8 min read
Bottom line
The Milwaukee 48-59-1818 charges four packs at the same time instead of queueing them, with two M18 bays and two M18/M12 hybrid bays. Milwaukee rates four FORGE HD12.0 packs at 100% in 90 minutes. It bolts into a PACKOUT stack, so the crew's charging station travels.
What the 48-59-1818 does differently
The Four Bay Simultaneous Super Charger fills all four bays at the same time rather than working through packs in a queue. Milwaukee rates it at up to 10x faster charging for four packs, and quotes four M18 REDLITHIUM FORGE HD12.0 batteries at 100% in 90 minutes. A single FORGE XC8.0 or FORGE HD12.0 pack takes a 35 minute supercharge to 80%. CHARGE ADAPT splits current across the bays, and the COOL-CYCLE active cooling system pulls heat out so packs keep moving instead of sitting in a cooldown hold.
| Spec | 48-59-1818 Four Bay Simultaneous Super Charger |
|---|---|
| Bays | (2) M18, (2) M18 and M12 hybrid |
| Charging behavior | Simultaneous across all four bays |
| Four FORGE HD12.0 packs to 100% | 90 minutes |
| Supercharge to 80%, FORGE XC8.0 or HD12.0 | 35 minutes |
| Cooling | COOL-CYCLE active cooling system |
| Charge distribution | CHARGE ADAPT adaptive distribution |
| Power source | AC |
| PACKOUT | Modular connectivity with PACKOUT components |
| Size | 10.12 x 15.47 x 9.53 in |
| Weight | About 11 lb |
| Housing | Polycarbonate |
| Warranty | 5 year limited |
Every charge figure above is a FORGE figure, which tells you what the charger was built around. It ships bare, no packs, and it's in stock at Red Tool Store at under $500.
Simultaneous vs sequential on a four battery crew day
Here's the bottleneck nobody prices into a tool budget. A crew running rear handle saws, SDS Max hammers and M12 ratchets off the same pack pool ends the day with four dead batteries and one charger. Sequential charging means the fourth pack doesn't start until the first three finish, so the charger is still working when the first truck rolls out. Simultaneous charging starts all four together and turns the overnight window into one cycle instead of four back to back.
| Charging setup | Batteries ready by morning | Bench space |
|---|---|---|
| One sequential charger, four dead packs | Packs finish in order, so the last one is still charging while the earlier ones sit idle | One charger, plus a pile of packs waiting their turn |
| Four separate single-bay chargers | All four charge together, but you're tracking four cords and four outlets | Four footprints, four plugs, four things to pack out at the end of the job |
| 48-59-1818 Four Bay Simultaneous Super Charger | All four bays run as one cycle. Milwaukee rates four FORGE HD12.0 packs at 100% in 90 minutes | One 15.47 in wide unit that stacks into PACKOUT instead of covering the bench |
The middle row is the one most crews end up living with, because buying more chargers is the obvious fix. It solves the queue and creates a cord problem. One four bay unit keeps the plug count at one and the packs in a single place, which matters most in a van or a gang box where bench space is the scarce thing.
Two M18 bays, two M18/M12 hybrid bays
Milwaukee splits the deck into (2) M18 bays and (2) M18 and M12 hybrid bays. A mixed-platform crew can drop two M12 packs and two M18 packs into the same unit, or fill all four with M18 when nobody's working off the small platform. Plumbers with M12 ratchets and M18 hammers, and electricians running M12 in the pouch and M18 on the cart, stop keeping two separate chargers alive.
If you're still sorting out which packs belong on the truck in the first place, the Milwaukee M18 battery comparison walks the lineup by capacity and physical size. Pack choice drives everything downstream: how many the crew needs, how often they come back dead, and how much charger you have to own.
PACKOUT mounting and where the charger lives
Milwaukee lists modular connectivity with PACKOUT components, so this charger stacks into the same tower as the boxes it feeds. It measures 10.12 by 15.47 by 9.53 inches and weighs about 11 pounds, so it rides as a normal stack member rather than a shop fixture. Power is AC, which means wherever the tower lands, it still needs an outlet or a power source at the end of the day.
Pairing it with FORGE packs
Both published charge figures are FORGE figures: four M18 REDLITHIUM FORGE HD12.0 packs to 100% in 90 minutes, and a 35 minute supercharge to 80% for a FORGE XC8.0 or FORGE HD12.0. That's the pairing this charger was designed around. The same HD12.0 pack is what Milwaukee quotes for over 24 holes at 7/8 in by 6 in with the 2917-20 SDS Max hammer, and up to 700 cuts per charge with the 2931 rear handle saw.
