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basil horangic (Basil)
Registered Member
Username: Basil
Post Number: 4
Registered: 12-2007
Posted From: 24.62.146.212
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 31, 2007 - 10:52 am: | |
I have a 12v Eagle with a 5000w modified sine wave inverter already installed on the starter batteries. I am putting in two SW4024 inverters on 8 4D house batteries wired for 24v. Could I feed the sw4024s on the shore input side using the output from the MSW inverter underway? Would the 4024s be damaged by MSW input on the shore side? Would they actually clean up the MSW waveform if I set them to layer on power over 2000w each? |
George M. Todd (George_mc6)
Registered Member
Username: George_mc6
Post Number: 337
Registered: 8-2006
Posted From: 207.231.75.253
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 31, 2007 - 1:09 pm: | |
Good morning Bazz,
As I told you the other day, "Ask a question, and we'll be glad to answer." I wasn't expecting a question like this, but I had better put my money where my mouth is, and TRY to give an intelligent answer.
A 5000 Watt inverter will draw 417 amps of 12 Volt DC to produce 5 KW of 120 VAC, theoretical perfect. (5000 W is 41.7 amps at 120 Volts) An MSW inverter won't be over the low 90s in efficiency, which would make the actual draw somewhere between 440 and 450 amps at full load. At 50% load, you would still be drawing over 200 amps! At this point, I don't think I even need to get into CABLE sizing and alternator output rating do I?
I feel the 4024s would work on the MSW input, and from your question, I assume you have seen MSW waveform? Would they "clean it up?" Somewhat, I think? Only to the extent of their output percentage in relation to total load though. 2/3 'dirty' power + 1/3 'clean' power = 1/2 clean power? The output quality is going to be an average of the input. The odd little bumps in MSW tend to produce heat and no power, and affect the frequency count of sensitive appliances. The answer someone else gave to an "iffy" question like this a while back was, "might work, might not."
So, would I do it the way you are suggesting? Let me be polite and make a suggestion of my own instead. Bolt up/belt up a 24 V alternator, wire the ignition terminal of the 24 V regulator to one side of a 12 V relay. The other side of the 12 V relay goes to 24 V positive. Connect the relay coil to the load side of the bus master, so you only "field" the 24 V alternator while the master is on. There are other ways to control the field, as discussed in "Keyed Ignition" a ways below, depending upon how much original wiring is left in your bus. Or you can do it with a "one wire" alternator, and be done with it.
Whew,
George |
Richard Bowyer (Drivingmisslazy)
Registered Member
Username: Drivingmisslazy
Post Number: 2028
Registered: 1-2001
Posted From: 75.108.73.33
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 31, 2007 - 1:32 pm: | |
I am having trouble understanding what you are trying to accomplish. Lets see, 12 volt to the 12 volt inverter gives you AC output. Feed that AC to the input of the 24 volt inverter and it bypasses thru the transfer switch in the 24 volt inverter and then on to the load. What has been accomplished?
Since the bypass of the 24 volt inverter contains no filtering, I do not think that would clean up the output of the 12 volt inverter.
Richard |
Jerry Liebler (Jerry_liebler)
Registered Member
Username: Jerry_liebler
Post Number: 318
Registered: 3-2005
Posted From: 75.117.209.54
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 31, 2007 - 5:09 pm: | |
Basil,
You MUST get this answer in writing from Xantrex. But I'm over 90% certain you'll DESTROY the SW4024s (I fully understand how they work internally). Give me a call, there are much beter ways to do what you want.
Regards
Jerry 4107 1120 |
basil horangic (Basil)
Registered Member
Username: Basil
Post Number: 5
Registered: 12-2007
Posted From: 24.62.146.212
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 31, 2007 - 7:21 pm: | |
Thanks for the input.
Jerry, I would love to talk. Could you give me your number? I definitely don't want to mess up my 4024s before I use them. I did call Xantrex a few months ago when I bought the inverters, they said "don't know, test it out".
Richard, my goal is to use the 12v 50DN output for charging if it is easy. The bus came with a 12 inverter already installed off the 50DN, so the thought came to me to that I could use that. With lots of stuff to do I am looking for shortcuts.
George, I'd prefer the easy way out using the already installed inverter, but I did look into bolting a 24v alt on the 8v92. The only mounting I could find was from Prevost for ~$750. Do you know of a cheaper 8v92 mounting? Also, if a one wire alt avoids relays, any reason not to use that? I am not to familiar with alternators.
