| Author | Message | ||
| Jack Tucci (Tuccitown)
Registered Member Username: Tuccitown Post Number: 22 Registered: 3-2006 Posted From: 199.3.115.254 Rating: N/A |
I would like to replace the two toggle swtches that turn on the coach and start the coach with a single keyed ingnition on my 4905. Anybody do this? Looking to not have to reinvent the wheel. Thanks, Jack | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 704 Registered: 12-2000 Posted From: 76.3.169.171 Rating: |
Not sure about on a GM, but I recently installed a keyed switch on a MCI 102A3. I went to a local auto supply store and purchased a universal ignition switch. The switch has 4 positions Accessory, Off, On, & Start. Connect battery positive to BATT terminal, wire from OEM start switch to START terminal, and wire from OEM master switch to IGN terminal. Hope this helps, Jack | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 143 Registered: 10-2006 Posted From: 66.90.229.85 Rating: N/A |
Jack's switch is the right idea , but if you wire the house / coach solenoid to the ACC position , you get automatic house battery charging. Seamless. FF | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 326 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
AND, if you happen to put the switch in the ACC position, you get automatic house/chassis battery discharging, oops. (Just put the solenoid coil on the ign term with the rest of the load, then its off with the eng.) G | ||
| David (Davidinwilmnc)
Registered Member Username: Davidinwilmnc Post Number: 215 Registered: 7-2005 Posted From: 75.180.200.138 Rating: N/A |
As to the solenoid... Mine's wired so that there's a 3-position switch (auto, off, and joined). In the 'auto' position, if the ignition is on and the 'Not Gen' light has gone out, the battery banks are connected. In the 'on' position, the banks are joined together - good for a jump start off the house batteries. Off keeps the banks separate. I meant to add this about topic at hand. I have a big latching solenoid that I use as my disconnect for my start batteries. I mounted the momentary switch for it in the parking brake console facing the driver's seat. It's hidden well enough (black toggle on a black surface) and pretty much does what a keyed switch does - keeps unwanted people from starting the bus. David (Message edited by DavidInWilmNC on December 23, 2007) | ||
| James Stacy (Jimstacy)
Registered Member Username: Jimstacy Post Number: 119 Registered: 1-2001 Posted From: 75.63.12.220 Rating: N/A |
To keep the current load off the ignition switch, I pick a constant duty solenoid with the key switch,put all the load on the solenoid. Switch contact life should not be a problem. Trouble free for ten years. | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 163 Registered: 3-2007 Posted From: 76.4.148.149 Rating: N/A |
just for future info do any have a wiring diagram of this for us older newbies LOL. I might just do one myself on one of my coaches. gomer | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 148 Registered: 10-2006 Posted From: 66.90.229.46 Rating: N/A |
AND, if you happen to put the switch in the ACC position, you get automatic house/chassis battery discharging, oops. NOT oops , but for most coaches that only charge the house set on 120v , a bi monthy treat for the start batterys. | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 327 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
FF, Don't want to get picky here, but what happens when you drive a coach somewhere and park it with the interconnect solenoid wired to the acc position, and turn the new key to the acc position? (Aside of leaving the key in the coach, which is just what he doesn't want to do.) 1. The solenoid draws a little bit of current all the time it is energized, that's not a big deal, but. 2. The house and the chassis batteries remain interconnected, and after a few days of boondocking, the HOUSE AND THE CHASSIS BATTERIES ARE BOTH DEAD, PERIOD. As I really tend to forget things, especially those that go away quietly, I personally wouldn't want to take a chance on leaving my house & chassis batteries connected while parked off shore power? IMNSHO, David has the best way of wiring this, either with a key switch, or without, which is through the "NOT GEN" RELAY. That gives the option of an easy house battery jump start with the addition of another switch. More to think about... A solenoid simply tied to the master switch connects the house and chassis batts as soon as the master is turned on, which is going to put an equalizing drain on the chassis batts while starting the engine. Now, somebody is going to say that these 4 position ignition switches disconnect the ACC position while starting, which is correct. Ok, but is the chance of dead chassis batts, plus leaving the key in the new switch in the acc position unattended, worth charging chassis batts in some coaches while stored? G | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 231 Registered: 2-2001 Posted From: 208.6.60.4 Rating: N/A |
