| Author | Message | ||
| R.C.Bishop
Rating: |
As I told someone today, there are some things I know a little about, some that I know quite a bit about, but others that I seem to know nothing about.....so the question. I have a 200 amp Schlotsky (sp) and can read the english.....alternator in the middle, and at each end separate battery terminals....but....where does the alternator line come from?....the alternatior itself, the regulator, or????? My regulator has a single large wire that goes directly to an ammeter and, then under the chassis to parts unknown. I have not yet chased it, I don't want to boil the batteries or mess up the inverter, so am treading carefully. BTW, ...2 @ 8HD starting batteries and 5 Marine deep cycle house batteries. Thanx for any specific and detailed input!!!  Duh..... RCB '64 Crown Supercoach (HWC) | ||
| Sean Welsh (Sean)
Rating: N/A |
The center terminal of the isolator gets the main charge output wire directly from the alternator. Now, how you then connect the regulator is the $64,000 question. If you have a Delco/Remy, the regulator connects to the alternator via one of the F terminals. It also connects to chassis ground, as well as to a keyed ignition source. The last connection is the battery sense lead, and it is this lead that must be carefully routed to one or the other set of batteries -- you need to pick one, and I recommend the chassis battery. If you connect this lead to the alternator output instead, ahead of the isolator, you will not get enough charging voltage on the output side of the isolator. So make sure it is connected directly to the battery positive terminal. If you provide more specifics about your alternator and regulator, I may be able to give a more detailed answer. HTH, -Sean | ||
| christopher Rating: N/A |
sean i think i can connect a gm one wire right into the pos side of my house batterys. what gauge wire di i use for a 20 ft run? thanx christopher | ||
| John that newguy Rating: N/A |
http://www.thejump.net/fishingarticles/Ship-Shape.htm | ||
| TWODOGS (Twodogs)
Rating: N/A |
chris.... #10 or #8 | ||
| R.C.Bishop
Rating: N/A |
So then, a switch is ALWAYS necessary when an isolator is used? (Good diagram on the site JTNG provided.) ...my coach batteries are completely isolated from the house batteries as it is....no connection whatever. Presently charge the house batteries thru the inverter ( via genset or shore power) . ???? RCB | ||
| Sojourner (Jjimage)
Rating: N/A |
"So then, a switch is ALWAYS necessary when an isolator is used?" No but it wise shut-down power when not being use, to all circuit including starter to avoid drainage from bat if one of many remote switch is left-on. Most (if not all) all MIC buses are equip and it a good thing. About silicon diode, they have drop voltage of (Point) .7 volts. So it will be slower to get full state of charge. FWIW Sojourn for Christ, Jerry | ||
| Sean Welsh (Sean)
Rating: N/A |
Christopher, I'm not sure I understand your question... If this is related to the isolator topic, a one-wire will not work with an isolator, because the one-wire type system reads voltage right at the alternator output, not at the batteries. If you're simply asking about connecting your alternator output directly to your battery system, I would need to know what the ampacity of the alternator is to give you a gage recommendation, since the "one wire" is carrying all the charge current. It is almost certain that 2D's recommendation of #10 is incorrect for most alternators. Usually, alternator current requires 1-ought or more, but, again, I would need to know the ampacity. RCB -- The switch is only required to move loads (e.g. starter) from one battery system to the other. In a coach, a bridging solenoid is usually used for "emergency starting" purposes. Sojourner -- the diode voltage drop is the reason one connects the sense lead to the battery side of the isolator. The regulator then boosts the alternator voltage accordingly, compensating for the drop. Of course, some of the power is still dissipated in the isolator as heat, so it will take longer to recharge an empty battery this way. -Sean | ||
| R.C.Bishop
Rating: N/A |
Sean...after reading your first above post a number of times....devouring it, as it were, I think I understand the mechanics, however, what is NOT clear to me is this: a)... the Alternator is connected DIRECTLY to the isolator center post via a SECONDwire from the alternator?? b)...the chassis battery is wired to the regulator ( I do have a Delco Remy), no problem up to here....then you say "The last connection is the battery sense lead, and it is this lead that must be carefully routed to one or the other set of batteries --".... c)... from which post on the alternator?... in other words, how does one determine which is the battery sense lead?? I think I have it figurted out, but would hate to make an error and "fry the batteries". d)... if the second battery post on the isolator is wired directly to the house batteries for instance, what regulates the charge going to those batteries? Stay with me..... and many thanx!! RCB | ||
