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Change Batteries Like a Pro


Winter often means dead battery season. You might be cruising along with your battery getting the job done and things seem just fine. Then, the mercury drops and suddenly your battery just can’t give your car what it needs any longer. Time for a new battery. You’ve got this… right? Well, maybe. As vehicle technology changes, even a task that used to be simple and straightforward just isn’t that easy any longer. But, armed with your trusty Booster Pac or Jump-N-Carry jump starter and a simple accessory, you can make this now complicated task more manageable.

Why do we say this task is more complicated than it used to be? Well, in the old days, the worst thing that could happen if you changed out a battery without taking precautionary steps was that you would lose your radio presets. This was a hassle, for sure, but didn’t impact vehicle operation. So, once the new battery was installed, you spent 3-4 minutes (tops) resetting your radio stations and you were good to go. Now, the radio presets are the least of your worries. On late model vehicles, a wide variety of electronic components can lose stored settings, such as how the vehicle has adapted to your particular driving style. This can lead to erratic vehicle operation after the battery replacement as well as other electronic glitches that can be difficult to resolve.

One way to prevent these problems during a battery change is to utilize a memory saver to keep the vehicle powered throughout the swap. A memory saver is simply an auxiliary 12 Volt battery connected to the system. They come in many shapes and sizes and can utilize different strategies for the vehicle connection. But, from our point of view, if you own a jump starter you already possess an auxiliary 12 Volt battery. Now it is just a question of how to use it to interface with the vehicle.

For most vehicles, the simplest and most straightforward approach is to use a memory saver connector, such as our SOLAR ESA30, to create a connection from the jump starter’s 12 Volt outlet to the vehicle’s OBDII port. The beauty of this approach is that the OBDII port is an always-on connection to the vehicle. In the early days of the jump starter, we recommended connecting via the vehicle’s 12 Volt outlet, but about 20 years ago, most manufacturers changed their 12 Volt outlet configurations such that they power down when the key is in the off position, which renders this method ineffective. So, we switched to the OBDII port using the ESA30.

When connecting a jump starter for this purpose, using the ESA30, we recommend a specific connection sequence to ensure that your memory saver will effectively perform its task:

  1. Connect the ESA30 memory saver connector to the jump starter via the 12 Volt outlet. Confirm a proper power connection by observing the LED light of the ESA30. A lit LED shows power is flowing.
  2. Disconnect the ESA30 from the jump starter.
  3. Connect the ESA30 memory saver connector to the vehicle via the OBDII port. Confirm a proper power connection by observing the LED light of the ESA30. A lit LED shows power is flowing from the vehicle.
  4. Leaving the ESA30 connected to the vehicle, reconnect it to the jump starter via the 12 Volt outlet. The LED on the ESA30 should still be lit.
  5. Now, you are ready to change out the vehicle battery.
  6. Once the new battery is installed, disconnect the jump starter from the vehicle.

Note: There are some things to remember when using the ESA30 to prevent unintended damage and other issues

Remember that, when you change out the vehicle’s battery while using a memory saver, the vehicle’s electrical system is still live – that’s the whole point – and all usual care must be taken with the electrical system. To prevent a short circuit and loss of vehicle memory, do not allow the vehicle’s disconnected positive battery cable or the output cables from your jump starter to touch vehicle ground.

Prior to connecting the memory saver, verify all vehicle accessories are OFF. To prevent overloading of a vehicle fuse or other vehicle damage, do not use the Memory Saver if the vehicle’s current draw is 4 amps or more when the vehicle is in a KEY OFF condition. Also, vehicle systems often cycle after the vehicle is turned off. Such cycling can place heavy demands on the vehicle’s electrical system. Before connecting the memory saver, turn the vehicle’s key to the OFF position and wait for 25 minutes. Doing so will ensure that all vehicle cycling is completed (most vehicles).

Some vehicles, for reasons related to the warnings above, are not compatible with the use of a memory saver connector to connect a jump starter via the OBDII port (BMW X5, some Volvo models, for example). Typically, these vehicles are higher end vehicles with advanced electronics or sophisticated power down routines. On these vehicles, you will often find starting points in the engine compartment (the battery is typically stored in an odd location), which are the manufacturer-preferred connection location for jump starting. These starting points provide a great alternative to connecting via the OBDII port, since, like the OBDII port, they are typically always on and have the added benefit that they are designed to handle high power loads. When using this method, the jump starter positive cable is connected to the vehicle’s positive starting point and the jump starter negative cable is connected to the ground starting point (if available) or a standard engine or chassis ground. This article, by Karl Seyfert in Motor, provides a great example of what can happen when you try to provide memory saver function to a vehicle through the OBDII port when said vehicle does not like that method.

Now, you’re done, right? Well, maybe. On many vehicles, yes, you are done. But, some vehicles require a battery reset after a new battery is installed. Check your owner’s manual for details related to this as it relates to your specific vehicle. Most late model BMW, VW, Audi, Porsche, Volvo, Jaguar, Land Rover, Ford, Nissan and Infiniti vehicles have this requirement. You can typically get this reset done at your dealer, your trusted local mechanic and many auto parts stores.

Taking these steps, using a tool you likely already possess, can make the difference between a quick, easy and worry-free battery replacement and on that results in lingering problems in your electrical system. Have you ever experience strange vehicle behavior after a battery change? If so, we’d love to hear about it (and how you ultimately resolved it) in the comments below.

2 Responses

  1. can you use a milwaukee 12v battery connected to the car’s positive and negative cables via the use of alligator clips? Not for starting. Just to provide a reliablesource of power. We used to use 9V batteries plugged into the cigarette lighter but that doesn’t seem to work now.

    1. Robert – Thanks for your question. I would say it depends on the battery and your means of connection. What is the fully charged voltage of the Milwaukee battery? If it is 12.8V-14.0V, it may work just fine. You would need to be very careful about your connections and, once the battery is connected, be careful to avoid causing a short, which could be both dangerous to those working around the vehicle and damaging to the vehicle. Thanks, Jim

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