2024 2500HD Gasser Doesn't Charge in Park!

jake111 · October 29

Put my old slide-in camper on new truck. Didn't seem to be charging camper battery. Hmm, didn't seem to be charging truck battery either. WTF? Took it out for a spin and slowly it came up to 14v on the dash gauge (couldn't check camper while driving, you know). Idling in driveway, no charging anything. 2000 rpm, no charging. You must be kidding!! Finally found that if I put it in Neutral, it slowly came up to 14v, even at idle. Why would some clever GM engineer think this was a good idea?

Maybe others can verify that they all do this, or if it's just my truck.

jake111 · October 29

More... well, I guess it will charge in Park . . . sometimes. If I turn on the headlights and let the battery run down a little, then start the truck, it starts charging (although under 14v).

So I guess it's ok. But if you have a camper or trailer attached and want to check that the truck is charging the house battery, you might have to shift to Neutral to check (with parking brake set and somebody sitting in the driver seat to make sure it doesn't roll away).

Wxman · October 29

Have you experimented with the Tow/Haul mode? I think it is supposed to boost charging voltages. Don't know about the idle/park/neutral stuff.

Another JR · October 30

Welcome to smart alternators! It is designed to properly power your truck electrical system and recover your start battery while reducing accessory drag when high output is not needed, but it isn’t ideal for parallel charging a camper battery with 50 to 60 feet worth of wire losses, especially at idle.

The proper solution is a DC to DC charger such as the Victron Orion series installed at your camper battery. While they cost a bit over $200 for a 30 amp charger and you’ll need to run 6 awg positive and negative wire for the whole run, the good thing is you will already be set up for a lithium battery conversion if you decide to do that.

jake111 · October 30

Obviously, I live in the past. In a discussion with a friend, we speculated that maybe it had something to do with getting better EPA or mileage numbers, by shutting down the charging system when not needed. The tow/haul comment by Wxman above got me looking around.

I just looked through the owner's manual (digital version so I could search). No mention of tow/haul doing anything to the electrical system.

Searching the 'net showed "Regulated Voltage Control" on some old models. Sounds likely even if the name has changed. To overcome the problem, the suggestions were to either (1) turn on tow/haul, or if that didn't work well for your application, (2) turn on headlights.

I think the important thing is to be aware of this. I will be satisfied to know I can adjust whatever I need. While driving, so far the dash gauge seems to sit mostly at 14v (I only have 500 miles on the truck). But if it doesn't stay there, just turn on the headlights or t/h.

That still doesn't explain the difference between being in Park or Neutral, but there are a lot of things that can't be explained (don't get me started!).

Thanks for the replies!!

Another JR · October 30

Do you have the base 170 amp alternator?

bruceb58 · October 30

I have a 50A Victron Orion DC to DC in my trailer. Sometimes I need to turn on headlights or seat heaters to get the alternator voltage high enough to allow the Orion to start. Once it starts, it puts a high enough load on the alternator to keep the voltage high without having lights or the seat heater on.

Another JR · October 30

18 minutes ago, bruceb58 said:

I have a 50A Victron Orion DC to DC in my trailer. Sometimes I need to turn on headlights or seat heaters to get the alternator voltage high enough to allow the Orion to start. Once it starts, it puts a high enough load on the alternator to keep the voltage high without having lights or the seat heater on.

I have not had that occur with my 30 amp Orion. It just comes on after the programmed delay period after truck start. I have the 220 amp upgrade alternator and ran 6 awg wire. The total wire length for positive and negative is just under 60 feet.

What wire gage do you have running to the 50 amp Orion?

lineman1234 · October 30

I just took a pic today, its in drive sitting but is the same in park or neutral. . Its charging, as when the batts are happy its much less on the meter.

As i have my front/rear dashcam always on, it uses power overnight or parked, i do have a second batt installed. It will charge just a little more on the meter as rpm goes up, but little. As needed it will charge, drop when both batts are happy.

