Anyone install GM police dual battery in Yukon?

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vitez

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An awkward subject title I know but I couldn't fit exactly what I wanted within the letter limit. I guess I'm excessively loquacious in my verbiage.
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I've got a 2008 Cadillac Escalade ESV I bought used in 2011. The AC Delco battery died within 2 months of my ownership. That should have been a sign, but I replaced it with a new AC Delco from a GM dealer. It lasted about 2.5 years and was replaced on warranty. It just died again, warranty expired. I bought an aftermarket labeled battery from a local battery distributor. 3 batteries in less than 6 years of ownership? Grrrrrrr. The vehicle is completely stock. I don't listen to music or watch DVD's with the key off. I only put about 10,000 km a year on it. The battery does seem a bit small for a 6.2L LS3 engine.

I found a few threads on Cadillac forums about guys adding a second battery to solve this problem. Chevy Tahoe's in police spec come with two batteries from the factory. Evidently, GM parts are available to install a second battery, and the second battery tray is already present, so it sounds not too difficult.

Has anyone done this?
 
Adding the weight of a second battery may (or may not) change the height of the front of the vehicle enough to make it necessary to get different springs for the front end, and or it may require a new alignment at the new lower height, and or it may not be possible to do an alignment until new (higher load rated) springs are installed.
 
Originally Posted By: JimPghPA
Adding the weight of a second battery may (or may not) change the height of the front of the vehicle enough to make it necessary to get different springs for the front end, and or it may require a new alignment at the new lower height, and or it may not be possible to do an alignment until new (higher load rated) springs are installed.


That sounds excessive.. I would think a fat man vs a tiny woman would be more difference
 
Lots of people with GM trucks install the 2nd battery. Should be a number of how to threads on the GM truck boards. The best thing you can do for the health of your battery is to keep it charged fully with a good quality charger. Whether you install a 2nd battery or not.
 
As an example, back in the days before air-conditioning was standard equipment vehicles often had two different specked front springs, one for vehicles that did not have AC, and another for vehicles that did have AC.

Once some friends and I tried to improve the suspension on an old family station-wagon that was sitting low in the front. We installed new springs specked for the same vehicle with AC, though this vehicle did not have AC. The results were that it sat too high to get aligned. We had to get new springs specked for the vehicle without AC to get the front to sit at a proper height so it could be aligned.

So one of the things you might check is to see if there are different springs specked for the vehicle if it has two batteries.
 
Id say the battery life is being negatively affected by the temperature it reaches underhood when driving/idling, and poor voltage regulation.

Clean the battery to firewall and battery to engine grounds. This might allow better voltage regulation.

Apply a smart charger to battery overnight monthly, no less than 6 amps, preferably 10 amps.

You will not have a good return on investment adding a second battery, Instead of replacing one battery every 2.5 years, you will be replacing 2 batteries every 3.5 to 4 years.

Unless of course you also use the smart charger monthly overnight religiously.

Best ROI, recharge the battery overnight once a month. Perhaps modify existing battery tray for larger higher capacity battery when this battery fails.
 
That truck has torsion bars not springs. IF it the battery did make a difference you could correct the lean by just giving those a little adjustment. But it wouldn't. A battery on an escalade is like a fly on your shoulder. They are rolling 6K lbs empty.

I helped a friend install a 2nd battery on his plow truck. It had some inefficient hydraulic over electric setup that would dim the lights severely when lifting. Would eat batteries and alternators.
The 2nd battery cured his problems.
With the heated seats, all the lights, and other dodad's that truck has it might be hitting the battery at idle.

The only thing I could say is buy the batteries in a matched set. Mixing age/sizes might not be good.
 
Last edited:
Originally Posted By: vitez
Has anyone done this?

Yep. Although I've spent more time removing half-@ss, dual battery hack jobs.

Seriously though, in your situation, this is just a band-aid approach. If you're killing batteries with regularity, something has gone awry; if it's beyond your paygrade, bring it to a competent individual who can diagnose what's going on with the charging system/battery.
 
Regarding using an AGM battery, there was just today another thread where someone mentioned that installing an AGM battery in a vehicle not set up to provide the proper voltage for an AGM will result in the AGM battery only lasting 2 years. So you could be paying twice as much for an AGM battery expecting it to last about twice as long and only have it last 2 years.
 
Last edited:
Originally Posted By: JimPghPA
Regarding using an AGM battery, there was just today another thread where someone mentioned that installing an AGM battery in a vehicle not set up to provide the proper voltage for an AGM will result in the AGM battery only lasting 2 years. So you would be paying twice as much for an AGM battery expecting it to last about twice as long and only have it last 2 years.
i dont believe that. my agm batteties always out lasted wet batteries by a huge amount
 
10k km a year? That battery is never fully charged. As has already been said earlier, put the battery on a smart charger once a month, and you will see a much longer life.
 
