crasster Posted December 27, 2010 Share Posted December 27, 2010 I did a stupid thing, (I think). My old battery isolator was bad from my 87' Dolphin. I changed it out with one from Oreilly auto that was a 90 amp. My old one had 3 wire terminals, my new one has 4. Old one 1) Alternator 2) Vehicle battery 3) House battery New one 1) Alternator 2) Vehicle Battery 3) Ignition wire 4) House battery STUPID ME (I think) I never connected the ignition wire. So anyway, I start the RV and drive around for a WHILE, I guess about 16-18 miles. I start to get on the highway, and lose a LOT of power after going 40 mph. Then it gets slower and slower. I begin pleading with God that I make it home so I don't have to tow it. I was about 2 miles away. So I get off the highway and start making turns down residential streets. The vehicle studders and studders more every time I have to stop. So I "stop" stopping. I keep it REAL slow looking very carefully at stop signs so I would not have to hit the brake. I just REALLY wanted to make it home. I turn down this strreet, turn down the next street and come up to a light for a major intersection - left hand turn. The RV will only go about 10mph now. I keep my fingers crossed, and what do ya know, green left hand arrow. Knuckles are white while I turn left. Getting close to home now.... RV can only go 5 mph now. No brakes turning down my street because I thought braking would kill the engine. I drive all the way down the street, no brakes going into my uphill driveway. I amazingly get all the way up, and hit the brake to avoid hitting the fence, and the RV dies. LOL!!!!! I MADE IT! So anyway, that's my story. Now on to the questions. 1) I guess my mistake was not connecting the ignition wire and the isolator was not allowing the alternator to charge the battery??? Where can I find a good source (under hood or simple place) for an ignition wire? Also does the ignition wire have to be a heavy duty thick wire for a lot of current, or something just to switch it on? (RV is 22RE & Isolator is on driver's side) 2) It made me think about the house batteries more in the event that an alternator dies. If I started my genny then "jumpered" the two terminals on the isolator for both the house battery and the RV battery, wouldn't that have kept me running in that event. Would this also let me charge a drained battery from the generator? Is the "jumper" idea a simple idea, or are there draw backs? (My house batteries are 2 6V golf cart batteries wired in series, don't know if they have enough crank amps for the RV - but perhaps they could keep the RV going if I faced this again - if the alternator dies on the road, or ignition wire goes loose / bad / corroded... or whatever. Just crank the Genny, jumper the isolator poles, and keep driving till safe. Anyway, my main question roots around question 1. The other is just something I'm pulling out of my nether regions LOL and dreaming up solutions with. Thanks everybody. -Chris R. Quote Link to comment Share on other sites More sharing options...
Gulfstream Greg Posted December 27, 2010 Share Posted December 27, 2010 The ignition wire supplies voltage to the alternator terminal inside the isolator. Toyota alternators need to see voltage presence on the output termanal of the alternator before they will generate power. The ignition wire fools the alternator into thinking its still hooked up to the battery. The isolator does exactly what it does, isolates so the alternator can't see ether battery. Can't remember where I pulled my ignition from, I think the windshield wiper circuit. It really does not supply any current but a 5 amp fuse I believe is suggested in-line. If you don't already have one, a volt meter is a handy tool. Quote Link to comment Share on other sites More sharing options...
crasster Posted December 27, 2010 Author Share Posted December 27, 2010 As some of you know I have been struggling with my main electrical power, so I'll give an update followed by questions. 87 dolphin 22 RE Originally I got a battery light + brake light. I read this was a bad alternator. So I took all the anti freeze out, took out the alternator, and took it to Autozone. The guy tested it, and said "It checks out Okay". Brought it home, reinstalled - battery & brake lights back on. I read that it could be my battery isolator and to remove the cable going from my battery TO the isolator and put it directly on the top nut of the alternator. I did so and the lights went away. Okay so I figured it must have been the isolator. So I purchased a new isolator at Oreilly auto. It had 4 terminals: 1) Truck battery 2) Alternator 3) Ignition 4) House battery I stupidly left off the ignition wire and almost got stranded. So I ran a fused wire from the windshield wipers to the ignition wire. So here is where I'll post my volts while running. 1) Truck battery 12.20 Volts - measured at Isolator connector & ground. 2) Alternator 1.22 Volts <==== What?? - Measured at Isolator connector & ground - Also measured at top nut on alternator & ground to the same results. 3) Ignition 12.21 Volts - measured at Isolator & Ground 4) House battery - 12.51 volts I absolutely have no idea. Every part of the "mechanic" in me says its the alternator still & the guy at Autozone didn't test it right. It does not make sense at all to me. 1.22 volts at the top nut of the alt & ground while running? Dunno if that is it or if there is some other "trigger" to turn on the alternator to test it. NO DASH LIGHTS? Thanks for putting up with all my questions ;o) Just trying to rebuild this thing with my boys. -Chris R. Quote Link to comment Share on other sites More sharing options...
