| Author |
Message |
bruce king (67.170.101.3)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 12:38 am: | |
I'm considering installing a larger car radiator on the old condensor door in my mci-9. Basically what I'm considering is taking my quiet diesel, and plumbing the radiator hoses to the bulkhead, and then attaching a car radiator to the expanded metal door and then running radiator hose to the bulkhead.
The problem that I'm trying to solve is twofold:
I was driving around last winter, and ran into some really cold weather between missouri and wyoming -- the whole way was cold. really cold. like -20 cold. and the extreme cold really killed my batteries. I've got 16 t105s, and at that temperature, they really didn't have much kick left. So I want a way to warm up the batteries, and the waste heat from the generator seems like a good candidate.
And the second is that I'd rather not punch holes in the door or floor of the first bay, where the generator is, if I can help it. The sound really isn't the issue, but would like more
ventilation for the generator.
I've located a 93 ford probe radiator, that is roughly 32" by 14", and will clear the floor of batteries that I've got in the condensor compartment now, and weighs about 5lbs dry. Since i'm gonna place it on a door that used to support a much meatier radiator before, I figure structurally it'll be ok. The probe radiator is $20 at a local junkyard.
Anyone done this? The ford radiator is roughly 2.5 times the surface area of the existing onan radiator, so I figure that it'll cool adequately. I'm inclined to spend saturday hooking it up and running the generator to see if it cools it sufficiently.
What sort of 12 or 24v pump would you guys suggest if I want to increase the flow through the radiator?
Bruce |
Marc Bourget (209.142.38.81)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 1:22 am: | |
Bruce,
What are you going to do for a cooling fan?
Doubt that the heat from the genset will do much against -20 deg cold. What was the voltage of the batts? Were you throwing a charge into them?
The genset's water pump should be enough to handle the engine's needs, as long as you don't have too much resistance in the system.
What are you doing for a surge tank, etc.
Onward and Upward
Marc Bourget |
bruce king (67.170.101.3)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 2:10 am: | |
The batteries are 6 volts, wired 4 in series to provide 24 volts to a trace sw4000 inverter. So i have 4 groups of 4 batteries each. In order not to freeze my tookus off, I ran electric blankets off the inverter, and ran 4500 watts of electric heating off the generator.
I could run the electric heat off the inverter, but typically it would go from full charge to the inverters low battery cut off voltage in 3 hours.
I may relocate the batteries to the middle of the bus where the road heat radiator is to better control their temp.
The surge tank on the genset is about a quart, and fed with a 1/8" plastic tube off the radiator cap. I was gonna study it and then weld up an equivalent with some of the polypro i've got laying around from the construction of the holding tanks.
Cooling fan is another question. I'm wondering if making the radiator twice as big will cool enough to let me get away without one. The genset has a high-temp cutoff, so feel pretty good about experimenting.
Bruc |
Marc Bourget (209.142.38.81)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 7:31 am: | |
Bruce,
Interesting discussion in the absence of more data, like the size and heat load of your genset engine.
No fan will complicate your radiator installation somewhat, I'd think, at a minimum, you'd have to mount it somewhat horizontally and baffle etc. to take advantage of convection airflow. The size of a sufficient radiator has to be so much larger if you're relying on convection airflow for cooling. A radiator is rated by the mfg for resistance in inches of water across the core at a specified airlow. This presumes sufficient airflow rates to generate turbulence which aids cooling (read below) A totally passive, convection based radiator would be something else entirely.
If you recall cigarette smoke, you remember some graphic evidence that gases of different temperature are imiscible. You may run into this problem. The locally heated air around the tubes will layer and the necessary cooling air will slide on by. The local air will almost insulate the setup. I think the fin/tube structure has to be significantly different if you wish to rely on convection cooling alone. Take a look at the baseboard radiators for an aquahot installation for example.
Does the Probe have a thermostatically acutated automatic electric fan?
Hope this approach (sans my mental ruminations) works for you!
Marc |
TWO DOGS (63.185.81.25)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 8:24 am: | |
elec. fans are all over salvage yards...pull min. current,would definitly use one |
Jim Ashworth (Jimnh) (172.139.136.55)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 8:46 am: | |
You'll need a cooling fan and it should draw in from the door because of higher air pressure there when driving. Where is it going to exhaust with the 16 batteries on the floor? Another consideration is the dirt and salt that the fan will draw in and spray all over the batteries causing corrosion and possible paths for self-discharge.
With being able to run the genset during cold weather, the batteries' role becomes less important. Since you're running the genset for the electric heaters, the inverter should be charging the batteries or supplying 24v up to 250 amps and should provide for all the 24vdc electric you need.
I would leave things just the way they are based on what I can gather from these posts.
Jim |
TWO DOGS (63.185.64.238)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 9:37 am: | |
ductwork from onan rad. could be re-routed for winter travel |
BrianMCI96A3 (64.12.116.135)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 9:59 am: | |
To be honest, if you weren't having cooling problems with the gen. I'd probably avoid messing with it, there are real long term disadvantages to an improperly designed cooling system.
However, a sufficiently creative person might be able to route an exhaust cutout that diverts the gen exhaust under the batteries during cold weather.
Brian |
BrianMCI96A3 (64.12.116.135)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 10:09 am: | |
An alternative to diverting exhaust GAS to warm the battery bank, might be using the exhaust's HEAT by wraping piping around the exhaust then pumping coolant around the exhaust and under the batts.
