Tool systems

[John Rumm]

They could in theory - in practice they standardise around a couple of common cell form factors.

[John Rumm]

I get the impression they were waiting for patents to expire, rather than license them like Hitachi / Hikoki did...

[Theo]

P=V^2/R. For a given motor winding resistance you get power to the square of the voltage. The winding resistance is set by the physical size of the tool - don't want to add 4x the copper to achieve the same power.

So makes a lot of sense to have a higher voltage.

Again, you're limited by the physical cells. 18650s go up to ~3.5Ah, 2170 to ~5Ah. An 18v pack is 5s, a 36v pack is 10s. You have to get the right number of cells and you can only have 1p, 2p, etc. A few types use pouch cells (Dewalt Powerstack) but they're not too common (perhaps more expensive or not so good for cooling, apparently they can grow/shrink 10% in use?).

Theo

[charles]

This "same size" saved me having to go out and buy a load of tools.

There are unbranded batteries on ebay which fit Ryobi tools and seem to work well.

[charles]

I've been using Ryobi +One for many years. Very happy with them.

[Sam Plusnet]

Make it 5. From EGO, I only have the 56v mower (but 2 batteries, 2.5AH and a 5AH). Oh I have 5 18V 5AH Makita batteries shared amongst 6 Makita 18v tools.

[Andy Bennett]

How's your EGO batteries holding up? I only have 1 6Ah one that was supplied with the mower. It's over 7 years old now and still seems no loss of capacity - well chuffed.