2022 Ram Diesel Batteries

[Topzide]

Just a bit of info for hooking up a maintainer, wire it in through the 7 way trailer connector. This way you wont have to open the hood or add another connection point somewhere. I just did this and am only seeing 0.1 volt drop difference from maintainer to batteries! Just though I'd pass on this info. I asked about this and others have stated they've been doing for years! Wish I'd stumbled upon sooner, but at least I did! Batteries can cause a bunch of headaches for us with all the electronics in today's trucks!

 

[SSchang]

AH64ID has the correct answer to my problem. As I said, I installed Amp power running boards on my truck, and powered them through Aux Switch #1. The running boards need to have power available to them at all times, so I turned Aux Switch #1 on and left it on. What I didn't know, and AH64ID enlightened me on, is that the Aux Switches don't switch the accessory power (to my running boards) on and off. The switch energizes a relay that enables power to the accessory. So that relay was turned on all the time. It doesn't draw lots of power, probably less than an amp, but over a few days it will draw the passenger side battery down to the point that there's not enough power between it and the main battery to crank the engine over.

AH64ID, thanks for your help.

Now if I could just understand why it didn't draw both batteries down the same, and when I put my battery charger on the passenger side battery, it said fully charged even thought it was deeply discharged.....

 

[AH64ID]

Now if I could just understand why it didn't draw both batteries down the same, and when I put my battery charger on the passenger side battery, it said fully charged even thought it was deeply discharged.....

That indicates a bad crossover cable, loose connection, or a bad battery.

The AUX switch diagrams don't indicate where in the B+ system the AUX PDC gets it's power from, so we can't rule out a connection/crossover issue, especially with the crossover on the firewall, that would draw off the passenger only battery even thou the AUX PDC is on the drivers side.

Quick test for that would be to see if there is a voltage difference at the batteries while idling, unless you have dual alternators.

Most likely the battery is just weaker, or has a bad/failing cell. If you have a charger that can do a recovery cycle that might help. I would disconnect that battery, charge it, and then run a recovery cycle.

 

[SSchang]

That indicates a bad crossover cable, loose connection, or a bad battery.

The AUX switch diagrams don't indicate where in the B+ system the AUX PDC gets it's power from, so we can't rule out a connection/crossover issue, especially with the crossover on the firewall, that would draw off the passenger only battery even thou the AUX PDC is on the drivers side.

Quick test for that would be to see if there is a voltage difference at the batteries while idling, unless you have dual alternators.

Most likely the battery is just weaker, or has a bad/failing cell. If you have a charger that can do a recovery cycle that might help. I would disconnect that battery, charge it, and then run a recovery cycle.

Good idea on the voltage difference while idling. I'll try that when I get the truck back later today. I asked the dealer to install a new battery on the passenger side. It's snowmobile season for me, and I have a couple trips planned to Quebec. If I don't replace the battery, I'll spend the entire saddlebag tour worrying that the truck won't start when I get back. It will probably sit in -10 degree or colder temps for a week before we get back to the truck & trailer.

 

[HVAC2]

Not to hijack this thread but has anyone else had issues with batteries in their 4th gen? My OEM set crapped out about 60k, and I just had to replace the replacements about 104K. I replaced the bats only old 3rd gen at 180K and I only did that for reassurance.

My 18 has original batteries and this last storage session was almost 4 months. She cranked up just fine. But in Cali and temps in the mid 60s.

 

[SSage]

My trucks have the same voltage readings on both batteries, that don't sound right. They are tied together, so they should read exactly the same when hooked up. I've had one go bad though and the other was normal. I replaced both, you want them as closely matched as possible. Same age, same batch, exact same brand etc. One thing I have learned is the flooded batteries are all about the same, you just buy warranty time. I've been using the cheap $80 batteries from Walmart, just changed out two 6 year old Group 65's in my old truck. AGM Deka only lasted me 3 years, I know they recharge faster, but they don't last for me.

 

[AH64ID]

Good idea on the voltage difference while idling. I'll try that when I get the truck back later today. I asked the dealer to install a new battery on the passenger side. It's snowmobile season for me, and I have a couple trips planned to Quebec. If I don't replace the battery, I'll spend the entire saddlebag tour worrying that the truck won't start when I get back. It will probably sit in -10 degree or colder temps for a week before we get back to the truck & trailer.

I know the feeling and keep a portable jump box in the truck just for those occasions where I parked for an extended period in the cold.

Take a look at the document in this post and see if you can enter Shipping mode. That will save batteries. You may not be able to as there is different information on whether or not it's disabled above 110 miles. It has been disabled on my 2018.

