Battery powered devices

I have just borrowed a battery lawn mower.
It was purchased based on the obvious information Stating that it included a 4AH battery. The product is sold as a 42Volt mower. Great! that’s 42x4=168wh. But no! once you remove the battery and read the specs it states 36V and 144Wh!
That is blatant misrepresentation in my books.
Do I approach the manufacturer or the vendor for compensation or Just report the misleading conduct to the ACCC?

I just checked MY mower’s battery (its in for warranty repair ATM) it states 270Wh and 5AH. That’s 54volt but the product is sold as a 60Volt. Much closer but when I walked down the isle of mowers I was doing the calculations and comparing stated voltage times AH of battery.
How accurate are the other brands I didn’t buy?

Stihl, Ego etc reference their equipment according to the battery system used. 18, 36, 54V etc. Multiples of 3.6V the nominal/rated voltage of the most commonly used lithium ion cells. IE the average voltage between fully charged and discharged. BU-303: Confusion with Voltages - Battery University

Note that since a battery discharge voltage is not perfectly linear multiplying the Ah rating of a pack by the nominal pack voltage is an approximation. In real world use the higher rates of discharge increase losses within the battery. The actual Wh capacity in normal use may be considerably less than the nominal pack capacity. Stihl as one example provide two Ah ratings for their yard tool batteries. A cell manufacturer rating against a recognised standard, and a lesser value based on Stihl’s expectations when in normal use.

Some are likely to agree. Although it’s likely a correct statement of the maximum voltage provided by a fully charged battery under minimal load conditions. IE not useful in any way practical when assessing the performance of the battery powered implement.

The Choice reviews of battery push mowers included assessing the area each model could achieve on a single charge.


DeWALT sell their batteries (their system uses 20/60/120 V advertising) with the following explanation that is inline with what @mark_m has posted.

“* Maximum initial battery voltage (measured without a workload) is 20, 60, and 120 volts. Nominal voltage is 18, 54, and 108. 120V MAX* is based on using 2 DEWALT 60V MAX* Lithium ion batteries combined having a maximum initial battery voltage (measured with a workload) of 120 volts and a nominal voltage of 108.”

So truthfully a 120 maximum initial voltage but nominally 108 volts for the 120 MAX. 20 volts for the nominal 18 volt and 54 volts is the nominal voltage for their 60 volt MAX system. So both statements of voltage are true, but some use of maximums to sell a product and differentiate it in the marketplace. It would be hard to argue by the ACCC or others that it is deceptive as they have clearly defined how that voltage claim was substantiated, sure it is a marketing ploy but one they can stand up in Court and demonstrate it is truthful. Probably the worst someone could claim was it was use of allowed/legal puffery.


There are a couple of factors to consider about battery voltage that make a simple calculation tricky.

First is that Ohm’s law V=IR tells us that once a current flows in a battery to provide power to some device, there is a change in voltage related to the resistance. All batteries have some degree of internal resistance, so a voltage measured under no current flow will be higher than that measured under load.

The second is that as charge stored in a battery is depleted to provide a current flow, the electomotive force, or pressure to provide a current, measured in volts, decreases. To the point where the voltage has dropped to a point where either there is no longer enough voltage or current to power a device.

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As long as they all follow the same system the Max voltage is irrelevant but a useful comparison.

I’d like to think so.
Perhaps it’s not that simple.

  • Stihl uses 36V for its AK home and AP professional battery systems including walk behind lawn mowers and chain saws.
  • EGO use 56V for their larger yard tools, push and ride on mowers.
  • Ryobi’s latest ride on uses 2 x 36V battery packs in series, and calls it an 80V mower.

The Choice battery lawn mower reviews show limited differences between the Stihl and EGO walk behind/push mowers, despite the obvious difference in battery pack voltages.

Hopefully Choice continues to add new reviews of the less expensive battery powered yard equipment. The latest battery ride ons less likely. I suspect any differences in performance between the EGO 56V and Ryobi 72V systems will have little to do with the chosen system voltage.

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Thats good upfront advertising. If they all do that then the comparisons are valid

It boils down to WH (watt hours) its the amount of work that can be done. We assume the motor is capable of doing the task then WH tells you how long you can do that taks for. Ok there are some nuances in that higher voltage tends to result in lower IR losses but for a first level comparison they should all quote WH IMHO

I’ve written before about the need for global standards for battery packs.

We have such standards for small batteries, eg, size wise AA, AAA, BB etc and with standard volt of either 1.2 or 1.5 per cell. The obvious benefit, is the device becomes separate to the battery. hence makers of equipment can remain specialist at that.

I think with rechargeable also some standards for the amount of power stored would be valuable.

However, with the increasing replacement of mains and petrol tools, it seems obvious to me that we also have battery packs of a standard size and power.

