Car batteries are not meant to last forever. Sooner or later, they need to be replaced. When you see your car having a lack of time in cranking the engine or the headlights are dim, you know the battery is ready to retire.
But the first mistake that new vehicle owners make is changing the battery without a memory saver. This action leads to a complete reprogramming of your precious car data & programs stored in those complex computer systems.
What is a Memory Saver?
Cars these days run on a network of computer programs that operate the entire vehicle from radio to anti-theft system. But when you remove the battery from the vehicle, the information of those programs are erased.
So you need to contact the car dealer to reprogram the whole vehicle which will waste both your time & money. This is where the memory saver comes to your rescue.
Memory saver is nothing but a simple connection to a spare battery that supplies enough power to the system to keep the computer program alive & running. You can find memory savers all around the market at a rather hefty price. But why buy memory savers when you can just make one yourself even if you don’t have any prior knowledge at all.
Why OBDII Connector?
But before going down to the details of how you can make a memory saver, you need to know the types. There are two types of memory savers, one is the cigarette lighter memory saver & the other one is the OBD memory saver. Both types are based on the cigarette lighter socket & OBDII port of your vehicle.
The problem with the first one is that cars manufactured in the last 15 years have cigarette lighter sockets that only work when the car is running. But that would make it impossible for you to replace your battery with a cigarette lighter memory saver.
Steps to Homemade Memory Saver
That’s why we will be demonstrating the ODBII memory saver. Let’s jump right to work.
Step 1: OBDII Plug
First, you need an OBDII connector that you can plug into your cars OBDII. You can easily find connectors online or your nearest electronics store. But if you want, you can spare that time & build an OBDII connector yourself at home.
Your car’s OBDII connector has 16 holes so you might be wondering how you can make a 16 pin plug for it. Well, you don’t need all the pins, you just need 2 pins to work with the OBDII connector. Calculating from the top left side, pin 4 & pin 16 are the pins you will be needing to connect to the OBDII.
Have a piece of hardboard or plywood board & then illustrate the pinhole exactly like the OBDII connector at the proper place. Place two Nig head nails with a narrow tail end that can go into the pinholes on the board & drill them in.
Now you have the tail end side of the screws on one side going into the pinholes & the heads are appropriate to strap both wires around them.
Step 2: Diode & Battery Connector
After successfully making the OBDII connector, you have to now work on the other side of the wire, the battery part. You have to connect the wire to a battery so that it can supply the necessary power to run the system. The pin 16 wire needs to go to the positive side of the battery & the pin 4 wire connects with the negative side.
You have to use a battery connector according to the type of battery you are using. If you are using a battery pack with XT60 female, then you need an XT60 male connector. The connector should be according to your spare battery.
But the important fact here is to use a Diode. The diode will ensure that there is a one-way flow into the vehicle. The cathode of the diode is connected to the pin 16 wire & the anode part connects with the positive side of the battery.
Step 3: Proper Insulation
After we have completed the battery connection part, our OBDII memory saver is almost ready. But due to exposed metal wire parts, it can become dangerous to use while handling them. So you properly tap on the OBDII plug screw heads so that the head of the wires are not exposed. Then tape the diode & battery connector part with the wire.
Step 4: Testing the Memory Saver
Now that we have constructed the memory saver, we have to test it properly before running it. If you connect the OBDII plug to the connector of your car, then the multimeter will show zero current flow at the end of the battery connector. This means that the diode is working properly to give a one-way flow.
On the other hand, if you calculate the voltage above the heads of the screws, then you will find the voltage of your batteries on the screen of your multimeter. This means you are all set to replace your battery & protecting your precious system with the memory saver to back it up.
If you want to reduce your efforts you can also assemble a memory saver with alligator clips & an OBDII plug, but that would cost you some money. Make sure you replace your battery fast because your spare battery drains a lot faster. But if you have constructed the memory saver properly & used a 12V battery, you should be fine.