| Author | Message | ||
| Wayne Buttress (Flyingb) (66.52.189.208)
Rating: N/A |
I have an Eagle 20 with a 300amp/12volt alternator for the engine systems. I would like to use it for charging the house side also. Most of the battery isolaters are max. for 200amps. Does this make any difference? Does anyone know the amps of the alternator used for the 24volt A/C. I'm pulling out the bus A/C system and was thinking of trying to trade the 24v A/C aternator for a 12v/150amp. There are many ways to charge both battery banks, I'm trying to keep it simple. Thanks for any input, Wayne | ||
| Johnny (63.159.187.82)
Rating: N/A |
DON'T do this just on my say-so, but what about running 2 isloators in paralell, so each can't possibly get over 150 amps? I'm no expert, but I've done enough wiring that I really can't see any reason it wouldn't work. Electrical experts? | ||
| Scott Whitney (24.205.235.84) Rating: N/A |
I am no expert either, but I don't see any reason you can't use two isolators in parallel. However, since I just recently hooked up all my house batteries, and inverter etc., it ocurrs to me the extra work of cabling up a second isolator might outweigh the expense of locating (if possible) a bigger isolator. With the difficulty and expense of working with 4/0 cable and lugs etc, it might be easier to pay the extra for a bigger isolator to begin with. To jumper two isolators together, you'd need three extra heavy duty cables, I believe. I also have a 300A, 12v alt. My solution was to use a 400A (300A continuous) rated marine battery switch to tie the two banks together. However, this method is not foolproof cause you must remember to isolate them while camping and combine them while driving. The way I figure, with all the other tasks related to a bus drive adding one more item to the 'pre-flight' list was no big deal. Actually, I could make two check lists - one for arriving in camp and another for beginning a drive. Scott | ||
| Johnny (63.159.187.82)
Rating: N/A |
A good place for heavy wire: I use 0-gauge welding cable, & get it at a welding-supply shop. | ||
| Scott P. (152.163.204.203) Rating: N/A |
One problem with using two isolators in parallel is that if one of them fails, the other is instantly overloaded and will cook. Though I guess this is no worse than if one large one should fail. In either case you got nothin' left. | ||
| C. Ray Powell (Raypowell) (64.12.102.163)
Rating: N/A |
I just bought a 300 amp isolator from Wrico. I beleive two 150 amp isolators will cost almost as much as a 300 amp C Ray | ||
| Scott Whitney (24.205.235.84) Rating: N/A |
Hi C Ray, May I ask how much the 300A isolator was? Scott | ||
| Jim Stacy (12.87.111.104)
Rating: N/A |
Why not use a constant duty solenoid and forget the isolator with its' voltage drop and current limits? Isolators are for folks who can't figure out a switch circuit. FWIW Jim Stacy | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
One thing to consider is that though the alternator is capable of outputting 300 amps, it's unlikely that a battery bank will demand charge at 300 amps for more than moments if even that. The 300 amps could be fully used if you were running air conditioners with an inverter or something like that, but it's unlikely that batteries would present that kind of load, so I don't think smaller isolators would fail.... Just an opinion of course Gary Stadler | ||
| Tom Caffrey (Pvcces) (64.114.233.192)
Rating: N/A |
Wayne, Anytime that you want to split loads through semiconductors such as diodes, you should buy them as a pair in hopes of getting two with very nearly equal properties. They have such a large forward drop that it would only take a small difference in them and one would wind up carrying the whole load. It is not unusual to find the drop anywhere from .4 to .7 volts. To find out if they will split a load, parallel up two to a fairly heavy load for one of them with an ammeter in each diode circuit and observe the readings. If they are nearly equal, you're in business, if not, you need a better match. If you are going to recharge your house batteries with a 300 amp alternator, making sure that the voltage regulator is not set high enough to get them hot is pretty important. If they should start to heat up because of the fast charge, you could get a runaway condition that could ruin your batteries. This most likely won't be a problem where it is cold outside, but becomes important if you get into the warmer parts of the country. Tom Caffrey PD4106-2576 | ||
| mel 4104 (208.181.100.51) Rating: N/A |
