UK Voltage / power query

[Telegram Sam]

I have an Aldi long reach hedgetrimmer supplied with a 20 V Active Energy Ferrex r/c battery. This combination is light to handle but woefully underpowered and keeps jamming. There is on sale an equivalent 40 V Ferrex battery. Confusing situation because some batteries and chargers seem to be dual voltage. Question is, if I fit the 40 V battery is there a good chance that it will blow (fry) my electrics? And/or does the mAh rating come into the equation? Tks.

 

[Avo Mk8]

Question is, if I fit the 40 V battery is there a good chance that it will blow (fry) my electrics?

If you fit a 40V battery to a 20V tool, you will likely destroy one or both, except they ought to have different connections to prevent this!

Lithium batteries and the like store a lot of energy, are potentially dangerous.
They can have safety measures incorporated in them such as temperature sensing and sometimes digital communication between battery and tool. Different manufacturers can adopt different approaches, so circuits can vary, for which reason different brands are typically not interchangeable.

I urge you not to experiment by trying "incorrect" batteries in a product!

Lithium-Ion Battery Dangers: The Stats | Checkfire Ltd.

How dangerous are lithium-ion batteries? Here, we dive into the statistics and risks associated with lithium-ion batteries.

www.checkfire.co.uk

And/or does the mAh rating come into the equation?

The mAh rating indicates the amount of charge the battery can store and deliver, ie typically related to how long it will give the necessary voltage before it needs recharging.

If you need more 'oomph' to do the job - drilling or cutting - you really need all of:
A more powerful motor in the tool, which may mean higher voltage
The higher voltage battery to operate the more powerful tool, and
The higher mAh rating for the battery that comes with that.

 

[Telegram Sam]

If you fit a 40V battery to a 20V tool, you will likely destroy one or both, except they ought to have different connections to prevent this!

Lithium batteries and the like store a lot of energy, are potentially dangerous.
They can have safety measures incorporated in them such as temperature sensing and sometimes digital communication between battery and tool. Different manufacturers can adopt different approaches, so circuits can vary, for which reason different brands are typically not interchangeable.

I urge you not to experiment by trying "incorrect" batteries in a product!

Lithium-Ion Battery Dangers: The Stats | Checkfire Ltd.

How dangerous are lithium-ion batteries? Here, we dive into the statistics and risks associated with lithium-ion batteries.

www.checkfire.co.uk

The mAh rating indicates the amount of charge the battery can store and deliver, ie typically related to how long it will give the necessary voltage before it needs recharging.

If you need more 'oomph' to do the job - drilling or cutting - you really need all of:
A more powerful motor in the tool, which may mean higher voltage
The higher voltage battery to operate the more powerful tool, and
The higher mAh rating for the battery that comes with that.

Thanks let me ponder what you have said. It would seem that there isn't a way of getting more oomph from the existing tool / hedge trimmer, under-powered as it is. It seems that it is all a matter of the voltage - and I can't experiment without risking overloading the tool. What I find confusing is where in the description of the replacement batter(ies) it implies dual 20 / 40 V.

 

[Avo Mk8]

Thanks let me ponder what you have said. It would seem that there isn't a way of getting more oomph from the existing tool / hedge trimmer, under-powered as it is. It seems that it is all a matter of the voltage - and I can't experiment without risking overloading the tool. What I find confusing is where in the description of the replacement batter(ies) it implies dual 20 / 40 V.

If the manufacturer is offering a 40V battery for your specific tool as a plug in alternative to the 20V, that's fine.

Is there both a 20V version, and a separate 40V version, of the hedge trimmer, that the 40V battery is for?

There could be dual voltage batteries, designed for different voltage tools - that's a separate topic.

I wanted to emphasise that, unless explicitly stated in the instructions for the tool, it's not OK to just double the voltage of the battery. It could be dangerous.
I would be quite surprised if it would physically fit though!

 

[Avo Mk8]

It seems that it is all a matter of the voltage

Just to pick up on this point, it's really a matter of current.
Depending on the design of the motor, its power is related to the strength of permanent magnets designed into the motor, the winding(s) - (thickness of wire and number of turns etc), how any electronics driving it have been designed etc, and ultimately the amount of current you can put through the system before it starts overheating and destroying itself.
The only way you have to increase motor power "from the outside" is to increase the voltage, which seems what you are motivated to do. But it risks burning out the motor, and anything else in the tool that uses that voltage.
If the motor were to short circuit, the amount of energy in the lithium battery, liberated all at once, can cause a fire or explosion. That's my main concern - your safety!

If you want a more powerful hedge cutter, you need one with a more powerful motor.

Edit - just been looking at the Ferrex 20/40V battery. You can fit it to your hedge trimmer, but the trimmer will still run from the 20V connection, with the same result as at present. The battery may last a bit longer than the ordinary 20V one though.

 

[Telegram Sam]

Thanks for the research / advice. Not what the man from Amazon had to say, but then he was a generalist

 

[Telegram Sam]

Thanks.
To put it bluntly, in layman's language - there is no advisable way for me to get more (torque?) from my 20 V Aldi r/c hedge trimmer (to stop the blade jamming on thin stems) other than to invest in a new hedge trimmer?