Same thing towing the camper, as needed it will charge the camper batts, through the one way diode on the camper charge wire, as needed, then level off and repeat as needed as i have a DC freezer in the rear kitchen always going and whatever is on for camper load like the gas detector.

bruceb58 · October 31

20 hours ago, Another JR said:

I have not had that occur with my 30 amp Orion. It just comes on after the programmed delay period after truck start. I have the 220 amp upgrade alternator and ran 6 awg wire. The total wire length for positive and negative is just under 60 feet.

What wire gage do you have running to the 50 amp Orion?

I installed 2 AWG with a 120A Anderson connector.

I also have the 220A alternator.

The reason it comes on immediately after a truck start is that the alternator is always putting out full voltage after the engine start. Once the Orion turns on, it has sufficient load to keep the alternator putting out the high voltage.

This is my 3D printed connector box.

Edited October 31 by bruceb58

jake111 · October 31

I just ordered a Victron 30amp DC-DC so things will work more reliably with the smart alternator. And I ordered a Victron 120vac charger so the next time I need a house battery, I can go Lithium. They won't get here before my upcoming camping trip, but we have hookups this time, so it really doesn't matter. I'll watch to see how the old system does since the camper has an isolator that connects over about 13+v and disconnects below that (worked fine for old school alternator). I know, welcome to the 21st century...

bruceb58 · Saturday at 06:19 AM

On 10/31/2024 at 1:53 PM, jake111 said:

I just ordered a Victron 30amp DC-DC so things will work more reliably with the smart alternator. And I ordered a Victron 120vac charger so the next time I need a house battery, I can go Lithium. They won't get here before my upcoming camping trip, but we have hookups this time, so it really doesn't matter. I'll watch to see how the old system does since the camper has an isolator that connects over about 13+v and disconnects below that (worked fine for old school alternator). I know, welcome to the 21st century...

Should have ordered the new 50A XS model, Far superior and they got rid of a lot of problems of the older 30A units.

Another JR · Saturday at 05:58 PM

11 hours ago, bruceb58 said:

Should have ordered the new 50A XS model, Far superior and they got rid of a lot of problems of the older 30A units.

The current model Orion Smart 12/12-30 has been working fine for me for the last 4 years, and is an industry standard used by a large number of people. It relies on natural convective air cooling of its finned baseplate heat exchanger so it needs to be installed in a location and orientation per the instructions. I assume the new 50 amp unit will be very reliable as well. Victron has excellent design and build quality. I would select the model based on your electrical power system sizing decisions and not based on any worry about reliability of either unit.

bruceb58 · Saturday at 08:55 PM

3 hours ago, Another JR said:

The current model Orion Smart 12/12-30 has been working fine for me for the last 4 years, and is an industry standard used by a large number of people. It relies on natural convective air cooling of its finned baseplate heat exchanger so it needs to be installed in a location and orientation per the instructions. I assume the new 50 amp unit will be very reliable as well. Victron has excellent design and build quality. I would select the model based on your electrical power system sizing decisions and not based on any worry about reliability of either unit.

The 30A version doesn't have VE Networking like the 50A XS does so no remote voltage sense, no syncing with solar controllers and no compatibility with the Cerbo GX. The new 50A XS is WAY smaller. My 30A Orion which was actually newer than yours would reduce its output based on heat. The XS is 98.5% efficient vs the 30A version which was 87%(Which explains the heat issues). The way the cables attach is way better since there is a small cover that is removed to expose the connectors. It's also a lot smaller.

I sold my 30A version to buy the 50A XS.

Edited Saturday at 09:00 PM by bruceb58

jake111 · Saturday at 11:17 PM

The good news for me is that I don't need anything fancy, and 30 amps is more than sufficient. And significantly cheaper. I am thinking of mounting it on the outside camper side between that and truck bed. Pretty well protected from the weather and very airy.

I do see that I might need to experiment with some of the parameters to try to keep it charging at least most of the time while driving. I'm not sure I understood their description of some of the settings (like a 2 minute delay after startup?). Well, I will experiment and learn as I go.