| Author | Message | ||
| Todd Amon (Teqsand)
Rating: |
HI again kids, ok, stupid question #658 how can i check to see if my generator is outputting correctly and charging my coach batteries? I just put in 2 brand new 8d's and it started right up. but i need to know if they are charging. I pulled the battery cables off with it running and it stayed running, it works on non deisel cars, does it work on diesels? what terminals can i get a reading from? thanks | ||
| James Maxwell (Jmaxwell)
Rating: N/A |
Read your battery voltage after it has sat for at least 24 hrs. Start the engine, battery voltage should increase at least 1 volt for 12v, 2 for 24v. There are other methods but this will give you a general idea. Unless you have an electronic controlled engine in your bus, the engine does not need electric to start or run, only the starter. On the other hand, your gasoline engine in the car does, for the distributor or electronic ignition system. Diesel uses compression for firing, not electrical ignition. | ||
| Marc Bourget Rating: N/A |
Get a Volt Ohm Meter, preferably digital Sounds like, with the question as to which terminals, you may have a 24V setup? The positive and negative terminals that go to ground or the disconnect. Check the Batts while off/stopped record reading, for example 22.6V Fire up engine and see if voltage across the terminals changes. i.e. 28+, for example | ||
| NelsonThomas Rating: N/A |
-Some alternators need to be run up to about 1500 RPM before they will begin to generate power initially . I thought mine wasn't working so I took it to an alternator shop they tested it and it worked fine once it got up to speed. Nelson in Knoxville. | ||
| mci102
Rating: N/A |
Regarding Todd's stupid question...,it has inspired my very own stupid question. When Todd disconnected the battery cable while the engine was running, did that drop the field current to the alternator, and would that cause any damage to the alternator? | ||
| Stan Rating: N/A |
If you are talking about your 4104, it needs voltage to run. The shut down solenoid valve is a normally open valve and is held closed electrically when you turn on the master switch. If you take away the voltage, the valve switches to the open position and the air pressure closes the injector rack to the stop position. The only time this wouldn't happen is if you had still not built up air pressure after starting. MCI102 No damage to alternator without field voltage. | ||
| Luke Bonagura (Lukeatuscoach)
Rating: N/A |
Hi Stan & Folks: On Alternator equipped coaches, once the coach is started, you can disconnect the alternator and run all day long, Just remember that for coach heat, A/C, lights, etc, all you will have is the Battery Voltage. Without relay voltage, an alternator will not charge and is just as Happy as you to Spin Along for the ride without having to Work!!!! I Hope this HELPS!! Happy & SAFE!!! Bussin" to ALL!!! LUKE at US COACH | ||
| Luke Bonagura (Lukeatuscoach)
Rating: N/A |
Hi Folks: As I was about to leave for the day I forgot most, what I wanted to say to the original poster. In My Opinion: THERE ARE NO STUPID QUESTIONS!!!! But there can certainly be STUPID answers!!!! Especially on these Boards, I suggest that you each read often and consider the source. I talk to folks all day long who spout out incorrect facts and I can tell which Boards they are reading, but most importantly are believing incorrect "Feed Back"!!! Just food for thought!!! LUKE at US COACH | ||
| FAST FRED Rating: N/A |
Ordinarily removing a battery terminal from an operating alternator (with out REMOVING the field current FIRST) will blow at least half , and sometimes ALL the output diodes. NEVER EVER disconnect the batt from any running alt equipped vehicle if the alt is operating. So the question could be, WAS the unit charging , or IS the alt charging NOW? Any $10.00 volt meter on DC will show alt output just by reading the batterys volts. 12.8V or under good batts but not being charged, Anything over 13.2 or so is breaking even , with some charge , over 13.6 to 14.4 (depending on temps) you are charging fine. FAST FRED | ||
| Kyle Brandt (Kyle4501)
Rating: N/A |
When in high school, I had heard that you could 'test' an alternator by removing the neg battery cable. Well I did this test with the head lights on to verify that I had a bad battery. The resulting voltage spike blew out EVERY light bulb that was on, blew out the diodes in the alt and ruined a new radio. While I was replacing the dash light bulbs ( that '69 chevy was obviously designed to prevent dash bulb changes) I promised myself to NEVER do that again! A digital volt meter is an excellent addition to your tool box. I got mine at Sears for less than $20 and it came with a thermo-couple temperature probe. I have used it often. (Much faster and easier than changing all the light bulbs :^) Kyle | ||
| Stan Rating: N/A |
Luke: I am sorry if I misunderstood the question. I thought the original question was about removing the battery cables, not the alternator output cable. | ||
| Marc Bourget Rating: N/A |
By my reading of the above, removing the output cable of the alt or the batt cables WHILE THE ALT IS CHARGING is going to cause damage. Removing the field wire, stops energizing the fields and stops charging output. Then, I believe, it would be safe (to the alt) to remove the alt output or batt cables. Did I read it right? Onward and Upward | ||
| John that newguy Rating: N/A |
