You should disconnect the negative terminal first, then the positive terminal. When you reconnect do the opposite.

 

That is only done to prevent arcing if the positive terminal is accidentally grounded while removing the terminal. It has nothing to do with current flow, or anything else.
You can't ground out the positive terminal if the negative is disconnected first. (unless you cross the battery posts)

 

Hi Guys, my 2008 frontier SE V040DE starts great all the time accept 2 days ago. It turned over slow but started and ran fine. If I drive it for 15 - 20 minutes it will start right up every time. If I don't run it from one week to the next it does the slow turn over thing but it starts. That is for now it does.
I checked the battery terminals and the battery everything is fine, but I noticed there is a small spark that will jump between the battery post and the terminal when I take the hot wire off.
I don't think I have a clock or I should say I never saw one on the dash, and nothing else is on that I know of.
What could be drawing power from the battery?
Mileage is 108,000, battery is 6 months old.

Radio memory, body control and/or powertrain control modules, ABS module, for a few and I assume you have all but not familiar with that vehicle's modules. However, almost all vehicles built in the last x-number of years have a parasitic drain due to control modules of some sort and/or radios. And like Invasion08 stated, always disconnect the negative terminal first.....

 

Hi Guys, my 2008 frontier SE V040DE starts great all the time accept 2 days ago. It turned over slow but started and ran fine. If I drive it for 15 - 20 minutes it will start right up every time. If I don't run it from one week to the next it does the slow turn over thing but it starts. That is for now it does.
I checked the battery terminals and the battery everything is fine, but I noticed there is a small spark that will jump between the battery post and the terminal when I take the hot wire off.
I don't think I have a clock or I should say I never saw one on the dash, and nothing else is on that I know of.
What could be drawing power from the battery?
Mileage is 108,000, battery is 6 months old.

Do you have a phone charger plugged in all the time?
Get the battery checked. It doesn't matter how old or new it is.
Get the alternator checked.

 

I believe the spark the OP was referring to is due to an electrical load.

A much bigger spark will occur (and likely cook the ecm) if you accidentally ground out the positive terminal with your wrench while removing it, AND the negative cable is still attached. So as a precaution, it is usually suggested to remove the negative first... such as "Don't touch the positive with the negative connected."

My point is nothing electrical can be damaged in any way by removing either cable first... if you're careful.

 

i Think your trying to word it so you are still correct, even though the correct, careful, and suggested way is to remove the negative terminal first. So there is no chance of accidentally causing any damage.

 

Hi Guys, my 2008 frontier SE V040DE starts great all the time accept 2 days ago. It turned over slow but started and ran fine. If I drive it for 15 - 20 minutes it will start right up every time. If I don't run it from one week to the next it does the slow turn over thing but it starts. That is for now it does.
I checked the battery terminals and the battery everything is fine, but I noticed there is a small spark that will jump between the battery post and the terminal when I take the hot wire off.
I don't think I have a clock or I should say I never saw one on the dash, and nothing else is on that I know of.
What could be drawing power from the battery?
Mileage is 108,000, battery is 6 months old.

All "modern" vehicles have a constant battery drain; stuff like clock, stereo memory, ECU all draw a tiny bit of power. This is normal, and my 2004 Frontier can readily go 2 months sitting and start right up.

1. Get your battery tested under load, even though only 6 months old.

2. Google "parasitic drain" and measure your drain when truck is sitting, and see if that's excessive.

 

The way my 1980-81 high school auto tech instructor taught it and this is clearly LONG before the amount of electronics that more modern cars utilize:
Current flows from positive to negative...therefore removing the negative cable first and re-connecting it last precludes the current from being pushed through the circuits - such as connecting the positive cable last. It is safer to pull the current through - as opposed to push-ing it.
Too much semantics?

I've always done it this way whether uninstalling/reinstalling a battery or attaching/unattaching jumper cables. I don't recall any sparks/arcing occurring w/ this method. And there are clearly always sparks/arcing when tending to the positive cable last when reattaching.

Modern vehicles are clearly far more sensitive to electrical issues simply due to the amount of components...so why 'increase' the risk?

