800-362-5397 M-F 6am-5pm PST.
MENU Menu Icon

view large photo

PriorityStart! 12v ProMax Low Voltage Disconnect Switch - PSI-12V-PROMAX

Free Priority Mail Shipping to USA *

OR Simple-Click Checkout
In Stock
Share this item with your friends

Product InformationStore Part Number: PSI-12V-PROMAX


Install PicturePriorityStart! is an automatic computerized on/off switching system protecting battery voltage and starting power. If battery voltage drains below 11.7 volts when engine is off, it automatically DISCONNECTS the load. The battery voltage immediately recovers.

To RECONNECT and START the vehicle: Just step on the brake pedal, activate the headlights, or use another accessory inside the vehicle, and starting power is automatically RECONNECTED! NO DEAD BATTERY! Designed to handle 1000 starting amps.

No hard wiring or modifications. Transferable. Manufactured to ISO, USCG, and SAE standards. Maintenance free.

Universal design on PriorityStart! works with 12-Volt top and side-post batteries. Same unit: Easily adaptable! No modifications are necessary.


  • ProMax specially designed for all OEM or stock vehicles. Now new circuits give voltage surge "spike" protection.
  • Easy to attach–3 Connections
  • Maximizes Battery Life–Maintenance Free
  • Handles 1,000 Starting Amps
  • Engine Run & Hazard Light Protection
  • Universal Design Fits Both Top-Post or Side-Post Batteries


*Flat Rate shipping is for the lower 48 states only.

Tech Specs

  • Weight: 1.5 lb
  • Shipping Weight: 2.0 lb
  • Model: PSI-12V-PROMAX
  • Manufacturer: BLI/Priority Start
  • Regulatory Approval: Certified to SAE J1171, ISO 8846, CE, USCG Certified
  • Manufacturer Part #: PSI-12V-PROMAX
  • Made In: USA

Customers who bought this product also bought:

Reviews and Ratings

5.00 Average
5 Stars 1
4 Stars 0
3 Stars 0
2 Stars 0
1 Stars 0
Rated 5.00/5 Stars from 1 customer reviews.

Do you own the PSI-12V-PROMAX? Please, tell us what you think about it. It helps us provide you with better products. Please note that it may take up to 72 hours for your review to appear.

Saves aggravation
I installed one of these on a friend's rarely driven Cadillac several years ago. Finally spent the money and put one on my occasionally driven Jaguar. Works great and much better than having to start the car every week to keep battery charged, or disconnecting and reconnecting battery. Easy install, delivered on time. Pricey but worth it for lazy guy like me.
Is this review helpful?
Written by on Aug 05, 2020. Verified Purchase — (3 of 3 customers found this review helpful

See More Reviews

Manuals & Tutorials

Dual Battery Setup


Order Line: 1-800-362-5397
M–F 6am–5pm PST
Tech Help: 541-474-4421
Fax: 541-471-6014
276 Tech Way, Suite A
Grants Pass, OR 97526