You read it right, Stan. You didn't misunderstand anything. Todd said: "I pulled the battery cables off with it running and it stayed running, it works on non deisel cars, does it work on diesels? " Luke must be tired, or is following the posts and not the original question. His remarks regarding "stupid answers" became meaningless, once realized that if one does not read the question, one cannot provide any correct answer. An alternator (or generator), all the light bulbs; any other electrical ancillary equipment, do not burn out when a battery goes dead, goes open... or shorts. Taking off the battery connection while the rig's running won't do damage, but the engine may or may not run... If it does or not, doesn't prove if the alternator or generator is charging or not, it may only prove (if it proves anything at all) that it's putting out -some- amount of voltage. The proper way to test to see if the generator or alternator is capable of charging the batteries had already been described. Check the voltage when it's not running, then check the voltage while it's running (on my MCI, I'll have to build air pressure until all the idiot lights go out, before the thing decides to charge; is his bus like that, too?) Once the lights indicate that all's well and ready to roll, the voltage at the batteries should indicate a higher voltage than while not running (the batteries may indicate some bubbling also, while charging. The manual says that it's normal with MCI). | ||
| Kyle Brandt (Kyle4501)
Rating: N/A |
For what its worth, (I am not an electrician and I do not fully understand the 'magic' of how electricity works) but the battery, alternator, voltage regulator, etc. make up a system that is designed to work together. As it was, my '69 chevy had a dead cell in the battery. I had the lights and radio on, and the poor old alt was at max output to run everything and charge the dead battery. When the battery was being disconnected, there was a spark and an ensuing voltage increase. The over voltage is what blew out all of the bulbs, the radio (I was in high school, so it was a cheap radio) and the diodes. When this happened the engine still ran, it just burned up the points faster. I put in a new battery, but the alt was over charging and killed that battery and new lights quickly. So I replaced the alt and 'verified' that it was good by removing the battery cable again. It was still burning out lights and killing my battery! I finally took the car to the "Mr Alternator" in town. He got a good laugh off me! He then explained what had happened. I ended up buying two alternators and an extra battery that I would not have needed if I had simply checked the battery voltage at rest and charging. I also know some who have had no trouble from disconnecting the battery while everything is running. I still won't do it again. So I do know from experience that you can mess up a lot more than needed fixing by following bad advise. Good luck with your efforts Kyle | ||
| Gary McFarland (Gearheadgary)
Rating: N/A |
1) No magic involved 2) A Dead cell does not pull more current from the alternator 3) Electricity does not "Force itself" through the various devices in a circuit, the amount of current is determined by the resistance of the device. the alternator puts out 14V, more or less, that's it. 4) Mr Alternator was still laughing after you left. Gary | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
I would guess that your alternator, or more probably a generator in those days, was cranked up to maximum output trying to get a charge into that dead battery. When you removed the battery cable, the voltage jumped (or stayed) at maximum for an instant before the regulator could bring it back down to the nominal charging voltage. I suspect it was at least double of what it should have been and that is why you were burning things out. Richard | ||
| Kyle Brandt (Kyle4501)
Rating: N/A |
Just so eveyone knows, lots of people laugh after I leave (some don't even wait). The laughter of the guy I bought my bus from is louder than everyone else :^) Hi Gary, So was it just my immigination that it was burning things up? The third alt was the same as the second. Hi Richard, Thanks. Kyle (The source of laughter for many many people) "No one gets too old to learn a new way of being stupid" (one of Murphy's laws) | ||
| John that newguy Rating: N/A |
Men.... Kyle... A simple example: A guy's got a dead battery (-0- voltage). He jump starts the car, removes the jump battery, closes the hood, drives to Walmart and buys a battery. The car stalls en route. It won't start because the battery's dead. It didn't take a charge. It's "open" for all practical purposes. That's the same as having no battery connected. He jump starts it again and continues on to the store. He buys a battery, installs it, starts the engine and drives off. No bulbs are out. No alternator has to be replaced. No ignition parts are burned up. I have no clue about any 1969 vintage car and why or why not anyone's burned up their investment. My guess would be that the alternator, generator or voltage regulator was at fault to begin with and should have been tested and replaced, not the battery. But that's another matter. The question was not: "do I or don't I disconnect the battery while running", it was "how do I find out if the battery's being charged". If the voltage is higher when the engine's running, it's likely putting a charge into the battery. Check the voltage at the battery - running and off, to tell. | ||
