Truck Apu DC generator

[kcarsey]

Here is a Video of a QD6000 which uses the 3 cyl D722 Kubota

https://www.youtube.com/watch?v=Iu6LiBxOSRQ

I think they are pretty quiet especially when running at lower speed ~1500 rpm

At full output I think they run at 2200-2400 rpm. The smaller QD generators are Invterter just like the small Honda models.

The Cummins/Onan are probably lined with something similar to https://www.westmarine.com/buy/west-...06_180_006_004

[cadillackid]

Look at the sander enhanced HD7 compressors , they have an even better curve.. it’s going to take quite a bit of Horsepower to overdrive that compressor.. I also think their book is a little off as I’m running 65,000 btu of evaporators off an JD7 and it cools great, mine is overdriven a bit but for 30k I don’t thinl you need to spin it at 4000 rpm.
Heistopher

[kcarsey]

I have a lot of numbers/ideas/graphs in a google doc that I constantly update as I do more research. One of the biggest challenges i've come across is 1. how much cooling do I really need? and 2. what components will achieve that. Finding a compressor that can cool x btu at y rpm isn't terribly difficult. The harder part is figuring out how many evaporators do I want? what size should they be? how big should my condenser be, etc. 65,000 btu is a heck of a lot of cooling. From what i've been reading a lot of folks get by with two 15k btu roof top, although this solution would have to be able to keep a reasonable temp going down the road also. I'm sure what you have was already installed that way from the factory, which if so then of course use it by all means.

I guess what i'm saying is, if i'm in a bus scrap yard, do I need to bring home a 65k btu evaporator?

With absolutely no numbers to back it up other than off the cuff research on what others do, a goal in the back of my head I've been shooting for is 36k btu max capacity, then maybe something with a 2 speed blower (also lower engine rpm) for times when less cooling is needed.

Something I came across: Pretty expensive but neat, and could just do a ducted system. https://www.truckac.com/units-a-c-he...-0p-t6789.html

[BlackJohn]

Kcarsey, hi, does that Kubota have a PTO? That would be ideal.

Run that at 1800rpm's and you get 60cycle,110-220vac power from some generators, depending on how many poles they have. Most gas gens run about 3600 and can't sip fuel like that diesel.
Might be worth finding an engine that does have the PTO.

Even my Yanmar, 2 cyl, has two PTO. front and rear so could run a genny easily and perhaps a water pump etc also.


John

[cadillackid]

Remember my busses aren’t converted so I run AC for the road and I do a lot of driving in the south even in summer.. 65k in a 7 window bus is right for a stock insulated road diving system. Factory units in school busses typically ran 120k plus for a 11 window conventional with tinted glass.. if you are super insulating and covering or removing or replacing with better windows you’ll need less AC for the road but engine heat and sun heat are the real deal when on the road. When parked you can get away with a lot less AC, many people here seem to be OK with sweat rags when driving as long as they can sleep cool.. me personally I wanted to be more civilized than 1948 so I build AC that will keep me cool in Texas and Florida in July on the freeway..
Christopher

[Tango]

"I wanted to be more civilized than 1948 so I build AC that will keep me cool in Texas and Florida in July on the freeway.."




You could learn a lot from the way this young man thinks!

[Deezl Smoke]

Originally Posted by Tango

"I wanted to be more civilized than 1948 so I build AC that will keep me cool in Texas and Florida in July on the freeway.."




You could learn a lot from the way this young man thinks!

It's funny cuz the people in 1948 were soooo much more "civilized" than the people of today with their identity politics and all the other crap that goes with.


But I can fully understand not wanting to be stuck to a vinyl seat after driving a couple hours in texas during the summer. Or have the skin on your hand fuse to the door handle.

[Tango]

Totally agree that the "people" were more civilized...but the technology of comfort was way behind.

[cadillackid]

Possibly but as a computer geek and a gay man I’m sure glad to be living in 2019 vs 1948..
In some ways we have gone backward but many ways we are moving forward...
Christopher

[kcarsey]

Originally Posted by BlackJohn

Kcarsey, hi, does that Kubota have a PTO? That would be ideal.

Run that at 1800rpm's and you get 60cycle,110-220vac power from some generators, depending on how many poles they have. Most gas gens run about 3600 and can't sip fuel like that diesel.
Might be worth finding an engine that does have the PTO.

Even my Yanmar, 2 cyl, has two PTO. front and rear so could run a genny easily and perhaps a water pump etc also.


John

Not exactly sure what you mean by PTO as far as related to the engine. Normally PTO (power take off) are accessory attachment points on a vehicles main transmission. They take power from the main engine/trans to drive an accessory such as hydraulic pump, air compressor, vacuum pump, etc.

Single phase a/c generators are 2 pole for 3600 rpm and 4 pole for 1800 rpm.

I was suggesting the use of a small 3 cyl engine dedicated to driving a/c compressors and also a 12v alternator. With a setup like that I would not even need/want an a/c generator. the 12v alternator isn't required to run at a constant speed, could run my evap/condensor fans while a/c is on and also charge my house batteries. My plan would include an pure sine power inverter to run any a/c loads that I need.

[BlackJohn]

My bad, forgot to mention the engine is mated to a transmission of course. Wouldn't take up much more room so just another option I guess. Lots of those engines around from lawn tractors.
Thanks for your reply.