I suspect that a 40V device will weigh more than my 20 V one which is a significant consideration - at arm's length - also.

Can't win ..

 

[Avo Mk8]

Thanks.
To put it bluntly, in layman's language - there is no advisable way for me to get more (torque?) from my 20 V Aldi r/c hedge trimmer (to stop the blade jamming on thin stems) other than to invest in a new hedge trimmer?

I found a video where 'Big Clive' reverse engineers the Ferrex 20/40V battery, and it's clear that the battery provides not just a simple electrical source, but that there's digital communication between the tool and battery (and between charger and battery when on charge).
It's more complicated than you might think!
There are two separate battery packs in the 20/40V version, each with a microcontroller monitoring what's going on. I'm pretty sure that for 20V tools, the dual voltage battery just supplies 20V, as if it were just an ordinary 20V battery. So to me there doesn't appear to be any advantage to trying a 20/40 battery in your hedge trimmer.

This will give you a flavour of the technical stuff:

View: https://youtu.be/7b6njqV9nsA?feature=shared

I suspect that a 40V device will weigh more than my 20 V one which is a significant consideration - at arm's length - also.

The 20/40 battery has twice the number of cells in it compared with the 20V version, it's bigger, and will weigh almost twice as much!

Can't win ..

I don't think you can.
If you're mechanically minded, you could try stripping the mechanics of the blades and gearbox, and see if you can reduce friction of moving parts so that little power is wasted, so the motor can give the hedge maximum aggro!

 

[Telegram Sam]

I found a video where 'Big Clive' reverse engineers the Ferrex 20/40V battery, and it's clear that the battery provides not just a simple electrical source, but that there's digital communication between the tool and battery (and between charger and battery when on charge).
It's more complicated than you might think!
There are two separate battery packs in the 20/40V version, each with a microcontroller monitoring what's going on. I'm pretty sure that for 20V tools, the dual voltage battery just supplies 20V, as if it were just an ordinary 20V battery. So to me there doesn't appear to be any advantage to trying a 20/40 battery in your hedge trimmer.

This will give you a flavour of the technical stuff:

View: https://youtu.be/7b6njqV9nsA?feature=shared



The 20/40 battery has twice the number of cells in it compared with the 20V version, it's bigger, and will weigh almost twice as much!

I don't think you can.
If you're mechanically minded, you could try stripping the mechanics of the blades and gearbox, and see if you can reduce friction of moving parts so that little power is wasted, so the motor can give the hedge maximum aggro!

 

[Telegram Sam]

I think your answer + conclusions couldn't be clearer. Tks for saving me a lot of time and expense.

 

[PS Electrics]

Just to pick up on this point, it's really a matter of current.
Depending on the design of the motor, its power is related to the strength of permanent magnets designed into the motor, the winding(s) - (thickness of wire and number of turns etc), how any electronics driving it have been designed etc, and ultimately the amount of current you can put through the system before it starts overheating and destroying itself.
The only way you have to increase motor power "from the outside" is to increase the voltage, which seems what you are motivated to do. But it risks burning out the motor, and anything else in the tool that uses that voltage.
If the motor were to short circuit, the amount of energy in the lithium battery, liberated all at once, can cause a fire or explosion. That's my main concern - your safety!

If you want a more powerful hedge cutter, you need one with a more powerful motor.

Edit - just been looking at the Ferrex 20/40V battery. You can fit it to your hedge trimmer, but the trimmer will still run from the 20V connection, with the same result as at present. The battery may last a bit longer than the ordinary 20V one though.

bigclivedotcom on YouTube did a tear down of a lot of the Aldi Ferrex stuff. The 20/40v battery is two 20v batteries in one pack. The 20v tool when plugged into the 20/40v dual battery will use both 20v batteries in Parallel thus doubling the Ah available. This just means the tool will run effectively twice as long.

 

[PS Electrics]

bigclivedotcom on YouTube did a tear down of a lot of the Aldi Ferrex stuff. The 20/40v battery is two 20v batteries in one pack. The 20v tool when plugged into the 20/40v dual battery will use both 20v batteries in Parallel thus doubling the Ah available. This just means the tool will run effectively twice as long.

You beat me to it!

 

[PS Electrics]

Thanks.
To put it bluntly, in layman's language - there is no advisable way for me to get more (torque?) from my 20 V Aldi r/c hedge trimmer (to stop the blade jamming on thin stems) other than to invest in a new hedge trimmer?

I suspect that a 40V device will weigh more than my 20 V one which is a significant consideration - at arm's length - also.

Can't win ..

Maybe consider this article on choosing a battery powered Hedge trimmer.

Is 20V Sufficient for a Hedge Trimmer? - Redway Power™

While 20 volts may not match the raw power of higher options, it remains a suitable choice for many homeowners, offering a balance of power and convenience.

www.redwaypower.com

This bit might be of use


Voltage Level Cutting Capacity (inches) Runtime (minutes)

20V Up to ¾ Approximately 30-45

24V Up to 1 Approximately 45-60

40V Up to 1.5 Approximately 60+

 

[Telegram Sam]

Thanks, very appropriate!