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Discussion Starter · #1 · (Edited)
Background:
There's a random parasitic draw in my Xterra. I can't have it sit for more than a week and rely on it to start. It could be a number of things (from the alarm, to the remote start system, to the stereo) as I have a fair amount of aftermarket equipment installed. My wife's car is also in the same boat. 99% of the time this isn't a problem as we run our cars usually everyday. But on vacations (i.e. leaving the cars at the airport) its an issue.

In my research I came across a product called Priority Start. Its supposed to monitor the battery voltage, and when it drops below a certain threshold (11.7V) it temporarily disconnects the car from the battery, saving you more than enough power to start the car. This would allow our cars to sit, and as an added bonus guard against accidentally leaving the lights on, or chargers plugged in the car.

Product page: http://www.prioritystart.com/12vpromax.php
Best Price I found: http://www.batterymart.com/p-prioritystart-12-volt-promax.html

A little more info on why I bought this, what it does, etc in my initial thread: http://www.thenewx.org/forum/showthread.php?t=90754

Un-boxing:
The PriorityStart, the positive cable connections, negative cable connections, negative cable battery post and battery attachment band. The device itself seems fairly robust. The negative cable though is a little flimsy. Likely it doesn't need to be thick, but I did some work to protect it (more on that later).




Install:
1. Disconnect negative battery terminal and set aside. (I like to cover mine in a rag just in case.)


2. Disconnect positive battery terminal, tuck away. (Again wrapped under red rag.)


3. Remove battery mount (the bar over it), push battery as far right as you can within the base tray (this makes more room to fit the PriorityStart on the side of the battery). Wrap the mounting band around the battery. Sorry for the flip off!


4. Wrap PriorityStart under the band, test mount on left side. Check for space. Loosely re-attach battery bar mount.


5. Here I pulled the PriorityStart up on top of the battery to work on, you can see it under the attachment band. Also, now attach the negative wire to the PriorityStart.


6. I didn't like have the wire exposed. Its not in the instructions, and this is optional, but I'm anal about wiring. I keep automotive wire loom and used it to cover the PriorityStart negative wire. I also electrical taped the connection under the loom and taped the loom as well. Also you can see that I started working on the connection to the battery negative terminal. Installing the PriortyStart post and electrical taping that.


7. Completed negative wire / terminal loom.


8. Next connect the PriorityStart and the car negative cable to the negative post on the battery. (All positive connects are still disconnected). NOTE: I put the PriorityStart negative post between the car's negative cable. I originally attached it to the post / nut on the side, but did not feel it made a good connect. Sandwiched in the middle its solid.


9. Next attach the PriorityStart positive cable to the battery positive terminal. You will hear a gear like sound, this is the PriorityStart powering up and closing its relay. Then attach the car's positive cable to the PriorityStart terminal. Once connected, begin to position PriorityStart to its side mounting spot.(I did not take separate pictures for these two steps. They are both exampled here.) Also, if anyone is wondering - the two extra wires on my positive terminal are my horns and audio amp.


10. Wide shot of everything hooked up.


11. Test start car. (Everything works!)


12. Optional, though the band is OK, I had some large zip ties lying around and put one on for good measure. Below is the final install.


You can also buy an optional mount from PriorityStart: http://www.prioritystart.com/holster.php

Though I didn't find it worth the extra money. Even without the zip tie, between the band and the connection cables its in there pretty solid.

Testing the PriorityStart

1. Note the GREEN light indicating that the PriorityStart is functioning, connected, and that the car battery is OK / connected.


2. Lets hook up the voltmeter and take a look. Xterra is not running AND key is out of ignition. Battery is reporting 12.35 Volts.


3. Turn on headlights and start draining the battery. (Again car not running)


4. Didn't take too long. As soon as the headlights began drawing power the battery voltage dropped to 11.6 volts. This is below the 11.7V threshold for the PriorityStart. Within a few minutes PriorityStart spooled up and disengaged the car from the battery. Note the red light.


5. Headlights are now off since the battery has been disconnected from the car.


6. Once the battery is disconnected, the load is removed and immediately battery voltage returns to 12.05V. Enough to start the car.


7. Hop in the Xterra and turn the key to the ON potion. I hear the PriortyStart gear engage. (It requires a NEW draw and then it reconnects the car to the battery. The instructions note to tap the brakes in most cars. But in the X it looks like you can almost start the car normal.) My dash lights went on, but the gauge needles started doing the weird things they do (vibrating) when the battery had been disconnected. I briefly returned the key to the off position, then back to the ON. Everything normal. And it started right up!

Review:
Overall this is a nice little insurance policy. It saves you from being stranded and guards against the battery dying. And once a (non-deep discharge, standard in the X) battery is drained, even once, you've reduced its lifespan.

