High Output Alternator Upgrade - Has anyone done this?

[IsleDog]

Originally Posted by ghhardin

What is a PTO generator?
A Tractor Power Take Off (PTO) generator is one of the quickest ways to turn your most trusted piece of farm equipment into a mobile power plant. PTO generators convert the energy from the output shaft of your tractor into electricity with minimal loss.

some HD trucks have an option on the transmission for a PTO to be installed. it can run hydraulics, air pumps, and generators. Usually though, the truck must be stopped and a high idle controller installed to bring the engine RPM up a bit. these PTO units can output HUGE amounts of electricity, including 480 3 phase.

https://www.youtube.com/watch?v=f2WCgrHl65A

you could also convert your roof AC over to a 12V unit. but that requires a way bigger charger when plugged into shore power. there is some discussion about this in the Dynamax threads, something like 100 amps of 12v DC power to run one.

[Oscarvan]

There is no PTO on the RV Allisons that I am aware of.

[aeblank]

I used to work for a company that made generators that would run off the PTO. Way more than a normal person would want.....

[rickkey2]

I think this subject is being over analyzed IMO
The on board generator is there to make power when needed so use it.
When its hot and the dash air won't cool it down I run my 8kw generator and my roof A/Cs and cool things down while driving down the road. To me the diesel fuel used to run the generator is minuscule in the scope of things. I start my generator about a half hour before we arrive at our destination anyway to get things cooled down or warmed up ( winter ) during set up at site. These systems are there to be used. I think that your generator will do a heck of allot better than a high output alternator. Please let us know what you end up doing and how it worked out. Sounds like to me it's going to cost allot to do what you want to do and burning a little more diesel is more cost effective.

[rsdata]

I would think that if you do not have an engineered off-the-shelf option of adding alternator output, then maybe you would be better served to find a ventilated corner of the coach (somewhere, not being an owner, I don't have a clue where) and just use a 3000+ watt gas or diesel powered inverter/generator available off-the-shelf to power a dedicated AC roof unit...

just a thought...

[ghhardin]

LOL - YES my rig has a 10K generator.....


... I just want to see if I can replace it with batteries..

[Oscarvan]

Some of us just like messing around with it because we can.... See my blog below....

[bob5560g]

Dear ghharrdin, aka Tim the Tool Man Taylor,

As an EE, your knowledge is vast whereas mine is only half-vast... but can every inch of associated wiring handle the hundreds of amps of current from the Binford Model 12,000 alternator you envision? Any smaller gauge wire in the entire charging system will become a (flammable) fuse if too many amps run through it....

Good luck, and have the Widow Hardin tell us how it turned out.

[Photo Lab]

Originally Posted by ghhardin

LOL - YES my rig has a 10K generator.....


... I just want to see if I can replace it with batteries..

Sure enough, a man after my own heart! As a now retired Controls Engineer, I always tend to overthink things, as nearly all of the respondents do.

however, this is an area in which I've had more experience than I like to admit, mostly when dealing with bus conversions on regular highway coach shells. In my first bus, the alternator was a 150 amp Leese Neville, which worked very well for the normal loads. Bear in mind however, that the regular bus heater/air conditioner has a 3/4 to 1 HP electric motor to run the blower. So, I added an additional, automotive 90 amp alternator, which was the big dog at that time, in the middle seventies. I connected it to the house battery bank, and also connected the blower motor to that bank. Since the motor only drew a bit over 50 amps, I figured I was good, which I was not. In about 50 miles, the heater quit...the 90 amp alternator had self destructed.
I found that automotive electrical systems are in no way what one would expect in other systems. For example, the 90 amp alternator was rated for a duty cycle more in keeping with the original application, about 20%. While determining this, I also learned that auto wiring size is determined by voltage drop, and units such as the fan and starter motors are designed to operate correctly on the voltage delivered under load. That is why the wire always seems too small. It also has high temperature insulation in most cases.


