Mack E7 Etech what to do as tap water was run rather then coolant

[Gorilla]

On 4/21/2025 at 11:17 PM, Geoff Weeks said:

"thing is i have four 920ah batteries"

That I got to see! I had 4 155 amp/hr batteries for a total of 620 amp/hrs and they all are bigger than the std gp 31 truck batteries.

Deep cycle gp 31's are 135 amp/hrs, cranking gp31's would likely be a bit less.

I think you are confusing CCA with amp/hrs, they are not the same thing.

When an electrical load is placed on the truck, the alternator will take up that load up to the capacity of the alternator, then the batteries start depleting. Converting from rotational belt to electrical and back to rotational is not an efficient process.  Fixed RPM means that load is fixed. It also means it can't reduce draw at lower loads and can't increase when needed, like pulling a hill. So when a fan is needed to pull air across the condenser, you'll have only one choice, with an electric fan, where as an engine driven fan can turn slowly at idle,using very little power.

A/C compressor use "face seals" to hold in a fix amount of refrigerant at pressures exceeding those of the trucks air system. The older Hortons anyway, not sure on the new stuff, also use face seals for the air. They also use O rings for the piston seals.  I find moisture in the air causes most problems, be it with the fan clutch or elsewhere.

No mfg of a truck or bus engine relies on an electric fan, that should tell you something right there. On motor coaches where direct belt drive for the fan is not practical, hyd drive is used.

Your money, your choice, but wouldn't be mine.

Sorry i ment cca not ah, my bad.

As for the electric fan it will power on as required and takes 25amps at 24volts while my alternator is 100amps at 24 volts therefore ample headroom, it wont run 100% of the time and will be actuated by the same computer signal the horton fan was actuated by but rather then pneumatic it will be electric. Mainstream manufacturers do what is cheap not what is best, its about providing a product just good enough to pass the warranty period at minimum cost, a clutch fan is much cheaper to make. 

[Gorilla]

On 4/21/2025 at 11:42 PM, Geoff Weeks said:

Thing I'd want to compare is the free-air CFM of the factory (at rated speed) and the CFM of the electric. I'm not sure where you would obtain the spec's but that is what is important.

nobody will give you factory specs and im not entirely sure they bothered to test them, but the 10,000cfm fan is overkill for sure as system tested on a baja truck in the desert

 

[Geoff Weeks]

As I said, your money, your choice. It seams like your mind is made up, so go ahead, but report back how it work for you.

[Gorilla]

On 4/21/2025 at 11:46 PM, Geoff Weeks said:

My air ride truck and trailer would go 45 min running down the hiway between compressor cycles. I am not stranger to eliminating air leaks. Anything less then 15 mins while running down the hiway between cycles and I was looking for leaks.

few trucks I have been around can meet or beat that, and mine had air fan clutches, just saying.

mine was shocking thus spent a few weeks replacing all push on fittings with compression ones plus all joiners removed and new lines run.  I just got the price on the electric fan and lets just say im going to rebuild my air clutch

[Gorilla]

On 4/22/2025 at 12:52 AM, Joseph Cummings said:

The electric fan thing is doomed to failure. You are talking about at least 25 HP to run a fan. The motor on that fan in the picture is nowhere near 25HP.

25hp x 746 watts / 24 volts = 777.083333333 amps. And that is not even allowing for losses. 

wait WHAT? are you kidding me? it takes 25 amps, does 10,000cfm which is about right, my 2000cfm fan on my car has a 10 amp fuse at 12v.

[Geoff Weeks]

I have not seen another truck that can cycle the air compressor only ever 45 min while going down the road, pulling an air ride trailer on an air ride tractor.  Most I see are under 5min cycle times.

[Gorilla]

On 4/22/2025 at 4:34 AM, Joseph Cummings said:

And going from mechanical to electrical, and then back to mechanical from electrical is two extra times entropy is going to rear it's ugly head

It's just adding more I2R and friction losses to the system;

If you go down the line of thinking that you can make energy appear out of nowhere, or make energy disappear, you end up believing in things Like Stan Myers "it runs on water" or this rediculas thing of Mr Yoon's

 

how often has a electric fan failed on the many cars i have owned in many years?  ZERO is the number, how many times has a clutch fan failed?  quite a few, now there is air operated fans that are prone to leak. 

 

[Geoff Weeks]

11 minutes ago, Gorilla said:

how often has a electric fan failed on the many cars i have owned in many years?  ZERO is the number, how many times has a clutch fan failed?  quite a few, now there is air operated fans that are prone to leak. 