John

[TJones]

Originally Posted by kcarsey

Not exactly sure what you mean by PTO as far as related to the engine. Normally PTO (power take off) are accessory attachment points on a vehicles main transmission. They take power from the main engine/trans to drive an accessory such as hydraulic pump, air compressor, vacuum pump, etc.

Single phase a/c generators are 2 pole for 3600 rpm and 4 pole for 1800 rpm.

I was suggesting the use of a small 3 cyl engine dedicated to driving a/c compressors and also a 12v alternator. With a setup like that I would not even need/want an a/c generator. the 12v alternator isn't required to run at a constant speed, could run my evap/condensor fans while a/c is on and also charge my house batteries. My plan would include an pure sine power inverter to run any a/c loads that I need.

That is what I am thinking. The alternator can be used with an advanced alternator regulator or an alternator to battery charger to get the 3 stage charging for the deep cycle batteries. Sterling Power seems to have some good options for this. I believe thier alternator to battery charger could be connected to 2 alternators. Charge from the bus alternator while underway and complete the charging cycle from the APU. It would probly require some additional diodes to protect the alternators from reverse currant.

https://www.sterling-power-usa.com

Ted

[kcarsey]

TJones,

You bring up a significant problem that I have had in the back of my head: how the heck to charge batteries and power devices with all those power sources.
1. Main engine alternator, could just use a battery isolator to charge engine +house batteries.
2. Apu alternator that I’d be running from my small engine along side a/c compressor, probably 140 amp unit.
3. These small engines have their own alternator but it’s usually small, 40 amps. I’d keep the apu starting/charging system completely separate with its own small starting battery.
4. Solar charger

So how the heck would someone manage all these power sources and not overcharge or charge too quickly the house bank, but also at the same time power electrical loads like the 30-40 amps that condenser and evap fans will likely require.

[john61ct]

Originally Posted by TJones

advanced alternator regulator

Let the alt be rough output.

Get a BB DC-DC unit to front-end the bank, fine tune inputs from **any** old DC source.

[TJones]

Originally Posted by kcarsey

TJones,

You bring up a significant problem that I have had in the back of my head: how the heck to charge batteries and power devices with all those power sources.
1. Main engine alternator, could just use a battery isolator to charge engine +house batteries.
2. Apu alternator that I’d be running from my small engine along side a/c compressor, probably 140 amp unit.
3. These small engines have their own alternator but it’s usually small, 40 amps. I’d keep the apu starting/charging system completely separate with its own small starting battery.
4. Solar charger

So how the heck would someone manage all these power sources and not overcharge or charge too quickly the house bank, but also at the same time power electrical loads like the 30-40 amps that condenser and evap fans will likely require.

This is the best option I have found.

https://www.sterling-power-usa.com/s...ycharger.aspxt

It has 3 stage charging for house batteries and separate charging for start batteries. It gives priority to the start batteries.

The condenser evaporator fans would best be attached to the start battery bank so that the house batteries can go through the charging stages: bulk, absorb and float. If there were a large load on the house battery side it would take longer to charge the house batteries and they might not make it to a fully charged state while you want the ac to run.

The solar would need it own charge controller.

Ted

[john61ct]

Their BB units giVe much more flexibility, and can be stacked if more than 60A continuous is required.

Why invest in just your alt, when you can use the BB to front your bank to all your DC sources, no need to spend extra on any other fancy charging gear?

[TJones]

Originally Posted by john61ct

Their BB units giVe much more flexibility, and can be stacked if more than 60A continuous is required.

Why invest in just your alt, when you can use the BB to front your bank to all your DC sources, no need to spend extra on any other fancy charging gear?

Your right the battery to battery charger looks like it would work well, especially if a person wants to use a 24v battery bank. I think the major difference between the battery to battery and alternator to battery is the max charging currants. Also the alternator to battery charger pulls the alternator voltage down to force it to produce max currant. More currant, but it might be harder on the alternator.

Ted

[kcarsey]

Originally Posted by john61ct

Their BB units giVe much more flexibility, and can be stacked if more than 60A continuous is required.

Why invest in just your alt, when you can use the BB to front your bank to all your DC sources, no need to spend extra on any other fancy charging gear?

Who is they, and what exactly is a BB unit. Sorry, I either might have missed in an earlier post or maybe i'm just unaware.

[Booyah45828]

Wow, not sure how I missed this thread. Kudos to you for thinking of doing this.

I have a truck apu on my bus. It was originally a blackrock apu unit. I bought a pair of them from a truck scrap auction for cheap and made what I wanted out of the lot.

Most semi truck apu's in stock form are pretty quiet. I think mine was originally rated at 60db, which is fairly quiet concerning generators.

Anyways, It's a 2 cylinder yanmar diesel engine. It uses a serpentine belt attached to the flywheel to turn a 6kw sincro generator at 120/240vac. On the other side it has a standard v-belt that turns the waterpump and a 40 amp 12 volt alternator.

The ac power is fed to a cheap 5.5kw generator panel. I also have a 12v fuse panel for all the 12v stuff like cooling fans, glow plugs, alternator, fuel pump, etc.

I've been meaning to do a write up and post some pics, just haven't had the time. Ask any questions that you have.

[john61ct]

Originally Posted by kcarsey

Who is they, and what exactly is a BB unit. Sorry, I either might have missed in an earlier post or maybe i'm just unaware. [emoji144]

Sterling

https://baymarinesupply.com/sterling...er-bb1260.html