| Sean Welsh (Sean)
Rating: N/A |
RC, " a)... the Alternator is connected DIRECTLY to the isolator center post via a SECONDwire from the alternator?? " I'm not sure what you mean by "second" wire. If you have a typical externally regulated alternator for bus applications, such as the Delco 50DN, the alternator itself will have, most likely, four terminals. These will be labeled DC, F1, F2, and R. The DC terminal is the main output of the alternator, and should be the one with the huge wire on it. In an isolator installation, you want to wire this terminal directly to the center (input) post of the isolator. There might also be a strap connecting DC and F1, and you want to leave this strap in place (see below). There should be nothing else connected to the DC terminal at all. Where a problem comes in, sometimes, is that the coach manufacturer will have run one heavy cable from the battery positive to the alternator, and a second, short heavy cable to the starter from the alternator. This is just to save cable -- without isolators, there is no need to run separate cables all the way from the battery to these two high-current devices. In an isolator system, you need to replace the short jumper with a longer cable directly from the battery, since the DC post on the alternator is no longer hot-at-all-times. " b)...the chassis battery is wired to the regulator ( I do have a Delco Remy), no problem up to here....then you say "The last connection is the battery sense lead, and it is this lead that must be carefully routed to one or the other set of batteries --".... c)... from which post on the alternator?... in other words, how does one determine which is the battery sense lead?? I think I have it figurted out, but would hate to make an error and "fry the batteries"." OK, let me try to go through the whole thing from the regulator end. The external regulator will also have four terminals: FLD, BAT, IGN, and Ground. The FLD terminal is what controls the alternator. This is the only wire that goes directly to the alternator, and it connects to the F2 terminal there. (The F1 alternator terminal goes directly to battery positive, but it will usually work OK to just strap F1 to the DC output, as long as there is enough residual magnetism in the alternator.) The F1 and F2 terminals are the two ends of the alternator field wiring, and the regulator works by controlling the ground end of the field, while the other end is connected to positive voltage. The IGN terminal goes to the switched "ignition" system -- meaning it is hot when the key or master switch is ON. This terminal tells the regulator to switch on and do its thing. The Ground terminal, naturally, goes to a good chassis ground. I recommend connecting this to the same ground lug as the negative battery post, to minimize problems. The BAT terminal is the "sense lead" that I talked about earlier. This is the way the regulator knows how much charge to call for from the alternator. This terminal should be wired directly to battery positive, right at the battery itself. " d)... if the second battery post on the isolator is wired directly to the house batteries for instance, what regulates the charge going to those batteries?" Aha! You've asked the golden question. This is the big downside of using isolators (instead of, for example, bridging relays). You *must* choose one battery bank or the other for the sense lead hookup. So the regulator will call for charge based only on that bank's needs. The other bank has to just take whatever it can get. Due to internal wiring issues in the regulator, which was never designed for dual-bank systems, you need to also connect the IGN lead to the same battery system. For this reason, it is simplest to connect the BAT lead to the starting battery, since a direct source of switched power is the master switch otput. However, if you want to run the BAT lead to the house batteries instead, then use a relay to provide switched power from the house batteries to the IGN terminal (connect the relay coil to the master switch on the chassis side). Also, if you choose to (or need to) run a direct wire from battery positive to the F1 alternator terminal, this wire should come from whatever battery you use for BAT and IGN. BTW, the one terminal I have not mentioned, the R terminal on the alternator, is called the "Relay" terminal. This is a half-wave rectified DC output from the alternator, which is often used to operate a relay which causes the "charge" light to extinguish, and perhaps energizes the passenger blower system. On many coaches, the tachometer is also connected to the relay terminal, since it is a wave output directly related to RPM. Relays connected here work on half the DC voltage of the charge output (i.e. 12v relay on a 24v alternator). If, after reading all this, you think you have a *different* alternator/regulator combination than the one I've described, contact me again, because you may have to do something very different. -Sean | ||
