Energy5.07.2022

Most affordable power trolleys for surviving Stage 6 load-shedding

There are numerous inverter trolleys for sale in South Africa that can run essential appliances to get you through load-shedding for less than R10,000.

While many households are looking into fully-fledged backup power systems with big batteries and large solar arrays, some cannot afford to spend tens of thousands of rand on such a system.

South Africans looking for cheaper alternatives might have thought a conventional uninterruptable power supply (UPS) could do the job.

However, these are intended for keeping electronic equipment powered for only a few minutes after an outage.

A quick browse through the energy departments of online stores like Takealot, Everyshop, and GeeWiz, and you will see one popular option: the inverter trolley.

These systems combine an inverter and a sizeable battery to provide simple plug-and-play backup power for a handful of appliances.

But there are some caveats to consider regarding power trolleys, particularly the more affordable variants.

Lead-acid vs gel vs lithium-ion

Cheaper power trolleys typically come with lead-acid batteries, some of which might have deep cycle capability, to an extent.

But none have the battery chemistry for significant usage over the long term.

That means they generally last for only a couple of hundred cycles before their useable capacity is significantly reduced, and a replacement might be required.

In addition, most have a depth-of-discharge (DoD) of roughly 50% from the outset.

The typical 100Ah 12V lead-acid battery has a theoretical maximum capacity of 1,200Wh, but should ideally never drop below 600Wh charge to prevent shortening the battery’s lifespan.

Gel batteries have a slightly better cycle life but still come nowhere near the longevity or DoD of lithium-ion.

Lithium-ion batteries have a DoD of 80% to 90%, which means you have much greater capacity available to use.

While lithium-ion is much more expensive per Wh, many types can also last for over 1,000 cycles, saving you money in the long run.

Enertec lead-acid battery and Hubble lithium-ion battery. While both have a capacity of 1,200Wh, the Hubble battery can use 100% over 3,000 cycles and retain 80% capacity afterwards, whereas the Enertec will effectively die after 200 cycles at 50% discharge.

The size and power of your trolley will depend on your demand, but if you are looking at spending less than R10,000, you cannot hope to power hungry appliances with elements like kettles.

Entry-level power trolleys come with 720W or 1,440W power output, short of the 2,000W or 3,000W that electric kettles typically use.

However, powering desktops, laptops, a TV, Wi-Fi router, and phone chargers should be no issue for these units.

Another factor you will have to consider is the rate of charging.

That will be essential to ensure your battery can build up sufficient charge to carry you through the next stint of load-shedding.

Many power trolleys come with 10A or 20A chargers, typically providing 10Ah or 20Ah of capacity per hour.

The actual rate might be slightly lower depending on the charging efficiency of the inverter.

Pure sine vs modified sine

Finally, you should also confirm whether the devices you plan to power are compatible with a modified sine wave or pure sine wave,

Wiltronics explains that in pure sine wave inverters, the inverter’s alternating current (AC) power closely matches the actual sine wave, which is essential for running devices with AC motors.

In modified sine wave inverters, the polarity switches from positive to negative.

These are suitable for simple systems and should not cause problems with PCs, TVs, lights, and routers.

We’ve compiled a list of some of the most affordable power trolleys and small lithium-ion battery packs in South Africa. These were in stock at the time of publication.

The typical example load of 150W is taken from Geewiz and is based on powering a TV, laptop, Wi-Fi router, and lamp.