Reply
 
Thread Tools Display Modes
 
Old 07-19-2007, 10:35 PM   #1
Skoolie
 
Join Date: Jul 2007
Posts: 151
Year: 1950
Coachwork: don't know
Chassis: cheverolet
Engine: to be determined
Rated Cap: 28
my ideas for a electric generation

guys again this is my first skoolie so this may be grade skool but thats where I am at
My idea to join 4 24 volt deepcells together in series just like a big rig, then get two alts. off a couple of salvage diesels.
the first will be an add-on to the engine. the second will be ran off an small engine. then to an invertor. wire the bus for 12v and 110
I thought that 24 vlt dc reduced to 12vlt dc to 110ac would cause a slower rate of depletion of the batteries and less amp draw.
the reason I would dump another alt on the motor, Is less chance of compromising the engines charging system.
an alt on a small gas engine would not put drag on the gas motor like a generator does under a electrical load.
I'll have a generator too.
So what are my flaws good idea bad idea or is this just elementary skool or overkill
whats your advice
dale
delbertinie is offline   Reply With Quote
Old 07-20-2007, 07:08 PM   #2
Bus Geek
 
the_experience03's Avatar
 
Join Date: Feb 2006
Location: Saint James, MN
Posts: 2,669
Send a message via MSN to the_experience03 Send a message via Yahoo to the_experience03
Re: my ideas for a electric generation

Anytime you convert energy from one form to another you lose energy in the process. This includes going from 24 volts to 12 volts. On the plus side, however, I have read that a 150 amp load on a 24 volt alternator is not much more taxing on it than a 150 amp load at 12 volts. I'm not sure that I believe this as you are doubling the wattage output, but it is amperage (current), not voltage, that makes heat as a general rule so I can see the basis for that idea.

You will have some problems, namely that the whole bus is already wired for 12 volts. Now you COULD run all the bus electrical off a single 12 volt leg of the 24 volt system, but then you're limited to the capacity of that smaller battery. In addition, the 24 volt system would be limited by the weaker of the two (or four or whatever) 12 volt batteries you're running. I keep saying 12 volt because I have never seen a 24 volt lead acid battery other than in aviation and I sell the suckers for a living. Most 24 volt systems rely on a pair of Group 8DA 12 volt monsters wired in series.

Now here is an option....they DO make 24 vdc to 120vac inverters. They aren't cheap generally speaking, but I think you might be able to pick one up for a decent deal on eBay or at a local truck stop. Still though...I have to wonder if it is worth all the trouble.

As for the alternator off the small aux. engine....This is an option I have looked into, actually. I have an old vertical shaft 28ci Briggs motor from a lawn tractor that I keep meaning to mount up in this fashion. I actually plan to run two alternators. One will be a regular 12 volt piece while the other will be a modified 12SI General Motors model with the regulator tweaked so I can use it as an onboard welder. I like to go wheeling, but I have yet to install a welder in my truck. Atleast this way I would have one at base camp. The modification also makes them capable of delivering 120 volts DC which is fine for running anything with a brushed motor like my grinder.

Best of luck to you. Let us know what you're doing with this idea. Bouncing ideas back and forth is what has created some of the better modifications seen on this site.
__________________
http://farm4.static.flickr.com/3024/...09f20d39_m.jpg
Skooling it...one state at a time...
the_experience03 is offline   Reply With Quote
Old 07-20-2007, 11:15 PM   #3
Skoolie
 
Join Date: Jul 2007
Posts: 151
Year: 1950
Coachwork: don't know
Chassis: cheverolet
Engine: to be determined
Rated Cap: 28
Re: my ideas for a electric generation

ok invertors are something that I understand the concept but I have had no experience with.
It seems to me that they would drain batteries pretty quick. I do not know how many amps they draw or how to select the proper one for my application other than the higher wattage the more 110 capability they have.
Is it better to have multiple smaller wattage ones to run specific items or is it better to have one big one to run multiple items.
would it be better to run 4 deep cycle 12vlts in parrellel than in series. keep the the voltage at 12 and use the extra alts to charge the batteries. I know that the amp draw would not change but would the battery depletion be slower.
You did understand that I wanted 3 seperate alternators on the bus 1 (stock) alt to power the bus engine lights ect. 1 Extra added to the motor to chagre the extra batteries while the bus is mobile. Finally 1 to be powered by a small gas engine to charge the rv batteries while the bus is non mobile. Like said in the last post, its seems to me that generator tends to add a load to the gas engine and make it work harder when it has an electrical load added. a alt. how ever does not seem to do that. So while the right combo of pulleys the right rpm for the alt could be achieved and not tax the motor, thus reducing fuel consumption on the gas motor. Also a smaller horsepower motor could be used to save more fuel.
Ok am I still all wet or is there any merrit in my idea
Dale
delbertinie is offline   Reply With Quote
Old 07-28-2007, 11:14 PM   #4
Skoolie
 