The only downside is that if you like to run aftermarket lights WITH the car OFF, the product would likely intervene early on. For those running aftermarket lights you'll either want to keep the car running or bypass the priority start and wire directly to the battery.

But for the average owner of an X or really any car its a good little device. Time will tell how reliable it is. For now I'm going to run the one on my X for a week or two before putting the 2nd PriorityStart on my wife's car. But supposedly these things are used by fleet vehicles and police departments.
 

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Very cool! Good write up as well. I am in the process of reworking my electrical/charging system. New alternator, battery terminals, and fuse link yesterday, new battery in a month or so. This may make the list as well.

Any idea if it works while the X is running too? For example, engines running but your winch and aux lights drain the battery faster than the alternator can keep up with, will this shut everything down? Forcing you to turn everything off and restart the vehicle?
I ask because my winch sucks power from my battery even with a running engine to the point of almost dying.
 

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Discussion Starter · #3 ·
Thanks!

My sense is no. The device is supposed to sense a running engine and not disconnect a battery.

I found this on thier website when I was researching getting one:

Does PriorityStart! disconnect the battery while the engine is running?
"No. PriorityStart! is designed to provide battery protection when the engine is NOT running (ignition switch in the off position). It will not disconnect the battery when the engine is running, even though the battery voltage level drops below the factory-set safe threshold. Circuits within this product recognize an "engine running" condition by sensing electrical "noise" (30 mill volts) created by fuel injectors, fuel pump, fan motors, etc., and will not disconnect the vehicle battery. If a vehicle alternator or alternator belt fails, the "engine running" circuitry recognizes the condition and prevents disconnection at the 11.7-volt threshold, allowing the vehicle to continue on the reserve capacity of the battery. In such a situation you are entirely dependent on the reserve capacity of the battery. PriorityStart! will not disconnect the battery as long as the engine is running."


Very cool! Good write up as well. I am in the process of reworking my electrical/charging system. New alternator, battery terminals, and fuse link yesterday, new battery in a month or so. This may make the list as well.

Any idea if it works while the X is running too? For example, engines running but your winch and aux lights drain the battery faster than the alternator can keep up with, will this shut everything down? Forcing you to turn everything off and restart the vehicle?
I ask because my winch sucks power from my battery even with a running engine to the point of almost dying.
 

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really cool, thanks for the write up! adding it on the list
 

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Discussion Starter · #7 ·
Thanks for the kind words guys.

As a small update, I've installed the second unit in my wife's car. Everything works fine.

Her's took quite a bit longer to test drain. The draw on her car was not as bad as my X. Her battery started at 12.4V and running the headlights + flashers, with the car off only drew enough initially to drop the voltage to 11.8. Just barely above the 11.7 PriorityStart needs to see to dissengage the battery. After about 40 minutes of running the lights on the MKZ (it was more like 5 min on my X) the PriorityStart spooled up since the voltage dropped low enough.

Got in the car, and fired right up. So far they both work great. Nice little insurance policies.
 

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Good idea on this...just wonder how does it interact with the alarm, etc.? Meaning, does it become disabled and when it reinstates power, does the horn start honking and stuff? (forgot what vehicle did this, but hated that...whenever you'd disconnect the battery and reconnect, the alarm would go off until you pressed the fob. I don't think it was the Frontier though, so hopefully these are not like that).
 

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Cool thing to have but couldn't you have just picked up a battery tender?

I guess it depends on your situation, if you park your car for a week at the airport this is your only option since you can't plug a tender in.

One down fall would be that it disabling your alarm/security system.
 

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Discussion Starter · #11 ·
Good idea on this...just wonder how does it interact with the alarm, etc.? Meaning, does it become disabled and when it reinstates power, does the horn start honking and stuff? (forgot what vehicle did this, but hated that...whenever you'd disconnect the battery and reconnect, the alarm would go off until you pressed the fob. I don't think it was the Frontier though, so hopefully these are not like that).
The alarm does go off once power is restored. Over the winter I ended up relying on the priority start quite a bit. If it engages, power is cut to the truck. So you have to open the door manually w/the key. Then put the key in the ignition, turn to the ON position, and the battery will re-connect. Now your alarm is on - hit unlock on the key fob and it shuts off. Then take the key out of the ignition. Put it back in and start up.

If his battery dropped to 11.6 within 5 mins of his headlights being turned on, the battery is toast.

I do like the concept though.
You got it man. I thought I had a vampire draw and/or the X just couldn't sit for a week plus. (Its one of a few cars and does not see daily usage). Those issues still could be the case, and I'm glad I installed the priority start - but the main issue was a bad Yellow Top Optima battery. I've since replaced it and the truck can sit for several days (have yet to go longer since replacing) and starts up without the priority start.
 
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