Makita XT257M review (DC18RC XPH07Z XDT08Z BL1840)

DC18RC battery charger

The DC18RC battery charger that was included is a bit odd.
The first thing you are likely to notice is that it advertises a different charge time for the different battery capacities. As none of the charge rates appear to exceed the 18 V / 9 A output shown on the bottom, I am not really sure why. There are a number of possibilities, but none really make sense in this context. Presumably is has something to do with heat dissipation, as it always does, but the tools should draw more current, and they don’t have fans.
After charging my battery, the battery seemed to be at room temperature but I found the charger case to be quite hot. I don’t have a thermometer on me but I can say it was significantly hotter than any charger I have ever used, and use mostly Chinese knockoffs to charge my LiPos. As a result, I decided to open the case.
DC18RC_450px

Although the case contains a fan, it is isolated and only blows air through the battery. In addition the airholes on the charger only access the area inside the red lines where the fan is. All of the FETs and power circuitry on the charger are effectively cut off from any air circulation. My mind is boggled.

DC18RC internals

The red line denotes isolation from outside air. The Al sinks would almost be better off painted black and relying on radiative dissipation.

This could be because dusty environments are expected, but if that was the case I would expect the battery would get dust blown into it from the fan. Interestingly, the fan has, what is possibly a filter(?) on the blower output. It doesn’t seem like it would filter much so it may just be to prevent screws from falling down into the fan. Either way, the lack of anything on the input side of the fan makes me worry that dust would just get backed inside the fan.

centrifugal fan in DC18RC

Not shown: The other side of the centrifugal fan which has no filter.

Other Componets

So far the drill seems awesome. I will update after more usage if I don’t forget.

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