








🔋 Twist, Disconnect, and Drive with Confidence!
The Ampper Side Post Battery Disconnect Switch is a robust 12V, 125A-rated rotary switch designed for GM side post batteries with a 3/8" terminal. Featuring a corrosion-resistant brass contact and a user-friendly knob, it allows quick battery isolation to prevent power drain and enhance safety for cars, boats, RVs, and ATVs. Compact and easy to install, it’s the essential upgrade for any professional seeking reliable battery management.








| Operation Mode | Off,Twist |
| Current Rating | 125 Amps |
| Operating Voltage | 12 Volts |
| Contact Type | Mechanical |
| Connector Type | Screw Terminal |
| Brand | Ampper |
| Terminal | Blade |
| Item dimensions L x W x H | 3.9 x 1.5 x 1.5 inches |
| Circuit Type | 1-way |
| Mounting Type | Panel Mount |
| Actuator Type | Rotary |
| Contact Material | Brass |
| International Protection Rating | IP65 |
| Number of Positions | 2 |
| Control Method | Touch |
| Connectivity Protocol | X-10 |
| Color | Side Post |
| Unit Count | 1 Count |
| Number of Items | 1 |
| Manufacturer | Ampper |
| Model | Am-CBS31 |
| Item Weight | 5.3 ounces |
| Product Dimensions | 3.9 x 1.5 x 1.5 inches |
| Item model number | Am-CBS31 |
| Is Discontinued By Manufacturer | No |
| Manufacturer Part Number | Am-CBS31 |
| Special Features | Used for car battery systems, compatible with GM side post batteries, disconnects the battery safely, eliminate any power draw from the battery when vehicle or boat is not in use, isolate and secure the electrical system |
| Voltage | 12 Volts |
R**R
It works well.
Battery position made it a bit difficult to install but that’s not the products fault. It’s well made and it works as it should.
P**.
Good quality
Well made works as designed. I installed it on my travel trailer. Only needed one gave the other one to a friend with same trailer and battery set up.
F**R
Works good
They work good and do the job they claim. There is no stainless steel as claimed or brass in them. SMJ 25
K**C
Very sturdy.
These work very well for anything that has a parasitic drain. Also theft prevention.
L**R
Poor Quality Is Apparent Over Few Months' Time
I use many of these type of battery disconnects in my fleet of vehicles. Some of these disconnects have been in place for many years and all have provided excellent service. This one is, however, not up to par. Poor quality becomes apparent quickly as individual parts separate (not just the knob/screw). Specifically, the "sandwich" of the two metal pieces with the plastic insulator in the middle separates when you turn the knob to break the circuit allowing the two metal pieces to touch one another thus reestablishing the circuit. So, the only way to reliably break the circuit is to remove the screw knob completely and separate the plates from each other which is, of course, an absurd "solution" to the problem. Further, even if one were to accept this significant product flaw, now that the parts are separated from one another, it becomes that more difficult to reinstall the screw knob especially given limited space around most batteries. Additionally, on a separate matter, I worry that electrical contact will be lost between hardware that attaches to the battery and battery itself due to poor design (bolt loosens too easily) -- should this occur while running the engine, alternator damage will occur. I will now try to modify and fix various problems if I can not find a quality disconnect to replace this one. Very poor experience. Seems like another example of a Chinese-manufactured product done poorly.
J**D
Functions
Didn’t fit what I wanted it to. Drilled the hole bigger for my jet ski and it worked after that.
R**A
You got one shot
Metal is weak and the threads were messed up within an hour of working. Do it right because if you don’t, the threads won’t hold up. I accidentally cross threaded one of the bolts. It didn’t even take that much.
A**R
A MUST FOR CAMPER BATTERYS
USE IT ON CAMPER
Trustpilot
3 days ago
5 days ago