Electrical Article - Group 31 Battery Modifications to a 2nd gen RAM

[pepsi71ocean]

Hey Guys, So my old group 27 batteries finally took a dump. I left the radio on in my truck for about 2 hours while I was loading up scrap, and it was enough that after starting the truck the batteries were just beyond this.

 

Anyways, I did some quick looking and decided to upgrade to the famed Group31's. And the results are nothing less then amazing.

 

So not only did the truck start up super fast, but even with the grids banging away the battery voltage went from 14.0 to 12.8V with the grids going off, and you don't even hear the change in the engine or the whine of the alternator, unlike with my old group27's

 

Anyways here is how you do it.

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Tools you will need.

1. A dremel or a drill with a drill bit.

2. A propane/ butane torch.

3. Battery Charger

4. Line wrenches for battery cables

 

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Procedure

 

1. You pull your old batteries out.

 

From here you will need a dremel, or a drill with a big drill bit. Either works good.

 

 

2. So first thing you need is to do is trim these notches off. If you don't the battery will not sit flat on the bottom of the tray, and this is crucial for the battery temp sensor to work correctly.

And the other side

 

 

3. Start by heating up the battery box sides with a torch. Take your time, as it is better to go slow and steady then race this step.

 

3A You want to torch from end to end.

3B So when you torch one side so it is nice and warm and pliable, you swap to the other side, and then before you drop the battery in you re-hit the first side again for another 30-45 seconds then drop her in.

 

 

To this end

 

4. Now torch away

 

 

5. Now after it is warm drop the battery in.

 

 

6. Let it cool down, and then pull it out. When your doing this you'll have to do this several times, its best to heat it up, and then drop it back in.

 

7. After each time you heat it up and drop the battery down you need to trim the plastic.

 

 

Here you can see the plastic where its getting bigger.

 

 

8. Now its important to keep doing this until the battery sits on the bottom of the tray.

 

 

This is the battery sensor, that my finger is on.

 

9. Hook up your batteries

9A. You may need to adjust the crossover cable between the two batteries in order to make the drivers side snug.

 

10. Use your 2/10/50 AMP battery charger to charge your batteries up. Once charged it works great.

 

 

 

Some additional notes.

 

1. I had to adjust the slack on the crossover battery cable so I could get the drivers side positive terminal to fit on snug.

2. The battery hold downs do fit just fine, if you get the battery all of the way to floor.

3. There is about an inch of clearance between the top of the batteries and the hood.

 

4. Its best to charge your batteries until they are fully full before starting the truck for the first time.

 

 

I'll update this with some videos in about a week when the weather turns.

 

 

 

 

View full Cummins article

[pepsi71ocean]

@Mopar1973Man did you do this to your truck Mike?

[Mopar1973Man]

Nope.

 

27 are just fine and dont need more weight of group 31 which can start our truck with one battery like back in the 1st Gens.

[gipperkid]

Instead heating the battery tray, could the sides just be trimmed off? Or could a spacer be placed on top of the sensor?

[kzimmer]

4 hours ago, gipperkid said:

Instead heating the battery tray, could the sides just be trimmed off? Or could a spacer be placed on top of the sensor?

 

Trouble is, if you place a spacer on the temperature sensor, the heat from the battery won't properly transfer to the sensor and you may overcharge the batteries. Also, your posts might touch your hood.

Edited March 13, 2020 by kzimmer
More info.

[AH64ID]

Even if you don’t feel/hear the alternator with the grid heater post-heat cycle it’s doing the same amount of work. Amps are amps, and the grids pull the same regardless of what batteries are installed. It may reduce the sudden pull, but it’s still the same amount of power. 
 

You did the mod beautifully, but I’m just not sure it’s worth it. 
 

Group 65’s will fit with fewer mods, really just hold down spacer as they are shorter. Last I looked you can increase AH and CCA’s with a 65 over a 27. 

Edited March 14, 2020 by AH64ID

[Octafish]

Great write-up Ocean!

You did a fantastic job.

Much appreciated!

 

 

[Scarecrow]

I installed the group 31's when my 34's went bad after 10 years. I just used a body saw to trim the edges of the battery tray and dropped them in with no problems. As to whether or not they're worth it, all I can say is when it drops to -30 to -40 f around here, and it does regularly in the winter, 1900 cold cranking amps is a very nice thing to have.

