Ram 1500 eTorque Voltage question

[Tech234]

First of all, being my first post..... Hello All

I have a 2021 1500 5.7 with eTorque. In the last few days I noticed the voltage gauge dropping while driving, down to just above 1/4. Then it would creep back up to just under half and they cycle keep going for a bit. Being a new truck I called the dealership and have an appointment for next week to have it looked at. I was hoping to get some thoughts from the team here before I take it in, while driving voltage is 12.78 - 13.09. It seems low to me, thinking back to my alternator vehicles that they should be around 14 while running, but knowing eTorque is another animal.
I hooked my OBD2 scanner up and below is what voltage looks like while driving.

Thanks for any input

RPM	Voltage
1289​	12.918​
1286​	13.014​
1285​	13.079​
1283​	13.027​
1278​	12.97​
1280​	12.851​
1281​	12.85​
1278​	12.844​
1276​	12.897​
1279​	13.047​
1282​	13.048​
1285​	13.061​
1280​	13.078​
1279​	13.057​
1292​	13.07​
1327​	13.052​
1318​	12.839​
1274​	12.959​
1273​	13​
1272​	12.836​
1270​	12.962​

 

[edrclark]

it is a little convoluted, at a high level, the trucks generator kicks out 48 volts to charge the lithium batteries behind the passenger side rear seat. Then there is a 48 volt to 12v battery charger that charges the starter battery

 

[BowDown]

Mine hovers around 14.3-14.5

 

[cj7]

First of all, being my first post..... Hello All

I have a 2021 1500 5.7 with eTorque. In the last few days I noticed the voltage gauge dropping while driving, down to just above 1/4. Then it would creep back up to just under half and they cycle keep going for a bit. Being a new truck I called the dealership and have an appointment for next week to have it looked at. I was hoping to get some thoughts from the team here before I take it in, while driving voltage is 12.78 - 13.09. It seems low to me, thinking back to my alternator vehicles that they should be around 14 while running, but knowing eTorque is another animal.
I hooked my OBD2 scanner up and below is what voltage looks like while driving.

Thanks for any input

RPM	Voltage
1289​	12.918​
1286​	13.014​
1285​	13.079​
1283​	13.027​
1278​	12.97​
1280​	12.851​
1281​	12.85​
1278​	12.844​
1276​	12.897​
1279​	13.047​
1282​	13.048​
1285​	13.061​
1280​	13.078​
1279​	13.057​
1292​	13.07​
1327​	13.052​
1318​	12.839​
1274​	12.959​
1273​	13​
1272​	12.836​
1270​	12.962​

You’re right, that’s too low. It’s below the float charging voltage of the 12v battery, let alone the boost voltage . Good catch, now hopefully the dealer is on the ball..

 

[ElkoNV]

Welcome to the forum, way to hit the ground running!

 

[Jnav]

You’re right, that’s too low. It’s below the float charging voltage of the 12v battery, let alone the boost voltage . Good catch, now hopefully the dealer is on the ball.

First of all, being my first post..... Hello All

I have a 2021 1500 5.7 with eTorque. In the last few days I noticed the voltage gauge dropping while driving, down to just above 1/4. Then it would creep back up to just under half and they cycle keep going for a bit. Being a new truck I called the dealership and have an appointment for next week to have it looked at. I was hoping to get some thoughts from the team here before I take it in, while driving voltage is 12.78 - 13.09. It seems low to me, thinking back to my alternator vehicles that they should be around 14 while running, but knowing eTorque is another animal.
I hooked my OBD2 scanner up and below is what voltage looks like while driving.

Thanks for any input

RPM	Voltage
1289​	12.918​
1286​	13.014​
1285​	13.079​
1283​	13.027​
1278​	12.97​
1280​	12.851​
1281​	12.85​
1278​	12.844​
1276​	12.897​
1279​	13.047​
1282​	13.048​
1285​	13.061​
1280​	13.078​
1279​	13.057​
1292​	13.07​
1327​	13.052​
1318​	12.839​
1274​	12.959​
1273​	13​
1272​	12.836​
1270​	12.962​

any resolution from the dealership? I’m in the intermittent charging club too..

 

[KWKSLVR]

What size is your starter battery? Is it an AGM?

 

[cj7]

Jnav, that says the engine alternator is not charging the battery...
If your’re running the AC full, have the seat heat and rear defroster on, and are holding all four electric window buttons past when the windows stop, maybe you can call that OK...