It upsets me that as I upgrade or replace such tools, I have to dispose of the still fully functional battery, because they don’t fit the replacement device. Also having several different battery packs, effectively all doing the same thing, but not interchangeable!

Lose lose. I lose, the planet loses

Establishing global standards takes time, often based on which specific product dominates. But in this case battery packs have know been around for many years, and no talk of standardising?

I think choice needs to lobby for this NOW! @RosieThomas @ashleydesilva

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@AlanKirkland has moved on to another job, the new CEO of CHOICE is Ashley de Silva. See this release about the new CEO

“ CHOICE is excited to announce the appointment of Ashley de Silva as our new CEO.

Ashley de Silva, currently CEO at ReachOut Australia, will commence at CHOICE in March 2024.

"Ashley has an impressive track record in the non-profit sector, most recently as CEO of ReachOut, a national online mental health service for young people,” says CHOICE Board Co-Chair, Anita Tang.

“Ashley brings with him a wealth of experience and a leadership approach deeply rooted in a for-purpose mindset. During his time at ReachOut he held a number of leadership roles and worked across a variety of areas including government relations, communications, research and more. We know he will be a great fit for CHOICE and we look forward to him taking up the CEO role in March this year,” says CHOICE Board Co-Chair, Nic Cola.

Ashley succeeds Alan Kirkland , who left the role in November 2023 after 11 years with the organisation, following the announcement of his appointment as a Commissioner of the Australian Securities and Investments Commission.”

Back to your battery adaptability, there are a number of reasonably cheap adapters available after-market for a number of popular batteries. As the nominal voltage of packs is equal across 18 volt, 36 volt and so on, with the use of an adapter would allow use across a range of products. Would manufacturers really like to lose their hold on selling only their branded products? I don’t think they would and as most are OS built the ability of our Government to alter their habits is severely impacted. HP as an example have virtually made it impossible to use any other cartridges other than their’s. Only way to discourage that behaviour is to not buy the product. Almost a double edged sword.

Thank you for you detail re the CEO. I did actually search online as I thought there was a change, but didn’t get a hit, even the Choice links aren’t up to date. Appreciated!

However, my comment is about battery standards, it isn’t seeking a stop gap solution. It is a need for Choice, as part of its campaigning, to look at global standards with its international partners. This battery disposal issue globally needs a resolution. I don’t care what product manufacturers want to increase their profit, that should not be a concern for Consumer Associations. But throwing away perfectly usable batteries, having to buy different batteries brands, that serve the equal process, is a consumer issue, as is waste generation.

Thank you raising your concerns.

I do not disagree with your concerns, the Consumer organisations do run campaigns about “rights to repair” and similar issues. Apple as an example have had to ditch the lightning connector and supply their mobile products with USB C ports due to a case in the EU Courts. Running the campaign/campaigns you suggest obviously has merit regarding wasting resources, the problem remains that corporations have immense power and thus influence over politics and political thinking.

Consider Global Warming and the impact of using fossil fuel (FF) on it. Billions probably but at least lots of millions get spent to obstruct, delay, divert, any changes that would otherwise curtail fossil fuel usage now, so very little change has happened. I personally don’t think that Consumer organisations will have much success in the rechargeable battery area, but you have raised it and I’m sure CHOICE will consider whether it is a worthwhile idea/ideal to pursue.

Now, I don’t place rechargeable batteries in the same class of spending as for FF. Difficulties still remain and firstly they don’t rock the boat too badly/harshly as far as Governments are concerned and lobbying with sufficient funding doesn’t have to be anywhere near as much as for FF to keep the status quo. Next is proprietary rights, Corporate ownership is held jealously, as I mentioned above like with HP, sure there are alternatives but businesses do not want to lose their profit centres. A drill may last 5,6,7, or longer, years but the battery may get to 2 or 3 years before it needs replacing. Where is the ongoing money coming from to protect the business profits (retail, middle men and manufacturing)…batteries….

Corporations are most probably going to win keeping their batteries proprietary. A user can choose to replace the packs, repack the packs, buy an adapter that suits, buy aftermarket alternative batteries, sell the skins and batteries and buy corded tools, choose to go manual (old school), not buy the product as it uses a proprietary power system, or stay with one system for all their needs. Making choices that hinder the profit making is probably going to cause more pain than a process to get laws changed, that may be the best tool in this case.


DeWalt FlexVolt and similar systems from other power tool vendors have an additional confusion. They can operate many existing tools at 18V, and rate the capacity in Amp-hours (e.g. 4Ah) at that voltage. On some equipment the battery pack reconfigures to 56V which would deliver the same total energy (18x4=72Wh) but at 56V that’s 1.33 Ah.
It would be much clearer if the battery capacity was given in Watt-hours (Wh).


Welcome, Ashley, and thanks Alan for your long service.

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