O.K., why not use an oil pressure switch or an air pressure switch to disconnect that ACC term interconnect? Oil would cut it off immediately on stopping the engine. Air would hold until pressure falls off (depending on your bus, 20 minutes to 2-3 days.) Oil switch would require a wire to the rear of bus. It could ground your relay coil. One of the sharper space age guys will likely now suggest a microprocesser to do the job. Jim-Bob | ||
| Moe Hollow (Moehollow)
Registered Member Username: Moehollow Post Number: 10 Registered: 12-2007 Posted From: 64.173.151.3 Rating: N/A |
I like the FF approach on lots of things, but in this case I would opt for a separate switch to connect battery banks. It's just not that much work to throw another switch, and I prefer the extra control. Of course, I have the 12/24 issue so I have not done anything. | ||
| David (Davidinwilmnc)
Registered Member Username: Davidinwilmnc Post Number: 217 Registered: 7-2005 Posted From: 75.180.200.138 Rating: N/A |
Jim-Bob, I'm not going to suggest a microprocessor to do this, but to use the 'not gen' terminal to allow the battery banks to connect. It's easy to get to - in the outside driver's elec. panel - and is based on air pressure, but the engine switch has to be on before any of this battery combining can take place. With my switch in 'Auto', the batteries all connect together when the engine is running and the 'not gen' light goes out (unless I flip the switch to off). David | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 152 Registered: 10-2006 Posted From: 66.90.226.167 Rating: N/A |
"I would opt for a separate switch to connect battery banks. It's just not that much work to throw another switch," BUT it is REQUIRED to remember to turn it off.MY WAY , no thinking involved. As a camper would hardly boondock with the keys in the ignition , How would he lock/unlock the door? I feel leaving it on for weeks in ACC is as likely as leaving the keys in the car on ACC. FF | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 328 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
12/23, 1000am, FF, "NOT oops, but for coaches that only charge the house set on 120v, a bi monthy (sic) treat for the start batterys."(sic) As I am still recovering from the concussion suffered from falling off yesterday's turnip truck, I just can't figure out how that would work without the key being in the acc position? G | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 329 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
I don't like being a grump, and it is the day before Christmas, so here's my offering on the whole ignition switch/solenoid controversy. Two ways to charge house batteries, OTR. 1. Diode separator. Pluses, wire it and forget it. Gives better charging of discharged bank when in parallel with charged bank, (normal condition immediately after boondocking.) Minuses, costs a little more than a solenoid. No emergency jumpstart option built in. (Emergency start/run option requires a solenoid as well.) 2. Solenoid. Pluses, less costly. Gives option of house battery emergency start with a little "logic" wiring. Also gives option of house battery/generator emergency run with coach alternator failure. Minuses, won't charge one flat bank as fast when connected to a charged bank, (the voltage regulator sees the charged bank.) A moot point after three or four hours of driving. Depending upon how the solenoid coil is wired, (see all the above posts!) flat house batts MAY be connected to the chassis batts when starting. Maybe a moot point, but maybe on a cold day with old chassis batts, maybe no go? Flat chassis batts too, if the interconnect switch is inadvertently left on. IMNSHO, a solenoid wired thru the not gen relay is the answer. NO interconnect while starting, only connects while generating. Oil or fuel pressure switches can be used to do almost the same thing, they just won't drop the solenoid out if the alternator fails. And that is splitting hairs. Emergency start can be a button, as it will never be forgotten in the on position. Take the button hot wire from the house battery positive. Emergency run, without the disastrous consequences of inadvertently leaving the switch on in other circumstances, can be done by taking the interconnect-switch hot wire from the LOAD side of the bus master. Merry Christmas everyone, its eggnog time! George | ||
| Moe Hollow (Moehollow)
Registered Member Username: Moehollow Post Number: 11 Registered: 12-2007 Posted From: 64.173.151.3 Rating: N/A |
FF, since when have you been against a little thinking? It seems to me that many of your suggestions involve a certain cognizance of what one is doing (like pull chain drains on the air tanks). I thought "works for me" was your battle cry. I depend on you for the core common sense solution. Don't go all techy on me. | ||
| Tony Gojenola (Akbusnut)
Registered Member Username: Akbusnut Post Number: 17 Registered: 11-2006 Posted From: 208.98.151.220 Rating: N/A |
