Hi all,

I was planning on using a battery tender on my 07 Tahoe. But I have searched and can not find an answer to whether our my Tahoe is a positive ground or negative ground? I've never used a batt. tender before and I don't want to put myself or anyone around me in danger by hooking this thing up incorrectly, and I don't want to do any damage to my vehicle or its electrical system either, lol! Any help or suggestions would be greatly appreciated!

EDIT: Forgot to mention I have dual Yellow top optimas in my vehicle. Do I need to tend each battery separately? or just hook the tender up to either the main or aux battery, and let it charge both batts that way? I don't know if that is even possible. lol.

 

All vehicles are a negative ground as far as I know, though if your car blows up, don't blame me, do more research!

 

I'm pretty certain your ride has a Negative Ground...
Most good Battery Maintainers have a auto-safe switch in them, where they will shut down if hooked up incorrectly, and auto re-set when the error is corrected. Also, your ride won't blow up if you accidentally get it wrong.

Now on the single or duplex system...
Set your Voltmeter at 12VDC.
Take one of the Positive Cables off either Battery.
Take a voltage measurement between that Cable (not the Battery Terminal) and a ground.
IF there is a reading, the system is not duplexed, and you only need a single Battery Maintainer.
IF there is NO voltage reading, you need a (one) Maintainer which has a dual (two) battery connections (not two Maintainers).

Now, on the Maintainer...
You get what you pay for ! Your Batteries need to be maintained at 12.4 VDC or slightly higher during periods of non-use. Just about any of them will do that BUT...
A situation called "Sulfaction" is created during periods of discharge below the 12.4 VDC minimum voltage requirement. That condition is what 99% of Battery failure is caused by. Sulfaction is something you can not avoid when your system is not being replenished and drops below 12.4VDC, and is collective. A good Maintainer has the ability to recover batteries from that.

So, you need a Maintainer that...
Has a single or two Battery Charging system, depending on the test, and
A DE-Sulfaction feature.

You can check places like EBay for a selection of Manufacturers of this "better" Maintainer, and, be expecting to pay about $100+ for it.

 

Thanks for the great info! I was looking at how to jump start the vehicle and the manual states to apply the + jumper cable to the positive terminal, and the - jumper cable to the stud on the engine block, so I believe this surely indicates a negative grounded system. I think? lol.

 

If my car blows up, I'll be sure to keep this thread updated. lol.

 

all north American cars are negatively grounded. If a tender is a battery maintainer hook it up to the car and measure the battery voltage of both batteries. If they are both the same and over 12.6volts, the charger is charging both batteries. If the batteries are isolated, hook up some jumper cables...positive to positive, negative to negative.

 

You think correctly :smile:

 

Thanks for the info! The batteries are wired in parallel w/ no isolator. I need to get a good multimeter and will try what you suggested.


YESSSSS! *fist pump* lol! Another question just popped into my head. So since our Tahoes are negative grounded, I think I have two hook up options for battery tending:

1) I can hook up the battery tender positive clamp to positive batt. terminal and negative clamp to negative batt. terminal

OR

2)Battery tender positive clamp to positive batt. terminal and negative battery tender clamp to engine block stud

Is this correct? Thanks in advance!

 

Thirty years or so ago I owned a Ford tractor that had a 6 volt, positive ground electrical system. The tractor was manufactured in 1949. I'm sure there have been some automoblies that were positive grounded also but probably not after WW2.

 

IIRC, Ford cars had positive ground 'til the mid-Fifties.

My Dad had Ford tractors from the 9Ns to the 900 series from the 40s to the 70s. I always liked them because the shifted easier than most of the others.