Liftmaster K79-40370, CONTROL BOARD, BATTERY CHARGER
The LiftMaster K79-40370 battery charger control board is used in gate operator systems that require a dedicated charging circuit for backup batteries. A failed charger board can leave batteries undercharged, overcharged, or unable to support the operator during power interruption. Because this part works with the operator electrical system and battery circuit, correct board identification is important. It is commonly associated with SL920, SL930, and select perimeter access systems, but it should always be verified against the parts diagram and the board installed in the control enclosure.
Compatible With
Common Compatible Models
- LiftMaster SL920 gate operator applications where K79-40370 is specified
- LiftMaster SL930 gate operator applications where K79-40370 is specified
- Select Elite automated entry and perimeter access systems using this battery charger board
Important Compatibility Notes
This is a battery charger control board, not a main logic board. Verify the existing board number, battery system, and operator wiring diagram.
Features & Specifications
| Feature / Specification | Details |
|---|
| Manufacturer | LiftMaster / Chamberlain Group |
| Product Type | Battery charger control board |
| Part Number | K79-40370 |
| Application | Battery charging circuit for select gate operator systems |
| Compatible Operator Type | Select commercial gate operators and perimeter access systems |
| Common Model References | SL920, SL930, and related Elite automated entry systems where specified |
| Notes | Match original board and charging circuit before ordering |
Also Known As / Related Part Numbers
- K79-40370
- 79-40370
- LiftMaster K79-40370
- Battery charger control board
- Control board, battery charger
Technician Note
If batteries are not charging, test the battery condition, transformer/AC input, wiring, fuse protection, and charging output before replacing the board. A weak or shorted battery can make a good charger board appear faulty.
Before Ordering Checklist
- Confirm the existing board is the battery charger board, not the main control board.
- Match the original part number to K79-40370.
- Verify the operator model and parts diagram.
- Inspect batteries, wiring, fuses, and transformer output before replacing electronic parts.
Important Ordering Warnings
- Do not bypass battery charging circuits or install batteries with the wrong voltage or capacity.
Professional Advisory
Battery charger board replacement involves electrical diagnosis. If high-voltage input or unsafe wiring is present, have a qualified gate technician service the operator.
Product Questions and Answers
Is K79-40370 a main control board?
No. It is a battery charger control board used in select gate operator and perimeter access systems.
Which models is it commonly associated with?
It is commonly referenced with SL920, SL930, and select Elite automated entry systems where the parts diagram calls it out.
What symptoms can point to a charger board issue?
Dead backup batteries, poor charging, battery fault behavior, or loss of backup function can point to charger, wiring, transformer, or battery problems.
Should batteries be replaced with the board?
Only if testing shows the batteries are weak, shorted, swollen, or unable to hold charge.
Can this board replace any LiftMaster charging board?
No. It must match the original part number and operator wiring diagram.