| John that newguy Rating: N/A |
Hey Kyle.... No-one around here is laughing at you. I remember hearing of the perils of disconnecting a battery while the engine's running, way back in the 50s. But hell..... we started cars without a battery by roll starting it and running off the generator or alternator to get it to wherever we wanted to go. If it stalled, we'd jump out and roll start it again. I never remembered anyone burning anything up by doing that...... except maybe the Mohair seat when the cigarette left on the dash rolled off.... Cheers, man. | ||
| Gary McFarland (Gearheadgary)
Rating: N/A |
Hi Kyle, I like a guy that is not mortally wounded by a poke in the ribs  Anybody's guess, my guess is your alt was putting out way too much. but it's only a guess. Could be sunspots too. Gary | ||
| Kyle Brandt (Kyle4501)
Rating: N/A |
My whole point was that 1) - (In agreement with the smart people) pulling a battery cable does nothing to tell you the condition of the alternator or generator. 2) - When you 'play' with electricity you can get unexpected results. The original post reminded me of a part of my mis-spent youth and I thought it a good example of unexpected results. And why a volt meter is a worthwile investment. So sorry to have sounded like an idiot, but some days it's the best I can manage. Kyle | ||
| Kyle Brandt (Kyle4501)
Rating: N/A |
Todd, I hope you have enjoied this as I have. Hey John If someone ain't laughing at me, then they must not be paying attention :^) Gary, I like the sunspot theory, it explains a lot! I was told once that smoke is what makes electrical stuff work. If you let it out, it probably won't work as well if at all! Just trying to keep things interesting. | ||
| Marc Bourget Rating: N/A |
I gave a quick check to my Smead books on 12V, looking for something like a diode that would protect the Alt in case of a disconnect that might result from a broken wire but couldn't relocate the reference. Somebody else out there able to comment on this? Marc | ||
| John that newguy Rating: N/A |
Comment on what, Marc? | ||
| Luke Bonagura (Lukeatuscoach)
Rating: N/A |
Hi FOlks: First to Stan, my post about stupid answers was not directed at you or this particular thread, and I should have made that clear, but did not!!! It had to do with several phone conversations I had with customers this week. And John the new guy, I did read the original post, but between my head and fingers, what I meant to say and I did say came out wrong. What I meant to say, in response to the original post, which I did read, was: you can disconnect the batteries, and not hurt the alternator, while the coach is running. Oh well, I goofed, and if I offended anyone, I Apologize!!!! Like I said, when reading a post, Consider the Source!!! This time it is ME with egg on his face. Then again, I have never pretended to be perfect!!! Happy & SAFE!! Bussin' this weekend to ALL!!!!! LUKE at US COACH | ||
| Marc Bourget Rating: N/A |
whether a distant recollection of protection for a suddenly disconnected alt while "alt-ing" really does involve a type of diode or whatever. Marc | ||
| Gary McFarland (Gearheadgary)
Rating: N/A |
Marc, is that some sort of new code? Gary | ||
| John that newguy Rating: N/A |
It's not the diode, but the -life- of the ode and what the ode has become before it died. It's just strange that it is that way, Marc. | ||
| Jtng Rating: N/A |
Hey Marc - Santa and his reindeer landed on the top of an outhouse. As they skidded to a halt Santa hollered out: "I SAID THE SCHMIDT HOUSE!" | ||
| FAST FRED Rating: N/A |
For folks that use a single alt to charge the house and coach batt set there are two ways of being safe. 1 wire the house stuff to the house bat set and only allow a relay to charge when underway. This is foolproof and probably the best choice. For those that prefer batt management with a marine manual rotary switch , DO purchase the ones with field terminals on the rear of the case. This is a Break before break setup , so rotating the switch will kill the field current , change battery config , and reapply field current. Since most of these are rated well under 1000A , ther better NOT in the start circuit of a DD. Some new alt energy alts are "Claimed" to have such grand diodes that a battery disconect won't wreck the alt , but proving this could be costly. FAST FRED | ||
| Jim-Bob (Pd41044039)
Rating: N/A |
Kyle, your understanding of what NOT to do is correct. While it is o.k. to disconnect the field wire while an alternator is running, Never disconnect the output. There will be a momentary voltage spike that is capable of killing the voltage regulator & maybe the diode bridge in the alternator. Johnthenewguy, I too did what you did with 50's & 60's cars with dead batteries. Some had generators, some had alternators. But ALL had relay type voltage regulators which though needing periodic adjustment, were not vulnerable to these spikes. GearheadGary, True that the device draws CURRENT according to resistance, but you can easily force more VOLTAGE through the device which can (and often does) destroy the solid state parts. This information is WAY more critical with today's cars that have ever more sensitive electronics & many many computers. My new Ford pickup's engine computer even controls the starter. Turn the key & it hesitates before it cranks! I wouldn't dream of disconnecting a battery cable on anything built since 1965 while it was running. A voltmeter is the way to troubleshoot. Jim-Bob | ||