| Tom Caffrey (Pvcces)
Rating: N/A |
RCB, output current from an alternator does not go through the regulator; it only regulates the voltage output by adjusting the field current. Alternator output normally goes straight to the battery, and through a shunt, if one is used. And in the case where there is an isolator installed, through the isolator. In very short runs, some alternators pass full output current through an ammeter to the battery, but this is uncommon. Sean, if I recall correctly, the forward drop of the Schottky diode is on the order of .2 volt. It was this low drop that led to their use in diode isolators. Because the voltage drop is so low, loss of power at the diode is slight and there is much less heat generated in the diode. Also, in most cases, the battery charge is affected very little by the drop. One thing to watch out for in the ratings is that some of these are rated for AC input, so they are conducting for only a half wave. In RCB's case, the 200 amp rating might be for the two diodes combined if it is not rated for the full 200 amps in one leg. Another thing that caught my attention was that the 50DN generator on our coach is frame grounded and the field terminal is supplied by the regulator, using the positive side of the system. I don't know what the Crown Supercoach might have in the way of differences, so what I bought up may not be relevant. All I'm suggesting is that if the generator is positive regulated, connecting the way Sean says will mean no output from the generator. It probably wouldn't be possible anyway as there is only one field terminal on ours; the other side of the field is internally grounded. Also, our 50DN does not rely on residual magnetism to start it; I think this is true of most alternators. Ours requires power to be applied to the field to get it started; that's the job of the sensing relay in our coach. There are a few alternators with a built in small magnet which is used to get them started without any power applied to the field. The strength of these magnets is too low to produce a useful charge; it just gets the ball rolling. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher | ||
| Sean Welsh (Sean)
Rating: N/A |
Tom, My 50DN is also frame grounded. However, the field is still brought out to two separate terminals -- F1 and F2. Most, but not all, 50DN installations are regulated on the ground side, just because it's easier to build the regulator that way. I'd love to know what model regulator you have. Also, I find it curious that you do not have both field terminals available on your 50DN. Of course, "50DN" is a series, and there were many models within that series. Also, I did not mean to suggest that the 50DN was designed to start by residual magnetism. It is decidedly not -- it's designed to have voltage applied to the field. I was simply indicating that most of them *will* start, if they have some residual magnetism, with DC bridged to F1. That's little help, of course, if you have a positively regulated system. Without relying on residual magnetism to start the DC output, a relay will be required to supply voltage to the field (in a negative-regulated setup that goes through an isolator). -Sean | ||
| Stan Rating: N/A |
Sean: I worked on many of the older GMC, MCI and Eagle coaches that used a 50DN alterantor and they all used the same regulator that was a voltage souce, not sink. When did the bus industry change to the sinking regulator or is this a european bus design? | ||
| Sean Welsh (Sean)
Rating: N/A |
Stan, I'm sure you know more than I about the subject of what charging systems are normally installed in buses. As far as European coaches, I can't speak to what is done over there when they use Detroit engines. My own coach was probably built with a Mercedes, which would have had a Bosch charging system. All of that was replaced with a Detroit here in the states. I did some research on the 50DN charging system and common Delco-Remy regulators back when I had a problem with mine, and that research showed the most commonly used regulators to be ground-side. (My own is also ground-side, and I thought that was weird, which was what led me to the research.) I can't tell you what applications those regulators were intended for... If your experience is that positive-side ("P-type") regulation is more common in buses, I bow to your greater experience. -Sean | ||
