Makita 3 and 4 Amp batteries interchangable??

[<Toiler]

Hello, I have several Makita LXT 18V tools, some of which are about 8 yeares old and their batteries (all 3 Amp) are not holding their charge as well as they did. I was thinking of replacing the batteries with the 4 Amp ones but the Makita site says that only those tools with a star stamped on where the battery connects are OK for 4 Amp batteries. None of mine, bar a recent purchase, have said star.

Now its over 50 years since I did A-level physics but I seem to recall that the load would limit the supplied current to what it required so why can't I use a 4 Amp battery on my tools?

Anybody care to explain please?

Regards, Toiler

[Andy Burns]

I think the star is about the tool and battery talking to each other over some extra pins on the connector.

All my LXT tools have the star and I don't have any batteries greater than 3Ah, so I can't tell you anything about what might happen if you try an 4Ah or larger battery on a non-star tool ...

[The Natural Philosopher]

MIGHT be vagaries of the charging circuitry. But otherwise your understadning is correct.

[Andy Burns]

However there are plenty of websites out there that say Makita LXT tools without either a star or a yellow connector are restricted to 1.5 or

3.0Ah LXT batteries

[The Natural Philosopher]

Its an odd thing, but there are very few authoritative sources on the net. Largely they repeat the same stuff they got elsewhere.

Usually without crediting it.

so a false idea can be supported in millions of sites, all of whom cite each other for support.

Cf Climate change...

I've used electric motors and batteries extensively, and there is no logical reason not to put a higher capacity battery in a tool. Unless there is a charger that cant handle it.

Or of course the more mundane reason, that they want you yto buy a new tool to take advantage of the better battery.

[Andy Burns]

A lot of that goes on, but there are official makita sites that say what to look fo r (yellow or star) to ensure tools will work with batteries larger than 3.0Ah, e.g.

So the information seems correct, just that there's no explanation *why* the change, given the problems that badly treated LiIon batteries can cause, the probably didn't want to say too much if there was a potential future liability issue.

But they say don't use it with the tool, rather than don't use it with the charger, in fact they say any LXT charger can charge any LXT battery.

They've altered a "tab" to prevent the new batteries fitting the old tools, ok some people talk of filing the tab off so it fits, and it working.

Given that it's in their long term interest to maintain as wide as possible compatibility between tools and batteries, rather than make a quick buck selling a few extra batteries and pissing-off customers, there must have been a reason for the change, such as adding or moving protection circuit between tool and battery?