can a brain go bad and drain my battery?

I searched the forum and did not find an answer that directly relates to my question and I apologize if this has been asked before. If so feel free to just link the previous post. I had installed a Code Alarm CA-630 VSS alarm / remote start unit a little over a year ago into my 07 Nissan Xterra and it had worked flawlessly until about 3 weeks ago. I came out one morning and nothing, absolutely no juice at all. I thought gee it was -10 last night maybe the cold? After a jump start it worked fine for the day, or so I though. Next morning nothing. So in the end I removed all the fuses from the alarm unit and charged up the battery and it has started every day no problems since. So my question is can the main brain unit go 'bad' and cause a drain? Can it still be the wiring even after pulling the fuses and after so long? I'm not willing to replace the unit until I am sure and I sure hate to replace the fuses and have the battery go dead again. Not good for the battery in the long run I hear. Any ideas? Thanks in advance for taking the time to reply.

Yes that is possible, you should probably measure the current draw using a DMM. Another thing to remember when adding aftermarket accessories, is that #1 your vehicle is not designed to handle having extra things on it. You have to make a decision on whether you need to upgrade your battery/charging system to handle the extra loads. When everything is new generally it is not required, but can be necessary on vehicles that have been around the block a few times. Hope that helps!

I concur with racer. I am not sure what condition your battery is in but if it has been deep cycled, gone completely dead, in the past; it usually will not recharge to full capacity. The extra load the security system is imposing on the battery while the engine is off can cause it to drain. Especially in the cold.

Well the thing is the battery, along with the vehicle, are only a year and a half old. The alarm was installed and working for over a year through one winter already. I even popped in my Optima yellow top out of one of my classics and it was completely dead the next morning too. After pulling the fuses from the brain the vehicle has started strong every day for the past three weeks with the OEM battery installed and recharged. Now hearing that it is possible that a brain unit alone can cause a drain on a battery I will start testing for the drain, wire by wire. Ughh, just what I wanted to avoid. I thank you for your quick responses and will post back if anything out of the ordinary pops up. Thank again.

Simplest way to test is to put the DMM in line with the battery teminal, and measure the amps with the alarm fuse in and with it out. That will tell you for sure, if the problem is with the alarm or not.

BTW I had to replace my battery in my 2007 Jeep Wrangler already, stuck a yellow top in, and havent had any issue since. You mention you had yellow top as well. Was it fully charged? They have a long shelf charge, but take forever to recharge once depleated. Might be a good idea to check your terminals for corrosion etc and possibly have the charging system checked. Just eliminate things one at a time.

Properly installed no it can't.  It draws about 30milliamps at rest  unless a relay was engaged all the time but that would have flattened the battery in about 15 hours.  The proper way would be to let the battery sit over night then do a voltage test followed by a drop test. An alternative would be to remove what has been installed then charge the battery, run it for a few days and if the same problem recurs, you're looking at battery, alternator or both.