How Self-Charging Hybrids Work

Wednesday 7 July 2021, 1:40PM
By Dave Allen Motors

With more and more hybrid vehicles entering the NZ car market, a question we are asked often here at Dave Allen Motors is "what is a self-charging hybrid and how do they work?"

You may have heard the term 'self-charging hybrid' more recently here in NZ, as it been appearing in advertising for certain cars for several years now on TV or in the papers. It can be a little confusing at first, but the term is just another name for a normal hybrid car.

A 'self-charging hybrid' is a car that can drive itself using electric power alone but cannot be plugged in to charge like a plug-in hybrid or (PHEV) cars can. Technically, a PHEV is an electric vehicle that’s also fitted with a conventional engine that’s used for both charging and driving when the battery runs low, or when extra power is needed.

Before plug-in hybrid cars started to appear, this was simply called a hybrid car. Basically, a self-charging hybrid is a traditional hybrid car, such as a Toyota Prius or Aqua, two of the more popular models sold here in NZ.

While a plug-in hybrid can be driven only on electric power if you regularly plugin, the only way to drive a traditional hybrid on electric power is to allow it to charge itself up using the onboard petrol engine. This is why it's called a self-charging hybrid.

Both types of hybrid are great for driving in the city, as they allow the engine to be shut off in congested traffic conditions, saving fuel and reducing local emissions. However, as 'self-charging hybrids' tend to have smaller batteries than plug-in hybrids, they're more likely to need to switch the engine on if you are stuck in traffic for a long time.

How does a hybrid work?

Most hybrid (or self-charging hybrid) cars feature a petrol engine, an electric motor and a small battery pack. As you drive along, some power from the engine and kinetic energy recuperated from slowing down and braking is used to charge the battery pack – this is what leads some manufacturers to use the term 'self-charging. Then, as you accelerate, electricity from the batteries powers the electric motor and helps the car gain speed, making the petrol engine’s job easier and improving fuel economy.

When enough charge is in the battery pack, most hybrid vehicles can also pull away just using electricity and travel for a short distance at low speeds, using no fuel at all.

Hybrids also require very few changes to your driving habits, because they can be parked anywhere (you don’t need to find a charging point), refuelled at any petrol station and require the same level of care and maintenance as any ordinary car. A major hurdle for electric vehicles in NZ has been ‘range anxiety, with early models often having a range of fewer than 200kms and the need to find a working charging point to top up the batteries. A hybrid doesn’t need to be charged and can drive for hundreds of km's on a tank of fuel.

Because of the small capacity of the battery packs fitted to hybrid models, they can’t travel very far, or for very long, on electric power alone – typically less than a couple of km's. If you want to travel for a greater proportion of the time using just electricity, a plug-in hybrid model is more suitable, as most of these can be driven for 30-50 km's without the conventional engine kicking in. To achieve this, plug-in hybrids require a much larger battery pack that requires charging from a mains supply or public charging point, but they're also significantly more expensive to buy as a result.

We hope this article has helped spread some light on the subject for you. We import a wide range of hybrid vehicles at Dave Allen Motors

to suit most budgets. If you have any further questions don't hesitate to contact our sales team or our Business Manager regarding finance options.