| R.C.Bishop
Rating: N/A |
Hey, guys, thanx for all the interest and input......I have not abandoned the subject....and in fact am still trying to " sort out", as it were, what in the heck you are all talking about... I have backed off that project to consider what has been suggested....fortunately, not in a hurry. just want to be able to "charge both " as I drive. I just don't want to mess up the whole system because I didn't do it right. What I don't seem to have under control in my thinking is the way the battery(ies) are hooked to the alternator. The only large cable I have from the alternator goes directly to an ammeter (sp) and then to points beyond, as yet unknown to me. The battery positive and negative both go elsewhere.... and that, is, as they say, where the rub comes in. As soon as the ground is dry enough to get under the coach, I intend to chase each to it's end. I have an old jeep....51 M38A1, and I have cogutated on how the generator (alternator?) on that is connected.... to the battery, regulator, starter, etc and so far haven't gotten much out of it. I may have to resort to a course in such things. Life seemed simpler in those days....if you know what I mean Thanx again for the input. RCB | ||
| Stan Rating: N/A |
RCB: You need to spend some time with a bus charging system wiring diagram. It may seem daunting at first glance but spend the time to trace the wires from the alternator to their end. When they go through relays or switches visulise (or draw out) both positions of the contacts. It helps to sketch out the circuits as you go along. You already know that field voltage is required to make it produce voltage and the regulator regardless of the type is constantly measuring the battery voltage and adjusting the output voltage to achieve the required voltage. Once you fully understand the circuit, you will be miles ahead of many of the posters on the boards and you will have no fear of troubleshooting or repairing the system. Even if the system has been modified, when you know how it is supposed to work it is easy. All of the wiring is straight forward and the magic that goes on inside the regulator is not your concern. The external voltage readings tell you if the regulator is working. | ||
| R.C.Bishop
Rating: N/A |
Thanx, Stan....I had pretty well come to that conclusion. I appreciate your sensitive words....also those of Tom and Sean. I work my way thru most all difficulties, with good help like available on this great board, and I am confident we'll get thru this one. As stated previously, it's not a matter of life and death....just convenience.......for myself and any future owner of the coach. The engine is amidships and cables go in every direction from there. Regulator is located up front next to driver. Batteries are to the rear of the engine on drivers side....the alternator is on the curb side. Just a lot of chasing....Hope it dries out in New Mexico soon. I need to get under the bus!! Thanx, again, RCB | ||
| Tom Caffrey (Pvcces)
Rating: N/A |
I guess if I ever have to hunt down a used 50DN, I better do some checking on whether it will work on our coach. One nice thing about alternators; they can work regardless of the direction that current flows in the field, as long as the regulator can control it. Thanks for the information. Tom Caffrey PD4106-2576 Suncatcher | ||
| R.C.Bishop
Rating: N/A |
Back on the subject of isolator wiring after a couple of months off.....here's what I've done....the results are questionable. I removed the very large wire (00 I would guess) from the alternator ( this wire I presumed goes to the battery). I attached the wire to one end post on a three post isolator marked "battery A". I then put a new 00 wire between the alternator and the center post of the isolator. This was the *only* change at the alternator. Ran a 00 cable, 16 feet, from house battery set to the other end post of the isolator, marked "battery B". The house batteries (5 of them) are chassis grounded and feed the inverter which is also chassis grounded. The result= alternator putting out about 12.5 volts *at the alternator* (+ to post,- to chassis). Reading at each battery post on the isolator is about the same.(+ to post - to chassis) A strange reading of 0.63 or so between each end post and the center post of the isolator. Very low reading on the ampmeter in the coach...10+. I drove nearly 50 miles and it did not change at any time. Prior to installing alternator, the ampmeter always showed a charge.... ??????? Ideas anyone? Thanx RCB | ||
| Sean Welsh (Sean)
Rating: N/A |