So what's the problem and what difference does it make how the interconnect solenoid is energized? It's easier and cheaper to incorporate a reminder than to introduce a complex hi-tech alternative. I use a separate switch but have a neon indicator light next to it to remind me. I light it up while otr, turn if off when I stop. But when I'm on the power pole or running the generator it stays lit while my inverter/charger takes care of the house batteries and the 8-d's at the same time. I have left it parked and plugged in, solenoid closed with the light telling me so over quite a few long Alaska winters and never a problem. kiss, wfm tg | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 564 Registered: 11-2005 Posted From: 206.40.238.128 Rating: N/A |
Jack, Have you noticed how complicated this is getting? Ignition switches are famous for failing, even the OEM ones, and after-market ones are worse. The original two toggle switches are simplicity itself in operation and very simple to replace? | ||
| H3-40 (Ace)
Registered Member Username: Ace Post Number: 715 Registered: 10-2004 Posted From: 70.221.82.208 Rating: N/A |
I JUST replaced my keyed ignition switch because I thought it had failed. It wasn't the culprit but now my keys stay in the ignition all the time. The entry door lock was, and still is a separate key. Since the ignition switch wasn't the problem, I may just put the original back in and keep the new one as a spare! Electronics? They may be good when they are working but they sure are hell when they don't! I THINK I finally have all the bugs on mine worked out. This weeks trip down south to Bussin' and back should tell me more! Ace | ||
| Jim & Linda Callaghan (Jimc)
Registered Member Username: Jimc Post Number: 44 Registered: 2-2004 Posted From: 66.175.206.159 Rating: N/A |
I agree with Gus, simple works. If you really feel the need, you can replace the master on off switch with the type where the toggle is a red plastic key that pulls out to keep someone from playing games. Nice thing about the master on off is that when left on, the no gen light and oil light should be lit to let you know. If you need to use something without turning on the master, you can always wire another circuit that uses a separate switch with a led on the switch to remind you its on. Jim | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 154 Registered: 10-2006 Posted From: 66.90.229.218 Rating: N/A |
"I just can't figure out how that would work without the key being in the acc position?" NOTHING, In the acc position , the result would be similar to normal operation with the engine running, the coach merge solenoid would be closed enabiling the charge of the house , automatically. Parked , if the key switch were put to ACC the house (on its 120v charger) would seamlessly charge the start batts. The hassle with transistors (diode seperiator) is the chance of undercharge , from the usual 3/4v lower output to the house set. Auto stuff is produced at a low price for throwaways , a Marine, Cole Hersey ignition lock is USCG rated to handle 15A cont , and many have silver contacts. About $20.00 or +300% of an auto zone car part from China or Mexico , but worth saving up for. FF | ||
| David (Davidinwilmnc)
Registered Member Username: Davidinwilmnc Post Number: 218 Registered: 7-2005 Posted From: 75.180.200.138 Rating: N/A |
"BUT it is REQUIRED to remember to turn it off.MY WAY , no thinking involved." FF, if you read the description of the setup I use, there is an AUTO position, where the switch stays. The house batteries are connected to the alternator when 1) the engine switch is on and 2) the 'not gen' light is off. In other words, the battery banks are combined when the alternator is charging UNLESS I flip the switch to off. What could be more simple than that while still allowing for the option of not combining battery banks (perhaps a cell is bad in my house bank, etc)? Do it your way, sure, but don't take the flexibility out of the setup. David | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 330 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
FF, First off, Merry Christmas! That's most important. Now, you have dodged around answering my comment three times, and this time you have added something else to your last post, apparently in an attempt to avoid a reply to the first post? In your first post you said "Hook the solenoid to the ACC position, and you get automatic house battery charging." That is correct, however, as I then posted, "you get automatic house/chassis battery discharging if you leave the key in the ACC position, oops." You then replied: "I would opt for a seperate switch...As a camper would hardly boondock with the keys in the ignition...I feel leaving it on for weeks is as likely as leaving the keys in the car." THEN you say: "For most coaches that only charge the house set on 120V, A BI MONTHLY TREAT for the chassis batteries?" Now, if that isn't leaving the key in the ACC position FOR OVER TWO MONTHS, what is it? My only reason for beating this thing mercilessly, is to avoid someone leaving an interconnect on accidentally while parked, and finding dead chassis batts a couple of days later. George | ||
| Moe Hollow (Moehollow)
