Directed 520T

12 Volt Backup Battery and Sensor

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• 12 Volt Backup Battery System
• Powers siren when battery is disabled

Learn more about the dei-520t
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Product Highlights

• 12 Volt Backup Battery System
• Powers siren when battery is disabled


  • 12 Volt Backup Battery System
  • Powers siren when battery is disabled
  • 1-year warranty

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The DEI 520T battery back up is Good you have to know how it works

The DEI 520T battery back up is Good you have to know how it works I have installed over 200 of them in the past year with all car alarms code-Alarm and VIPER the best alarms to use is the DEI VIPER alarms as there is no feedback on the remote start wires like code-Alarms the only thing I don't like is DEI recommend only the alarm unit itself only on the Gray wire of the 520t this unit will only put out 15 to 20MA max after that it will drop the output below 12v on the Gray wire power output wire for the alarm and drop the output power on the red battery wire this is why the 12v batter back up will go dead after any ware from 1 to 3 mounts any accessories like 509u 508d or the DEI tilt sensor and dei relays is over the current limitations of DEI.

SOLUTION to this problem I have found that you run a fuse wire from the car battery to the Red back up battery this will be your solution to this the back up battery and the Gray wire will match the output power of the car battery and when the car is running will max out at 13.9 to 14.5v also you can now upgrade from the BS 12v .08AMP battery to a 12v 1.5AMP or even an alarm battery 12v 4.5AMP the car battery will charge it.

By mike on August 5, 2011


found this helpful.

so far so good

Installed and seems to work fine. Messes with virtual tach on the Clifford 50.7x. Had to hard wire in the tach as it was not sensing the car was started. Other than that everything seems to be great. It was easy to install. Make sure you use diodes on the triggers when sharing common trigger inputs. Thanks again Sonic. Another great purchase.

By James on December 23, 2011


found this helpful.

Good buy

This is a really good optional accessory for the Directed made car alarm system. I recommend this product.

By Alen on December 28, 2009


found this helpful.

Good investment

If you have a DEI alarm you need this add-on. If a thieve wanted to make your alarm useless, all he needs to do is disconnect your battery. This add-on makes this impossible. If your battery is disconnected the alarm still work and also will be triggered.

By Jake on January 17, 2009


found this helpful.

Reliable Backup Battery

This was a breeze to install in my first DIY car alarm install. The instructions provided with this backup battery are very simple. Just tap into a constant 12v wire and feed it into this unit.

By Josh on November 18, 2015 checkmarkIcon Verified purchase


found this helpful.

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