odd?

[Phil Pascoe]

I've just bought a 4ah Milwaukee battery. I thought it didn't seem any larger than the 3ah I'm used to so I put them side by side - exactly the same, bar the labelling. I weighed them - both 717g.

 

[Myfordman]

It's not unusual for some cell brands to add weight to their lower capacity cell to make them "feel" right in the hand.
I've also seen some BigClive tear-downs where products have lumps of steel inside for greater gravitas.

 

[Phil Pascoe]

If that's the case it's very carefully done to get them matched to the gramme.

 

[paulrbarnard]

Might just be improved cell technology or a relaxation of the charging parameters for the cells

 

[Terry - Somerset]

It seems that establishing the state of charge of a battery is complex and subject to estimation. I am not an electrical engineer so take this at face value!

One way to confirm whether one battery has a greater capacity than another would be to place it under load. See how many (say) 6" screws can be fully inserted and unscrewed into a piece of timber. The battery with the greater capacity should, I assume do 33% more cycles.

 

[dizjasta]

Hi all I use this load tester to keep an eye on my Makita 18v batteries. The tester is connected using small electrical spring clips and M12 washers pushed into battery terminals.

 

[ColinDeVelen]

A Samsung 20R cell and a Samsung 25R cell are both the same size (18mm diameter, 65mm long). One is a 2Ah cell, the other is a 2.5Ah cell. They are both approx 4V fully charged. Connect 5 20R in series and you have an 18V 2Ah battery pack. Connect 2 of those in parallel and you have a 4Ah 18V pack. Do the same with the 25R and you have a 5AH 18V pack.
The same holds true for LG HD2 and LG HE2 respectively.
(can't say for certain about the torn down packs mentioned, but the steel could also have been for thermal transfer. Other packs may well do the same using thermally conductive paste.)

 

[TheUnicorn]

I guess they choose the chemistry / cells to best suit the casing, more econimical to use the same casing for multiple capacities, thats what it looks like from the website, I notice the current generation has the 2 and 3 AH the same size and 4 and 5 the same. Also saw they have an 28v range, which I've never heard of before

https://uk.milwaukeetool.eu/en-gb/cordless/batteries-and-chargers/batteries/

 

[Phil Pascoe]

My 2ah are two years old, the 2ah and newer 3ah are different sizes. The 3ah that I have that's the same size as a new 4ah is probably a year or so old.