Registered Member Username: Moehollow Post Number: 12 Registered: 12-2007 Posted From: 68.183.235.30 Rating: N/A |
Is there a way to link a 12v house bank to the 24v coach bank for reciprocal charging? | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 331 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
No turkey until about 3pm, so one more comment. I like a straight reply to a question, and I don't like adding other things to an issue, so I didn't. There was an incorrect comment about diode separator operation above, and I would like to explain their operation, so as to clear up the misunderstanding. Silicon semiconductor material (as in diode separators) does indeed cause a voltage drop of 0.6 Volts with current flowing across it. However, a diode separator causes NO VOLTAGE LOSS AT EITHER SET OF BATTERIES, due to the way it is wired into the system. The alternator output goes FIRST thru the separator, then into the chassis wiring, which isn't changed. Chassis wiring goes up front to the master switch, thru the switch, and back to the ign (or batt) terminal of the voltage regulator. The regulator uses THIS voltage as a reference to determine how much field current to send to the alternator to keep the BATTERY voltage (not the alternator voltage)at the regulator setting. Does this mean that the alternator output voltage is going to be 0.6V higher than it was? Yep. Is the bus battery voltage exactly the same as it was before? Yep. Do you have to adjust the bus voltage regulator after installing a diode separaror? Nope. Use a voltmeter on the batts before and after! Some months ago, someone expressed concerns over "power loss in a diode separator." Watts are the electrical unit of power, and are AMPS X VOLTS. So, at 100 AMPS of alternator output, times 0.6 Volts drop, you get a 6 Watt loss. In my opinion at least, that isn't worth talking about. I won't ask how much current the coil in a constant duty solenoid consumes! The smell of roasting turkey is making me hungry... Gobble gobble, George | ||
| Richard Bowyer (Drivingmisslazy)
Registered Member Username: Drivingmisslazy Post Number: 2023 Registered: 1-2001 Posted From: 75.108.84.4 Rating: |
George, you are absolutely correct. That is how my diode isolator was installed and I never had a problem with lower voltage on the battery. I did use a digital voltmeter at the battery to adjust the output of the voltage regulator till I had the correct charging voltage. Several have mentioned this drop across the isolator in the past and I feel they are all in error if the isolator is properly installed. Richard | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 332 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
Merry Christmas Moe, Tough one there, but here's a couple of thoughts. Rewire for 24 Volts, series instead of parallel, and install a solenoid or a separator, and a Vanner equalizer. This will work well for everything except a 12 volt inverter. The inv will want too much current for the eq. If you don't have an inv yet, strongly consider a 24 Volt model, for several reasons. A 24V model requires smaller cables, and is available in higher wattages. In a 24v bus, you arrive fully charged, and can use your inv OTR. The equalizer will give you all of the 12 Volt you want for the rest of your house needs. A 12V bank CAN be charged from a 24V bus, but it takes a bunch of solenoids, a couple of them normally closed to do it, and then you get into what someone else called a "unique" bus. Do you get his (and my) drift? I would go so far as to suggest "flea marketing" a 12 Volt inverter, for those of us with 12 Volt buses, and buying a 24 V? Another thought is to belt up/bolt on a 12 Volt alternator. Please post and tell us exactly what you've got, and what you're trying to do, and we'll think on it. Might not be until after an after dinner nap, but. Merry Cristmas, George | ||
| Moe Hollow (Moehollow)
Registered Member Username: Moehollow Post Number: 14 Registered: 12-2007 Posted From: 68.183.235.30 Rating: N/A |
I'll re-ask this in a new thread a bit later rather than to unnecessarily effect this one. Thanks, Moe | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 169 Registered: 3-2007 Posted From: 76.4.148.149 Rating: N/A |
Hey guys; let us make this simple. Take the starter push button and replace it with a keyed switch. Now leave the toggle switch in place that says Master. No one can start it without the key and you can do the same in the back as well. The heck with all them thar diodes and relays and solonoids. Whew my mind is warped now. gomer | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 156 Registered: 10-2006 Posted From: 66.90.229.112 Rating: N/A |