Maineah Posted December 28, 2010 Share Posted December 28, 2010 You'll have a blue wire that is fused (7.5 amp)that is part of the charge light circuit, two white wires that are hot all the time and a red wire that is fused (15 amp engine fuse) all of them have to have power in order for the alternator to charge with the key on. Now it is possible for the the isolator to have a bad diode in it and not charge the battery the little extra wire is to supply a voltage to the alternator B+ terminal it is connected to the "E" terminal on the isolator. With out 12 volts to the "E" terminal it won't charge now the caveat the "E" terminal has a diode connected to the alternator feed wire (maybe be marked B+ or A on the isolator)inside of the isolator what you need to do is turn on the key check the "E" terminal check it for power if not correct it. Now with the key on you should now have power to the big wire going to the alternator it does not carry any real power but it has to have power in order for the internal regulator to work that's what the extra wire is for on a 4 terminal isolator. If you do not have power to the alternator wire and you do at the "E" terminal replace the isolator. Quote Link to comment Share on other sites More sharing options...
crasster Posted December 28, 2010 Author Share Posted December 28, 2010 You'll have a blue wire that is fused (7.5 amp)that is part of the charge light circuit, two white wires that are hot all the time and a red wire that is fused (15 amp engine fuse) all of them have to have power in order for the alternator to charge with the key on. Now it is possible for the the isolator to have a bad diode in it and not charge the battery the little extra wire is to supply a voltage to the alternator B+ terminal it is connected to the "E" terminal on the isolator. With out 12 volts to the "E" terminal it won't charge now the caveat the "E" terminal has a diode connected to the alternator feed wire (maybe be marked B+ or A on the isolator)inside of the isolator what you need to do is turn on the key check the "E" terminal check it for power if not correct it. Now with the key on you should now have power to the big wire going to the alternator it does not carry any real power but it has to have power in order for the internal regulator to work that's what the extra wire is for on a 4 terminal isolator. If you do not have power to the alternator wire and you do at the "E" terminal replace the isolator. Okay, I think my problem is that I took the power for the E/Ignition terminal on the isolator from the windshield wiper fuse. After a bit of research, there is some type of "ignition wire" or something marked IGN (yeah right!) that is SUPPOSEDLY coming out of the alternator "plug clip". I'm supposed to splice in(not disconnect) that wire and run another wire to the isolator. This wire I'm supposed put a 6-7 amp fuse on it. Frankly, I'd be happy to find any IGN wire at all. I read that on some Toyota pickup forum but don't know if that makes sense at all. I'm pretty sure the isolator is good, as it is brand new. I'm sure duds happen, but probably unlikely. Also when I hook the alternator, house battery, and truck battery on together, and turn the vehicle ON, the alternator kicks in and I get 14.5V . So that confirms its probably not my alternator. All help appreciated -Chris Quote Link to comment Share on other sites More sharing options...
Gulfstream Greg Posted December 28, 2010 Share Posted December 28, 2010 The idea is when the ignition is on, power gets supplied to the E terminal. Verify that the source you selected to supply that power actually has power when the ignition is on. I threw out "Windshield wiper" circuit in your other thread because thats where I thought I hooked in. Also as a note I will be combining that thread with this one as they appear to be the same subject. Please come back to this thread and add to it instead of creating a new thread. Quote Link to comment Share on other sites More sharing options...
Viking66 Posted December 28, 2010 Share Posted December 28, 2010 You can hook the E terminal to the positive side of the coil like I did mine. That will give you power to the E terminal once the key is turned on. No splicing, just make a wire with 2 circle ends and you will be good to go. Quote Link to comment Share on other sites More sharing options...
crasster Posted December 30, 2010 Author Share Posted December 30, 2010 Found one problem! I think my NEW isolator that I bought from Oreilly auto is bad. I hooked the alternator excitation wire to the excitation terminal and NOTHING. Taking it back. Bought a simple 3 prong. I'll let yall know the results soon to bring closure. ) Quote Link to comment Share on other sites More sharing options...