jim has a good idea as i have used a constant duty solenoid for 23 years on my 4104 and it has never given any trouble , the control of the switchingis provided through the start switch so when you shut the motor down it isolates the battery banks it might work ok for you mel 4104 | ||
| Wayne Buttress (Flyingb) (66.52.189.58)
Rating: N/A |
Hey guys, thanks for the input. C.Ray, do you have an address for Wrico so I can look into the 300amp isolator? Mel, is there any requirements like size needed for the constant duty solenoid? I'm very week on DC circuits as youall can figure out. I'm at the point of setting up my charging system for the house batts. and trying to figure it out. | ||
| Scott Whitney (24.205.235.84) Rating: N/A |
WRICO INTERNATIONAL http://www.gowheels.com/wrico/ Phone: (541)774-4333 Fax: (541)774-6878 Email: To better reply to your questions, please call and talk to Dick. Mail: P.O. Box 41555 Eugene, OR 97404 Not much detail on the Web site, but you can contact them directly. I hear a lot of people think their gensets are top notch. Scott | ||
| jmaxwell (66.42.92.79) Rating: N/A |
Experience speaking, the 2 isolators in parallel did not work. In theory, yes, in real life, no, and I suspect, upon reconsideration, that my two failed because of the variable load on each, more so going to the house batteries. The two 165 amp units lasted one year and melted down, literally. Switched to 450 amp constant solenoid 4 yrs ago and no problem since. | ||
| Wayne Buttress (Flyingb) (66.52.189.204)
Rating: N/A |
Jim Maxwell, The solenoid sounds like the simplest solution. Where do you find the 450 amp constant duty solenoid? How is it wired? This is somethihg I totally new at, thanks for the help. Wayne | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
The best I could find was Stancor D.C. contactors from Newark Electronics (www.newark.com) part number 44F3645 (12v) or 44F3648 (24v) These are about$50 bucks each, single pole normally opened, and rated at 200 amps continuous, 600 amp surge. The coils are set up for continuous duty. I'd guess they would be quite sufficient... Gary Stadler | ||
| Wayne Buttress (Flyingb) (66.52.189.193)
Rating: N/A |
Thanks Gary, I checked out. I,m getting more confused by the minute. Some busnuts like the solenoid approch and others like isolators. I just talked to the local parts guy and he thought I was crazy for asking for a 400 amp solenoid and said I should go with an isolator. The problem seems to be my 300 amp alternator. I can find a number of solutions but most max at 200 amps or less. Maybe at the end of all of this I will have learned something. | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Hi Wayne, Either way will work, isolators or solenoid relays, although the problem you've run into is that your alternatior is big enough that it's capable of poofing a lot of isolators. Personally I like the solenoid approach more, because isolators are basically a solid state diode and have an associated voltage drop...to install one properly you'd "technically" have to turn the regulator up half a volt at the alternator to make up for the isolator's drop (which is not a "user-doable thing) but because you can't, the batteries never get the full 14.7 volts they want for a full charge. Plus the isolators easily availiable are not rated for 300 amps as you've found. With the solenoid I suggested, the 300 amps is not a problem, because they can handle 200 amps continuously and 600 amps on a surge. When you start charging drained battery banks, it's very unlikely that high currents will last more than a few seconds...batteries tend to take a lot of current for a small amount of time, and then settle down to a much lesser charging current for a long time. The 200 amp solenoid would easily handle this- that's how it's rated.... plus the fact that you'd be charging two banks of batteries, the bigger of which wouldn't even be going thru the solenoid. The idea then, is to hook up the solenoid so that once the engine is running, it is turned "on" sending charge to the starting battery. When the engine is "off" the solenoid disconnects the alternator and bus "appliance" system from the main starting battery and ignition circuits, so there is never a load on the starting battery until you turn the key to start the vehicle. The best way to control the solenoid would be to figure out a way to kick it in automatically once the engine is actually spinning (a pressure actuated switch on the oil line would be a perfect way)...this would be better than doing it manually, because you take the "oops I forgot" out of the