New Mack Release March 2

[Bullheaded]

I'm surprised no one here has brought this up yet. Just as I was predicting, they are going to ruin the Granite now too. get ready for the new Mack VHD

Mack is officially dead. Thanks Volvo.

[The Heinz]

Haven't heard of this yet, but I can see it happening. We apparently sold the first VHD cement mixer on the East Coast, hurray. The 24v system in the new Volvo's has been an absolute tragedy that has to end in a lawsuit from somebody. The batteries go dead all the time, so you better have a 24v charger, because a 12v will take eight hours to jump the truck off! Because apparently the EPA demanded there be X amount of modules controlling things, and one of them is in control of the batteries! THE BATTERIES HAVE A CONTROL MODULE. And it's gone bad in several different instances! I'm not having a fun time with it if you can tell. 

[Bullheaded]

On 2/5/2026 at 9:50 AM, The Heinz said:

Haven't heard of this yet, but I can see it happening. We apparently sold the first VHD cement mixer on the East Coast, hurray. The 24v system in the new Volvo's has been an absolute tragedy that has to end in a lawsuit from somebody. The batteries go dead all the time, so you better have a 24v charger, because a 12v will take eight hours to jump the truck off! Because apparently the EPA demanded there be X amount of modules controlling things, and one of them is in control of the batteries! THE BATTERIES HAVE A CONTROL MODULE. And it's gone bad in several different instances! I'm not having a fun time with it if you can tell. 

I'll never have those problems with my old 2-stroke Detroit, LOL

[kscarbel2]

10 hours ago, Bullheaded said:

I'll never have those problems with my old 2-stroke Detroit, LOL

The rest of the world runs 24V in heavy trucks and zero issues. It’s actually better.

Leave it to the EPA to sabotage proven engineering.

[Geoff Weeks]

Most  motorcoach's here run 24 volt. It isn't about the voltage or the EPA, it is about the mfg implementation of an ill thought out solution to a power issue. This is all on Volvo. 

[Mark T]

I think the increase in voltage is more about multiplexing. Wider range of voltage equals more signals that can be sent from processor to processor. So many components now have a module that used to work from an air signal, or some simple form of relay.  Way too overcomplicated anymore.

[Geoff Weeks]

Voltage doesn't effect mutiplexing as far as my understanding. That is done with a digital signal, which is why modules have to be "programed" to the vehicle and can not be interchanged at random between similar vehicles.  Either way it is the mfg choice of engineering that had led to the problem, not the voltage nor the EPA (24 volt is not mandated).

It is never "we have to make a crappy vehicle" it is "we choose to, because it is cheaper and more profitable".

[Geoff Weeks]

Back when I was bringing "gray market" European buses to meet DOT spec's the only thing that required 12 volt were Sealed Beam headlights. Sealed beam's were required at that time and no 24 volt sealed beams met the  DOT required beam pattern. 

At that time Motorcoaches  (MCI, and others) were also 24 volt, andused either a Vanner battery balancer or some solid state DC-DC were just coming on the market.

As others have said in many parts of the world 24 volt in commercial vehicles is the norm. The only today keeping it from being is backward comparability with older trailers and equipment. 12 volt cab accessories could easily be handled by a 24-12 DC to DC converter. 

[Mark T]

Going to 24 volts is way more than lights on newer trucks.  You're gonna see more stuff being electric on them ( think components like fans and such ) and whatever they are ???? every one of them is going to have it's very own form of ECM. Wouldn't surprise me a bit to see 36 or even 48 volt systems before too long.  One thing for sure, there won't be fixing a marker light or some other simple thing with a test light or volt ohm meter like most of us guys are familiar with.

[Geoff Weeks]

You misunderstand me, I wasn't saying it had anything to due with lighting. I only mentioned the lighting in terms of it being the only thing on the buses that WASN'T 24 volt.

Voltage has nothing to do with the problems Volvo has created. Some have pushed for higher voltages (Elon!). The higher the voltage the thinner the wire can be for the same "work". It brings other problems like flash over and the need for wider air gap in relays and switches for example.

Problems multiply once the actual voltage exceeds 50 VDC, so there is a practical limit on the higher end also.

Most problems seam to exist when more than one voltage "system" is used on one vehicle. It come more from implementation (corner cutting) then from the fact there are two (or more)voltages used.

