Quality of Batteries

[Farside]

The Aldi 20/40v batteries are very good, some of mine are four plus years old and showing no signs of weakening Fakita batteries seem to be a bit of a lottery, I stumbled across the Yofidra brand of tools and batteries, they seem to be as good as you can get.

Bob

@8ob
I've just discovered a Belfast distributor of these batteries.
Are you using a Makita charger, or one that comes with them?

 

[Turbo]

Quite a few of the fake batteries use recycled laptop cells.
Unfortunately they are not suitable for power tool use. Yes they are 18650 cells but internally different.

The maximum output discharge rate is called the c rating

A laptop cell is designed to give a steady lower amp output over 1 or 2 hours and has a low c rating.

A power tool cell is designed to give maximum output for a short period so has a high c rating.

There are smart batteries out there where you can alter the c rating with an app depending on what you need it for.

 

[Turbo]

I have used parkside cells to recell power tool batteries with good success.
The bare cells always test better than their rating, a 2Ah usually tests at between 2.1 and 2.2 Ah.

A Samsung or LG cell usually tests at its rating.

I've tested the batteries after quite a lot of use and they are still measuring at the same output.

 

[Turbo]

DO NOT use dewalt batteries with non genuine tools or adapters.

There is no under voltage protection in the battery and using it in anything other than in a genuine dewalt tool can completely flatten the battery and likely render it scrap.

Makita batteries have the protection in the battery and are safe to use with adapters in other tools.

Parkside x20v batteries are protected though there are folk online who claim they are not. I have used them with adapters on non parkside tools and they cut out when they get to minimum voltage.

 

[8ob]

@8ob
I've just discovered a Belfast distributor of these batteries.
Are you using a Makita charger, or one that comes with them?

I use the charger that came with the batteries, its nothing special. I will take a snap of it.

Bob

 

[J1nx]

You can’t simply go by pack manufacturer, the internal cells will vary depending on capacity, even within the same capacity they may vary depending on what’s available at the time.

Makita are generally favoured for knock-off tools and in the ‘makers’ world as they have better protection than the other brands. They have also been hacked now so you can simply build a little Arduino rig and get full diagnostics, I made one up for a couple of quid a few weeks back…

For 2 string batteries the 5Ah (these contain Sony/Murata VTC5 cells) is a good battery, better discharge capacity than the 6Ahs (VTC6 cells) but the 9 and 12 obviously have even more output power capacity by having extra parallel strings. The 12Ah LXT will give about 2200W, only bettered by the 40V XGT 8F (VX40 cells) battery that can potentially do over 3.5kW output.

 

[Turbo]

You can’t simply go by pack manufacturer, the internal cells will vary depending on capacity, even within the same capacity they may vary depending on what’s available at the time.

Makita are generally favoured for knock-off tools and in the ‘makers’ world as they have better protection than the other brands. They have also been hacked now so you can simply build a little Arduino rig and get full diagnostics, I made one up for a couple of quid a few weeks back…
View attachment 529172

For 2 string batteries the 5Ah (these contain Sony/Murata VTC5 cells) is a good battery, better discharge capacity than the 6Ahs (VTC6 cells) but the 9 and 12 obviously have even more output power capacity by having extra parallel strings. The 12Ah LXT will give about 2200W, only bettered by the 40V XGT 8F (VX40 cells) battery that can potentially do over 3.5kW output.

Do Makita use 18650's in all their LXT batteries? I've never had anything bigger than a 6Ah apart.
I thought that they might use the 21700 in the bigger capacity batteries like other makers.

I have heard a few complaints about the 6Ah Makita not being any better than the 5Ah, that explains it.

 

[J1nx]

Yes, all the LXT’s are 18650, even the brand new ones. I assume it’s because they have designed so many tools with battery compartments or slots that won’t allow any additional width. The 2x18V tools are almost all two batteries with a fag paper between them that the small increase in width for 21700’s would be incompatible.

The new 9 & 12 were resisted for so long by Makita as they aren’t 100% compatible due to extra depth but at least they work on most tools.

They were forcing people to XGT 40V if they wanted tools to compete with Milwaukee HO but it wasn’t working great as XGT is a price point higher. IMO the XGT packs are the best power tool battery on the market, by some way, but consumers don’t really see the extra value so won’t pay for it.

Milwaukee went 21700 and tabless construction in the 18V, keeping compatibility and price down, at the expense of stuff customers don’t see, like the huge currents required, no balancing, less protection and more basic BMS/diagnostics.

The CXT (10.8V) range now has, I believe, a 21700 based battery but it’s impossible to get over here for sensible money despite being out in Japan for a while.

 

[Turbo]

Milwaukee went 21700 and tabless construction in the 18V, keeping compatibility and price down, at the expense of stuff customers don’t see, like the huge currents required, no balancing, less protection and more basic BMS/diagnostics.

Yet to work on a Milwaukee battery.
But what you are saying surprised me. Surely for high performance pro tools like Milwaukee they need the batteries well balanced and protected.
This will mean reduced battery longevity.
How are they joined if they are tabless?

 

[colnerov]

 

[J1nx]

Yet to work on a Milwaukee battery.
But what you are saying surprised me. Surely for high performance pro tools like Milwaukee they need the batteries well balanced and protected.
This will mean reduced battery longevity.
How are they joined if they are tabless?

Most don’t balance, tbh it seems to make less difference than most people think, just shortens the number of cycles with less effect on high quality cells. All these will be some form of NMC chemistry and with balancing they could get to about 2000 cycles with 80% capacity, realistically without balancing and in tool pack environments I think 500 cycles would be good going and perfectly reasonable. It’s definitely nice to have and does reduce the risk of thermal runaway if a weak cell is detected rather than masked and overcharged.
Even some EVs don’t balance, think the Leaf was famous for it.

The cell caps are effectively the same, just the electrode inside is continuously in contact (tabless) or just a tab which limits performance. They will run much cooler at the same current which is handy as at end of discharge on high drain tools the current is rising and will often trigger thermal cut-off before it’s fully depleted.

 

[eddie49]

How are they joined if they are tabless?

The tabs in question are not the external nickel strips spot-welded or soldered onto the cell. They are internal, made of aluminium or copper, and connect the "swiss roll" inside to the metal case and the end-cap.