I don't believe it would have to be a very efficient system to keep the battery bank sufficently warm.
Brian |
DrivingMissLazy (66.168.175.51)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 10:50 am: | |
My genset was plumbed into the radiator of my Eagle and even with that large radiator, it would not keep the genset cool. I added an auxiliary 16 inch fan from Pep Boys and that solved the problem. The fan had a thermostat that turned it on at 180 degrees, I believe.
You also might consider a finned heat exchanger for the battery compartment if you have a hot water heating system for the coach.
Suggest you talk to Dick Wright at Wrico for more hints.
Richard |
Buswarrior (Buswarrior) (64.229.211.18)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 7:01 pm: | |
Hello Bruce
I'm thinking you may be fixing the wrong broken thing.
By way of introduction, I live in Canada, where a busnut design criteria regards -20 as moderately cool, not cold, if you know what I mean.
Think of it like this: from -20 to 70 is a 90 degree burden on your equipment. Somewhere warm at 100 is only a 30 degree burden on your equipment to reach 70. Cold is a much bigger challenge than heat, when it comes to energy consumption.
In -20 weather, you will be hard pressed to stay warm with only 4500W of electric heating. If you still have a relatively stock coach, you'll wait hours (all day) to raise the temp from cold, and there will be cold drafts roaming around all the time. Even with a foam insulated coach, with most of the glass removed, how did you seal up the front end? The gaps under the driver in the floor for steering and controls and the defroster are notorious for drafts, and the windshields suck the heat out.
Electric heaters are power hogs in the eyes of a battery system. Your batteries will last a while longer when they are warm with a load like this, but your improvement might not be worth the effort.
Try out your battery bank right now by forcing a continuous load equivalent to your heating desires on them in warmer climes. You might not get much more time from them. And then the energy used to keep the batteries warm won't pay you back in equivalent gains. Better to use the heat inside.
Truckers up here use some styrofoam insulation in their battery boxes so they retain the heat of charging longer. My batteries will sit on styrofoam and have degrees of enclosure depending on the season. Don't completely enclose them!
Basically, in winter weather, depending on your design choices, you have to expect that you will be running the generator full time to stay warm, unless you have a big enough fuel burning furnace that draws a relatively small amount of power in relation to a quarter of your battery bank (battery bank only pulled down to 50% and really cold steals another 50%)
And by big enough furnace, I'm talking more furnace than you've seen in a stick and staple. There's another reason you don't see RV's on the roads in winter - they typically don't have enough furnace in them for comfort.
(Hmm, wonder which came first... no winter travel or inadequate furnaces?)
Also remember condensation. For the health of the occupants, as well as the coach, you have to exchange some air, which places an even greater burden on the heating. Same as a house up here in the frozen north, condensation running down the windows means insufficient air exchange and too high humidity inside. And it'll be ice inside, not water, at -20.
I would be more inclined to figure out which way you would like to use the generator's waste heat to help heat the interior of the coach through the use of radiant heat, heat exchangers and the like. In conjunction with a webasto coolant furnace, and some radiant piping, you could build a heating system that should last the night without the generator running, with your big battery bank only running a circulation pump and the webasto.
That's the way I'm heading. I have had to listen to fans blowing in coaches professionally for too long. I'm going to try listening to water trickling through pipes, and the related expansion and contraction ghosts to see which I dislike more...
Next coach, I think I will pursue one of those neat no electric Dickenson ranges that Fast Fred pointed us to awhile back.
Do what makes you happy, the rest of us can get stuffed.
happy coaching!
buswarrior |
bruce king (67.170.101.3)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 9:42 pm: | |
Excellent message buswarrior.
You're right; 4500 watts of heating only brought the interior temperature up to slighly above freezing. This was before I converted the inside, and after that experience i'm putting as much insulation everywhere that I can; on the walls, under the floor, behind the cabinets, etc.
For sleeping purposes, the electric blankets' 40 watts was what kept it from being terribly cold, but I was wearing ski clothes most of the trip.
The eventual plan does include a webasto, mostly because cranking the engine when it was cold took a very long time. |
rbt137 (4.5.49.239)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 03, 2004 - 10:16 pm: | |
I have a 7kw with an overtemp sensor that has the coolent system plumbed into the webasto system.
When in snow country, the radiator is blocked off and the only cooling is through the webasto system. I control generator temperature by monitoring the incoming heat lines. The generator will run until the battery banks are 90%. On occasion, the interior may get too warm & it will be necessary to open vents.
When the batteries are charged, genset is shutdown and the webasto runs off the batteries for the rest of the night. The inverter will run off the second set of house batteries and will power heat tapes (waterlines) until morning.
In the summer, the genset waste heat is simply dumped into the baggage compartment and then blown out with a fan. In extreem hot weather the baggage door is open and a false floor allows waste heat to exit directly. (with the door closed, the waste heat can be redirected back into the baggage compartment)
works for me........ |
Bill Butler (172.138.175.5)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 05, 2004 - 7:11 pm: | |
My 4905 was professionally converted by Texas
Coach. The radiator for my 10kw generator w/Kabota diesel
is located on the opposite side of the coach right in front of the rear wheel. It is a small car radiator w/ a electric fan and works just fine.
I checked the flow and it seems to be enough.
There is no booster pump. The hoses used are 1"
ID. |
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