Alternators used in highway coaches on the other hand, are rated for continuous output, more like a generator set. Eagle buses, which I have considerable experience with, as well as MCI or Prevost, typically have a 250 amp oil cooled alternator. While Eagle moved to a 350 amp air cooled unit, with V belt drive and 12 volt output, the others chose to stick with the 225 to 250 amp units, but went to a 24 volt electrical system. The HVAC system in both of those have a 1-1/2 HP blower motor and a 2 HP condenser fan motor, while the Eagles have two 3/4 HP blower motors, and the condenser fan is a clutch controlled engine driven fan.

What is the point here? Automotive alternators are not designed for continuous output at the rated amperage. You CAN buy a 350 amp alternator, assuming you can find enough real estate for it (about 10" in diameter and a foot long, 80-85 pounds)but using the optional aftermarket unit you mention is probably a better option, and operating a continuing load while on the road, the size of the battery bank should not enter into the equation. Still looks like running the gen set is the best option, but not the one which allows the best bragging rights!

In retrospect, when I look back on my bus conversion days, I surely would have liked to have available the very low cost PLCs now available! I was happy to have a CD player that worked properly on the road and a DVD player!

[Bluepill]

Even if I could build this project for under a thousand dollars, I wouldn't do it.

1. Adds complexity; therefore reduces reliability.

2. Unless you plan to remove and sell the generator to offset the cost of the new system, you are just sitting on a ten thousand dollar investment and getting no ROI.

3. The generator needs to be run regularly under load to exercise it anyway.

4. You cannot hear the generator running while on the road, so that's not an issue.


To me, the first rule of practical applied engineering is:
Just because you CAN do it doesn't mean you SHOULD do it.

I'm sure that Feynman would agree.

[Oscarvan]

Originally Posted by Bluepill

Even if I could build this project for under a thousand dollars, I wouldn't do it.

1. Adds complexity; therefore reduces reliability.

2. Unless you plan to remove and sell the generator to offset the cost of the new system, you are just sitting on a ten thousand dollar investment and getting no ROI.

3. The generator needs to be run regularly under load to exercise it anyway.

4. You cannot hear the generator running while on the road, so that's not an issue.


To me, the first rule of practical applied engineering is:
Just because you CAN do it doesn't mean you SHOULD do it.

I'm sure that Feynman would agree.

It appears the nay-sayers are properly represented. You did give me an idea though.... Yes, remove the generator but not because I could sell it.... the "drawer" up there is the perfect place to store about 10,000Ah worht of Li-ion...(When the price comes down..... )

[ghhardin]

I did the weight calculation



My Onan 10K weighs 765 lbs that means I could install about 25 RB100-LT series 12V 100Ah lithium iron phosphate battery can charge at temperatures down to -20°C (-4°F).



This would give me 25,000 AH @12VDC..


Replace the house battery weight with a transformer at 300 lbs and the rig would be weight neutral...


BTW - 25,000 AH at 12VDC is a LOT of power



Adapting a powerwall technology is most likely a better approach as they are all self contained and optimized.





https://news.energysage.com/battery-...right-for-you/

[ghhardin]

This is the link that compares the whole house self contained battery backup and transformers...


https://www.businessinsider.com/home...wall-2-2016-10

[rsdata]

with the large amount of real estate on the top of the bus I am surprised you are not also considering solar panels as a charging mechanism for your massive battery bank...

I just returned from Pensacola area, ( to a snowy reception here at home) but I have to mention the abundant pine pollen I was washing from my TV every other day, which would lead me to also design some type of auto-rinsing system for the panels.

This is a great mental exercise for all respondents here for sure.

As an afterthought, would not a 24V system require less wire gauge then a 12 V system?