| John that newguy Rating: N/A |
Jim-Bob- The Mercedes wasn't fried when the battery positive cable was found to be lose and making/breaking connection for the few hundred miles we drove, wondering why it was running so poorly. Our Buick, with all it's electronics, never uttered a faulting word when it's battery died while on a shopping spree. It just stopped taking any kind of a charge! The battery post was found to be unattached to the rest of the battery. Whoever installed it, must have banged the terminal down, weakening the internal connection. It reminds me about the RV! Lots of electronics that didn't flinch when the battery ground(s) were all found to be totally rusted and corroded through! You don't suppose that the new-fangled all electronic wiz-kid systems also incorporate some sort of electronic detection for missing battery voltage, thus saving the pain of replacing every component when one of those "voltage spikes" takes place? Or could some engineered electronic design actually prevent one of those "voltage spikes" from taking place? If they did, why didn't they duct tape the information to the firewall? It's always better to be safe than sorry and I would never argue that. But telling a kid that it's not safe to cross the street against the light because a car might not see him and hit him, verses telling him that if he did, a big monster is going to eat him..... matters. Improperly jump-starting an engine with a dead battery can be hazardous; disconnecting one while the engine's running can be hazardous.... The sparks and possible ignition of the battery gas from those sparks, is the monster. There are many, many batteries sitting in the back of garages, useless due to burned-through battery posts that had been caused due to battery connections left loose. When they burned through, they became an open circuit. There isn't a pile of burned electronics sitting next to the pile of batteries. Sorry if I sound rude, Jim. It's difficult to type it out... | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
snip "This is a Break before break setup , so rotating the switch will kill the field current , change battery config, and reapply field current." A minor correction in FF's statement. That is a break before MAKE setup Fred describes and also it kills the field VOLTAGE instead of the field CURRENT. When you kill the voltage, the current automatically stops. BTY, this ia a technical error that many people make and in no way is to reflect on FF's input. Richard | ||
| mclough Rating: N/A |
ONE MANS OPINION they way I tell if my alt was working is to take off the neg. cable and then listen to engine. the idle will go up in a correct working alt.because the load is lifted off the engine. at least thats what happen to me. | ||
| Tom Caffrey (Pvcces)
Rating: N/A |
mclough, you'd be better off just turning the headlights on and off. It's more reliable and should be risk free. Regarding the recent mantra about taking the NEGATIVE battery cable loose when you want to disconnect your battery; If you have a Heart inverter system with a Link to control it, there is a big warning in the manual about disconnecting the negative battery while the inverter is turned on. I lost an inverter and I believe that this item may have been the cause because I could not find any other reason for the failure. My tests showed that the computer in it quit. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher | ||
| FAST FRED Rating: N/A |
I believe Break before Break is the correct term . The field is cut and the switch can then Break one of the battery conections (with NO Fear). With one batt connection open the switch can be turned off or to connect to either another batt. set , or combine the sets. ONLY after the switch is in fulll contact will the fields current , and alt output be established. Break before break,and then make before make. FAST FRED | ||
| john wood Rating: N/A |
Its make before break | ||
| Tom Caffrey (Pvcces)
Rating: N/A |
The terminology doesn't work very well for this case, but I believe Fast Fred is closer. I think there ought to be a better way to describe it, but I don't have any good ideas. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher | ||
| Kyle Brandt (Kyle4501)
Rating: N/A |
Hi All, In the series "Designing the balanced energy system" series in Bus Conversions (5-96 I think), David Smead (sp?) covered this very well. Alternators make 3 phase ac power and use diodes to rectify it to dc. If the alternator is under load and is interupted, the voltace WILL momentarily go up, this COULD be over 100 volts. If the diodes (in the alt) are rated at 200 volts, they will PROBABLY survive. If they are rated at 100 volts, they will PROBABLY DIE. David's series is a GREAT source of good information (not hear-say) and should be read by ANYONE with electricity in their conversion, bus or camper. This thread has identified for me some excellent contributors who understand the subjects they post on. It has also exposed some others who do not understand the subjects they claim to be knowledgeable in. Thanks to all that post, it makes this forum an invaluable tool for my conversion. | ||
| Chuck -PD4104 Rating: N/A |
