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12V or 24V
Alternator Open Circuit Protection Device
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12V or 24V<br>Alternator Open Circuit Protection Device
12V or 24V Alternator Open Circuit Protection Device
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12V or 24V

Alternator Open Circuit

Protection Device

3.5-L * 3.5-W * 2.3-H in

90 * 90 * 60 mm

0.5 Lbs. / 0.25 Kg


2 Year Manufacturer's Warranty!

Quantity Price
1 $76.00
2 - 9 $74.00
10 - 49 $72.00
50+ $70.00
Price with Options:

(Discounts, if applicable, will show in the "Shopping Pallet")

Notice: The prices shown are for merchandise and do not include shipping. Shipping will be billed separately.

Prices shown may be changed without notice.

12V or 24V Alternator Open Circuit Protection Device
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  • Protects alternator from massive spikes caused when a cable is loose or a fuse blows.

  • Simple safe emergency route for that spike to be discharged giving full protection to the alternator’s regulator.Does not carry the main current so only light wiring is required

  • Works with any alternator or splitting device (12V or 24V).

The 12V or 24V alternator open circuit protection device is a highly effective alternator protection device which prevents high voltage back EMF spikes from destroying your alternator’s expensive regulator and internal diode pack. It prevents extreme damage occurring to your main and auxiliary system devices. Most common faults which cause this problem are:

  • Loose wires causing an alternator wire to become undone/loose causing sparking.

  • Failure in a split diode/relay charging system, open circuiting this system.

  • Someone switching off engine’s electrical power when engine is actually running.

  • Defective rotary battery selection switch causing arcing during rotation.

  • Failure of a fuse if fitted in the alternator’s circuit.

All of the above events could easily destroy your alternator’s sensitive parts, this device will prevent this by diverting any high spike build up to earth. This is effective from full power to no power fault events on the alternator. Most alternator regulators and internal diode packs will be damaged by spikes in excess of 40V. The 12V or 24V alternator open circuit protection device is designed to absorb spikes in excess of 18V (12V) and 36V (24V systems).


(We do not supply any cables with the protection device, we recommend the use of a 10A cable (place device as near to alternator as possible)

Simply connect the positive/negative output connection from the protection device to the positive/negative output of the alternator. It’s always best to connect the device ring terminal to the inside of the bolts of the alternator’s main power cables. There will already be the main alternator outputs on the alternator’s stud. For maximum protection remove the main cables after (thus sandwiching in the protection cable). If the tensioning nut on the main cable becomes loose the main cable will fall off first leaving the protection device on the alternator, this will save the alternator. If the protection device cable is on top of the live cable (not held in by the live cable) then, when the device cable falls off, the alternator will not be protected.

In the event there are no nuts then it’s up to the installer to connect the wires as close as possible to the alternator’s main power output. The closer the protection device wires are fitted the more possible events it can protect for.

The red LED (high voltage warning) will illuminate if alternator voltage is between 16.0 to 16.5V and over (12V unit) or 32.0 to 33.0V and over (24V unit). WARNING only given for high voltage at alternator, this is an event we cannot protect for. If this WARNING is given, the engine should be shut down immediately and should be investigated and the high voltage source should be identified and rectified. In the event of spike protection being engaged there is no event LED to indicate this due to its extremely high voltage and extremely low duration. The device will simple do its job and protect the alternator. The warning is more for a long term voltage fault. If the alternator’s own regulator fails for normal reasons and the alternator’s voltage rises, the LED will simply warn of the high voltage at the alternator, this device cannot actually stop the high voltage from occurring.




There are 2 ways to get an exact quote for the base shipping for your 12V or 24V alternator open circuit protection device order.

1.  Contact us at (801) 566-5678 9am-5pm Monday-Friday or email [email protected] or go through our Contact Us page




2. Place your order by clicking in the shopping pallet “Proceed To Checkout”

a. Enter your information so we can get you a shipping quote

b. Select the “Shipping Method” of preference

c. Confirm the “Choose one payment method” has “Shipping Quote Request” selected

d. Click the “Check Out” button

e. You’ll receive a confirmation email of your request, as will we


We’ll research the exact shipping cost and send you an invoice to your PayPal or email or you can add it to your pallet in $1 Shipping Increments for your 12V or 24V alternator open circuit protection device order.



Quantity discounts show in the “Shopping Pallet”.

We love to meet or beat any competitor’s price!


Higher volume discounts, price matching or questions?

Contact Carl, our resident specialist.

9am-9pm Mon-Sat MDT

(801) 566-5678

or email

[email protected]


[email protected]

or through our Contact Us page

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