equation.... So the scenerio is this... the alternator is permanently wired to the big bank of batteries that you will run your appliances from when not driving. This is the bank that will take the massive charge rate anyway, so the solenoid isn't even concerned with this part of the circuit. When you start the engine, the manual or oil-pressure operated switch turns the solenoid on, enabling your "starting" battery to charge. This battery would NEVER take a full 300 amps, so there's not a problem with the 200 amp solenoid at all.... Hmmmm, after thinking it out for you, I think this is exactly the way I'm going to do mine!!! Here's the schematic.... http://www.heartmagic.com/zzbatteries.jpg Regards Gary Stadler | ||
| Richard Bowyer (Drivingmisslazy) (66.190.119.82)
Rating: N/A |
Gary, the schematic looks great except that the contacts of the contactor are shown normally closed. I believe they should be open, until the oil pressure switch closes, which in turn will close the contactor contacts. Richard | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Correct, they should be normally opened I'll note that on the drawing... Gary | ||
| Wayne Buttress (Flyingb) (66.52.189.234)
Rating: N/A |
Gary, Thanks you're solved my problem for me. The light finally came on in my old brain. I've ordered the contactor and will install it according to your schematic. Thanks to all for the input, it helped me alot. Wayne | ||
| FAST FRED (65.59.78.84) Rating: N/A |
If you need a solenoid that has 200A cont rated , with 6ooA inrush the folks at Wrangler sell them for under $50. list www.wranglernw.com item 29-983 Wrangler is also a good source for battery cables with the good flag ends, made up as cheaply as you could cluge a set. FAST FRED | ||
| OAE Palmer (208.164.102.66) Rating: N/A |
Once again this forum proves its worth and that there are plenty of people here with the knowledge to solve problems, and are willing to do so. To be uninformed or uneducated about a subject you NEED to understand is one of the most vexing problems in life. That we can come here and present our ignorance and request help and recieve it from those with experience is golden. Rarely have I come across such an understanding and informed group, or one so quick to help those without the skills or knowledge and are in need. I want every contributor to know that there are many among you who deeply appreciate the help and perspective we all provide. Speaking for myself, I can say without hesitation , that whether it is my problem or anyone elses, every solution offered or problem solved only adds to the betterment of my life and my abilities to maintain my "home" to the highest degree possible. I wish it were possible to return these favors in kind and in person. I value and appreciate this forum more than ANY other aspect of my PC......just as I value the input for all the contributors. Thanks to each and every one of you. | ||
| Wayne Buttress (Flyingb) (66.52.189.204)
Rating: N/A |
OAE Palmer, Well said, the help here is invaluble. I can only hope to able to pass on what knowledge I learn in the process of converting my bus. It's nice to know one can still pound info into the ole brain. Thanks Fred. I'll check it out. Can hardly wait to get the electrical systems finished and on line. Wayne | ||
| JimStacy (12.87.110.174)
Rating: N/A |
Gary, My system has been working for several years just as you have drawn it. I did add a "pick" circuit to the solenoid from a small plug-in relay operated by 120VAC (not on the inverter circuits). Then when AC is present (as with a land line or gen set running) the 120VAC relay operates and energizes the main solenoid so the Inverter/ Charger can charge both banks. Works great, no heat, no voltage drop, no action required - completely passive. FWIW Jim Stacy | ||
| R.C.Bishop (128.123.88.39)
Rating: N/A |
Here! HERE!, OAE. Couldn't agree more. It is a Gold Mine and just for the price of asking a question, or less. Our hat is off to all who have made my past year a lot of fun with our coach conversion. EVERY input is valuable and appreciated. What a great thing it is to have choices and freedom of expression with honest, if not always judicious, opinions. Which I suppose goes on to prove, there are a lot of ways to build a mouse trap.....and a bus conversion.  RCB | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Great idea Jim! I don't have to do that on my rig because my battery charger has four diode-isolated outputs and it could charge 4 separate banks if I wanted it to. But not having that, your design is a great idea!! Gary |