Yes.
Various GM PPV, SEO, diesel and 'plow-package' trucks are often OE fitted with dual batteries. High-output alternators are typically specified for vehicles so equipped, as well.
All the PNs and schematics are readily available from GMpartsdirect et al.
Get friendly with your preferred dealership's parts gent because all the hardware for a clean retrofit/upfit is just a click and check away.

Nevertheless, I don't believe your lack of a dual battery setup is primarily responsible for its heretofore marginal battery life.



Originally Posted By: JimPghPA
Adding the weight of a second battery may (or may not) change the height of the front of the vehicle enough to make it necessary to get different springs for the front end, and or it may require a new alignment at the new lower height, and or it may not be possible to do an alignment until new (higher load rated) springs are installed.


Corner weighting is additionally recommended as a precautionary measure, even in these ~5500-pound trucks.
 
Originally Posted By: JimPghPA
Regarding using an AGM battery, there was just today another thread where someone mentioned that installing an AGM battery in a vehicle not set up to provide the proper voltage for an AGM will result in the AGM battery only lasting 2 years. So you could be paying twice as much for an AGM battery expecting it to last about twice as long and only have it last 2 years.


I hope that was not paraphrasing my words.

There is not much difference in the voltages an AGM or Flooded battery wants. No vehicle holds Ideal absorption voltages for best possible full recharging in minimal time, adjusted for battery temperature and a known % state of charge starting point. Nor does any vehicle's voltage regulator drop voltage to perfect temperature compensated float voltages when the rare instances of a truly fully charged battery does actually occur, which is pretty much never in a vehicle.

Everything is a compromise, Vehicle manufacturers simply do not care about the achieving the best possible battery life by ensuring fast 100% recharges. They do care about overcharging and thus the voltage regulators are timid, as an 85% charged battery will still easily start the vehicle.

My vehicle. I have modified my voltage regulation, and can twist a dial on my dashboard and choose any voltage between 12.8 and 15.3v, watching a voltmeter, ammeter and an AH counter that tells me where my battery % is generally at, and a battery temperature sensor telling me what temperature the battery is.

But in general I choose 14.7v or 13.6v and add a tenth or 2 when battery is cold and reduce a tenth or 2 or 3 when battery is hot.

But I deep cycle my high $$ AGM nearly daily. If it were only an engine starting battery, well, number 1, I would not use an AGM, and number 2, I would not really shiv a git. I'd just plug in once a month to top off the easiest to warranty starting battery I could find, and if the terminals were developing corrosion, I'd clean them and reapply the grease around them better/thicker.

But if i did the charger overnight once a month on a basic flooded starting battery, I'd never need the warranty, nor be surprised when the battery got weak whenever that inevitably were to occur, several years later.
 
What group size are you running? I remember my former work's GMT800 truck took either a 75 or 78 with the 78 having more to it.
 
Originally Posted By: Nate1979
Lots of people with GM trucks install the 2nd battery. Should be a number of how to threads on the GM truck boards. The best thing you can do for the health of your battery is to keep it charged fully with a good quality charger. Whether you install a 2nd battery or not.
I agree
 
Originally Posted By: vitez
An awkward subject title I know but I couldn't fit exactly what I wanted within the letter limit. I guess I'm excessively loquacious in my verbiage.
smile.gif


I've got a 2008 Cadillac Escalade ESV I bought used in 2011. The AC Delco battery died within 2 months of my ownership. That should have been a sign, but I replaced it with a new AC Delco from a GM dealer. It lasted about 2.5 years and was replaced on warranty. It just died again, warranty expired. I bought an aftermarket labeled battery from a local battery distributor. 3 batteries in less than 6 years of ownership? Grrrrrrr. The vehicle is completely stock. I don't listen to music or watch DVD's with the key off. I only put about 10,000 km a year on it. The battery does seem a bit small for a 6.2L LS3 engine.

I found a few threads on Cadillac forums about guys adding a second battery to solve this problem. Chevy Tahoe's in police spec come with two batteries from the factory. Evidently, GM parts are available to install a second battery, and the second battery tray is already present, so it sounds not too difficult.

Has anyone done this?


Like others have stated.....Keep your battery charged! You have a 6.2L L92 with VVT, Not an LS3. Your not the first person to have battery issues with a GMT900 platform, The Alternator is "turned off" quite a bit to save fuel so your battery is never getting a full charge.
 
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