Powertech 8kw genset

[chuckd]

Well some of you have read my posts about my 12kw kohler becoming very warm and spewing smoke all over the coach.  I have purchased a new generator portion of the genset from a board member for a very reasonable price, and we will be taking the entire genset out, Perkins et al, and replacing generator portion and cleaning out and reinsulating the box it is in.  Not a project for the faint of heart, and I will be dirty when done.

But another option has come up.  I guy here in Mn has a 8kw powertech genset with only 320 hours on it.  It came from a S&S coach that had the generator portion come close to catching on fire also.  The owner held out, and got Powertech to replace the entire genset.  The seller bought the Kubota engine, quiet housing et al, and put a new generator on it.  He is asking $4500, which is reasonable, but not a steal.  But he has a buyer in Iowa that needs a 12kw genset, and he would take mine in trade.  So one of his friends is coming out next week to look at my set up and we will see what happens.  My genset has about 1800 hours.

I have looked at the current draw of my Crusiair's and they draw somewhere from 13 to 20 amps depending on model (I don't know which model I have) - worst case would need 60 amps running current.  So the 8kw will handle that, but now sure if it will start all 3, but won't be doing that all at once anyway.  I run electric heaters and do not know the wattage of them, but will find out.  Would have to do some power monitoring if I went with the Powertech, but it might be an option.  It will run my cook top, but would love to replace that with a propane unit - probably not going to happen.

So any thoughts on making a switch like this?

Thanks in advance

chuckd - who is watching the water rise on the St Croix

[belfert]

I have that same basic generator that I bought new in 2006.  Mine has the Cat/Perkins engine instead of the Kubota as they didn't have a Kubota in stock at the time.  Everything is the same except the actual engine.  Price at the time was the same for either.

I only paid $6,000 including shipping which was a steal.  Someone else asked and they wanted at least $6,000 plus shipping.  I have no idea why I got such a deal.  $4,500 to me seems a bit steep, but new ones have gone up a lot too.

Anyhow, I really like mine.  You're welcome to come over to look at it as I live in Shoreview, MN.

[Tom Y]

Try Wes, At 606-843-9889. An RV wrecking yard. I have no intrest here, just another place to look.  Tom Y 

[FloridaCliff]

Chuck,

$4500 from Powertech would be reasonable, as they would give you a warranty and stand behind it.

I wouldn't pay much over 3-3500 from an individual with NO warranty.  And then it better be like new.

Everyone has good intentions during the sale, but if it blows up next week, its all yours.....

BTW, I bought a used 8Kw from PT at around 3500.  picked up.

Cliff

[luvrbus]

Better stick with 12 kw Crusiair's are like any other AC unit the amp draw will go up in a 100+ degree temps and they are temperamental about starting without the correct voltage, great units I loved mine but I had 12.5 kw generator 8kw is going to be marginal for you with 3 Crusiairs  

good luck

[FloridaCliff]

I have looked at the current draw of my Crusiair's and they draw somewhere from 13 to 20 amps depending on model (I don't know which model I have) - worst case would need 60 amps running current.  So the 8kw will handle that, but now sure if it will start all 3, but won't be doing that all at once anyway.  I run electric heaters and do not know the wattage of them, but will find out.  Would have to do some power monitoring if I went with the Powertech, but it might be an option.  It will run my cook top, but would love to replace that with a propane unit - probably not going to happen.

Chuck,

On the power side, I totally agree with Clifford.

You are to close the edge with 3 roof airs.  Go with at least a 10Kw.

This is supposed to be fun, not spending all your time on power management...

Unless you enjoy that sort of thing..

Cliff

[belfert]

You are to close the edge with 3 roof airs.  Go with at least a 10Kw.

Three roof airs should take less than 6,000 watts.  You could start to run into trouble if you have an electric water heater, microwave, and fridge all running at the same time as three roof airs.

If one plans for a generator large enough to power every possible load at once the generator will be running well below optimal load most of the time.  You might even get into wet stacking issues.   Ask Sean about running a generator at under half load a lot of the time.

[luvrbus]

Won't happen in the real world Brian the RV people for years tried to run 2 roof airs on a 6.5 never happen it would get hot and shut down 1 unit or the generator and with your numbers a 4kw would run 2 ac units never work Brian like it or not the RV manufactures do know how to size a generator took a while but they did get it right.
I thought you were the one that said most bus people just run their generator at 1/2 load so the 1/2 gal a hour for fuel sounded right to you


good luck

[FloridaCliff]

You are to close the edge with 3 roof airs.  Go with at least a 10Kw.

Three roof airs should take less than 6,000 watts.  You could start to run into trouble if you have an electric water heater, microwave, and fridge all running at the same time as three roof airs.

If one plans for a generator large enough to power every possible load at once the generator will be running well below optimal load most of the time.  You might even get into wet stacking issues.   Ask Sean about running a generator at under half load a lot of the time.

(draw will vary by unit and company)

15K A/C unit,   start-up 3.5K, run 1.5K, 3 X 3.5 = 11.5k, 3 X 1.5 =4.5K

13.5K a/c unit,  start-up 2.75K, run 1.25K, 3 X 2.75= 8.25K, 3 X 1.25=3.75K

Good engineering practices requires you plan for all on at same time.

This is when new.  As they age they will continue to draw more amps to start.

With a refrigerator, hot water, microwave starting at any time, a safety margin is a good idea.

Cliff

[JohnEd]

See, now that's what I really really like about Clifford's approach.  FIND OUT WHAT DID AND DIDN'T work.  Then decide.  Those engineers were the bain of my existence with their "what should work" and "what the analysis proves".  All that is good for is the data needed to make the first try and thereafter the "results" are what you use to guide your decisions.  But if you don't have that experience data then ya gotta start shove'n money at the twits and keep your fingers crossed.  My life and tech problems weren't all that complicated though....like how much generator do I need for this installation?

I do hear more stories, or so it seems, about guys that have "way to much" generator and are suffering from that.  I have the two roof airs and the 6.5 but I have never had to run both at the same time and can's from the pole cause that capability is wired out.

I know I didn't do you  too much good.

John

[Fredward]

Keep in mind these are not "roof airs". They are Cruise Airs. Basement models as I recall. I don't know if they draw more or less, but just thought I would point that out.
FRed

[JohnEd]

That is a Nick question if he has the time or is even home.  He sells both unless i am mistaken.

Thanks,

John

[belfert]

I thought you were the one that said most bus people just run their generator at 1/2 load so the 1/2 gal a hour for fuel sounded right to you

I know that much of the time I am using no more than 1/2 of my generator's power.  I've read a lot of posts and talked to people who don't end up using the full capacity of their generator.

The Powertech 8KW generator at 75% load takes .56 gallons per hour per the book.  The book probably understates the fuel usage but still 1/2 gallon an hour at half load should be easily doable.

[Len Silva]

I would not be calculating for trying to start all three AC's at the same time and once they are running, it is highly unlikely that two or three would be trying to start simultaneously.

If necessary, it would be fairly simple to automate power management so the water heater is not on when all three units are running.

Personally, I would go with 8kw and a little management.

[TomC]

I have a friend that had the 8kw Powertech in his previous truck.  When he sold the truck the Powertech had just over 23,000hrs on the engine-with the gen head being replaced once.  That's like 920,000mi on that engine!.  Good Luck, TomC