Join Date: Jul 2007
Posts: 151
Year: 1950
Coachwork: don't know
Chassis: cheverolet
Engine: to be determined
Rated Cap: 28
Re: my ideas for a electric generation

alright guys I realize this one is a dead horse.
Now that I have been given some wonderful advice and a lot of research
I realize why gens are the norm and inverters are a secondary source
got to learn to crawl before you can can walk
well maybe I'm in 1st grade now instead of kindergarten
I think we declare this one dead dale
delbertinie is offline   Reply With Quote
Old 08-20-2007, 12:54 AM   #5
Bus Geek
 
the_experience03's Avatar
 
Join Date: Feb 2006
Location: Saint James, MN
Posts: 2,669
Send a message via MSN to the_experience03 Send a message via Yahoo to the_experience03
Re: my ideas for a electric generation

I still like the alternator-lawnmower engine idea even though I have STILL yet to put mine together. My logic? I can charge the batteries and use 12 volt items and my inverters all at the same time. Yes, you can do that with a gennie too, but you do run into some losses. Alternators also do a great job of charging batteries by breaking up sulfation and never overcharging them. Why don't they overcharge? Because they undercharge of course! An alternator will only charge a battery up to about 90%. At that point the current is not enough to effectively charge it...but a battery charger could be plugged into the inverter which is running off the batteries. With the alternator running you would actually have ample power to bring the batteries up to 100% charge. Crazy stuff...

More than anything I like the price for the alternator-small engine setup in that it can be done for darn near nothing.
__________________
http://farm4.static.flickr.com/3024/...09f20d39_m.jpg
Skooling it...one state at a time...
the_experience03 is offline   Reply With Quote
Old 08-20-2007, 08:07 AM   #6
Bus Geek
 
lapeer20m's Avatar
 
Join Date: Nov 2003
Location: near flint michigan
Posts: 2,653
Re: my ideas for a electric generation

some idea's i've played with, and my thoughts on each.....

I've tried to use a small lawn mower engine to run a high amp alternator. An alternator only charges when you put 12 volts to the small wire and energize the circiut. IF a 100 amp alternator has the field charged with 12 volts sitting on a table, you can barely turn the alternator by hand if at all. It takes a suprising amount of torque to spin an alternator under load. You can easily stall a 4 hp engine that is running against the govenor by turning on the alternator. you have to build a rheostat into the small 12 volt wire circuit so the alternator can be turned on slowly. you can increase the load on the engine until think you've reached the optimal engine load. You might not be able to produce 100 amps, but you can produce the max amount of amperage that the engine is capable of.

the pro's....it's really cheap if not free to build one, and an alternator has built in one of the best voltage regulators money can buy, great for charging batteries. Variable speed is a huge bonus. an alternator makes the same voltage at any speed (above like 1000 rpm or something) but the amperage is increased as the rpm's increase.

the con's.....it is difficult to make this system work good. it's loud! like having a lawn mower running full throttle right next to your bus. it's very innefficient. Gas motors are not efficient to start with, and neither are automotive alternators. How much fuel does a 4 hp lawn mower engine take per hour? Probably at least 1 quart of fuel i would estimate. That's 1 gallon every 4 hours.

I gave up on this idea

Next i tried a $500 generator I got from home depot. It wasn't any quieter, but it was a lot easier to use. just pull the cord and you have electricity. You can charge batteries, run power tools lights refer's ect. This worked very well, and sincei had a jacuzzi on a 40 amp 220 volt circuit i found the big geni to be a viable option for short use. Then i went off-grid for 10 days. I found that the big geni consumes 1 gallon of fuel every 2 hours. This is far too much fuel consumption.

I mostly gave up on this idea, i do however keep the geni as a backup when i go off grid for a week or more

Next i purchased one of those fancy honda eu2000i generators (specially designed alternator/inverter), then i created a jacuzzi that only uses a small amount of current. I attempted to run the geni for a few hours powering the bus and charging my house batteries with a 40 amp charger. When the batteries were nearly full, i'd shut off the geni and run the bus off battery power for a few hours then repeat the cycle. After a couple of days, i was suprised at how much fuel i was using. Then i did a test. I ran everything off the geni except the battery charger and found that i burned less fuel in a day powering everything off the geni than i did charging batteries and shutting the geni down for a few hours.