Maineah Posted January 3, 2011 Share Posted January 3, 2011 A 3 terminal isolator will not work with a Toyota alternator it won't charge. The alternator B+ wire does not receive power from the batteries it is blocked by the internal diodes it has to see 12 volts in order to charge that is what the little "E" wire is for once the B+ has power it will charge and the power will flow to the batteries through the diodes in the isolator. Quote Link to comment Share on other sites More sharing options...
DanAatTheCape Posted January 9, 2011 Share Posted January 9, 2011 Found one problem! I think my NEW isolator that I bought from Oreilly auto is bad. I hooked the alternator excitation wire to the excitation terminal and NOTHING. Taking it back. Bought a simple 3 prong. I'll let yall know the results soon to bring closure. ) sounds like you are using a starter solenoid -- wrong part - they are designed for short periods of duty. THe one you really need is readily available. All it does is connect the cabin battery to the house battery via the positive terminal --- when ever the ignition is on power is available to the wipers so that is the hot source to the solenoid -- hence the solenoid closes and (assuming the engine is running and the alternator is outting out) both batteries charge. Turn off the engine and the solenoid opens and separates the batteries so you can run your cabin battery down & still start the engine to travel. to troubleshoot measure voltage at each battery w/o engine on - should get 12.5 assuming batteries are charged. Start the engine and it should rise to the same voltage on both batteries (or very close). I did not like using the chassis as a ground so I added a ground wire running from the bolts attaching solenoid to chassis to a good ground Quote Link to comment Share on other sites More sharing options...
crasster Posted January 11, 2011 Author Share Posted January 11, 2011 Okay I'm STILL completely confused. Let me clarify what I have right now. I bought a battery isolator from Oreilly auto. It's the diode kind. Here it is: Battery Isolator It has 4 total terminals as listed: 1) - For battery 1 2) - For alternator 3) - Terminal E for excitation 4) - For battery 2 I've returned one just like it because I thought it was bad, and this one is NEW out of the package that I currently have that I didn't have at the start of this post. Here is what all 4 terminals are hooked up to: 1) - Truck battery 2) - Alternator large wire 3) - Red wire in the wiring harness on the back of the alternator that reads 12+ volts ONLY when vehicle is on. No volts when off. Left most pin on the 3 wires going into the back of the alternator wire harness. The connector looks like this on the back of the isolator. (I put an X under the pin wire that I spliced (not cut) into and put a jumper to terminal 3 (or E)). || = = X When vehicle is on, pose number 3 (or E) reads 12+V. 4) House battery. When truck is on, Alternator is ONLY reading 1V. If I connect the main battery directly to the alternator wire, I get almost 14V. The only thing I can think of is that I messed up somewhere with terminal 3. But I have no idea what it could be. As far as I know, I need a 12V source going to it when the vehicle is on. I've tried this both with the windshield wiper fuse and the alternator wire. Same exact result. Somehow the alternator is NOT seeing either battery. Again, when directly hooked up to the battery alternator is fine. I'm confused! Help!! ;o) Thanks Quote Link to comment Share on other sites More sharing options...
Maineah Posted January 12, 2011 Share Posted January 12, 2011 Sorry for the poor copy but here is what is inside of your isolator and how it works. The little "E" as you see supplies voltage to the A terminal through the diode when you turn the key on because the battery diodes block the 12 volt feed to the alternator terminal and the alternator must see 12 volt at the big wire or it will not charge. Quote Link to comment Share on other sites More sharing options...
crasster Posted January 14, 2011 Author Share Posted January 14, 2011 Sorry for the poor copy but here is what is inside of your isolator and how it works. The little "E" as you see supplies voltage to the A terminal through the diode when you turn the key on because the battery diodes block the 12 volt feed to the alternator terminal and the alternator must see 12 volt at the big wire or it will not charge. Heck I thought it was a great copy ;O) This is what has me completely confused. I have 12V at the E terminal (with key on, off when key off). Truck battery on terminal 1. House on terminal 2. Alternator on alternator. For some strange reason, it's simply not working. I probably have something goofed up somewhere, but I'm scratching my head on this one. All I'm getting on this setup from the alternator is 1.5V. Not good. If I try to test the alternator by joining th truck battery with the alternator, it starts charging 13.6+V! I mean obviously something MUST be wrong with my E connection. I've tried getting 12V from two sources now. 1 was from the windshield wiper fuse and the other directly from the 3 prong wire harness that plugs into the back of the alternator. Same result with each power source. Only 1.5V from alternator. I'm scratching my head because it seems that this should be fairly simple... Compared to the solar power setup I installed for my home, this should be a snap. ;o) Just very confused. Quote Link to comment Share on other sites More sharing options...