RC, As I mentioned way up near the top of this discussion, isolators do not usually work with one-wire alternators, because there is a voltage drop across the isolator, and the one-wire unit has no way to "see" what voltage is going in to the batteries. So if the alternator/regulator you have does not have an external voltage "sense" lead, the only way to get any charge to go into your batteries is to set the voltage output (if possible) about a volt higher to compensate. The .63 reading you are seeing is probably the voltage drop. I'm not sure why you are getting the same reading at the alternator and at the isolator outputs -- the readings should be different by a volt or so. However, this may be an issue of the quality of your voltmeter, or it may be that the batteries have already been charged to this level, so you are reading the battery voltage and not the alternator output. | ||
| R.C.Bishop
Rating: N/A |
Sean...I took what you previously stated into consideration and have to think that is probably correct. However since I am not sure what a *one wire* alternator is, it is difficult to understand exactly what you are saying. The alternator I have has one wire to the battery(isolator now) a 14ga, or so wire to/from the regulator, and a ground strap to the engine. No other wires. HOWEVER...the battery cable (from alt to battery) goes thru an ampmeter first. "So if the alternator/regulator you have does not have an external voltage "sense" lead, the only way to get any charge to go into your batteries is to set the voltage output (if possible) about a volt higher to compensate." Sean....where does one set the higher voltage? At regulator or ??? "I'm not sure why you are getting the same reading at the alternator and at the isolator outputs -- the readings should be different by a volt or so. However, this may be an issue of the quality of your voltmeter, or it may be that the batteries have already been charged to this level, so you are reading the battery voltage and not the alternator output." Both sets were fully charged via shorepower and solar to start batts. 13.4 for house.....12.3 for starts... Tell you what...I'll send a couple of pics directly to your email address if that is acceptable. Please so state. Thanx for the comment. RCB | ||
| Sean Welsh (Sean)
Rating: N/A |
RC, Sounds like you don't have a one-wire setup, since you have an external regulator (if I understood this last message correctly). Just to answer the question, though, a "one-wire" is an alternator with a built-in regulator. The alternator is grounded through its mount to the frame of the coach. There is one and only one wire connected to the alternator, and this goes directly to the battery. The alternator provides charge current to the battery through this wire, and the internal regulator in the alternator also uses this wire to "read" the battery voltage in order to adjust the charge output of the alternator. Your alternator has a second wire, which goes to the external regulator. This is good. So the one large wire coming from the alternator, which previously went directly to the battery, should now go to the center post on ths isolator. So far, so good. Let's look at the regulator. This should have three or four connections. One should be a direct connection to ground. One is the output terminal which is connected to the F post on the alternator. That's the 14ga wire you mentioned. Make certain this wire is good, and that nothing else is connected to it on either end -- it should go directly from the regulator to the F alternator terminal. The other terminal on the regulator is the battery sense lead. There may or may not also be a separate terminal for turning the regulator on and off, which would be marked "I" or "Ign". The sense terminal is usually marked "B" or "Bat." Make sure there is a good wire connected to the B terminal of the regulator. This wire should go direcly to the positive terminal of the battery. You'll need to choose which battery to use, but I recommend you use the starting (rather than the house) battery. IF there is no separate "I" or "Ign" terminal, you may need to connect the B terminal to the switched side of the "ignition" system. If that's the case, someone more familiar with Crowns than I am will have to tell you where to tie in to get the best battery reading. Or you can use a relay, which is probably best anyway -- connect the "B" terminal to one of the relay load terminals, and connect the other load terminal directly to the battery positive. Then use a switched ignition source from any convenient spot to activate the coil of the relay. If the regulator does not see the correct voltage level of the battery, it will not call for the right amount of charge from the alternator. Trace the wire from the B post of the regulator and see where it goes. I'm guessing that is the source of the problem. You are welcome to email me photos or whatever, or you can call me to discuss directly. My preferred email adress and my cell number are on the contact page of my web site, http://OurOdyssey.US -Sean |