 

That is not a valid comparison, cars and heavy trucks.  How many have I seen, plenty. How many cars have you seen go 3 million miles on the original alternator? My '83 still had the original 26SI when I sold it. Comparing cars to trucks is comparing apples to dog turds.

[Gorilla]

32 minutes ago, Geoff Weeks said:

That is not a valid comparison, cars and heavy trucks.  How many have I seen, plenty. How many cars have you seen go 3 million miles on the original alternator? My '83 still had the original 26SI when I sold it. Comparing cars to trucks is comparing apples to dog turds.

Actually it is a valid comparison.  Everything is bigger and thats about it.  New trucks dont to a million km without a rebuild yet i know of cars with a million km still going strong, my old landrover was never rebuilt and all original including alternator with 540,000km.  As for the 26si, thats a brushless alternator so it should pretty much never fail.  An electric motor is an electric motor, there are better and worse quality ones......

[fjh]

1 hour ago, Geoff Weeks said:

As I said, your money, your choice. It seams like your mind is made up, so go ahead, but report back how it work for you.

Geoff ! I had a customer that has been running this system on a M11 powered  louisville dump truck for a lot of years he used three car fans and had room for more It works fine for him ! That said I don't know how it would be on something with 500 plus  pulling huge weight  and hills! Around town work its a decent way to go! that said if it were a great idea the the bigg guys would have been using it!  Volvo now uses a two speed water pump ! 😡 more shit to go wrong!

[Joseph Cummings]

Electricity is not some magical energy amplifier, all the conversions are a net loss of energy. It's called "entropy"

entropy 

A thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work, often interpreted as the degree of disorder or randomness in the system.

There is no escaping it. Whatever horsepower is required to run the fan to cool that engine, is going to be drawn from the crankshaft. Every step you add is a net energy loss. Belts are losses, alternators are losses, the wire is a loss, the electric motor is a loss. Introducing more steps into the energy flow makes things less efficient. Every one of those steps turns some of the energy to heat, and then it gets lost into the environment without doing work like turning the fan blades and moving air.

"The first law of thermodynamics states that energy is conserved and cannot be created or destroyed, only transferred or transformed from one form to another. The second law of thermodynamics states that in any natural process, the total entropy of an isolated system always increases. "

 

Edited 12 hours ago by Joseph Cummings

[67RModel]

What about a viscous fan hub? I know its a strictly mechanical device and the ECM on a newer engine might not be happy if there was no input or output from/to a fan. I don't know. My 94 RD has a viscous fan clutch and I never seem to know what that c**ksucker is doing. It spins on startup then seems to decouple but the drag keeps it spinning but probably not at engine speed. Its all very confusing. but no matter what amount of load you put on the engine the water temperature never gets above 175F.  ¯\_(ツ)_/¯

[Joseph Cummings]

Controlling fan speed to only move enough air as needed is for sure going to save energy. Even closing the shutters is going to lessen the energy consumed by the fan. Put your hand over your vacuum cleaner hose and you will hear the motor speed up because you have taken the load off of it. Same goes with centrifugal pumps. Put an ammeter on one and shut off the valve on the discharge. The amperage draw will go down because now the pump is no longer doing "work"

[Geoff Weeks]

2 hours ago, Gorilla said:

Actually it is a valid comparison.  Everything is bigger and thats about it. 

Nope, car engines are not run near full output all day long. Truck use is far different. Try running that car at 3/4-full throttle for 10 hrs a day and then tell me it is the same.

I have put mine through pull for 45min full throttle at speeds below 25 MPH, what car does that?

Trucks require airflow for the ATA,condenser, and radiator, all are independent needs.

My '83 originally had a viscus drive and it was missing when I bought the truck (fan driven all the time).

I had a 6.9 service truck that had a viscus fan and you could hear it lock up and unlock during the day. I was pushing that truck hard, 12Klbs for the truck and towed a tandem axle trailer also, It didn't get any better fuel mileage than the L 10 semi either, but the semi was moving 4x the weight and much more wind resistance.

Viscus can work, but it wouldn't be my 1st choice. On my 83 I went with a Horton, because I had one handy.  I've had good luck with Bendix, and it would be my 1st choice, as it fails safe (no air, spring applied ). Also had an electric clutch (Facet) on a 3406B that worked ok, took small trailer wheel bearings and seals, but parts became hard to come by as they quit making them when "computer contols" came out, The coil would put quite the "kick" back into the electrical system when the relay opened.

Kysor front air, can be adapted to any fan drive not drilled for rear air, so is another option for replacing viscus or Facet.

[Joseph Cummings]

Notice it has cooling fins. That alone tells you it's wasting a good bit of energy