[aircommuter]

I didn't see where there was any mention of wire sizing. The duty cycle post you did receive is correct. Those alternators can put out those ratings for a short time and as the batteries charge it tapers off. This is partially the reason your other generator weighs what you said, As for replacing the 10K generator with a battery pack is not a very good comparison as the battery pack will only produce power for a limited time unlike the generator that will keep producing it continuously as long as it has fuel. What ever you do to charge batteries still uses fuel plus inherent losses. No free ride. As for PTO generators they are gear driven from a gear on the transmission or transfer case if you had one. Generally they are not designed to be engaged while driving. They still use engine fuel as well unless you are planning on going downhill all the time. Sounds like you are planning on something that will give you free power. They advertise electric cars that way too. Meanwhile the majority of the electricity is still coming from coal, oil, and gas. then huge generator losses and line losses.
Typical losses are around 70% not including all the fuel spent to get these fuels out of the ground and to generator plant. Cheap and clean is such a fallacy.

[ghhardin]

I would luv to standardize on 24V/48V and am investigating that possibility...

Most of the residential "wall" solutions work off of 48V..
The link earlier in the thread - The Sailboat analogy is equivalent to the Land Yacht..

https://www.integrelmarine.com/
This was pretty interesting as the solution charged and stored in 48 V and then down-converted to 12V


I have been having the internal debate with myself regarding utilizing Solar versus Diesel & Landpower. My thinking is since I do not plan on boondocking for extended periods of time - (most likely weekend trips - wife, kids, dogs & job). If I am driving the rig every few days or connecting to land power every few days then solar may not be as necessary. However, I do understand the value of it. It is the straw versus fire hose trade off..

[ghhardin]

Agreed, nothing is free... I am under no impression energy cannot be created and every transform loses energy. This is true for both mechanical & electrical systems and heat is the most likely byproduct of this inefficiencies.


I fully acknowledge, wire-gauge is a function of Amperage... Better go BIG else they melt ;/


I am a Telsa owner and have lots of practical experience in power consumption... Mostly when the car tells me I wont have enough power to make it to the charging station. Its call pucker factor - the tighter you squeeze the further you can go - LOL

[Oscarvan]

Originally Posted by rsdata

with the large amount of real estate on the top of the bus I am surprised you are not also considering solar panels as a charging mechanism for your massive battery bank...

Ah, I love it.....

Let's for easy math say a 100W solar panel is 4'x2', so 12.5 W per square foot. Let's assume a nice sunny day in Death Valley and we get 100% efficiency for 10 hours.... that's 125W

25,000 Ah is 300,000 watt...... at a 50% discharge that's 150,000 W (To put that in perspective.... in death Valley you'd be running your AC..... 10A 10 hours at 120VAC is 120,000 Watt)

So...... to reload in a day we need 1200 square feet.... Bus is 40x8 is 320..... you need 4 buses.

Or..... 4 days.

Now you can tweak these numbers in every direction, but the bottom line is that there is NOWHERE NEAR enough real estate up there to create the energy we use.

Can it help? Of course. But it's not near enough so you need another source and the other ones (generator/shore/engine) would create a lot more in shorter time so the thousands spent on covering your roof would have a bad ROI.

Que the people boon docking on solar out there. With a propane fridge, no AC and 3 LED bulbs to read a paper book by. That's not what we're talking about here. We're talking about using these buses with all the doodads operational.

[Oscarvan]

But I'm starting to like the idea of massive generation off the engine and a massive Li-ion bank.

The way we use ours..... drive...... lunch in a rest area, drive.... nap at a Wallymart, drive..... campground would be perfectly suited.

Enough stored energy to run Heat/AC/Make hot water/Cook/Shower for 12 hours, enough generating capacity to put it back in in 5 hours of driving.......

No generator, no aquahot, no furnace, no propane..... Big AC centralized heat pump system in the basement (with resistance backup) with high pressure/small diameter zoned ducting everywhere (including the dash) Nice and clean.....

Almost have to start from scratch and build it with none of the nonsense cabling/plumbing in there..... And an engine 100 horse bigger than the GVWR calls for....

Hmmmmmm......

[ghhardin]

Oscarvan - LOL I came up with the same math.. hence my approach of using the diesel to Fast Charge the battery bank...


BTW - Every watch the movie Mars? where he uses the solar arrays to power the rover? I thought it would be fun to try this across the US....I did the math for my telsa - OMG I needed a big trailer with lots of solar panels and it would still take me days to charge the tesla