High current silicon diodes are a fairly new invention. They first became practical in the 1960's. In the early days, it was very difficult (read: expensive) to make a high current diode with a high peak inverse voltage (PIV). The auto manufacturers were very cost conscious, and as such used 50PIV diodes in 12V alternators. If you disconnect the battery cable, or have a cell open up, you WILL get a voltage surge. The size of the voltage surge is dependent on how much, and how quickly, the current the alternator is producing changes at the time of the disconnect. If the alternator is just running the ignition coil, and the battery is fully charged, the surge will only be a couple of volts. If the alternator is charging a deeply discharged battery, or one with a shorted cell, ... it will be much larger, perhaps several hundred volts. And, if the alternator is driving the heater, wipers, headlight, AC, etc.... the surge may be all but nonexistant... It has to do with how much the load abruptly changes. In normal operation, the battery eats any surges that happen do to load shifts. As time went on, the semiconductor manufacturers got better and better at making diodes that could withstand higher PIV's. It got to a point where they had to actually work to make a diode that was as poor as a 50PIV diode. As a consequence, the cheaper diodes are now the higher voltage diodes. So, in a modern alternator, you will still get a high voltage surge, but the diodes are more likely to be able to survive. But the regulator, stereo, and computer might be less able to survive, depending on their design. One thing to note, EVERY car manufacturer today has warnings in their service manuals stating that you can damage your electrical system by disconnecting a battery, or running with a bad battery. They also all have warnings about using the alternator to charge a dead battery. That too can kill the modern car alternator (and the battery) The alternator will produce way too much current, and over heat. Use a voltmeter. DVM's can be had for under $10. They will tell you in an instant whether your alternator is charging your battery. 13.8 to 14.8V is charging, anything less isn't. -Chuck - PD4104 | ||
| John that newguy Rating: N/A |
It COULD snow in Islamorada. http://members.1stconnect.com/anozira/SiteTops/energy/Alternator/alternator.htm Kyle - When my old wind-up wall clock ticks each second, it's hand moves back for an instant prior to moving to the next mark. I wonder why I don't get a bit younger... (Just a bit each second, would be nice) But that's off-topic. Since the alternator's design and inherent circuitry is engineered to cause the alternator to produce more power to meet the demand for more power the instant that more power is demanded......... (can a woodchuck - cut what?) And since all above (saving re-typing) was made to instantly stop the generation of extra power when extra power is not needed...... Why would removing a load cause the alternator to produce -more- power, rather than -less-? And why would it cause the alternator diodes to crash and burn? Is the "-WILL-" part of the author's comment, the nanosecond of time that it takes the circuitry to react to the need for more or less power and to make that change? (The power then, would not "go up", but would stay at whatever it is, for that nanosecond of time it takes to respond). If so, and assumed such a thing will cause severe damage, then it should be noted that: The scenario of highly unstable and highly damaging voltage fluctuation -would- occur constantly, since something as simple as turning the air conditioner on high while pushing in the cigarette lighter (or having both pop off simultaneously), would cause the substantial amount of power being produced to remain in limbo long enough to burn up devices (and that alternator?). (Funny, but that doesn't happen) However Kyle, the sparks and/or static electricity from removing battery cables while the battery is being charged, may cause problems to other electronic circuitry that may not be reasonably protected from such "accidental" occurrences. The alternator was designed to produce more when a load requires it and less when the load is gone. Do you really think that removing a load "too fast" will cause it's demise? To suggest that the alternator will be fried by doing so, is a bit like my wall clock's hand moving backwards and me getting younger.. Almost all newer automobiles carry warnings about "jump starting" the vehicle. Likewise, welding on any vehicle should be done with care, since the newer electronics can be damaged if left connected. It would be prudent to be concerned, that banging a battery cable off and on (engine running or not) might be a problem to some sensitive circuitry. And Tom made note, that removing a battery ground may cause current to follow to ground, through a ground path not designed for that much power (the inverter circuitry). That is something worth noting, since we (bus convertors) are the ones designing the electronics of our own conversion. If we don't insure proper electrical design to the components we are installing, we may suffer when some odd occurrence (like a detached ground) takes place (and yes, craphappens). The boat people have more to be concerned with, since grounding and power are run a bit differently (in most cases). The AFD devices were produced for that sector, and are not usually found in automotive applications. Should we use one...? I won't. I already ran a week of work chasing a "high voltage" condition (based on some BB suggestions), only to find that 32 volts is normal upon initial starting of the MCI and 28 volts normal (average) running voltage. I'm fearful of battery explosion from sparks, so I try to be careful around those 8Ds. I would not recommend tapping those terminals off and on while it's under load for that reason. There's one bunch of power sitting there; getting a shock from a wet battery case to positive terminal, is worth the experience (watta rush). The alternator? You can weld with that beast. | ||