Volvo seams to have chosen the route of 24/12 voltage on their trucks to meet an end result, not as the end result. It was their "solution" to implementing some requirement, not the requirement has to be 24 volt.  

[james j neiweem]

The Present Pinnacle CHU is part of this VHD Granite/reveal also I believe. May be the end of the Pinnacle as we know it. Mack as we knew it is long gone replaced by Volvo offerings. At least the name is still alive>

[Mark T]

I didn't misunderstand one bit. Volvo might be the first to use this setup, but it's what's coming with all of them. You will be surprised to see how much of a truck becomes more and more dependent on new technology. It'll all be proprietary too. If anything these things have become cheaper to manufacturers.....not end users. There's more systems on newer stuff that was never even thought of not that long ago. Colission avoidance driver monitoring.... goes on and on. These trucks are outpacing the casual mechanic in leaps and bounds.   

[Mark T]

1 hour ago, james j neiweem said:

The Present Pinnacle CHU is part of this VHD Granite/reveal also I believe. May be the end of the Pinnacle as we know it. Mack as we knew it is long gone replaced by Volvo offerings. At least the name is still alive>

The Granite replacement is in production. They're in the bullpen at Macungie.

[Geoff Weeks]

I think it has come down to how well things have been thought out. One big disaster is: backward compatibility.  

It is like "feedback carburetion" was. Bandaid on top of badaid until the system collapsed.  Once Mfg finely came to the conclusion they couldn't meet requirements with what they always had turned to, then and only then did things get better. Once carburetors  were abandoned, and FI took over we went from engines lasting 100k to 2x-3x. Engine life wasn't the thing that pushed the change, it was emissions.

24 volt has always been better in higher power use applications. It was why it was used elsewhere for more that 1/2 a century. 32 volt has been used in marine for a long time, 36 less so. 48 has an operating voltage of over 50VDC and is getting well into the area that you solve one issue and create 2 more. 24 volt is far better than 12 for cranking big bore diesels.  What kept it out of this part of the world was backward compatibility. A 12 volt trailer would need retrofitting to be towed by a vehicle supplying 24 volt to the trailer. Back in simpler times a nose box and resistors allowed a 12 volt tractor to tow a 6 volt trailer. 

When designing electronics, it cost a little more (not much) to make the compatible with multiple voltages around the same range, so stuff like ABS, radios Stab control, engine controls etc, could be made future/backward compatible but have not.

The last time we went though a voltage switch vehicles were far simpler. Still VW kept 6 volt until the mid 60's, and 6 volt bulbs (including sealed beam headlights) are still readily available  more that 50 years after the last car using them were produced.

[Geoff Weeks]

1 hour ago, Mark T said:

Going to 24 volts is way more than lights on newer trucks.  

This made me think  that 

[Mark T]

I still think the higher voltage has something to do with digitalizing signals from one processor to another.  If the signal is given a value read in volts or milivolts or whatever, it allows for more signals. Along with everything else that can be done with higher voltage, and advances in batteries.  It's crazy stuff guys such as ourselves would never think of (or want to)  It's kinda amazing some of the things. For one that they can do it.....and why they would continue to make these things so complex. It's true, a 24 volt system worked great for starting a large motor (something us guys would understand) but it's way way more complicated now.

[Geoff Weeks]

If I had to guess, I think it is far more to do with key off draw, which is becoming critical in all vehicle as the electronics become more and more complex. 

 In most cars, for example 50ma was the max figure, I have heard that has be increased on the newest stuff. 

How that translates to trucks, if key off loads go up, the truck is trying to start with less than full battery. We have reached the limit of what 4 gp 31's can crank in parallel. It becomes cheaper and more reliable (in theory) if you raise the voltage, decreasing the current needed to crank. The choice would be more gp 31's in parallel, adding to weight and storage room or take those 4 gp 31's and divide into two groups of 2 in series.  The same amount of power is used, but the highest load (cranking) is a bit more tolerant if the voltage is higher and the current less.

It is just like 6 volt can crank a 450 CID engine if all the connections are perfect, but 12 volt will still crank if the connections are a little less than perfect.

