Battery change, what did I do wrong?

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Reggaemon

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Did a battery replacement on a 2009 Subaru, original battery was getting weak.
I put a memory setting saver powered by a 9 volt it the cigar lighter.
I turned the key to accessories,the light on the saver came on.
Left the key in the accessories position and removed the battery.
At this point I checked for voltage at the battery terminals with a DMM, no reading.
I thought I should have had 9 volts here.
Installed new battery and turned the key off and unplugged the memory saver.
Started the car and found that all my radio presets were gone and the
gas pedal/throttle felt soft.
Why weren't my settings saved?
 
Doubt a 9V can support the accessory loads. The impedance is just too high on those little 9v batteries. On old cars sure, but anything where there is some actuation on the acc mode that stay on a while, it may have knocked the battery to a real low voltage.
 
I tested the 9 volt before and after I used it and it showed 9.20 VDC both times.
I thought these memory savers were made for today's cars because they have so many
electronic setting to save. Older cars had push button radios and no computer modules
so they would not have anything to save.

I had the key in the accessories position because the cigar lighter is not powered in the off position.
 
I've heard that those are hit or miss on some vehicles. When I replaced the battery on our STS I used one, and it worked perfectly (and it has a lot of stuff to save). Same on the Durango-all the presets were there after changing it.
 
Originally Posted By: Reggaemon
I tested the 9 volt before and after I used it and it showed 9.20 VDC both times.


9.20v with no load on it?

Battery testers place them under a calculated load to determine if it's good or not.
 
I have a coup[le vehicles that have interior lights that stay on for a prescribed time after door closes and longer if the key is in
 
Originally Posted By: Miller88
Those don't have a chance of working if you had to use accessory mode. They only work on always-live cigarette lighters.


I think that is the right answer.
 
Originally Posted By: Miller88
Those don't have a chance of working if you had to use accessory mode. They only work on always-live cigarette lighters.


Yep, exactly.

I use a jump box when I make battery switches. Clamp on the jump box to ground somewhere, and the positive clamp to the positive lead. Unscrew the battery terminals, make the swap, then disconnect the jump box. Jump box should be more than capable of handling the load.
 
Hi all,

On GM cars with RAP - retained accessory power, you don't want to remove the battery cable until RAP power has timed out with the car doors shut.. Because the OnStar system may consider a disconnected battery as a collision, it then activates a non-rechargable battery in the onStar box intended to enable communication via built in cell. The internal battery dies once exhausted - it can't be turned off!

Likely other cars have this 'feature' too!
 
Originally Posted By: i_hate_autofraud
Hi all,

On GM cars with RAP - retained accessory power, you don't want to remove the battery cable until RAP power has timed out with the car doors shut.. Because the OnStar system may consider a disconnected battery as a collision, it then activates a non-rechargable battery in the onStar box intended to enable communication via built in cell. The internal battery dies once exhausted - it can't be turned off!

Likely other cars have this 'feature' too!


How long should one wait with the doors closed for the RAP to time out before one disconnects the battery?
 
Originally Posted By: JimPghPA
Originally Posted By: i_hate_autofraud
Hi all,

On GM cars with RAP - retained accessory power, you don't want to remove the battery cable until RAP power has timed out with the car doors shut.. Because the OnStar system may consider a disconnected battery as a collision, it then activates a non-rechargable battery in the onStar box intended to enable communication via built in cell. The internal battery dies once exhausted - it can't be turned off!

Likely other cars have this 'feature' too!


How long should one wait with the doors closed for the RAP to time out before one disconnects the battery?


Turn off the key with the doors shut, and open the door. Once the door opens, retained accessory power is cancelled and turned off .
 
I know what you did wrong.You bought a newish car with a lot of superfluous electrickery in it.

I know what I did wrong. I put another battery in it in the same orientation, but its terminals were the other way around.

BANG.

My mistake was a lot stupider than your mistake.
 
Originally Posted By: EdwardC
Originally Posted By: Miller88
Those don't have a chance of working if you had to use accessory mode. They only work on always-live cigarette lighters.


Yep, exactly.

I use a jump box when I make battery switches. Clamp on the jump box to ground somewhere, and the positive clamp to the positive lead. Unscrew the battery terminals, make the swap, then disconnect the jump box. Jump box should be more than capable of handling the load.



My jump box has a DC to DC cigarette port. It works great leaving it plugged in my always on accessory port. It even has enough power to operate my door locks without the battery in the car.
 
When I replaced a battery on a friend's Forester, what I did was let the car's ECM "initialize" for 90 seconds with the key on, engine off to get the DBW throttle to "zero", and then we let it run to normal operating temp for 10 minutes to relearn its idle and fuel strategies.

Some cars have diodes in the cigarette lighters - it's best to use a memory saver that plugs into the OBD DLC, so it feeds 12V straight into the ECM/PCM's memory feed.
 
I quote (I don't have need to know anything about this new-fangled stuff myself)

"Memory Savers. Forget the cigarette lighter type. Buy a Sealey one that goes into the DL16 plus, saves loads of time having to re-programming modules. If you want to make your own memory saver, pin 16 is postive and pins 4 and 5 are negative in DL16 diagnostic plugs. "

http://www.remmington.info/advice.htm
 
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