Updated March 06, 2021 by Will Rhoda

The 9 Best 12V Battery Isolators

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This wiki has been updated 7 times since it was first published in October of 2018. If you own a truck, boat, RV or ATV that uses dual batteries, you may have noticed that when one of them drains or fails, it negatively impacts the performance of the other. These 12-volt isolators will allow you to charge both batteries simultaneously so that ancillary features, like car stereos, winches and complex navigation equipment, don’t decrease your battery life. When users buy our independently chosen editorial picks, we may earn commissions to help fund the Wiki. If you'd like to contribute your own research to the Wiki, please get started by reviewing this introductory video.

1. Aopec R12140B

2. JayCorp Dual

3. WirthCo 20092

Editor's Notes

March 02, 2021:

We spent a while digging through our existing choices, and eventually determined that most of them were still good picks for the category, but we did end up doing away with the Install Bay 5841730504, noting that it closely resembled some of our other relay-based choices, and noticing that it’s no longer listed on the company’s website — which led us to wonder whether this model might be facing discontinuation.

We also put some serious thought into axing the Zoostliss Cut Off and Audew Disconnect Switch, as neither of these options are actually isolators, with both essentially being simple kill switches. However, we decided that these picks were still worth including at the bottom of our list, for the benefit of users on a budget who don’t mind using devices like these to manually disconnect their secondary batteries when they’re not in use. That being said, the utility they offer is nothing close to some of the smart options higher up on our list, so please don’t think that we’re suggesting a disconnect as an apples-to-apples alternative to an isolator.

We added the NewishTool Switch Charge to our list, and it first caught our eye with its sleek, metallic housing, but what really held our attention was its integrated voltmeter, which takes simultaneous readings from both your batteries and displays them side by side on its simple LCD. As we included it on our list, we obviously think it’s a model well worth considering, but it should be noted that it offers no water resistance or accommodation for inrush current from motor loads, and its design also looks like it might not lend itself to as many installation options as some others.

For users looking for ways to help make sure their single-battery systems stay in ship shape, our rankings for solar battery maintainers may be of interest to you.

January 02, 2019:

While the Zoostliss Power isn’t constructed to handle a ton of current, reports indicate that it’s an ideal choice for light duty that provides remarkable value. A few models — such as the JayCorp Dual and KeyLine Smart — are designed with advanced technology that enables them to monitor the voltage of each battery individually to prioritize which requires focus for charging.

Special Honors

Eaton Battery Isolators This company's well known for manufacturing quality electrical hardware, and offers isolators suitable for six- to 48-volt and 25- to 350-amp systems. Their diode-based designs are available in a number of configurations, including some specifically built to work well with vehicles from particular, major car companies. eaton.com

American Power Systems Inc. Like a lot of options in this space, this company's offerings are designed to work with 12- to 24-volt extra-low voltage systems, but what makes them stand out is their 600-amp maximum current rating, which is higher than most. They also feature helpful indicator LEDs, and an auxiliary port to connect remote alarms, though I daresay that's a bit further than most users are likely to go. americanpowerinc.com

4. KeyLine Smart

5. Ehdis Relay

6. Stinger SGP38

7. NewishTool Switch Charge

8. Audew Disconnect Switch

9. Zoostliss Cut Off


Will Rhoda
Last updated on March 06, 2021 by Will Rhoda

After deciding that the pen was mightier than the pliers, Canadian electrical contractor William Rhoda abandoned his career and headed back to college, where he majored in marketing and advertising and won a scholarship along the way to earning a diploma in creative communications. His past career landed him a depth of knowledge in tools and hardware, while his current career schooled him in audio, video and camera equipment. During his leisure time, he’s learned lots about outdoor gear, and years of tiresome backyard maintenance have taught him all about pools and hot tubs. His recreational pursuits include rest, relaxation and revolutionary action, and his roommate’s a hairless cat.


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