 

Mark 

[pepsi71ocean]

35 minutes ago, AH64ID said:

Even if you don’t feel/hear the alternator with the grid heater post-heat cycle it’s doing the same amount of work. Amps are amps, and the grids pull the same regardless of what batteries are installed. It may reduce the sudden pull, but it’s still the same amount of power. 
 

You did the mod beautifully, but I’m just not sure it’s worth it. 
 

Group 65’s will fit with fewer mods, really just hold down spacer as they are shorter. Last I looked you can increase AH and CCA’s with a 65 over a 27. 

 

This is true, but I needed as much amperage as I could get. I have quite a few short trips per day. Mainly 5-15 mins at a clip. And those can be anywhere between 4 and 8 times per day. it sucks.

 

So for me the extra amperage given to me from the larger batteries helps overcome the short trips. My old group 27s were 850CA and the new ones are 1,150CA each, and at 0F 950CCA is allot of power. But for me I believe that the extra reserve will make it easier on the alternator and not kill my batteries when I'm constantly starting and stopping throughout the day.

 

@Mopar1973Man does my theory sound logical? Or, am I way off?

[AH64ID]

The larger battery bank will deal with the short trips better as it has a larger capacity; however, you will still have to put the same amount of energy back into the batteries as before. If you weren't getting enough miles to fully recharge before you still won't be. 

 

Maybe a trickle charger for when parked is a good idea. 

[IBMobile]

2 hours ago, AH64ID said:

Maybe a trickle charger for when parked is a good idea. 

How about a solar battery charger on the dash when parked?  You can cut off the clamps and install eye ring terminals to attach the charging wires to the battery posts.

https://www.amazon.com/s?k=solar+battery+charger&hvadid=78202816958563&hvbmt=be&hvdev=c&hvqmt=e&tag=mh0b-20&ref=pd_sl_8bhrojf8da_e

 

[AH64ID]

Just now, IBMobile said:

How about a solar battery charger on the dash when parked?  You can cut off the clamps and install eye ring terminals to attach the charging wires to the battery posts.

https://www.amazon.com/s?k=solar+battery+charger&hvadid=78202816958563&hvbmt=be&hvdev=c&hvqmt=e&tag=mh0b-20&ref=pd_sl_8bhrojf8da_e

 

Personally I’d want something with a controller. 
 

I also park my truck in the shop so that wouldn’t work. 
 

I will say that after a short trip I’m surprised how long it takes the charger to say the battery is at 100%. 

[IBMobile]

5 minutes ago, AH64ID said:

Personally I’d want something with a controller.

Something like this one?

https://www.amazon.com/Battery-Tender-021-1164-Maintainer-Microprocessor/dp/B004Q86JJ8/ref=sr_1_1_sspa?dchild=1&hvadid=78202816958563&hvbmt=be&hvdev=c&hvqmt=e&keywords=solar+battery+charger&qid=1584219474&refinements=p_89%3ABattery+Tender&rnid=2528832011&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzSE8xSDFPUzZZUE9SJmVuY3J5cHRlZElkPUEwODY2OTcxT0hTVzZBTVUwOEsmZW5jcnlwdGVkQWRJZD1BMDE1NDk1NTNVQUkyOFQ5RFRDUTcmd2lkZ2V0TmFtZT1zcF9hdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl

 

7 minutes ago, AH64ID said:

I also park my truck in the shop so that wouldn’t work. 

But it would work for people, like me, who park their truck outside.

 

 

[AH64ID]

16 minutes ago, IBMobile said:

Something like this one?

https://www.amazon.com/Battery-Tender-021-1164-Maintainer-Microprocessor/dp/B004Q86JJ8/ref=sr_1_1_sspa?dchild=1&hvadid=78202816958563&hvbmt=be&hvdev=c&hvqmt=e&keywords=solar+battery+charger&qid=1584219474&refinements=p_89%3ABattery+Tender&rnid=2528832011&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzSE8xSDFPUzZZUE9SJmVuY3J5cHRlZElkPUEwODY2OTcxT0hTVzZBTVUwOEsmZW5jcnlwdGVkQWRJZD1BMDE1NDk1NTNVQUkyOFQ5RFRDUTcmd2lkZ2V0TmFtZT1zcF9hdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl

 

But it would work for people, like me, who park their truck outside.

