminals and disconnect the terminal cables altogether while the car is in storage. In the meantime, thanks for clarifying and also for the heads up

 

[Juice]

Funny you should mention Optima batteries. For me, those only last about 5 years, and then start to lose charge. lol
I now have 4 wallyworld batteries. The one in our daily driver is 7 years going strong.

 

[Iceman62]

Sorry, but I'm "old skewl" when it comes to battery "maintainers/tenders/etc." (never hear them called stabilizers, sorry). I add the pigtail vfr-direct to +/- posts on battery cables. This way I know they're connected & working as they should. I'm getting anywhere fm 5-8 yrs from all types of betteries (motorcycle, riding mower, car, truck).

 

[Midlife Crises]

Battery tenders work. I use them when ever vehicles, toys or tools are placed in storage.
2005 Thunderbird with 4 year old Die-Hard.
2010 Mustang, OEM original.
2013 Edge, OEM original.
2016 Superduty, OEM original.
Then there’s the 07 Superduty (plow truck) that sets for months without any love. Replaced the OEM batteries last year with NAPA brand.
I suspect Motorcraft uses pretty good batteries.

 

[06 T-RED S/C GT]

It appears from the responses read that by connecting the battery tender's pigtail directly to the battery terminals rather than to the 12v power outlet in the dash is keeping batteries going between 5-8 years over just 3 years by connecting to the 12v power port. Therefore, it appears I'll be making the switch lol. However, it really sucks that a battery tender is still required in order to prevent a battery from completely discharging within just 10-12 day periods of non-usage which is totally unacceptable IMHO

 

[Iceman62]

My Bullitt sometimes site for 2-3 weeks w/o starting, during the summer...fires every time. I don't connect the tender until ~Nov (winter hibernation).

 

[06 T-RED S/C GT]

Whether its 10-12 days or 2-3 weeks of inactivity, still shouldn't draw that much current out of a battery in such a short period of time, to begin with IMO. Prior to my first S197 Mustang, I owned 3 Fox body Stangs that sat every winter in the garage and never had a battery tender connected. Needless to say, they all fired right up every spring with no problem. That being said, the OP also mentioned in his post that his battery goes completely dead after just 3 weeks of inactivity despite having a battery tender connected to his 12v power outlet. As also mentioned in a previous post, this is totally unacceptable nor does it make any sense, at least as far as I'm concerned anyhow

 

[Juice]

You can check for draw with everything off. 12 days or even a month is not right. I can go atleast 4 months of inactivity without a charger.
That said, if for some reason your battery is not fully charged, then I could see a no start after just a few days/weeks.

 

[06 T-RED S/C GT]

Yes, I totally agree that even a month is not right. This was the reason I took my first S197 Mustang to the dealership 4 different times to be tested. On the last occasion they kept the car for 3 weeks hooked up to an amp meter checking for draw. Needless to say, after the 3 week period, I was informed by the service manager that everything checked out normal but they still insisted to hook up a battery tender in order to keep the battery fully charged whenever the car is inactive for more than 10-12 days at a time, otherwise once the battery is no longer fully charged, the battery will go dead within 2-3 weeks of inactivity. Therefore I'm not quite understanding how your car can go at least 4 months of inactivity without requiring a tender charger to maintain and keep the battery fully charged. Unless your disconnecting the battery during the 4 months of inactivity? then I just don't see any other way for preventing a battery from discharging during inactivity. Perhaps your car's electrical system was an exception during the manufacturing process and is functioning properly as intended. However there have been many threads posted on these forums regarding batteries going dead within 2-3 weeks of inactivity which confirms that neither myself nor the OP are the only ones to have ever reported this as being a known issue