One other idea for comment. I was reading some old posts on 4024s and someone suggested just using a separate 24v charger connected directly to the batteries. Problem is I can't seem to find any chargers on the web over 600 watts at any reasonable price, but both sw4024s should charge at a 4800 watt rate I think. |
George M. Todd (George_mc6)
Registered Member
Username: George_mc6
Post Number: 338
Registered: 8-2006
Posted From: 207.231.75.253
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 31, 2007 - 11:33 pm: | |
Basil,
I was going to ask for comments from Jerry and Sean, (in alphabetical order) and we got one of them already! As you can see, Jerry sides with me on not to do it. I know that what you are trying to do is get 24V charging from your existing 12 Volt alternator, without buying more equipment, but it just won't work well. The VEE Detroits have 5 auxiliary drives on the back, and I don't know how many are occupied in your configuration. As info, the middle one is off the end of the blower drive, and runs twice engine speed, the next two are the ends of the cams, and run engine speed. The outside two, if I remember correctly can be geared to run between engine speed, and about 1.2 times eng speed. These gear drives should be plentiful in truck boneyards?
The "odd little bumps" in MSW waveform that I referred to in my first post are what cause problems in electronic equipment.
You also have to realize that the 4800 Watt charge rate you refer to in your post, will require 40 amps of 120 Volt AC. No big deal, you say, except that to get 40 amps of 120 VAC, YOU NEED 400 AMPS OF 12VDC, if your MSW inverter, and your 4024s were perfect! They're not... In a practical application, if MSW doesn't mess up the 4024s, and the output breaker of your MSW doesn't trip from the load of two 4024s wanting to charge a good-sized depleted bank, in three or four hours of driving at freeway speeds, you would have a charged bank, but this just isn't the way to go in my opinion. I haven't even mentioned the output of your alternator, but I am assuming it is not more than 250, and that is at about 1600 rpm or above?
I know Jerry to be WELL qualified, you can rely on what he says. My number is in my profile, and you aren't too far away, so.
George |
Sean Welsh (Sean)
Registered Member
Username: Sean
Post Number: 698
Registered: 1-2003
Posted From: 72.171.0.144
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 01, 2008 - 4:41 am: | |
I have to agree with Jerry -- I think you might damage the SW4024s. At the very least, I don't think it will work -- the SW series inverters are very sensitive to waveform, as they are trying to synchronize to it at all times. They expect to see a pure sine wave (generated by a rotating magnetic field, not electronics) on the inputs.
My own advice is to swap out your 12 volt 50DN for a 24 volt model, and use that to charge your house. Then ditch the 12-volt MSW inverter, and either put a smaller belt-driven alternator in for the (now minimal) 12-volt chassis side, or you could even run the chassis side off the same alternator using a high-end equalizer, such as one of the larger Vanners.
FWIW.
-Sean
http://OurOdyssey.BlogSpot.com |
john w. roan (Chessie4905)
Registered Member
Username: Chessie4905
Post Number: 796
Registered: 10-2003
Posted From: 71.58.48.5
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 01, 2008 - 12:48 pm: | |
You could get a good running takeoff 24 volt 50 DN alternator from NIMCO in New Jersey to replace the one you have. |
basil horangic (Basil)
Registered Member
Username: Basil
Post Number: 7
Registered: 12-2007
Posted From: 67.95.210.162
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 05, 2008 - 12:40 pm: | |
Sean, thanks, I talked to Jerry directly and he convinced me feeding msw into 4024s is a bad idea. I took a closer look at my engine compartment and a belt driven 24v alternator is going to be really impossible to fit the way it is laid out. The 50DN conversion comes to $1,000 labor, $900 alternator, $500 core charge since they won't take a 12v in exchange, and $450 for a vanner equalizer to run the chassis side, plus some big 4/0 cable to the house batts, so $3,000. Two questions on this, does the charging activity from the 50DN conflict with the charging activity from the 4024s if, say, the genset were running while underway? Also, can the equalizer move enough power over to the 12v system to keep the otr air running?
I also looked at some other choices.
1. Buy an aims 2000w 12v psw inverter and drop it in to replace the vanner msw i have, $570 plus an hour of my time. Feed 4024s psw power from that for otr charging. Need to figure out neutral gound bonding if i am feeding an inverter into the shore side of the 4024.
2. Run an Iota 12v 100amp charger off the existing msw vanner, $460 plus some cables and probably 4 hours of work to install and run them. In this case, would the charging from the Iota conflict with charging from the 4024s if say the genset were running?
3. Install a 100a vanner equalizer, but run it in reverse, pulling power from the chassis system at 12v and feeding the house system at 24v. Would need to figure out a way to automatically disconnect it when the alternator is not running so chassis is not discharged into the house. $450 plus probably 4 hours to install nicely.
The vanner moves 1100 watts, the iota charges at 1200, and the aims sends 2000. (Of course switching the 50DN would give me over 6000.) Which way would you go of the shortcut options?