Typical is:
- 11.4-12.6, engine off. Mine is usually ~12.3 right after shutdown, running the radio.
- 13.2 - 14.4 engine running. Mine typically 13.9-14.1, light load

YMMV

 

[Jnav]

Jnav, that says the engine alternator is not charging the battery...
If your’re running the AC full, have the seat heat and rear defroster on, and are holding all four electric window buttons past when the windows stop, maybe you can call that OK...

Typical is:
- 11.4-12.6, engine off. Mine is usually ~12.3 right after shutdown, running the radio.
- 13.2 - 14.4 engine running. Mine typically 13.9-14.1, light load

YMMV

Thanks for the response. I agree, and on a normal truck I’d know to pull the alternator and have it benched or replaced. With the Etorque system You’ve got the MGU, 48v battery, dc-dc converter, and more! Where the heck do I start.

12.6 volts at 75mph an hour into the trip just can’t be right.

 

[Richard320]

Thanks for the response. I agree, and on a normal truck I’d know to pull the alternator and have it benched or replaced. With the Etorque system You’ve got the MGU, 48v battery, dc-dc converter, and more! Where the heck do I start.

Loose connections. Especially grounds.

In the olden days when the alternator was controlled by a voltage regulator, I had a car that killed a new battery in a week. Yet the battery tested great after being charged. Even load testing it with an old carbon pile tester showed it good. Back together and test charging and the alternator was capable of over 100A. But the voltage was low. The problem was a bad ground. The same time someone sold the battery they sold belts. And they left the alternator pivot bolt loose. The internal regulator compared the output to its ground and it was great, but with the voltage drop, the battery was only getting about 12.3v and of course, the regulator wasn't seeing it lose voltage over time. Half a turn with a wrench and all the sudden, it was charging up a storm.

I imagine there is some voltage sensing circuit somewhere and voltage drop is voltage drop. Trace the negative cable to body and engine block. Check the connections on the MGU. Any deeper than that is best left to the dealer technicians. There's probably a whole bunch of plastic covers. You don't want to damage any clips or retainers before they get a look at it. Afterwards if you go checking things you can blame any broken clips on them.

 

[cj7]

Loose connections. Especially grounds.

In the olden days when the alternator was controlled by a voltage regulator, I had a car that killed a new battery in a week. Yet the battery tested great after being charged. Even load testing it with an old carbon pile tester showed it good. Back together and test charging and the alternator was capable of over 100A. But the voltage was low. The problem was a bad ground. The same time someone sold the battery they sold belts. And they left the alternator pivot bolt loose. The internal regulator compared the output to its ground and it was great, but with the voltage drop, the battery was only getting about 12.3v and of course, the regulator wasn't seeing it lose voltage over time. Half a turn with a wrench and all the sudden, it was charging up a storm.

I imagine there is some voltage sensing circuit somewhere and voltage drop is voltage drop. Trace the negative cable to body and engine block. Check the connections on the MGU. Any deeper than that is best left to the dealer technicians. There's probably a whole bunch of plastic covers. You don't want to damage any clips or retainers before they get a look at it. Afterwards if you go checking things you can blame any broken clips on them.

... good advice. I’d add one thing, if you’ve got a jumper wire with alligator clips on both sides, connect the engine block or MGU to the battery ground directly. Can’t hurt to see what happen, short term...

 

[MurphBigHorn]

Thanks for the response. I agree, and on a normal truck I’d know to pull the alternator and have it benched or replaced. With the Etorque system You’ve got the MGU, 48v battery, dc-dc converter, and more! Where the heck do I start.

12.6 volts at 75mph an hour into the trip just can’t be right.

Just got back from a weekend trip. On the way there, And after an hour in. Voltage dropped to 12.5v. I did stop and shut the truck off for a quick stop. After start went back up to 13.2. But 20miles later. I dropped back to 12.5 and Stayed that way for the rest of the 3hr drive. Mostly drove 70mph.

And same for today. But after 45miles it dropped to 12.5v again. And stayed at 12.5 all the way home.

When truck is off reading is 12.7 lol. Lower voltage running.


Also want to add. If I shut the truck off. And then back on voltage goes back to normal. Odd.

 

[Jnav]

Yes, same. @RamCares is this concerning? No warnings on the dash for me, but considering it takes 12.9v to charge the battery the truck is apparently not receiving a charge during the entire trip.

 

[Velocity]

I’ve never seen mine go as low as 12.5 but it runs from the high 12’s to high 13’s anywhere in between those all the time. I don’t believe I’ve ever seen mine in the 14’s either. I haven’t had any trouble yet but the voltage always seemed low compared to other trucks I’ve owned.

