Adding a Second Battery

rosepaule · September 23, 2019

I'm looking to add an additional battery to my truck for accessories. There is almost no where to put on under the hood that I can see. Anyone added a second battery yet? I dont believe there was a factory installed second battery option so I'm curious as to where people are putting them... if its been done yet.

Thank in advance.

I've got a 2019 GMC 1500 Denali 4x4 6.2.

1SLOW1500 · September 23, 2019

There is always a spot. Add a isolator and buy a frame mount and then get a sealed battery. Wire it all and never even know you have it till you need it.

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rosepaule · September 23, 2019

6 minutes ago, 1SLOW1500 said:

There is always a spot. Add a isolator and buy a frame mount and then get a sealed battery. Wire it all and never even know you have it till you need it.

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Thats what I thought... until I looked under the hood. There isnt much room for much, let alone a battery. It was easy on my 2007 Silverado... it had a spot for it already... Going with a Optima Yellow top... I see you are running dual Red tops.

TXGREEK · September 23, 2019

Thats what I thought... until I looked under the hood. There isnt much room for much, let alone a battery. It was easy on my 2007 Silverado... it had a spot for it already... Going with a Optima Yellow top... I see you are running dual Red tops.

Avoid Optima, they’re garbage! Get an Odyssey, excellent batteries.

rosepaule · September 23, 2019

13 minutes ago, TXGREEK said:

Avoid Optima, they’re garbage! Get an Odyssey, excellent batteries.

I've had Optima Yellow tops in every vehicle I have owned in the past 15 years except motorcycles.... 1 in a 03 Ferrari 360 Spyder, 2 in my 07 Silverado, 1 in my 03 Accord, and 1 in my 73 Nova.... All of them had lots of accessories and music... never once did one fail that wasnt my fault. I had one fail in the Ferrari after I discovered a short in a light that was always on.

Thanks though.

1SLOW1500 · September 23, 2019

Optima was bad for a minute when it was bought out and they switched to Mexico and quality was bad. But they are great again. I have had dozens in cars, boats,ATV, and trailers.
Also a lot of the optima is bad was the issue johnson controls being anti american and moving to Mexico that alone started rumors. But odyssey is good. Best for off self normal batteries I would look at XS power. Then there are the big boy batteries the racers run but the cost is insane.

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TXGREEK · September 23, 2019

Ok, just thought I’d warn you, good luck

1SLOW1500 · September 23, 2019

Thats what I thought... until I looked under the hood. There isnt much room for much, let alone a battery. It was easy on my 2007 Silverado... it had a spot for it already... Going with a Optima Yellow top... I see you are running dual Red tops.

I have a red and a yellow only because I had reds brand new sitting in garage but months later the stock battery was dieing soni call up to get a optima and they said it is a new battery type and Optima Carrie's it in yellow top so I said fine.
With my isolator the batteries are separated until the switch is on or the key is turned. Then if truck is running they both charge.
Nothing fancy but works.

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rosepaule · November 11, 2019

Bump.... looking to see if anyone has found a clever way to install a second battery without having to put it in the bed of the truck.

Trail boss 5.0 · October 4, 2021

On 11/10/2019 at 10:47 PM, rosepaule said:

Bump.... looking to see if anyone has found a clever way to install a second battery without having to put it in the bed of the truck.

I've been asking the same question for you about year now. Has anyone install a second battery yet?

Transient · October 5, 2021

Back in MY2007 the Tahoe/Suburban and Silverado were almost identical. Today they are very different. I had a 2007 Tahoe and installed the second battery by placing on tray already installed at factory, and securing with mount I bought at the dealership. It was that simple. I then changed several wires over to what the PPV/SSV Tahoes were using. These new Silverados don't have a pre-installed 2nd battery tray, and almost everything got moved to the opposite side of where it sat in the previous several generations. If I were to do the 2nd battery again, I'd start by trying to find schematics for the Silverados sold via GM Fleet to police and fire departments. If you can't find schematics, ask a friend that works at the fire station to let you look for a 2nd battery. I wonder if GM mounted it down low, or under the truck. It wouldn't be the first time something like this was done. Iirc, the only battery in the Chrysler Concorde (iirc), was at the bottom of the engine compartment. Maybe GM installs it under the rear seat in an enclosed compartment. The battery in my wife's 2017 Traverse is in the floor of the 2nd row on the passenger side. I have to remove floormats and slide the front passenger seat all the way forward if I want to remove it.

AJ Sullivan · November 23, 2021

I installed a howler siren on my truck between the rails just under the radiator. I haven't looked too hard, but I bet you could fab a tray that goes all the way across and holds a battery, even if sideways. I will have a challenge because I have a howler siren under there, but most of you should have no problem. Pull that plastic shield off and start looking around for mounting holes and placement.

I might get a wild hair and start poking around next week, if I am bored.

NancyA · December 25, 2021

I was recently at the dealership and mentioned a second battery to my service advisor as I was considering it. She said they were put behind the seat. Frankly, that sounds unlikely unless maybe two sealed 6 volt batteries were put in series behind the seat, but I thought I would mention it.

NancyA · December 25, 2021

I was just looking at deep cycle lead acid batteries for use in boats, probably computer UPS units, etc., on Amazon There are a number of different shapes and Ah powers. They are expensive but could fit nicely behind the seat. They have terminal that are inset, so screw in.

Also, with different shapes, a place might be found for them in the engine compartment. Perhaps two 6 volt in series could fit somewhere. I have been advised in the past for solar applications that if batteries are to be connected in series or parallel that they should both be of the same age, preferably bought new at the same time and equally charged before hitching them up.

Supreme Pizza · December 26, 2021

1) What do you need an extra battery for?

Powering accessories? What accessories do you need to power for hours, while the truck is not running?

When the truck is running, the battery is not being utilized. The alternator does all the work. So why do you need two batteries?

Assuming you want to do extended power draws on a battery while the truck is off, it it would be best to use a booster pack, so? Something that isolates your primary battery, so you can still start the truck after extended periods of battery use.

As far as mounting a second battery, there are many places to do so - but you should still buy two brand new matching batteries for this procedure, not one new one and one old one with different CCA.