Nbs Battery Replacement, And Negative Post Angled Clamp

ak63 · January 2, 2010

My 30 month old AC/Delco OEM battery failed, so I had to replace it.

Which GM engineer dreamed up the battery installation on the GMT900 NBS? Either it was really bad design, or driven by marketing to lock out certain battery manufacturers. First you have to remove the quarter circle brace. Then try lifting out the battery that has no handle (hint: tie a strap around the battery and lift it out).

Then I tried to upgrade to an Optima Yellow Top, only to find out that the negative battery cable has an angled clamp that requires the battery post to be within 1" of the edge of the battery. I can get the negative clamp about half way on, but not fully because the Optima battery post is not close enough to the edge. So I'm off to return the Optima and get a Diehard Platinum from Sears. Oddly that has the +/- posts swapped compared to an AC/Delco but I think it will still fit with some creative bending of the battery cables.

gmtech4 · January 2, 2010

30 months ,is there any warraty left ?or are you over milage?

ak63 · January 3, 2010

Good point, and something I did not think about. I do have 6 months warranty left and am below the mileage. However I think that all the dealer would have done was pro-rate my current battery and give me a similar quality "standard" battery. For various reasons my truck frequently sits for 5 days or more without being started. And on my property it is frequently started/stopped with minimal driving, and therefore minimal charging. That is why I wanted to switch to an AGM type battery that has better deep cycle characteristics. Consumer Reports lists the DieHard Platinum P4 34/78DT as having the best life in Group 34/78.

A couple of other install points. I had to Dremmel (cut) the plastic support ribs at each end of the rear battery plastic tie down shelf so it would fit under the GM metal tie down clamps. Also to more easily bend the positive cables I had to remove (cut) the end half of the lower red plastic preformed channel. This allowed me to prebend the positive cables to avoid strain on the clamp. I wrapped the exposed positive cables with similar black plastic spiral wrap to protect it from chaffing on any metal edges. I also prebent the negative cables to avoid clamp strain.

This all turned what should have been a 5 minute install (in any other vehicle) into an all afternoon exercise (including driving around town swapping the battery). It did not help that it is 12F here and I am not as nimble working in heavy clothing and thick gloves.

cfeiring · January 3, 2010

Hey Allan,

Did the sears batteries fit and does it seem to work and what was the cost/warranty for the batteries?

Just curious as If your experience is close to the norm I will be in your boat next Christmas so I just want the facts ahead of time.

ak63 · January 3, 2010

The Sears DieHard Platinum P4 34/78DT battery has a 48 month (four year) full (non-prorated) warranty followed by a 52 month (four years and four month) prorated warranty. So the total warranty period is over eight years. It cost me $190 + tax after returning the old battery. This is the regular price, so I guess if you planned ahead you could buy one at a better sale price. I reckoned with that warranty that the extra cost was justified.

Yes the battery fits, with the slight modifications I posted above. If you started with the right battery in the first place (and slightly warmer working temperature!) it would probably take about 30 to 45 minutes to make the change once you have the battery.

I'll come back and let you know how it works in about a week. I had no problem starting the truck, and there were no complaints from the engine management system.

gmtech4 · January 3, 2010

you could have had a free battery under warranty,no prorating ,the tech hooks up the little tester,it fails ,they get a code from the tester and they throw a new battery in and they get their money from gm because of the wee code.

MS3DALE · January 3, 2010

you could have had a free battery under warranty,no prorating ,the tech hooks up the little tester,it fails ,they get a code from the tester and they throw a new battery in and they get their money from gm because of the wee code.

+1 When the vehicle is under the 3/36 warranty there is no prorating on batteries.

On a side note.....thats a helluva' warranty on the Sears battery,Although I still wouldn't buy one as I have had great luck with AC-Delco's.

txab · January 3, 2010

you could have had a free battery under warranty,no prorating ,the tech hooks up the little tester,it fails ,they get a code from the tester and they throw a new battery in and they get their money from gm because of the wee code.

+1 When the vehicle is under the 3/36 warranty there is no prorating on batteries.

On a side note.....thats a helluva' warranty on the Sears battery,Although I still wouldn't buy one as I have had great luck with AC-Delco's.

And you have easy access to them. No making a trip across town to pick one up.

I agree they have been good batteries

ak63 · January 4, 2010

Oh well, live and learn. I don't know if it would have made any difference but I would have had to take the battery by itself as the truck would not start at all.

Anyway for my use I'm pretty happy with this battery, and hope to get at least 4 winters out of it.

Interestingly just a week before I had the battery tested at Advance Auto Parts while it was installed in the vehicle and it passed. I think their handheld tester was maybe reading the surface charge left over from me driving to the store.

txab · January 4, 2010

Oh well, live and learn. I don't know if it would have made any difference but I would have had to take the battery by itself as the truck would not start at all.

Anyway for my use I'm pretty happy with this battery, and hope to get at least 4 winters out of it.

Interestingly just a week before I had the battery tested at Advance Auto Parts while it was installed in the vehicle and it passed. I think their handheld tester was maybe reading the surface charge left over from me driving to the store.

Then they don't have a very good tester. Were they using a load tester or simply checking with VOM?

ak63 · January 4, 2010

It was a handheld electronic unit that tested the status of the battery and alternator/charging system before and during, and with and without extra loads (lights), and then printed out a status report. I don't know if that qualifies as a full load tester.

68haywagon · January 4, 2010

I work at Advance. We use a Bosch battery/system tester. It doesn't test like the older load testers. It actually analyzes the cells in the battery. It is all electronic and actually errors out when there is electrical activity left over from charging. The battery has to sit a few minutes to stabilize before the thing will perform the test. We got to play with it alot before our store opened. The system check feature is kinda cool too.

Mike