 

 

 

Yes that would be better for the batteries. 

[InGear]

18 hours ago, IBMobile said:

How about a solar battery charger on the dash when parked?  You can cut off the clamps and install eye ring terminals to attach the charging wires to the battery posts.

https://www.amazon.com/s?k=solar+battery+charger&hvadid=78202816958563&hvbmt=be&hvdev=c&hvqmt=e&tag=mh0b-20&ref=pd_sl_8bhrojf8da_e

 

I use the 5watt, 12volt ECO-WORTHY(shown on the same page as link for Amazon) with a 10amp charge controller from Wholsale solar. I began with a harbor freight cheapo that worked for long enough to be out of warranty. The charge controller is mounted on the cover for the air bag connectors. Theres a hot lead on the controller that powers the CB. It works well . The solar panel sits on the console/arm rest when parked and leaned up against the CB while mobile. The CB is mounted on a fabricated bracket that I cloned from one that Geno's sells. This set up has served me well.

[Royal Squire]

4 minutes ago, InGear said:

I use the 5watt, 12volt ECO-WORTHY(shown on the same page as link for Amazon) with a 10amp charge controller from Wholsale solar. I began with a harbor freight cheapo that worked for long enough to be out of warranty. The charge controller is mounted on the cover for the air bag connectors. Theres a hot lead on the controller that powers the CB. It works well . The solar panel sits on the console/arm rest when parked and leaned up against the CB while mobile. The CB is mounted on a fabricated bracket that I cloned from one that Geno's sells. This set up has served me well.

Got any photos?

[InGear]

On 3/15/2020 at 11:47 AM, Royal Squire said:

Got any photos?

 

The ground from the controller is attached to the body ground next to the battery. The charge controller manages the charge and shuts off when batteries are full charge and manages the alternator charge to protect the solar panel.

[Tractorman]

On ‎3‎/‎14‎/‎2020 at 11:09 AM, AH64ID said:

If you weren't getting enough miles to fully recharge before you still won't be. 

 

@pepsi71ocean, I agree with the above statement.  Another possible solution with other benefits is to wire the grid heaters with a manual momentary switch.  You get to make the decision as to how long the grid heaters stay on with your first engine start of the day.  No more post cycling after engine is started, so the alternator immediately goes to work replenishing the batteries.  This would significantly reduce the electrical load on the alternator during your day with many engine startups.

 

I have used this mod since my truck was new.  I am still running the original Bosch alternator.  It has received one bearing kit and two brush sets during its life.  Also, I went down in battery size to a Group 24 about two years ago.  So far, no adverse effects.

 

- John

[dave110]

6 hours ago, Tractorman said:

 

@pepsi71ocean, I agree with the above statement.  Another possible solution with other benefits is to wire the grid heaters with a manual momentary switch.  You get to make the decision as to how long the grid heaters stay on with your first engine start of the day.  No more post cycling after engine is started, so the alternator immediately goes to work replenishing the batteries.  This would significantly reduce the electrical load on the alternator during your day with many engine startups.

 

I have used this mod since my truck was new.  I am still running the original Bosch alternator.  It has received one bearing kit and two brush sets during its life.  Also, I went down in battery size to a Group 24 about two years ago.  So far, no adverse effects.

 

- John

100%. I had this issue at camp years ago. Not long enough trips in the cold weather to re-charge and by the end of the week I could hardly start my truck. Switching the grids is the most helpful thing I've ever done to my truck, well, other than changing out the 53 block..........

Edited March 18, 2020 by dave110

[pepsi71ocean]

13 hours ago, Tractorman said:

 

@pepsi71ocean, I agree with the above statement.  Another possible solution with other benefits is to wire the grid heaters with a manual momentary switch.  You get to make the decision as to how long the grid heaters stay on with your first engine start of the day.  No more post cycling after engine is started, so the alternator immediately goes to work replenishing the batteries.  This would significantly reduce the electrical load on the alternator during your day with many engine startups.

 

I have used this mod since my truck was new.  I am still running the original Bosch alternator.  It has received one bearing kit and two brush sets during its life.  Also, I went down in battery size to a Group 24 about two years ago.  So far, no adverse effects.

 

- John

 

This would most likely help, as i have starting issues once you get much below 22F without grid heaters. The truck refuses to start at that temp.