 

The way my 1980-81 high school auto tech instructor taught it and this is clearly LONG before the amount of electronics that more modern cars utilize:
Current flows from positive to negative...therefore removing the negative cable first and re-connecting it last precludes the current from being pushed through the circuits - such as connecting the positive cable last. It is safer to pull the current through - as opposed to push-ing it.
Too much semantics?

I've always done it this way whether uninstalling/reinstalling a battery or attaching / unattaching jumper cables. I don't recall any sparks/arcing occurring w/ this method. And there are clearly always sparks/arcing when tending to the positive cable last when reattaching.

Modern vehicles are clearly far more sensitive to electrical issues simply due to the amount of components...so why 'increase' the risk?

Actually, that's only true inside the battery. Outside the posts, current flow is actually from the negative to the positive ( electron flow theory ), but that's really kinda semantic and academic anyway cause except for some bizarre older Brit vehicles with a positive ground system, everybody builds them the same way. I always pull the Neg terminal first just to avoid potentially arc welding with the wrench. Did that once a few decades ago on a 1976 Camaro with the battery deep inside a fender cavity, learned that lesson fast and well, once done you never forget.

 

OK, OK, I was looking for the answer to the question, "is there a small draw on the battery from the electronics under the dash". Now I know this is possible, I will drive the truck 1 or 2 times a week, weather I need to or not. If that does not work I will attach a battery minder 24-7. Thanks Guys
Yes I know what terminal to remove first, I just did this to see if there was a draw on the battery.
Again Thanks to All

 

OK, OK, I was looking for the answer to the question, "is there a small draw on the battery from the electronics under the dash". Now I know this is possible, I will drive the truck 1 or 2 times a week, weather I need to or not. If that does not work I will attach a battery minder 24-7. Thanks Guys
Yes I know what terminal to remove first, I just did this to see if there was a draw on the battery.
Again Thanks to All

I would either test with a multimeter at home if you have one or have the auto parts store test it. Any aftermarket devices installed? Battery maintainers work well in keeping your battery charged. I have one on my ride on lawn mower and leave it plugged in all year long, besides when in use. Batteries sometimes can fail prematurely.

 

I think the original post was more to do with parasitic battery drain rather the correct battery connection procedures. I just had the same issue with a 2007 Frontier (not mine). The battery had gone dead after setting for a couple of weeks. I took the battery out and charged it fully. Put a small load on it for several hours and it seemed to hold fine. Out of habit I do take the negative terminal off first, and back on last. I watched as I put the negative terminal back on, and I did have a small spark. I should have put a meter on it to measure the current drain, but I was to lazy at the time. I'm not sure what is drawing current when the vehicle is off. I do notice it has the little blinking vehicle security light on the dash that flashes on and off with the vehicle is off. Also after I had "sparked" the negative terminal several times the alarms (flashing lights and horn) went bonkers when I hooked the negative terminal back up. Had to lock and unlock the truck with the FOB several times to get it to stop. My involvement with this is only because I replaced the battery for the owner 22 months ago and I have the warranty/receipt. Told the owner to start and run it a little more often and I will go from there. So far it's still working well.

 

My son in law has a 2019 VW something-or-other SUV and the battery went dead on him. He might have pulled the negative cable first on the old battery but installed the negative first when he put the new battery in. He said it barked twice at him when he put the positive cable on then. Results???? Almost $2,000 spent getting it running with it in the shop three weeks waiting on electrical parts to come from Germany. The final burned up piece is a part for the air conditioner that costs $1,400 and he won't buy it now as the summer is over. I can't give him advice about cars and trucks so I never said anything about the defroster now working well without the A/C being operational. So my daughter, who drives the vehicle most of the time, could be endangered because the windows are all fogged up because the defroster will not keep them clear. All the computers in the newer vehicles nowadays are so vulnerable to loss of current and low current and screwing up how you do even the simple things we used to do without the near catastrophic damage our mistakes cause now. I haven't changed a battery since we bought a new 2008 Tahoe Hybrid.