| Kyle Brandt (Kyle4501)
Rating: N/A |
Sorry guys, but I can't resist. John, I don't know what your area of expertise is or what your education level is to justify your insistance that FF, Richard, Jim-Bob, Chuck, I, and others are wrong about surge voltages. A wise man once said "a mind is like a parachute, if it isn't open, it isn't working". :^) | ||
| Marc Bourget Rating: N/A |
Would the phenomena of "Back Electromotive Force" explain what JohnTNG is seeking an understanding of? | ||
| Chuck PD4104 Rating: N/A |
John, The reason that a surge happens is the alternator will not instantly stop producing power when the field current is shut off. It actually takes a significant fraction of a second. What saves your precious electronic equipment from all the glitches and surges when loads change is your battery. Your battery simply refuses to allow the voltage to go up much over 15V without drawing buckets of current. The whole feedback mechanism in the voltage regulator is tuned to work with a battery as its continuous load. But don't believe me, get yourself a digital storage oscilloscope, and hook it up between the + battery lead and ground, and record what happens when you remove the battery from the circuit. I've already done the experiment with other inductive circuits, you should too. -Chuck PD4104 OBTW, nanoseconds don't apply to this kind of feedback system. A nanosecond corresponds to 1GHz. Automotive voltage regulators work in the milliseconds to seconds region. | ||
| Gary McFarland (Gearheadgary)
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I suppost that puts Luke, Myself and others in a position of not knowing what we're talking about then, huh? I've made it a point to refrain from long theoretical discussions on this list but suffice it to say that I've changed a few hundred batteries on running vehicles (Cars, Trucks, buses, forklifts, tractors, Cats, etc...) and never had a subsequent component failure. I would however think twice if I suspected the vehicle had a microprocessor in it. Gary | ||
| Gary McFarland (Gearheadgary)
Rating: N/A |
FYI: I was typing my post at the same time as chuck was submitting his. My post should not be taken as an answer to his post. I realize that you may have momentary spike, but if you need a 1GHz sampling scope to see it, it's not going to nuke anything in a non-microprocessor electrical system. Gary | ||
| Chuck PD4104 Rating: N/A |
Hi Gary, You don't need to use a fancy 1GHz sampling scope in order to see the spike. You can see the spike quite nicely in the brightness of your headlights. The reason I suggested a scope is you will never know the dimension of the spike if you use your headlights to measure it. Also, as I said, the spike will be at its largest when the battery is drawing alot of current, and then is abruptly removed from the circuit. One of the insidious things about electronic parts that are voltage stressed is they very often don't fail immediately. They make their presence known down the road a piece. I wish you would enlighten me on why you would ever want to change "a few hundred batteries" in cars, trucks, lifts, etc. with the engine running. Having personally witnessed a battery blowup, I cannot imagine myself hot swapping batteries on a regular basis. -Chuck PD4104 | ||
| Gary McFarland (Gearheadgary)
Rating: N/A |
Um..well... How do you jumpstart someone without cables? You leave your vehicle running, in case the "patient" runs your battery down, you transfer your battery to his rig, start it up, then move the battery back to your rig. Also, this is also nescessary if you don't have a good set of jumpercables (And I haven't had a GOOD set in 15 years, but I bet Johnny's got a set, tow guys usually do) You can't start big stuff with the crappy excuse for jumpers they sell nowadays. you have to have a good connection to the battery to carry over 500A. I've also never done this indoors, usually I've been in the middle of a field or at the top of a mountain somewhere, so an outgassing battery was pretty well ventilated. I have blown a forklift battery up in my face from fast charging it then installing it right away. Thankfully one of the guys got me to the sink for a washdown and I suffered no Ill effects. I must bow to those of greater experience at this point having never, not even once stared into my headlights while working on my battery. Gary | ||
| Chuck PD4104 Rating: N/A |
Hi Gary, Ok, I guess I can see doing that in a true emergency. Otherwise, no way. My good electrical system is worth more to me than helping some other guy (even when its me) avoid a tow charge. I have no desire to witness a battery blowup ever again. If you must do stuff like that, make sure that all the lights are on when you remove the battery. That will give your electrical system the best protection possible. I keep a good set of jumpers in my truck, and I have jumped everything from lawn mowers to backhoes. The trick is they must have a battery that is somewhat good to begin with. -Chuck PD4104 | ||