(Message edited by basil on January 05, 2008) |
George M. Todd (George_mc6)
Registered Member
Username: George_mc6
Post Number: 341
Registered: 8-2006
Posted From: 207.231.75.253
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 05, 2008 - 3:08 pm: | |
Bazz,
No to the equalizer running the OTR air, and,
NO, you can't get 24 V out of a 12 V equalizer connected backwards!
#2 would be the way to go, and just turn it off while on shore.
What's on the back of your engine?
George |
basil horangic (Basil)
Registered Member
Username: Basil
Post Number: 8
Registered: 12-2007
Posted From: 67.174.198.28
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 05, 2008 - 8:28 pm: | |
The normal mounting place on the lower right is very busy with belts going to the compressor and the drive for the condensor fan, plus a pneumatic belt tensioner and two big hoses coming across to a what I think is a power steering reservior mounted right in the center of the motor. Plus the oil fill tube would need to be moved. Anything there would be running off the cam pulley or the main drive pulley.
To the left there are miter box belts going from the main crank and no access to the cam pulley from that direction, plus not much room between the left side of the engine and the radiator fan shroud.
I have seen a truck alt mounted to an 8v92 but the bus had no otr air so the space to the right was all clear.
I was starting to think more about swapping the 50DN and using an equalizer given it provides so much power, but if you think it kills my otr air that is a problem. |
Sean Welsh (Sean)
Registered Member
Username: Sean
Post Number: 699
Registered: 1-2003
Posted From: 72.171.0.138
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 05, 2008 - 11:20 pm: | |
Basil,
Sorry, when I suggested ditching the 12-volt 50DN, I did not realize you were still running the bus air.
I still think that changing over to a 24-volt alternator will be the best strategy. The 24-volt 50DN is rated 270amps, for a total of around 6.5KW (maximum -- somewhat less continuous). The 12-volt units are rated at a maximum of 350 amps, for a total of only around 4.2 KW maximum.
You might then try to find a place for a smaller, belt-driven 12-volt alternator to get your OTR air running.
It is, indeed, possible to run the air off a voltage converter (equalizer), notwithstanding what my good friend George has written. The key is that you will be pulling the surge from the chassis batteries. So what you will need to do is to connect the output side of the equalizer directly to the chassis battery bank (and NOT to the center-tap of the 24-volt bank -- use a separate, smaller equalizer for that if you also have 12-volt house loads). And make sure you have plenty of reserve capacity on the 12-volt chassis batteries, such as a pair of 4D's, or maybe three group-31's.
You will then need to select an equalizer with a continuous output rating equivalent to the normal draw of your OTR air fans. Equalizers are available in ratings up to around 150 amps. If your air draws more than that, you will need to parallel a couple of units.
With regard to your question about charging conflicts between the inverter and alternator: when the batteries are well-depleted, there will be no conflict -- the outputs of the two charging systems will add together to charge the bank. However, once the batteries reach a certain level, then the regulator on the alternator will stop calling for charge if the other charging source (inverter) is still charging. This will cause the alternator output to drop to zero, and the "not generating" (or similar) light to illuminate on your dash. Happens to us all the time, and we simply then disconnect the paralleling solenoid that bridges the two systems. In your case, you could simply shut down the generator at that point, or ignore the idiot light on the dash (in our case, we also lose the tachometer, so we just disconnect the two systems).
HTH,
-Sean
http://OurOdyssey.BlogSpot.com |
Tom Caffrey (Pvcces)
Registered Member
Username: Pvcces
Post Number: 1168
Registered: 5-2001
Posted From: 65.74.67.83
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 05, 2008 - 11:22 pm: | |
Basil, I think you're talking to the wrong people about the 50DN.
I would do a little shopping, like on the boards and the various bus parts suppliers. There are a lot of good units around, and many for less money.
You can cut the otr air load by disconnecting one blower, assuming that your condenser fan is not electric. That might get your power requirements down to where you can live with them.
For what it's worth.
Tom Caffrey PD4106-2576
Suncatcher
Ketchikan, Alaska |
basil horangic (Basil)
Registered Member
Username: Basil
Post Number: 9
Registered: 12-2007
Posted From: 75.199.7.163
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 08, 2008 - 10:23 am: | |
George,
After some more investigating, I think you are right that the most cost effective and quick solution will be to put run an Iota 24v charger off the existing Vanner 12v MSW inverter. The 50DN change is definitely the right thing in the long run, but 1200 watts for $450 beats 6000 watts for ~$2500 right now because I need to keep the otr air at the moment.
The Vanner has a simple remote on/off switch mounted on the wall. I don't know much about relays or solenoids. Is there a simple way I can set up a relay so the Vanner is only (and always) turned on when the engine is running? |
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