Baffling Quick Battery Drain (1 Viewer)

[zonker]

First off I should explain.. I have a very strong background in electronics as well automotive electrics. However I am VERY baffled by what just occurred yesterday. I guessing that the answer is simple and I am just brain dead and need to retire from the shop!

The history. I have a dual battery setup.. utilizing the IBS control system. Several weeks ago I replaced the starting battery.. a Northstar 27F as it was just looking a little suspect to me. If the LC sat for a couple of weeks the voltage would drop into the 12.2 vdc range. Not awful low.. but suspect. Could be parasitic.. but my Fluke amp-meter did not indicate any draw with the ignition off. Besides it is 6 years old and the very cold conditions here in northern Nevada winters takes a bit of premature life out batteries. I replaced the battery with another Northstar 27F from Batteries Plus as they carry the Northstars.

For the past several weeks after replacing the battery I have driven the LC quite a bit. Nothing long distance.. but say a handful 40 mile roundtrips. No problems.. no issues. After sitting for a couple of days the starting voltage is solid at 12.8 vdc. Yesterday it was snowing in the Sierras and we wanted an outing so off we went to explore the visuals with snow on them. Before starting up the LC I pushed the display voltage button on the cab battery controller.. the standard 12.8 vdc popped up. We drive about 30 minutes up the canyon by our house.. shut down and headed off for a bit of a hike around. After about 20 minutes I have to head back to get something. Nothing unusual.. something like the headlights being on. No sounds.. no smells to make me inquire. My wife heads back after about 30 minutes as she is getting cold. She notices nothing and like my experience we have to walk straight at the LC as we walk back.

After about a total of approximately 45 to 60 minutes I too get back.. jump in.. turn the key and absolutely nothing. No clicks.. whirs.. knocks or anything. Check the battery display and the starter battery is completely DEAD.. according to the gauge somewhere below 11.2 vdc. I did not have a VOM with me.. so no way to verify.. but what would it matter.. nothing is on period.. let alone the starter. The reason I have dual batteries is we travel alone off-road and it paid off big time. Linked the batteries and the LC started immediately. Good thing as no one else was up the canyon!

Drove for about 30 minutes after starting up.. shut down and there is still NO discernible voltage in the battery. Guess I am not surprised but with a 150a alternator I should have seen at least a little bump. Decided it was time to get our butts home. 45 minute drive and after popping the hood with a VOM in hand.. I am now up to 12.0 vdc. Hooked up a battery analyzer and the battery tests just fine other than being low on volts / amps. Plugged in a smart charger all night. Obviously this morning the battery is fully charged. Left my VOM attached and after the voltage stabilized it is holding steady at 12.8 vdc.

Well to say the least I am completely baffled! I know there are great minds here on MUD that will set me straight on what I am missing. Of course I am assuming a faulty battery.. but how did it recover after charging. In mind if the battery was suspect the voltage would continue to decrease after the charger was removed.

Please chime in and educate me!!

 

[60wag]

Defective battery? Maybe put a load on it, like the headlights and see how long it lasts.

 

[pedwards]

I was gonna suggest the same. Maybe you can switch with your aux battery and see if it looses charge over time.

 

[zonker]

Hey @60wag .. thanks for passing along your thoughts. Earlier today I turned the headlights on multiple times and there was very little drain. Great option since they are pretty good load and I always drive with my headlights on. Then having them turn off when opening the drivers door. So after your post.. I went outside to go thru the process again.. just because I have no other ideas other than defective battery. First time I turned on the headlights.. butta bing butta boom. Headlight relay clicks and no headlights.. VOM goes down to 8.0 vdc! Wow.. I turned the headlights on and off at least 7 or 8 times earlier day to produce a load and all was well.

So thank you for prompting me do the load test again.. definitely bore definitive proof of where to go next in troubleshooting. Might even be the battery.. but if not.. at least I have a new clue!

 

[zonker]

Thanks for the multiple responses! Sure is looking like a defective battery. I was only supplying headlight load with each test. Now discovering that any load at all draws the battery down into crazy low territory. Remove whatever load and the battery recovers. Of course my initial thought was highly doubtful that it was the battery since it is literally brand new of very high quality. It also never crossed my mind that any load would literally "kill" this battery or any other so quickly.. but I have now seen that with my own two eyes on my VOM. Crazy! Of course this all adds up now as I never shut the headlights off when I shut down. Consequently yesterday I was starting with them in the on position and that left nothing in the tank for the starter. Blowing snow and definitely cold did not get me out to do any troubleshooting at the time. Pushing a button to link batteries was much easier and warmer. No plan to deal with it until today as a hot shower when I got home yesterday was much more important.

 

[zonker]

Oh yeah.. my apologies for stating that I knew something about electronics and electricity. If I was SO smart I would have fixed this issue in minutes and would not need to connect with the collective minds of MUD. Thank goodness for those minds!

 

[BILT4ME]

Do you have LED interior lights? If not, a failing door switch or a door left open could drain the battery quickly.

With my LED interior lights, I have left a door open all night and still had enough to start in the morning.

That could be a hard one to track, particularly during the daytime when you don't notice interior lights.

 

[zonker]

As we all expected.. definitely a defective battery. It was the only thing I could imagine from the start.. but hard to go down that mental road when it is only weeks old. Thanks to the MUD collective for chiming in and suggesting as such and keeping me on the straight and narrow!

Taking it back tomorrow for a replacement. Then I will just have to deal with the "we checked it out and nothing is wrong with it" "Has to be your alternator" Of course I will take your 19 year old.. highly experienced word for it.