New for 2018 is varying battery capacity. We have 3Ah, 4Ah and 5Ah packs. Bigger packs will take longer to charge from empty. The capacity is on the cell label next to the yellow connector.
Each pack has a sliding indicator on the side. This is entirely manual, but is very useful for indicating when a pack is known to be charged, flat, or partly discharged. Slide the slider to show green for full, red for flat, half and half for 'partly used'.
This is blue charger with 3 LEDs, and diagrammatic charging info on RH side. CHarges at up to 100W.
This is the set of 3 (2 half-width) chargers made from old Makita chargers. They have a set of 4 LEDs. (The full-width one only has 1 LED in 2018). Charges at 40W.
This is black all-purpose charger with blue LCD display. CHarges at up to 50W
The Yellow Propeak chargers do the same job, and insturcuctions are similar, but have no fan, no backlit display, and if pack is low voltage will charge at C/10 (10% of normal) until voltage rises sufficiently. Ensure that charge rate is set to 4000mA otherwise charging will be very slow. Charges at up to 50W (5W in C/10 gnetle start).
Simplest it try to charge it again and find that it says it is done in a couple of minutes (Up to 4 mins on the balance chargers). This may 'waste a life' on batteries that still work on the Makita charger. Checking it on the RC charger will not waste a life. It will quickly rise to 16.4V, and the current drop to 0.1A or so. That indicates a full pack. It will tell you so after a while (1-5 mins).
The drill batts are 4S2P 14.4V lithium ion packs (8 18650 cells: 4 in series, each being a parallel pair). This means that they are charged as 4-cell packs, to 4.1V per cell-pair. They can be charged at up to 3A rate. Battery 1 has connector wired as balance connector. No other packs have this yet (2017). The official Makita packs use Sony SE US18650VT (1.5Ah, 20A high-drain) cells, and we have a few with with Samsung INR18650-13Q (1.3Ah high-drain cells). All give a reliable 2.3-2.6Ah capacity in practice, even after 9 years expo useage.
At end 2017 we bought two 4Ah packs. The non-makita one uses LG DAHD21865 cells (2Ah, 25A). I can't read the Makita cell type without unwelding the pack. For 2018 we made 3 new 5Ah packs from Samsung 25R cells (2.5Ah, 20A) (Sponsored by uk18650.com).
The drill discharges at 26A current draw when drilling (~400W), so that's 13A per cell in a 2P configuration.
Makita have put very 'conservative' software in the batteries which will stop them working on the Makita charger, even when they are in fact fine. The monitoring board is powered off the 1st cell pair so that one tends to get discharged more than the others when left sitting for the 11 months of not-expo. If an unbalanced (or over-disharged, or too-hot) pack is inserted into the makita charger the charger and battery will do serial-coms negotiation, the charger will refuse to charge the battery and the battery will remember this. If you try this 3 times, the battery will mark itself bad and will never charge again on a makita charger. Only a replacement monitoring board can fix this (or new software if we knew how to nobble it).
Such batteries are normally still fine and charge on a sensible (RC - Radio Control, because RC people are the main market for these chargers) charger, possible after a balance charge to get the cells in the pack in sync again. Expo has a couple of these (Yellow Pro-power Prodigy II). Unfortunataly Makita don't build the 14.4V packs with balance connections to the cells, so the PCB has to be replaced to make this work easily for expo. For 2018 this was done for 7 of our packs, and 3 automatic balance chargers built.
Note that the drills have no battery-voltage monitoring at all, and the monitoring circuit is bypassed when conected to the drill (the charger uses a different connector-pair from the drill - that's why there are 3 slots). Thus the drill can easily be used to over-discharge a battery, so please stop drilling when it gets slow and put on a new batt, unless it's an emergency. Drilling with an excessively-sagged voltage is a good way to knacker the weakest cell-pair. If your battery does get to this state, try to charge it up as soon as possible. Cells must not be left at <2V for any length of time as they rapidly (hours/days?) degrade to useless in this state (and that pair will need replacing).