This is the method i use when i go to burningman. I average 15 hours per gallon of fuel with my little honda. I power a freezer, the jacuzzi, several 12 volt florescent lights, a dj sound system, and my cooking appliances: electric griddle, coffee maker, toaster oven, microwave (not all at the same time)

Living off a honda geni for a week to 10 days once a year is one of the most economical ways to make electricity. If i was living full time in a bus, i'm sure i would expirement with solar and wind. As a matter of fact, i'd like to get a small solar panel that makes a few watts of electricity that could keep my bus batteries topped off. As far as actually creating enough solar/wind power to live comfortably off of, It's difficult for me to justify spending the money.....unless i were to live full time in the bus and not have access to the power grid. For the price of 4 deep cycle batteries and a decent 2000 watt inverter you can buy the honda geni.

one more idea i think would work very well but have not yet tried is adding a 2nd alternator to the bus engine that only runs the house system. You can get a leece neville alternator (which is very commone among skoolies and big trucks) up to 300 amps or even higher output.

and back to teh comment about a 12 volt or 24 volt system. Alternators are rated in amps. You can alter a 300 amp alternator to make 24 volts. The unit will still produce 300 amps, but is now making twice as many watts. Watts is a measure of work, and the engine does have to do twice the amount of work to turn a 24 volt alternator makign the same amperage as a 12 volt one. That being said, a 24 volt alternator is not a bad idea. It'll make a lot less internal heat than a 12 volt alternator running the same load because the 24 volt alternator only has to produce half the current.

it's early in the morning, hope this all makes sense.

good luck with whatever you do
__________________
Quis custodiet ipsos custodes (who will watch the watchmen?)
lapeer20m is offline   Reply With Quote
Old 08-23-2007, 08:43 AM   #7
Bus Nut
 
Join Date: Feb 2007
Posts: 263
Re: my ideas for a electric generation

seems to me that if you have a diesel skoolie, a bigass alternator and a bank of batteries might be a good way to go. the reason is, diesels, unlike gassers are reasonably efficient at idle. an idling diesel engine uses surprisingly little fuel. an idling gas engine on the other hand is a pig. also, you could rig it up to charge only on deceleration. hook that wire it uses to know when to charge to the brake lights and viola, you got yourself a giant redneck prius. this idea might actually work in hilly areas or in stop and go traffic. wouldn't work worth a damn though in kansas.

does anybody have any idea how many gph an idling skoolie diesel uses?
pete c is offline   Reply With Quote
Old 08-23-2007, 07:26 PM   #8
Bus Nut
 
Griff's Avatar
 
Join Date: Jan 2005
Location: Off-Grid
Posts: 740
Year: 1982
Coachwork: Thomas
Chassis: IH S1723
Engine: IH V345 Gas V8
Rated Cap: 66
Re: my ideas for a electric generation

Quote:
Originally Posted by pete c
. . .you got yourself a giant redneck prius.
__________________
~(G)Q Arduously Avoiding Assimilation
Griff is offline   Reply With Quote
Old 08-24-2007, 09:14 PM   #9
Bus Nut
 
Join Date: Apr 2005
Posts: 274
Re: my ideas for a electric generation

Quote:
Originally Posted by pete c
you could rig it up to charge only on deceleration. hook that wire it uses to know when to charge to the brake lights and viola, you got yourself a giant redneck prius. this idea might actually work in hilly areas or in stop and go traffic. wouldn't work worth a damn though in kansas.

does anybody have any idea how many gph an idling skoolie diesel uses?
Great idea, however, I think once the field terminal receives power, the alternator makes power until it stops turning even if the field terminal is de-energized. I could be wrong though, but if this is correct, there should be a way to rewire the alternator internally to change this maybe? also, you could hook this up to a microswitch that supplies power to the field terminal when you let off of the throttle (or when it idles)
__________________
Brad Davis
79 International Wayne
"Big Blue"
bdavis441 is offline   Reply With Quote
Old 08-25-2007, 09:41 AM   #10
Bus Nut
 
Join Date: Apr 2005
Posts: 274
Re: my ideas for a electric generation

Okay guys, now you've got me thinking. Just for the sake of discussion.... how about a deceleration (or throttle-off) activated exhaust diverter valve going into a turbo driven alternator?
__________________
Brad Davis
79 International Wayne
"Big Blue"
bdavis441 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Electric bus. stonestatue School Bus News 0 06-17-2013 02:24 AM
Will this work, Electric ? Versatile Conversion General Discussions 3 09-12-2011 11:14 AM
electric stove? Mulelover Alternative Fuels | Electric, Propane, Wood Gasification, etc. 8 01-24-2010 09:45 AM
Electric cooling fan Kirbystud GM | Chevrolet Drivetrain 19 08-21-2009 05:19 PM
Propane vs Electric? odyssess Conversion General Discussions 1 08-07-2008 12:16 PM

» Virginia Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 12:21 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.