You could also look at the fuse block and see if there is an IOD fuse you could pull while parked.

https://www.turbodieselregister.com/threads/battery-saver-mode.272243/page-2#post-2692553

 

[HPSimpson]

Quick get away from that dealer!

 

[Ozymandias]

It is ONE Battery, divided into two units.

If one of these units is down, and the other not, then the ONLY cause for this is an internal malfunction of that unit.

It is not the cross over cable in this case here as we wouldn't see a perfectly fine charged drivers side unit.

Also these vehicle monitor the SOC of the units, both of them, it should give you a "low SOC warning" in the cluster.*

Your dealer is talking BS about draining from one unit as this is technically impossible.

Conclusion- you have a bad battery.
How to proof it?
Disconnect that unit and drive only with the drivers side unit which is perfectly fine to do so.
After a day sitting measure the voltage of the disconnected passenger side battery, it will be low even then.

That way you proof your dealer that you deserve a new battery on warranty.

*but that function only works on a battery that isn't mechanical defective like a cell short.

 

[SSchang]

So I got the truck back from the dealer last night. I ended up paying for them to put a new battery on the passenger side, and I'm going to reconnect my Amp Steps directly to the fuse box as I've done in my last 2 Rams. I thought the Aux Switches were the greatest idea in the world, but I believe they are not intended to be left turned on all the time. And I think letting my truck sit without driving it for the past 3 weeks helped highlight what was going on. I think if I had been driving it every day, the batteries would have charged and the drain due to the Aux Switch relay, and/or the defect in the passenger battery would have been hidden until at some point (like sitting in Quebec for a week during a snowmobile tour) the truck wouldn't start.

Thanks everyone for your help. BTW, the truck did start this morning at 2 degrees F, so one positive baby step.

 

[Brian B.]

Yeah, that is absurd. The two batteries are connected together and function as one large battery. It would seem it would have to be a bad cell as mentioned above, or a connection issue between the two. If it is a bad cell, the bad battery will drag the good one down with it eventually.

I am baffled by the nonsense that sometimes comes from dealers (in practically any field) where they should know better.

This is what happens when service (Circus) writers try to shotgun diagnose problems to customers without understanding the system they are attempting to diagnose. A good service writer won’t try to BS the customer.

 

[Don Campbell]

Recently purchased 2022 RAM 2500 Laramie with Cummins T.D. and at 6800 miles now it is on it's 3nd set of dealer installed batteries. Drivers side battery keeps going dead <4 vdc which for a SLA battery is a death sentence as they severely loose capacity if they do recover. Still at dealership (4th day) after my insisting there is a parasitic current draw killing that battery. The passenger side battery remains at 13.2 vdc and has never had this discharge problem. So either batteries are NOI wired in parallel or they are isolated in some fashion.
Moving on, dealer tech and shop foreman now starting deeper testing but only after I opened a RAM Customer Service Ticket. The RAM rep called on day 1 and is talking with dealer. In discussing with RAM rep. he mentioned that if a code is not present then it will be very difficult for the tech to find the problem as that seems to be their only guide. My question to him was...if battery goes dead are codes lost? Did not get an answer to that one. This truck is equipped with ELOGPS monitoring enabling me to set a battery low voltage limit to 12 vdc so I will get a phone message and possibly a chance to maybe catch any code sends. Being an intermittent is a real issue with these heavily instrumented systems. More to follow.

 

[petersonj]

In discussing with RAM rep. he mentioned that if a code is not present then it will be very difficult for the tech to find the problem as that seems to be their only guide.

@Don Campbell, this is not an encouraging statement. What happened to concept of "codes that are present" assisted the technician in resolving an issue, not "codes that are present" resolved the issue? It is unfortunate that there are many technicians out there that have never learned the fundamentals of what makes things work or not work. Without that understanding they are lost when there are "no codes present."

It would seem that your issue should be resolved fairly easily by a technician skilled in understanding the fundamentals of electricity and skilled in reading an electrical diagram - even without codes present.

- John

 

[Topzide]

Yes ,what a shame that without codes, a tech has no idea of were to start! I would have thought that you would check for current flow with the truck off. That tells you how much amp draw is happening; then you go to fuse block and start pulling fuses to check the amp draw difference. Very strange that it's just the drivers side battery. I thought they were tied together for the amperage needed for grid heater and starter to turn the 6.7 over. I hope that it can get figured out soon so that you can enjoy your trucks!

 

[Regcabguy]

Point of reference on mine.....

• Purchased new April 23, 2018
• Batteries replaced May 11, 2021
• 333,970 miles
• 5,830 drive hours

You must have callouses on your behind from that many miles.