| Gary McFarland (Gearheadgary)
Rating: N/A |
After the dumbass logger, farmer or whatever ran the battery down without fixing whatever was broke in the first place, I often got the call. When i came to see them it wasn't a social call but a gen-u-wine emergency, and they were paying cash, not because I was doing them a favor. If you have jumpers that will carry over 500A I'd like to know where to buy them. the last set I had I had to make out of a set of leads. I'll keep all that stuff in mind, as I stare into the headlights while changing batteries. Gary | ||
| John that newguy Rating: N/A |
You know the silly part, Gary.... First you're told that -if- the alternator is under load, that you should never remove the battery due to the higher power being generated; that it will cause the alternator to provide a damaging power "surge'...... Then, you're told to leave on your power consuming headlights if you insist on removing the battery while running, to provide a load..... protecting everything from a power "surge".... And somewhere between all that, it's admitted that it isn't actually a "surge", but the lack of the alternator's ability to sense the lessened need for higher power quick enough to cut back on the generating of it... You might be better off staring into those headlights than arguing. I'm on the way out the door now, to do just that. (mine get bright/dim with the AC or heat fans kicking in/out, btw) Cheers! | ||
| Gary McFarland (Gearheadgary)
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I just happened to notice that the original question was answered in 31 minutes, by jmaxwell and Marc. Correctly I might add. I should have kept to myself, but I couldnt help replying to the 'sploding headlights. I'm going back to staring at my headlights until the squirrels speak to me again. Gary | ||
| Gary McFarland (Gearheadgary)
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Or was it Ducks? | ||
| jOhN tHaT nEwGuY Rating: N/A |
Do they actually speak to you? That's great! The ones around here don't talk to me directly, but I can hear them talking behind my back. I hate that. | ||
| Gary McFarland (Gearheadgary)
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Funny, they were actually telling me how they glued this nasty plastic stuff to someones ceiling and they're sitting around chewing their nuts watching him try to get it off. I told them that was a funny way to pass the time but they told me they can't get a TV in their nest. Gary | ||
| niles steckbauer (Niles500)
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Don't know whats a funnier visual picture - squirrels watchin TV or Gary staring at his headlights - LOL - Niles | ||
| Gary McFarland (Gearheadgary)
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Hey, I'm just tryin' to see the light. Gary | ||
| niles steckbauer (Niles500)
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I guess thats better than chewing your nuts - Niles | ||
| Jtng Rating: N/A |
HAR de HAR HAR | ||
| Richard Bowyer (Drivingmisslazy)
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FF, I believe there are two sets of connections inside the marine switch. One set for the alternator field which is a break before make. This stops the alternator from charging while the high power leads for the battery are switched. I suspect the high power contacts are also a break before make to prevent paralleling the two batteries. It is possible that the high power terminals are make before break and would temporarily connect the two battery banks in parallel. In over 50 years of electrical and electronic work I have never heard of a break before break set of contacts. The terminology only applies to one set of contacts, not two. Since it is only one set, I do not understand why or how it could work. Maybe someone else can explain. Richard | ||
| Tom Caffrey (Pvcces)
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Richard, the marine switches I've seen have been break before make when swinging through the "off" postion and make before break when swinging throught the "both" position. Since the moving contact swings through a circle, they can be either. While I have not seen one of these with the alternator field contacts apart, it seems easy to visualize one additional fixed contact that the moving contact swings over. If the contact is supposed to be shut off before the field is disconnected from all batteries, then the wiper needs to be more than a half circle. If for one battery, it would only need to be around one quarter circle. I really don't know which way they chose to build them. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher | ||
| John that newguy Rating: N/A |
Holy Carp. Is this still being debated? Here: http://www.dockyardelectrics.com/Wire&cable/switches.htm (Keep in mind, that this outfit wants you to buy something. These switches may be needed on boats, but on a framed vehicle?) Sample text: AFD Explained "AFD is short for Alternator field Disconnect. The AFD is a second switch inside the battery switch, yet electrically isolated from it. The AFD switch closes before the battery switch contacts close and opens before they open. It is connected in the field wire between the voltage regulator and the alternator, preventing the alternator from producing power when the AFD switch is open..................." That's a "break before break", as FF said, isn't it, guys? | ||
