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Chuck Lott (68.219.167.56)

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Posted on Monday, June 21, 2004 - 7:33 am:   

Maybe a silly question, but here goes- I plan to add another alternator (12v), via the Jack Conrad (and others,method) for my 12V "House" batt bank.
My bus dosent have the OTR A/C & heat, So, I dont need the huge MCI Alternator making 24V. Seems like my "Bus" elect needs are slight and my house needs are much larger, And the alternator situation is kinda backward. (I have a 12V House system, dont want to change it to 24Volt)
Is there a "Feasible" (and that being the "Key" term) To disconnect the electrical from the MCI alt and perhaps regulate it to 12v ( with a 3 stage regulator)to charge my house batteries, and if so, I'd then add a small 24V alternator to do my 'Bus' items.
Even my headlights and windshield wipers are 12v and run off the house batts. All I have thats 24V are the starting circuit and turn/marker lights.
Respectfully, I don't want to rehash the 24 V vs 12V debate here again. Just want to know about the regulator.
Ideas?
DaveD (142.46.199.30)

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Posted on Monday, June 21, 2004 - 9:29 am:   

I would add a Vanner equalizer to the system. That will allow you to provide 12V to your house batteries and 12V accessories without changing the rest of your system. Changing lighting and starting circuits to 12V from 24V may require putting in heavier gauge wiring as the wiring now in place may not be adequate for the increased currrent required. Of course if your 12V batteries for the staring circuit are relocated close to the starter, this may not be that difficult to accomplish. The Vanner website has the appropriate schematics.

FWIW

Dave Dulmage
(MC-8)
Chuck Lott (68.219.167.56)

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Posted on Monday, June 21, 2004 - 9:55 am:   

Thanks Dale.

Just to clarify, I'm not changing the coach (starting and ext lighting) from 24 to 12 volt.
bowlingshoegiverouter (63.185.80.114)

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Posted on Monday, June 21, 2004 - 1:03 pm:   

everybody has different ways to solve problems...I would buy a G.M. one wire alt. for the house system,anywhere from 45.00 to 175.00 depending on how many 'amps' you want..
Stan (68.150.152.113)

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Posted on Monday, June 21, 2004 - 7:26 pm:   

Any attempt to change the 24 volt alternator to 12 volt will result in one half the current output unless you change the armature which I don't think would be ecconomical. Lots of the old busses used the same alternator (DN50 gear drive) in 12 volts. Shop around the bus companies and bus wreckers and you might be able to make a swap (your regulator and alternator) for the comparable 12 volt model.
Tom Caffrey (Pvcces) (65.74.65.65)

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Posted on Tuesday, June 22, 2004 - 10:18 pm:   

Chuck, one of the nice features of an alternator is that it puts out so much power at a low RPM. Another is that it is self limiting for current, so no current regulator is required.

If you were to apply 12 volts to the field of your 24 volt alternator and measure its output at different RPMs, I believe that you would find out that it will work; it will just require more RPM to reach its maximum current.

Its maximum current will remain unchanged, and it's only the current that causes them to heat up, so it would run cool enough.

My view is that you could just use the 12 volt regulator with the 24 volt generator until you decided that you weren't getting enough power from it. Then trade it for a bolt in swap to 12 volts.

I understand that the 12 volt model we have takes around 8 amps field current, so I would expect a 24 volt unit to take a little over half of that.

I gave this information to answer your question; if you use most of your generator's capacity, you will be swapping it out fairly soon.

Also, if you are using the relay terminal on your alternator for the starter protection and heating system relays, your output voltage on that terminal will be dropped about one half.

To preserve those functions, you will need to use an additional relay or make some other revisions of your wiring.

For what it's worth.

Tom Caffrey PD4106-2576
Suncatcher
Chuck Lott (68.219.205.112)

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Posted on Wednesday, June 23, 2004 - 7:27 am:   

Thanks for the informed responses. I'll just leave the big boy alone and a concentrate on the add on 12v system.
Chuck

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