Published on 19th Dec, 2022 by Cable Chick

Is it time to change to Rechargeable Batteries?

Is it time to change to Rechargeable Batteries?

Modern NiMH make good financial and environmental sense over disposables in most applications. Our blog looks at the pros, cons and best applications for NiMH cells so you can save yourself from the pitfalls of throw-aways NOW.

Time to Change your Batteries

We've all been there - a disposable Alkaline battery sitting in a rarely-used device leaks and ruins the electronics inside, corroding the circuit board. The only fix is to remove them when you're done each time, or remember to check them regularly enough to swap out the duds.

Or is it? NiMH batteries don't leak like Alkalines, and they have other benefits, too...



Batteries vs The Environment

Let's be honest - no battery is good for the environment. From the mining and processing to disposal, every step of the way causes harm. But, batteries are a fact of life - a necessary evil in the modern world of portable super computers and electronic entertainment. And, it's Christmas time, so there are a bevy of decorations and new toys around that need batteries, too!

That means the best we can do is limit our impact by choosing the most effective long-term options for our devices. Alkaline disposables are fast becoming a bad option for a great deal of applications, and we think our new line of AA and AAA NiMH rechargeables are worthy of your consideration - let's look at why.


Benefits of NiMH

  • Nickel-metal hydride batteries use less-toxic substances than disposables and they are recyclable.
  • If recharged at least 50 times out of their 800-1000 cycle lifetime, they are substantially better for the environment compared to disposable Alkalines.
  • NiMH batteries are far less likely to leak compared to Alkaline cells.
  • They can last longer and at a higher voltage than Alkaline batteries, too.
  • Modern NiMH cells have little or no 'memory effect'.
  • NiMH batteries provide 1.2 volts maximum (for 80%+ of their charge) compared to Alkalines which start at 1.5v and drop slowly to below 1 volt
  • More cost-effective over the lifespan of the battery


Drawbacks of Rechargeables

  • NiMH cells will self-discharge slowly over time (about 1% per day) so they only have around 2 months or so of stand-by time before needing a recharge.
  • Ideally, they require 'conditioning' cycles when new to reach their full potential.
  • Higher Initial Cost
  • A suitable battery charger is needed for charging
  • Some cell brands don't fit as nicely as Alkalines


Best places to use NiMH

Rechargeables can go in just about any device you'd usually put Alkalines in. We carry AA and AAA sizes that are suitable in almost everything, but there are places where NiMH outperform Alkaline, too.

NiMH really shine in high-draw devices that are generally expended in a single use. Think a powerful flashlight or remote control car, where you plug in freshly recharged cells and run them down completely before swapping in a fresh set.

Likewise, anything with an LCD screen is likely to benefit, such as digital cameras, GPS units and MP3 players (though it must be said those types of things generally have built-in cells these days). There are other specialty tools like snake cameras that use batteries and have LCDs, so some hand tools are also a good place to put NiMH.

NiMH is also an option in non-critical, low-draw devices like remote controls. The upside is that they are less likely to leak and ruin your device, and the downside is that the self-discharge nature of NiMH means more frequent replace/recharge cycles. If you've got a smart TV or universal remote and never touch your Blu-ray or Amp remote, NiMH's on-hand are the way to go.

Rechargeables are not recommended for critical tasks like in smoke alarms. Of course, finding a smoke alarm that takes AA or AAA cells is practically impossible, but you get the idea. If you'll be leaving a device unused or on stand-by for a long time (30 days or more) then Alkaline or Lithium is your best bet.


How to look after NiMH

If you're going to invest in a few sets of rechargeables, it can be very cost-effective long term to replace the rechargeables in your devices more frequently, keeping fresh ones topped-up and on-hand for immediate swap-in.



Looking after NiMH is pretty easy. First, get yourself a good quality charger (like those above) and charge up your new batteries. Overnight is best - the slower the charging speed the longer the battery's lifespan.

After that, you're ready to go. If you want to get the absolute best from your fresh cells, put them in a high-draw device and run them down flat, charge them, run them down, and charge them again. This will get you maximum energy density almost immediately.

Having NiMH on stand-by means charging up your spares once a month for best effect. Once every two months is also possible, but your stand-by batteries will have less in the tank in an emergency.

Keep your NiMH's as cool as possible (don't refrigerate them) as higher temperatures can speed up the self-discharge effect.


NiMH vs Alkaline vs Lithium

NiMH offers 1.2v nominal compared to Lithium and Alkaline which start at 1.5v

NiMH is a cost-effecive rechargable battery choice, with low up-front costs

NiMH will not last as long as Lithium, but can last longer than Alkaline in high-draw devices (less in low-draw)

NiMH can be recharged several hundred times. Lithium and Alkaline AA and AA cells are disposable

NiMH and Lithium have mostly flat discharge curve profiles. Alkaline is sloped (drops under 1v over time)

NiMH self-discharges over time (fortunately the better quality cells last longer). Lithium and Alkaline lose little over 10+ years.

NiMH works better in low temperatures than Alkaline, but Lithium is better still.

NiMH batteries are heavier than Lithiums and Alkalines

NiMH and Lithium batteries are much more recyclable. Alkaline batteries are much less recyclable.

NiMH batteries in regular use will last 2 to 5 years (more for some brands and when in less frequent use)


1.5v vs 1.2v

Some devices rely on Alkaline's ability to output 1.5v when new. Unfortunately, this means those devices chew through Alkalines at an inefficient rate, and are also unsuitable for NiMH cells.

For almost everything else, 1.2V is plenty, since Alkalines will fall to 1.2v nominal over time anyway, most devices are more than happy to work at that voltage. In fact, NiMH batteries have a relatively flat discharge profile, so keep 1.2v steady for 80% of their charge before dropping off quickly.

One side-effect of this flat vs sloped discharge profile is that some devices battery level indicator will be calibrated for Alkaline, and read as less full initially, stay full longer, and then give little warning when the batteries are finally depleted. This phenomenon is not harmful for the devices or the batteries, it's just a quirk of the technology.



Don't throw batteries away in your council waste bin. Putting any cells into landfill is bad, and they could find their way into a crusher before then and rupture, affecting more waste and making it unsuitable for landfill, too! They can even start fires, so please be careful.

NiMH batteries don't really need any extra care compared to Alkalines, but doing the right thing is more worth your time as the cells are recyclable.

Your local refuse centre will have a special place for NiMH cells, plus Officeworks, ALDI, Battery World and Bunnings also have their own drop-off for household cells (some take Alkaline, too!).

The best practice is to place sticky tape or electrical tape across the terminals, save up your duds, and then take them with you in bulk when you go shopping next. It's easy, safe and doesn't cost you a thing.



We might have missed something, so please contact us if you see room for improvement.

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