| Tom Caffrey (Pvcces)
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John that newguy, I just finished looking at Blue Sea's writeup on these units, and I think the quote you picked has a mistake in it. The battery switch has an independent set of contacts that are closed only if either battery is connected throught the battery switch. The field line opens before disconnecting the batteries, going either way. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher | ||
| John that newguy Rating: N/A |
Sounds like semantics, Tom. Fast Fred simplified the entire description by reducing it to the simplest explanation of what the (overall) switch accomplishes. There are two sets of contacts, one set for the battery(s) and one set for the field. I would think, rather than argue intensively, that "break before break/make before make" as FF said, would serve the purpose of what happens inside that switching device. Not everyone here is an engineer, or wishes to think like one. (am I speaking for myself?) Cheers! | ||
| FAST FRED Rating: N/A |
""Not everyone here is an engineer, or wishes to think like one. (am I speaking for myself?) "" No , that's why the KISS setups usually work far better than the Rube Golderg attempts at doing everything at once, or somehow. KISS makes it easier for the NEXT OWNER, as HE doesn't have to be a mind reader/engineer, to just go camping! FAST FRED | ||
| Richard Bowyer (Drivingmisslazy)
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JTNG, Perhaps then you would be kind enough to explain to me which circuit(s) are going to break before break and which circuit(s) are going to make before make and how a neophite would understand that there are two completely different electrical circuits that are inter-related and dependent on each other. My experience is that KISS does not always make it easier for the next owner. Some of the Rube Goldbergs that I have seen, in the owners attempt to KISS, really blew my mind. Richard | ||
| FAST FRED Rating: N/A |
"Perhaps then you would be kind enough to explain to me which circuit(s) are going to break before break and which circuit(s) are going to make before make and how a neophite would understand that there are two completely different electrical circuits that are inter-related and dependent on each other." The BEAUTY of a good marine rotary switch is the operator does NOT need to know anything. If installed correctly any imbecile can operate the system getting what he wants , simply by reading the marks on the case. Bat 1 , bat 2 or Both or OFF. Yes because the field is killed , one can even switch the batts OFF with out blowing the alt diodes. KISS , works perfectly with out knowledge , if its done right. Your results may vary, FAST FRED | ||
| Richard Bowyer (Drivingmisslazy)
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The question was never what the operator has to know. I agree that the operator has to know nothing. What I do not agree with is your explaination of what the internal workings of the switch contacts are, and that information is very misleading for someone trying to build a system. Richard | ||
| Marc Bourget Rating: N/A |
Then again, Dave Smead has photos on his website www.amplepower.com that demonstrates the basis for his opinion that Converters should throw the 1-2-Both Switches away! | ||
| Richard Bowyer (Drivingmisslazy)
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Marc, I believe that demonstrates exactly why I was trying to get the wording exactly correct on the switch action. Many times if you do not get something exactly correct, when dealing with electricity, you do not get a second chance. BTW I have contacted the ADF switch manufacturer directly to try and find out whether their switch makes the transition from one battery to the other properly. In their write up, it does not. Richard | ||
| John that newguy Rating: N/A |
Richard- I was merely trying to explain that FF's simple explanation of what that "switch box" does, does precisely that: OFF:= it breaks one circuit, then the other; The switch breaks the field connection, then the battery connection ON= it makes one circuit, then the other; it makes the battery connection, then connects the field. The fact that there are two sets of contacts inside that switch box isn't duly noted, but anyone getting this far into it (to even have an interest in such a switch), should have some smattering of knowledge of the intention/purpose of this switch debacle. And yes, I agree whole heartily with you. I don't feel it's needed on any RV or bus conversion. If the wiring's done correctly and all grounds are bonded properly, there shouldn't be a problem. Both our RVs used a simple solenoid to transfer power. Those devices frequently fail, leaving either both sets of batteries connected together, or no batteries connected. I never suffered electrical component failures due to it. What's really funny, is the guy that started this thread only wanted to know how to tell if his alternator was charging his batteries. He mentioned that he took off the battery connection and the bus continued to run.... could he assume that the alternator was working... Both questions were answered long ago... Switch-smitch...who cares? | ||
| Richard Bowyer (Drivingmisslazy)
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Yep. I agree. Lets get back to busses, and don't let the smoke out, it can ruin your whole day. Richard |