In other words, the packs doing the heavy work are the packs this charger turns around fastest. The Milwaukee FORGE battery series guide covers that family in more depth if you're deciding how many FORGE packs a crew actually needs.
Where it sits in the rest of the charging lineup
Plenty of the 2026 kits still ship with the M18 and M12 Rapid Charger. The 2917-22HD and 2918-22HD SDS Max hammer kits include one, and so do the 3026-21HD and 2931-21HD rear handle saw kits. That charger is fine for a one tool, two pack setup. The four bay unit is what you buy on purpose once a single charger stops keeping up with the crew. Our Milwaukee charger comparison lays the rapid and super chargers out side by side.
There's a fleet angle too. The ROLL-ON 7200W/3600W 6.0kWh power supply runs pass-through power, charging and discharging at the same time, and puts current out through two 20A GFCI duplex outlets. An AC charging station on the other end of that cord keeps working while the power supply itself takes a charge. On a gut remodel where the panel is dead, that's how full packs still show up in the morning.
Key Takeaways
- The 48-59-1818 charges four packs at once instead of working a queue, with (2) M18 bays and (2) M18 and M12 hybrid bays.
- Milwaukee rates four M18 REDLITHIUM FORGE HD12.0 packs at 100% in 90 minutes, and a 35 minute supercharge to 80% for a FORGE XC8.0 or HD12.0.
- COOL-CYCLE active cooling and CHARGE ADAPT distribution handle the heat and the current split across bays.
- Modular PACKOUT connectivity means the charging station stacks and travels with the boxes.
- AC power, about 11 lb, polycarbonate housing, 5 year limited warranty.
Does the Four Bay Super Charger really charge all four batteries at once?
Yes, that's the point of the 48-59-1818. All four bays run at the same time rather than working through packs in order, and CHARGE ADAPT distributes current across whatever's sitting in the deck. Milwaukee rates four M18 REDLITHIUM FORGE HD12.0 packs at 100% in 90 minutes, and lists the charger at up to 10x faster for four packs.
Can it charge M12 batteries too?
Two of the four bays are M18 and M12 hybrid bays, so yes. You can run two M12 packs beside two M18 packs, or fill all four bays with M18. For a plumber carrying an M12 ratchet and an M18 hammer, or an electrician split across both platforms, that's one charger instead of two.
How fast does it charge a single battery?
Milwaukee publishes a 35 minute supercharge to 80% for the M18 REDLITHIUM FORGE XC8.0 or FORGE HD12.0 battery. The four pack figure is 90 minutes to 100% with FORGE HD12.0 packs. Both numbers are measured with FORGE batteries, which is the family this charger was designed around.
Does it mount to a PACKOUT stack?
Yes. Milwaukee lists modular connectivity with PACKOUT components, so the charger stacks with boxes, crates and organizers instead of living loose on a bench. At 10.12 by 15.47 by 9.53 inches and about 11 pounds, it behaves like any other mid-size stack member and travels with the rest of the tower.
What powers the charger?
AC. It plugs into a wall outlet, a generator, or a portable power supply. The ROLL-ON 7200W/3600W power supply runs pass-through power, charging and discharging at the same time through two 20A GFCI duplex outlets, which is one way to keep a charging station alive on a site with no permanent service yet.
Is it worth buying if my kits already came with a rapid charger?
Depends on how many packs come back dead. A rapid charger handles a one tool, two pack setup fine. A crew running saws, hammers and ratchets off a shared pack pool hits the queue every single night, and that queue is the problem the four bay unit removes.
What warranty does the 48-59-1818 carry?
Milwaukee backs the charger with a 5 year limited warranty. The housing is polycarbonate and the unit weighs about 11 pounds, so it's built to ride in a stack rather than sit on a shop shelf. Battery warranty terms are separate from the charger's and follow whichever packs you're running.
Does the charger come with batteries?
No. The 48-59-1818 ships as the charger only, with PACKOUT compatibility built in, and it's in stock at Red Tool Store. Packs are sold separately. Since every published charge figure is measured with FORGE batteries, FORGE XC8.0 and HD12.0 packs are the ones that show the numbers Milwaukee quotes.