"For most coaches that only charge the house set on 120V, A BI MONTHLY TREAT for the chassis batteries?" Now, if that isn't leaving the key in the ACC position FOR OVER TWO MONTHS, what is it?" BY monthly is 2 times a month , not 2 months.Sunday? morning , every couple of weeks for a few hours. For folks out cruising that are stopped for months at the same place with no coach running , the house is usually tied to a charger , the starts not. There ARE marine chargers that will charge 2 or 3 sets of even various batts (WET AGM, FLOODED) but there Marine and pri$y. The setup I sugest is what is in every RV built in the last 50 years for a good reason. No thinking , except every 2 or 3 weeks to merge , so the starts won't go flat. *** If the V reg is set to sense the house set , the starts will be seeing that extra half volt. Most can take it and just need a bit of extra water,more often. FF | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 333 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
Fast Fred, I'm sorry, but you just don't understand how a diode separator works. They consist of nothing more than two large diodes, WIRED IN PARALLEL, mounted on a heat sink. They are installed with the input connected to the alternator output cable, with the other end of the cut cable attached to one terminal, and the house batteries attached to the other terminal. As I explained immediately above, the original bus circuit continues to the master switch, and then back to the battery or ignition terminal of the voltage regulator. THIS WIRE IS WHAT THE VOLTAGE REGULATOR USES TO DETERMINE HOW MUCH VOLTAGE THE ALTERNATOR IS SUPPOSED TO PRODUCE. As it is "electrically beyond" the diode separator, the regulator goes on just as it did before the seperator was installed, looking at the ign terminal and deciding how much voltage the alternator is supposed to produce. There is always some resistance in any wiring, so adding 0.6 Volts drop to the system doesn't change anything, as the regulator "sees" the voltage AFTER all the drop from the rear of the coach, thru the batteries, to the front, thru the master switch, and back to the regulator. What this means, is that if the bus had half a volt drop from the back to the front, and back again, BEFORE the separator was added, and the regulator is set for 28.0 Volts, the alternator puts out 28.5! Now, we increase the drop by 0.6, and the alternator will now put out 29.1, because that is what the regulator needs to see 28.0. As I explained above, separators have TWO diodes, wired in parallell, which means side-by-side. One end of EACH of them is connected to the alternator output, with the other end of one connected to the chassis, the other end of the other connected to the house. As these diodes are identical, and wired in parallel, and BOTH produce a 0.6 Volt drop, THE OUTPUT VOLTAGE ON BOTH SIDES OF A SEPARATOR IS THE SAME. George | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 334 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
Sorry, I don't know how it posted twice, maybe too much eggnog? Anyhow, I couldn't delete it because it was more than 0 minutes old. G (Message edited by George Mc6 on December 26, 2007) | ||
| Don Evans (Doninwa)
Registered Member Username: Doninwa Post Number: 98 Registered: 1-2007 Posted From: 66.45.165.58 Rating: N/A |
George, in an isolator the diodes are not in parallel. To be parallel the anodes and cathodes would both be connected. The cathode of each diode is connected to a different battery (bank). I think Fred is promoting a solenoid interconnection. No matter which system is used when charging from the engine driven alt, the start batteries are likely to be overcharged or the house batteries undercharged. A typical cycle goes something like this: 1. Engine started and bus driven somewhere with engine driven charger topping off the start batteries. 2. Park and use the house batteries partly draining them. No matter how the banks are tied together, isolator or solenoid, you now have the start bank that would be recharged in a matter of minutes and a house bank that needs some serious charge. If you where tied to a PP then the situation is reversed, but I am using an example of boondocking. Point is, there can be a large difference in state of charge of the two banks. 3. Start the engine and drive somewhere. If you have an isolator and the sense voltage is from the house bank the alt will charge until the house bank is charged which will over charge the start batteries. If the sense voltage is from the start batteries the alt will stop charging (heavily) before the house bank is charged. Same thing happens to some extent with a solenoid but it will average the sense voltage of the two banks and actually move current from one bank to the other. There are other considerations like the internal impedance of a battery will tend to increase as it reaches full charge and so forth but I am trying to keep it simple for the sake of discussion. Then of course there is always the situation where the banks are of different types of batteries and need a unique charge profile. That is why my plan for the new bus is for two alternators. One to take care of each bank independently with an interconnecting solenoid for jump start and redundancy if one alt dies. If I get real gun-ho, I will use the gear drive (big with adjustable reg) alt to charge the house bank and a simple one wire to maintain the start batteries. Biggest drawback is polluting that nice beltless engine compartment with a belt, ugh. With main disconnects on each bank and a fancy inverter I should be able to take advantage of the multistage charging, equalization, and other nice goodies to maintain each bank too. Don 4107 | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 336 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