It get worse in the cold. 12 volt batteries in parallel can do fine in normal temps but can struggle to produce the same current when cold. While job is the same,  the ability to make the required current at the lower voltage exceeds what the battery can do when cold.  

[Geoff Weeks]

40 minutes ago, Mark T said:

I still think the higher voltage has something to do with digitalizing signals from one processor to another.  If the signal is given a value read in volts or milivolts or whatever, it allows for more signals. Along with everything else that can be done with higher voltage, and advances in batteries.  It's crazy stuff guys such as ourselves would never think of (or want to)  It's kinda amazing some of the things. For one that they can do it.....and why they would continue to make these things so complex. It's true, a 24 volt system worked great for starting a large motor (something us guys would understand) but it's way way more complicated now.

I think you are confusing analog DC , where the only choice is "what is the voltage" and digital where a unique identifying pulsed square wave is placed on the buss. The individual modules respond to only their "query" on the buss. Like an old fashion party line telephone. These systems run on much lower voltage then the rest of the "normal" vehicle electrical system. 

It is the same way someone can be streaming a movie on their computer while someone else in the same house can be listening to music stream, while a third is downloading a program, all on a single modem. the signals get sorted not by voltage but by digital identifier.  

[Mark T]

I may be calling it the wrong name, but basically more computing needs more power.  Not to be a wise guy, but I think you might be surprised at how many systems and subsystems are actually on these new trucks (it's nuts)  There's so much on new stuff, they're shipped with a lot of things in a "dormant" state so as not to drain batteries. Dealers aren't even aware of some of the things that need to be activated when the customer takes delivery of a new piece of equipment ( all $300,000.00 of it ) . In some cases, technitions don't even know what's wrong when the customer comes back complaining. In some cases it turns out just something that wasn't toggled on before delivery. They're not done yet either. They're just gonna get more and more complicated, and support is gonna be worse and worse. You'd fall over if you saw some of the prices for something as simple as what was once a headlight. What was a 30 amp breaker is now 4 processors working in conjunction with 6 other ones. 

[Geoff Weeks]

7 minutes ago, Mark T said:

I may be calling it the wrong name, but basically more computing needs more power. 

I'll agree with that statement.  But the one single thing that draws the most and determines the limits is cranking and to a lesser extent firing of the injectors while cranking.  

Look at it this way, if  cranking a large bore diesel in cold draws the system voltage down to ~6 volts, that has cut the system in 1/2. a 24 volt system that looses 6 volts while cranking is still at 18 volts.  It is all about getting the truck running, once that is done, the alternator carries the load.

You can afford to loose 6 volts with a 24 volt system, you can not with a 12.  Injector firing is done at a much higher voltage on the new trucks, then system voltage. If the system is pulled too low it can't even fire the injector even if the engine is cranking fast enough to start.

It is becoming more and more common on newer vehicles to have charging voltage controlled by the ECM in order to quickly replace what was drawn off when the vehicle was shut down. 

Storage batteries  (common lead acid types) can provide small amounts of current for a long time but are extremely limited in how large a current draw they can provide for even a short time. It isn't a liner graph. A Maxwell supercapacitor can provide enough current to start a big bore diesel in -25F in the form factor of one Gp 31 battery, but can be totally depleted in 25-35 min by connecting a single headlight across it. It is the opposite of a battery, the Maxwell can supply huge amounts of current for a short period.  It does not store more energy than even a single group 31, but can release it all at once.  This is proven by the fact a single gp 31 can recharge the Maxwell multiple times (charging current for the Maxwell is less than 18 amps)

Key off loads could be handled by 4 lead acid  batteries in parallel and carry that load for a week or more, but not be able to crank the engine in the cold because the current draw exceeds the ability of the battery to provide, either provide more, or reduce the current needed. doubling the voltage cuts the current in 1/2. doubling the voltage does not increase the total capacity in watt/hrs of the system. You are still storing the same amount of energy, but can better access the stored energy when a brief large draw is on the system. 

I don't claim to be schooled on the latest, but the laws of chemistry and physics don't change. I do have an fair but by no means complete understanding of the modern systems on vehicles. I am by no means an expert. 

By raising the voltage, you are reducing the current required, and current is the limiting factor. Once the truck is running the charging system supplies not only the current to keep it running but also the current to replace what was used to start.