Powerbuilt 648539 Computer Memory Keeper, Red

If you disconnect your car battery, this device keeps enough voltage in the electrical system to prevent loss of radio station presets; and other presets, if your car has them (like phone or seat settings, etc).Be sure to test the socket you're plugging this into first to make sure it's "live" BEFORE you disconnect the car battery; if not, just set your key (or "start" button) to the Accessory position, then plug the Memory Keeper in prior to disconnecting the battery.Also, before I bought this, I had wondered why I needed it, and couldn't I just attach a 9 volt battery to the car battery cables? The reason you can't is that the car battery will "over-charge" the 9 Volt battery and possibly risk an exploding battery! This device has a diode built into it to prevent that.Works well, cost is very reasonable. Highly recommended.

I have an older Ford Explorer Sport Trac SUV and I was going to remove my battery - and it was recommended to me by a Ford mechanic, to make sure I had a small device plugged in to keep a small current in the system that would prevent any computer settings from being removed (like my combination code on my driver's side door). I looked around and found quite a few items that do this, with some being medium priced, while others were beyond what I had expected to pay.Then I saw this Powerbuilt 648539 computer memory keeper, and when I saw the price, I figured, "why not?" I couldn't believe the low price and had initially wrongly assumed that it would be a piece of junk - but I thought I'd give it a try anyway - and I'm glad that I did!Using just a 9V battery, I plugged it in - and then changed out my car battery. Everything was kept in check and I didn't lose anything - no combinations, nada. So this was a very good, inexpensive, investment and I strongly recommend it (at least for older cars).As always, your mileage may vary.

I just used this while changing the battery in my Lexus GX470. I plugged it in (with a new 9V), turned the ignition switch to Accessory and replaced the vehicle's battery in about 20 minutes. My vehicle's seat memory and radio presets were remembered, which were the most important items for me. It didn't save the clock time and I still needed to reset the auto up/down function on all the windows, but that was simple & fast to do.Overall, buying this memory keeper was well worth it.SEPTEMBER 2017 UPDATE: Just used this when changing the battery in my Lexus LS430 and it worked perfectly. The memory keeper was plugged in for 10 minutes with the car key switched to accessory while I changed the battery. Seat memory, radio stations and window settings were all remembered.

This is a handy little device you need if you’re going to do battery maintenance on your automobile, take your 9 V battery plug it into your 12 V socket receptor, and it will maintain a low voltage but constant power to your vehicles computer and you should not lose your presets For your vehicle, once you disconnect your vehicle battery and this is not attached in place you may lose your presets for your engine transmission definitely a radio

Worked fine I didn't lose any settings

This is a useful tool to have if you have a car that has a lighter outlet with constant battery power. The idea is that when you disconnect the car battery, the 9V battery will back-feed enough power through the system to keep things like radio presets and module parameters from being forgotten.However, that only works if the lighter outlet is live even when the ignition key is off. For many cars, turning the ignition key to the off position will electrically disconnect the lighter outlet completely, which means that this power adapter will not be able to keep anything powered up.Checking to see if your car has constant battery power at the lighter outlet is straightforward. Plug a phone charger into it, then turn the ignition off and remove the key. If the charger still charges your phone, the socket is alive at all times and this keeper will (probably) work. If not, it won't.Why is this important? Because many cars disconnect the lighter outlet when the key is switched off. In my experience, most import cars do this. My old Ford truck doesn't, but my Toyota does, and a few other import cars (Subaru, Mazda, etc.) in my circle of family and friends do as well.To be clear, this is not a fault of the tool, and this is not the reason I knocked off 2 stars. I already knew all of this going into it and bought the adapter accordingly. But a typical shadetree mechanic who buys this may NOT know it and will accidentally wipe out all of their memory presets thinking that this adapter is compatible with their car.Most times this is not a big deal-- a lot of the adaptive parameters in the various modules will relearn over time, and most people will not notice that they're wiped out. But I suspect that most people who buy this will end up spending $14 for something that doesn't work for them, and they'll never know why. Yes, caveat emptor, but it wouldn't take much to add a small disclaimer to the product description and save the average buyer some aggravation.In short, do some homework before purchasing this adapter, because it will be useless for a significant number of cases.

I had to change the batteries on both of our vehicles. This would have necessitated redoing all the memory presets/settings for the car. This little device worked like a champ and redoing the settings was unnecessary after changing both vehicle batteries. Ensure that the car is in accessory mode first, then go ahead and connect a 9-volt battery to this and plug it into a 'live' 12V accessory port before changing the car battery. Voila!

Didn’t need to reprogram one thing when changing out batteries