Don, I appreciate someone who will reply to the subject, stay on it, and I will gladly agree to disagree, with no hard feelings! That said, lets look just a little further. The anodes of both diodes are connected to the same source, the alternator output. We both agree. One anode is connected to each battery bank, we agree there also. Not calling this a parallel circuit is in my opinion splitting hairs, but we can disagree here amicably, and I am open to a suggestion on what then to call this circuit. Anyhow, lets consider this, which is the crux of the matter. Electrically there is a diode in the circuit between the alternator and each bank. The bus regulator SEES THE VOLTAGE DOWNSTREAM FROM THE DIODE, and this is the important part of this thought. The regulator uses this voltage to determine how much field current to send to the alternator, I think we agree so far? Now we need to think about Ohm's law for a minute. For simplicity, Amps=voltage/resistance. I agree with your numbers 1 and 2, but I have to disagree with number three, for the following reasons. Alternator output is going thru a diode, and into a battery bank, in two parallel circuits, for lack of a better word. One charged (Chassis) and one discharged (House after boondocking.) Voltage regulator reference is on the chassis bank, which is nominally 25 Volts charged, ignoring temperature, etc. Regulator setting is nominally 28 Volts, so the regulator will ask the alternator to produce 28 Volts downstream of the chassis diode. Now, as the anode of the house battery diode is connected to the anode of the chassis diode, 28 Volts will occur downstream of it also. This is the important part, because according to Ohm, ELECTRICITY FOLLOWS THE PATH OF LEAST RESISTANCE. So, the reg asks for 28 V downstream, the chassis batts are fully charged, so their resistance is high, and their current flow is low, but the house batts are discharged, so their resistance is low, and their current flow is high. The regulator doesn't know what is going on, and doesn't care, it just keeps on asking for 28 Volts, and it doesn't know how many amps it takes to maintain that voltage, or where that current goes. Since the house batteries are low, more current flows thru the path of least resistance, charging the house batteries faster. Reverse the situation, and the end result is the same. Low chassis batts, with high house batts, and the reg asks for 28 Volts downstream again. This time there is high resistance on the house side, so most of the current flows into the chassis side. It might help to think for a minute about the normal operation of a bus (or a car) with one battery, or two for 24 Volt. The regulator has no idea whether the battery is charged or discharged, it just maintains the VOLTAGE it is set at. The battery charging AMPERAGE is totaly dependent upon the resistance of the battery. Does the regulator have to put out more field current to the alt to charge a discharged battery? Yes, because the resistance of the discharged battery is low, so it takes more current to keep the voltage up. When the house side is low, and most of the current goes there, the reg is still asking for 28 V on the chassis side, and it will take a lot of field current to keep 28 V on the chassis side, with the house side being low, (thereby having less resistance) and taking more current. Using a voltmeter across a charged and a discharged set, shortly after starting the main engine will show the discharged set to be low, regardless of the interconnection method. But, if you look at current flow, you will see the greater amount going automatically (or accidentally) to the discharged bank. The internal resistance of batteries is the most important part of this discussion, as it is the basis of charging system operation. Since I can't have a "parallel" circuit thru the separator, you can't have battery "impedance" as that is an AC term only! I know FF is a solenoid proponent, and that's fine, but it is frustrating to ask the same question four times, and get four answers that don't deal with the question at all. I have just thought of a question which MIGHT put this all to bed. Why do diode separators have TWO diodes in them, when one in the chassis circuit would prevent the house side from discharging the chassis side? (The answer is NOT to keep the chassis side from discharging the house, either.) No, I don't sell separators either. The answer is to avoid the 0.6 Volt differernce between the banks. I'm done. George (Message edited by George Mc6 on December 26, 2007) (Message edited by George Mc6 on December 26, 2007) | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 232 Registered: 2-2001 Posted From: 208.6.60.4 Rating: N/A |