 

[Tech234]

MurphBigHorn that is exactly what my truck has been doing. Took it back to the dealer and it spent a week with them, they could not duplicate the issue. Of course the next day I have the same thing happen. I have noticed a trend, if start the truck with remote start 90% of the time I get the same low battery result while driving. As you said, restart the truck and the gauge bounces right back to the middle. Unfortunately my Ram dealer here is ahhhh lacking, so I guess I am stuck with it.​

 

[cervelo15]

Check out this thread, we’ve been running this same discussion under the 5.7 engine thread:

What Voltage Should Etorque Be at?

I have a 2019 etorque i just replaced the battery got stranded twice thats enough.... Im wondering what is the voltage parameters should it be at when driving when everything is on vs normal driving with no lights or ac? im also curious at what voltage during driving is considered to low and...

5thgenrams.com

I had all the same issues, but some of the responses helped me understand better why the voltmeter is all over the place. Love having a digital readout on the dash, but has made me crazy.

 

[DbrownLTE]

Just got back from a weekend trip. On the way there, And after an hour in. Voltage dropped to 12.5v. I did stop and shut the truck off for a quick stop. After start went back up to 13.2. But 20miles later. I dropped back to 12.5 and Stayed that way for the rest of the 3hr drive. Mostly drove 70mph.

And same for today. But after 45miles it dropped to 12.5v again. And stayed at 12.5 all the way home.

When truck is off reading is 12.7 lol. Lower voltage running.


Also want to add. If I shut the truck off. And then back on voltage goes back to normal. Odd.

Have 2021 longhorn limited 5.7 etorque, does exactly the same thing. Sat overnite and nearly wouldn’t start. First indication was remote start would beep once, not the normal twice and not start. We were in the middle of no where, so changed the battery, fixed the starting problem but watching the voltage meter it does the same thing as yours.

 

[MurphBigHorn]

I found out the voltage is actually normal with e tq. Once everything is charge. It drops down to 12.6 or so. I haven’t had any problems with mine since I posted this original post. I thought it was not right but it is. I even have a dash cam now that runs all night as long as the truck voltage dose not get down to 11.6 then the dash cam turns itself off.

Something else had drained your battery or it was just bad. I read a lot of the stock battery test good are but still bad.

 

[Hb92]

Loose connections. Especially grounds.

In the olden days when the alternator was controlled by a voltage regulator, I had a car that killed a new battery in a week. Yet the battery tested great after being charged. Even load testing it with an old carbon pile tester showed it good. Back together and test charging and the alternator was capable of over 100A. But the voltage was low. The problem was a bad ground. The same time someone sold the battery they sold belts. And they left the alternator pivot bolt loose. The internal regulator compared the output to its ground and it was great, but with the voltage drop, the battery was only getting about 12.3v and of course, the regulator wasn't seeing it lose voltage over time. Half a turn with a wrench and all the sudden, it was charging up a storm.

I imagine there is some voltage sensing circuit somewhere and voltage drop is voltage drop. Trace the negative cable to body and engine block. Check the connections on the MGU. Any deeper than that is best left to the dealer technicians. There's probably a whole bunch of plastic covers. You don't want to damage any clips or retainers before they get a look at it. Afterwards if you go checking things you can blame any broken clips on them.

My truck has been with the dealership for ~110 days now. They just told me it's fixed now. They replaced the MGU, power control module, and 4 harnesses (wires) some or all of which were High-voltage wires (orange insulator).

I 2nd your assessment that the wiring or connectors are the issue. My truck usually ran around 14.5V but randomly would shut off entering or exiting the start-stop cycle and would require a button push to restart. The cluster displayed battery warning and low voltage <12V and it would stay there until I let the truck sit for a few hours.

Dealerships I think in general are not equipped to diagnose these HV systems so STAR was involved - root cause, apparently, was one of the HV wires was obviously burnt up & probably shorting out against the frame or something.

Truck only had 22k ish miles on it when this started. Has 24k now I think.

Inspect wiring and connections closely.

FYI body has to come off the frame for the HV wire replacement.

 

[Dako]

I have a 23 Ram 1500, 5.7 with the E-Torque. At about 3000 miles it stopped charging and I got a check engine light and the battery malfunction indicator. Battery was at 12.2 v. Dealership replaced the high voltage E-Torque battery. In less than 100-miles same charging problem - indicators and 12.2 v. Dealership said there were some loose connections and a harness? wire had a weird indentation. Harness was not replaced. I drove it and now the charging system intermittently stops charging, noted as no rise in voltage with an increase in RPMs. I stop and restart it and then it charges in the mid-13 v range. I'm trying to get the truck replaced. I cannot trust it. I live in Arizona and a breakdown in the desert would be dangerous. Has anyone had a similar issue?