Back-to-school maintenance: Get your hybrid’s high-voltage battery checked
September is chock full of checklists, isn’t it? But even if no one in your family attends school, it’s a good time to begin preparations for the winter, an easy time to remember some maintenance tasks, and the best time (in our opinion) to plan a gorgeous fall road trip to see the changing foliage.
In this blog post, we’ll discuss hybrid high-voltage battery checks, which should be part of your fall maintenance plan.
What is voltage?
Voltage is the pressure that pushes electricity through a circuit. Have you ever travelled to Europe and taken your hairdryer along, attached a plug adapter, and subsequently jumped as your dryer shorted out?
That’s because North America runs on a 120-volt system, and Europe on a 240-volt one. In other words, Europe’s electrical systems have more pressure than North America’s. You need a power converter so you can operate your hair dryer in Europe.
However, most North American homes do have two 240-volt outlets: one for the oven and one for the clothes dryer. If you have a home charger for your hybrid or electric vehicle, that will also run on 240 volts. Everything else uses 120 volts.
What’s the difference between a high-voltage battery and a low-voltage battery?
Low-voltage batteries differ from high-voltage ones the way your garden hose differs from a hose attached to a fire hydrant. You can drink from a garden hose, but you’ll be seriously injured by the water spouting out of the fire hydrant hose.
The low-voltage batteries in a hybrid vehicle are 12-volt batteries. These batteries start the engine, stabilize electrical load, and provide power to lights and other electrical components.
High-voltage batteries range from 200 to 600 volts, depending on the manufacturer. You’ll find that information in your owner’s manual. These batteries propel the hybrid or electric vehicle.
AC and DC: What do they mean and are they important?
Types of current and yes.
AC stands for “alternating current,” and DC for “direct current.” We won’t dig into the nitty gritty of definitions here, but you need to know three important details:
- Batteries run on DC.
- All other components use AC.
- These types of current always need a converter to talk to one another.
Although you have DC and AC in any vehicle, this relationship plays a more important role in your hybrid vehicle because of the high-voltage battery: it needs to be charged.
Transformers change power from AC to DC and back. Your hybrid vehicle will have two transformers: an inverter to change the DC power into AC to drive the motors, and a converter to reverse this process and recharge the batteries.
How a high-voltage hybrid battery gets charged
Depending on the model, your hybrid vehicle will charge its high-voltage battery using any of several ways:
- Regenerative braking: This takes the heat generated by braking and funnels it back into the battery.
- Via a plug: Plug-in hybrid cars (PHEV) have a plug like an EV that you push into a socket to charge the battery. However, not all hybrids have this feature.
- ICE motor: The internal combustion engine of a hybrid car also contributes energy to the high-voltage battery when the car is running.
Why get a battery check?
Because of the high voltage running through your hybrid, having a technician inspect the battery and connected electrical systems ensures all components are working correctly and safely. Just like you should get your brakes checked for safety reasons, you should also get your high-voltage battery checked.
Why you shouldn’t check the battery yourself: Safety
What’s one of the first things we teach kids? “Keep your fingers out of the sockets.” The same rule applies to the high-voltage battery and its connected systems.
The reason you shouldn’t service your high-voltage battery on your own is precisely because of the high voltage running through it and several other components. This isn’t a case of unplugging a toaster and sticking a fork into it to pull out your “jammed” piece of toast.
Under the hood are bright orange cables connecting the high-voltage battery, motor-generator, and inverter/converters. The bright orange colour distinguishes these high-voltage cables from others. Only under certain circumstances can they be touched, and technicians wear heavily insulated rubber gloves to service them.
If your high-voltage battery dies on the road, do not assume it’s automatically safe to touch. Even if it can’t operate your vehicle anymore, it may still have hundreds of volts of energy running through it.
Taking this on a smaller scale, how often have you removed batteries from, say, your tablet’s Bluetooth keyboard, only to test them and see they still carry some power? A hybrid vehicle’s battery operates the same way.
You may read online about a disconnect device. Please leave this to a technician: if you don’t have the proper safety equipment and don’t know exactly how to operate the disconnect device, do not attempt it. Even on a dead battery, the high voltage can electrocute you.
Schedule a battery check at your nearest AUTOPRO service center.
Photo: iStock-1777461085