BL1013 battery for Makita tools

Today I'm writing about how a friend of mine ordered batteries for Makita on AliExpress, and how it all turned out.


I won't go into the details of what, why, and how. I just want to point out how sellers pass off one thing as something completely different.

Each battery comes not only in its own little box and bag, but also with an instruction manual.


It looks like a standard BL1013 battery. I think anyone who uses this brand's tools will recognize it.


It has some markings, including “For MAK-BL1013,” but of course nobody expected these batteries to be genuine at this price. What mattered to me was that the capacity was listed in both Ah and Wh—that's why they ended up in my hands.


There are five contacts on the end: two power contacts and three auxiliary ones.


It's fairly easy to take apart: use something like tweezers to release two of the three clips, then pull out the cells. The end of the pack is protected by a soft insert. Underneath is a connecting strip which, as it turned out, is thinner than the one usually used.
The cells have no capacity markings, just a name and the battery's manufacture date: June 2020.


At the other end of the pack is a board with the contact group. The battery has no protection circuit, but it does have balance leads and a thermistor contact. The two balance contacts are protected by 10 kΩ resistors.


To my surprise, the battery was reasonably well balanced, although the cells probably just have similar characteristics, since it's unlikely anyone balanced them deliberately.
While I was at it, I measured the thermistor resistance at room temperature: 17 kΩ.


The pack's total impedance is 52.7 mΩ. Subtracting the connecting contacts and wires leaves about 15 mΩ per cell, which is actually pretty good.


Since the battery came to me because of capacity issues, I hooked it up to an EBC-A10H battery tester and started testing.


The first thing that looks odd is that it charges at 1.5 A for an hour.


And it discharges accordingly. I tested it at load currents of 0.2, 0.5, 1, and 2C, as well as 10 A, where C = 3 A.
So instead of the 2–2.5 Ah you often get from clones, the actual capacity is a measly 1.4 Ah. In other words, it delivers less than half the claimed capacity.


I wouldn't call the heating minor, either. At 10 A, the battery case heats up to over 50 degrees.


So, what can we say?
No complaints about the appearance: it looks neat, and the plastic is decent. But this huge discrepancy in capacity completely wipes out any positives.
And here's the curious part: the product reviews (it's no longer for sale) are 100% positive. How?


There was one more small problem: I'd already confirmed the order.
Anyway, I wrote to the seller and attached photos of the test results. In response, he asked for a photo of the battery markings, so I sent that too. The next day, the seller replied (he's very quick to respond, by the way) that he was waiting to hear back from an engineer. But just a few minutes later, he said he was willing either to refund some money or give me a discount on my next order. I said I was opening a dispute to get a 50% refund for the missing capacity, and went ahead and opened one. Now I'm waiting for a decision.