Reading all of these posts turned on a light in my head. Many posting here (including me)don't use isolators because we have had problems with batteries being undercharged. It ocurred to me that the only way these isolators can work as George describes is if the alternator / regulator is the old style with a separate regulator. The one wire alternator which is most prevalent in our world can not work properly with an isolator because it senses the B+ directly at the alternator internally. And there will always be issues charging two separate battery banks with one alternator. The easy way is just install a second one wire alternator to charge the other bank. | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1166 Registered: 5-2001 Posted From: 65.74.67.83 Rating: N/A |
George, I don't know about other makes of buses, but I just reviewed the diagrams (two versions) for our 4106. One uses a sensing relay and the other uses a run position connection to turn on the regulator. This is done by turning on a relay. However, that's as far as it goes. The regulator, in either case, is supplied power for it's operation and regulation directly from the engine batteries. This means that the voltage regulation would follow the starting battery voltage, as far as I can see. We use a Pathmaker for an intertie between batteries, which is relay based, and it is adjustable for cut in and cut out voltages, as well as overvoltage protection. There is no problem with offset voltage regulation. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| Don Evans (Doninwa)
Registered Member Username: Doninwa Post Number: 99 Registered: 1-2007 Posted From: 66.45.165.58 Rating: N/A |
George, I am just trying to point out that neither system is ideal with all the possible battery combinations and charge/discharge situations and my plan for trying to iron out some of the kinks. Not trying to take credit for two alts idea either. Will it work? Hope so. Are we trying to make this more complicated than necessary? Probably, but what else are you suppose to do when it's too cold to work on the bus and I was not smart enough to head south where that is not a problem  Since we (I) got so far off the original question, I have a keyed alike ignition switch and door lock set up too. There will also be a separate hidden switch (besides the rear controls) to disable the start circuit to discourage dumb people. Any one that knows buses would not have much trouble getting such a simple system running. The control for the interconnect solenoid will be separate from the ignition with a lighted indicator. Don't take me too seriously, Nobody else does. I'm use to it. Don 4107 | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 171 Registered: 3-2007 Posted From: 76.4.148.149 Rating: |
I told ya so. keep it simple. remove the push button starter switch,install keyed switch,also at the rear with the same key, THAR YA GO gomer | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 567 Registered: 11-2005 Posted From: 206.40.238.187 Rating: N/A |
Gomer, Nobody's listening to simple methods. Busnuts like things as complex as possible with as many gadgets as possible not to mention the expense!! Never could figure this out?? | ||
| William D. Watkins (Sivrtnge2)
Registered Member Username: Sivrtnge2 Post Number: 166 Registered: 11-2006 Posted From: 70.11.202.84 Rating: N/A |
I say get a 2 inch paper clip, a toilet paper roll, 4 quarters, 100 feet of 4.0 wire, 2 clothes pins and some J B weld. Hook up a plastic cup to a piece of dental floss. There you go, works like a charm!!! I understand what you guys said as bout as much as you understood what I said!!! Gomer when I get to this point I will hit you up on a simple fix!!! | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 172 Registered: 3-2007 Posted From: 76.4.148.149 Rating: |
gus; It is called the "KISS" method. "KEEP IT SIMPLE STUPID" That is where I learned at the recording studio's when I recorded new songs and tha engineer would holler over the mic KISS and so I went form there. NOT TO SAY OUR BUSNUTS ARE THO. They are ALL to smart for my own good LOL gomer | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 564 Registered: 7-2006 Posted From: 66.217.105.80 Rating: N/A |
You oughta' get ten stars, Gomer!! | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 799 Registered: 10-2003 Posted From: 71.58.48.5 Rating: N/A |
I can't believe a simple job like this made 43 posts so far????? | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 173 Registered: 10-2006 Posted From: 66.90.229.203 Rating: N/A |
I can't believe a simple job like this made 43 posts so far????? Everybody agrees KISS is the way to , the problem is folks seem to disagree on how many failure modes need to be covered , and still be KISS. That's why buscampers call it MY WAY! FF | ||
| Ian Giffin (Admin)
Board Administrator Username: Admin Post Number: 1039 Registered: 7-1997 Posted From: 70.55.230.68 Rating: N/A |
Well, here's my thought on it: (Message edited by Admin on January 5, 2008) :-) Ian www.busnut.com |
