Remote mounted gen radiator ###pics added

[Joe Camper]

I sent a Marathon out into the black rock desert for burning man last year and that one ran for 8 days straight and the d/c fans were up to the task. 2 fans on 2 speed switches completly ducted out sucking air out of the front suspension tower and blowing it down and back. They had the ability to keep the coolant temps low enough to cycle in and out in the hottest weather.

[luvrbus]

Yea Joe I know Marathon used DC fans for while I have 4 laying out behind the shop

good luck

[TomC]

Cleaver mounting the gen battery on top of the alternator control box.  Personally-I would mount the battery on the floor next to the generator so that all the vibration from the gen-especially on start up and stopping are not transmitted to the battery.  You'll get longer life out of the battery without all that extra vibration.  Good Luck, TomC

[JohnEd]

WAL,

With all the encouragement yo seem to be getting for usng "TWO" dc fans you might consider adding a second fan to your system running it in the "push" mode. 

Your install looks neat.  Shame you might have to disgard all that craftsmanship, and I mean that sincerely, and rip it put.  Maybe get cozy with Joe Camper to get more details on his success.  Of course if Clifford has a pile of take-outs there is sure info in that.

When you visit Clifford maybe you could throw three or four of those DC rad fans in your bay.  They work well for adding air flow over your OTR condenser when your engine is at idle on a hot day.  I used one for "whole house ventilation" in the Winnie.  SUPERB!  Would cool off the interior in moments....not minutes.

Clifford,

I could use a few of those fans myself.  Let me know about a price and shipping.  Maybe WAL could help you box them up for me if that is an issue.  No need to use any but the cheapest/slowest freight.  Thank you, Clifford....in advance.

John

[luvrbus]

Now we went from Waynes 1 fan setup to 2 they didn't work out all that great for Marathon cost them a few 17kw and 20kw generators so they stopped using the setup didn't work good for Hemphill Bros with theirs either in the H-45.
Dick Wright just replaced a generator for a friend in his Marathon 1994 vintage the 12v DC fans are gone but we all do it different so we use what works for us

good luck

[JohnEd]

Clifford,

It looks to me that we are all on the same page.  Your point is that they, DC rad fans, have a history of failure and others have gone on record of seeing lots of them in service.  Without your follow-on comments, I think future readers might see one comment as a contradiction of the other.  I don't think that is necessarily true.

I am still interested in getting some of those fans in your "pile out back".  How can we get together on this Clifford?  Shipping and such..... compensation.

Thanks,

John

[Lin]

On the other hand, I think that the 24v DC fans that came out of my original OTR heat setup would do the job. 

[rv_safetyman]

Lin, really interesting thought. 

I just went out and looked at one of the units I took out of my Eagle and it is  shaft driven squirrel cage blower (12V).  As I recall, they moved a lot of air and that type of blower should not have a big issue with static pressure.

I am guessing that it is about 2/3 the size of my 120 V squirrel cage blower, but it might have enough capacity.  I will see what I can find for the ratings.

I really hate that my 120V blower takes up about 25% of one leg of the generator.  I manage, but have to work at making sure the loads are balanced.  The 12V unit would draw a bunch of amps from the batteries, but the inverter puts a high current in when it sees 120V.

Would have to work out a relay system, but that should not be a problem.

Jim

[eagle19952]

I am not sure why my generator cooling works but it does and very well,I have the exact same 4 cyl Kabota 12kw gen as I see here.
From Chino to Williams,Albuqurque to Flagstaff,Tioga Pass,Ammarillo and who can remember where else and not asingle overheat (KNOCKING ON WOOD).

My set-up is in the 2nd (middle) roadside bay,gen end too the front,
a plastic pusher fan, pantograph bay door < (upper) with the majority stainless X-metal intake air, radiator mounted to gen framework and then the "cooling effort output,pushed air" sealed into a air tight plenum opened/cutout to the ground via a 9"X 14" "heat exhaust" ...with a curved sheet metal "air deflector/director" at the top of the plenum.
All of this is in one bay and equals about 1/3 of the bay,which is walled and sealed from the curb side, and has foam eggcrate noise abatement. 
I would say it has the ability to "hold" alot of heat but it does not.
What works for me may not for you but I have no plans to mess with what works.
Good Luck
PS I am all electric 220v AC

[Lin]

Jim,
As I understand what you are saying, even though whether the blower is 12v 24v or 120v, it will need similar amperage, taking it from a different pocket (the batteries) could have a benefit.  I an not sure why it would be a significant difference though.  Please explain.  Thanks

[luvrbus]

Lin, I saw a MCI 5 at one of the Caverns rallies that used that blower motor and fans for engine cooling he said it worked but the bus was for sale LOL

good luck

[rv_safetyman]

Lin, I have a 10KW generator.  When wired for 240, that gives about 40 amps on each of the two legs.  I have the blower on one leg, and it takes about 11 amps.  Thus, 25% of one leg is spent powering the blower.  On a 10 KW you really have to be careful of making sure the loads on each leg are close.  I have ammeters for each leg and can shed load as needed.  I can also turn down the inverter charging, but that does not have a huge impact. 

It would be nice to have 40 amps available on each leg.

Jim

[Oonrahnjay]

Jim,  As I understand what you are saying, even though whether the blower is 12v 24v or 120v, it will need similar amperage, taking it from a different pocket (the batteries) could have a benefit.  I an not sure why it would be a significant difference though.  Please explain.  Thanks  

Lin, I hope that people who know electrics better than I do will comment, but what may be similar is the wattage of the fans.  In a good bit of theory, the electrical power could be 11 Amps at 120v or 110 Amps at 12v. (*)

The real life part that's missing here is that we're looking for air flow.  As has been noted, "squirrel cage" (or centrifugal) blowers will pull from a semi-vacuum or blow air into a backup or high-pressure area.  Plain blade fans will move air but if there's a restriction either on the suction or output side, they'll drop down on their air movement and also increase the current draw.  IF (and that's a big IF), a 1320 watt fan running on 12v moves as much air and moves it as efficiently under different conditions as a 1320 watt running on 120v, then basically the power usage is about equal.  

(Of course, if you're making 120v and you want to run it on 12v [or 24v], then you have to factor in battery charging losses.  Also, the wiring, switches, breakers, and fuses on 12v will be quite large -- and maybe too large to be practical.  These are practical considerations that you'll have to figure in to your own conditions in your bus.)  

But to go back to the power draw, one unknown factor is whether the 12v and 120v fans do indeed provide the same air flow (under all conditions).  If it takes 1500 watts to provide the same cooling on 12v and 1000 watts on 120v, that's a strong push toward the 120v system.

It's important to look at the amperage use (and your practical conditions) but the efficiency of that power use in doing the work is important, too.

(*  I'm using RVSafetyMan's (Jim's) power use as an example.  YWMV.)

[Lin]

I stand corrected--wattage it is.  Thanks

[wal1809]

Craigslist and $25 bucks.  Found an a/c guy in Pasadena.  He had it running on the shop floor when I got there.  It pushes enough air to loft your eyelids while your standing there.

I teresting tidbit.  He told me to use an amp meter to check the amp usage.  At the same time use a piece of sheet metal over a portion of the intake.  The amp usage will rise and fall depending on the amount of restriction. 

He restricted the fan intake by 50 percent and it was blowing twice as strong as when it was wide open.  He said restricting it properly to the amp rating on the motor will give maximum motor life.
I got hung up at work but managed to cut a new mounting board, install the fan and mount it to the box.  Tomorrow I will vet it wired in and take some photos.  Thank you fellas for all the help. Wayne