Maineah Posted January 15, 2011 Share Posted January 15, 2011 OK now try turning the key on (don't start the engine) and see if you now have 12 volts at the "A" terminal. It does not matter what battery is on what terminal (1 or 2) so that is OK. By jumping the battery terminal to the "A" terminal eliminates the battery side of the isolator and actually the “E” also because that in it’s self is supplying 12 volts to the “A” terminal. You might try jumping the "A" to the coach battery and see what it does. I think you can see how the diodes keep the batteries separated but still allow them to be charged and what happens when you turn the key on so some where there is a failure to communicate. If all else fails and you have no voltage to the “A” terminal with the key on stop by radio shack and buy a 25 amp diode and connect it between the “E” wire and the “A” wire (the white stripe is the pointed end of the diode) They need a diode in there so it can’t try to charge your battery through your wiper wiring. Quote Link to comment Share on other sites More sharing options...
Gulfstream Greg Posted February 1, 2011 Share Posted February 1, 2011 Heck I thought it was a great copy ;O) This is what has me completely confused. I have 12V at the E terminal (with key on, off when key off). Truck battery on terminal 1. House on terminal 2. Alternator on alternator. For some strange reason, it's simply not working. I probably have something goofed up somewhere, but I'm scratching my head on this one. All I'm getting on this setup from the alternator is 1.5V. Not good. If I try to test the alternator by joining th truck battery with the alternator, it starts charging 13.6+V! I mean obviously something MUST be wrong with my E connection. I've tried getting 12V from two sources now. 1 was from the windshield wiper fuse and the other directly from the 3 prong wire harness that plugs into the back of the alternator. Same result with each power source. Only 1.5V from alternator. I'm scratching my head because it seems that this should be fairly simple... Compared to the solar power setup I installed for my home, this should be a snap. ;o) Just very confused. Can you take a picture of what you have wired? Also there should have been a schematic (how to hook it up) included with the isolator. Here is a link to the schematic. http://toyotamotorhome.org/forums/uploads/1169594953/gallery_1_48_17162.pdf Now note that the schematic shows the "E" terminal being connected to the IG (ignition) wire of the alternator. The "E" terminal can connect to any voltage source that is on when the ignition is on. It does not have to go to the IG alternator wire. The rest of the hookup is just like the schematic shows. Quote Link to comment Share on other sites More sharing options...
crasster Posted February 26, 2011 Author Share Posted February 26, 2011 BUG MAY BE FIXED with my isolator. Working on it today in nice weather. It's funny because it seems so straight forward.... Not sure if I got it right. Here is how I have it setup. 4 Terminal Isolator Battery 1 connector - Truck Battery. A connector - Alternator E Connector - To Alternator wiring harness. Small red wire coming from alternator that has 12V OFF when key in ACC mode, but 12V ON when key is in the ON position. (Traced to IGN terminal on alternator) Battery 2 Connector - House Battery. Here are my tests: TEST 1 - KEY in OFF position Battery 1 connector - 12V + A connector - 0 E connector - 0 Battery 2 - 12V + TEST 2 - Key in ACC position Battery 1 connector 12V + A connector - 0 E connector - 0 Battery 2 - 12V + TEST 3 - Key in ON position (vehicle not started) Battery 1 Connector - 12V+ A Connector - 1V E connector - 12V+ Battery 2 Connector - 12V+ TEST 4 - Vehicle on and running Battery 1 Connector - 11.96V A Connector - 1V E connector - 12V+ Battery 2 Connector - 12V+ I REALLY do think I have this thing wired up right. This is my 2nd 4 terminal isolator from Oreilly auto. It is a 95 AMP so it should be fine I would think. I returned the last one wondering if there was a defect and this was doing the exact same thing. I'm baffled completely. Maineah suggested that I run a 25 AMP diode. They have a rectifier at Radio Shack, but I decided to open up an old inverter that I have that doesn't work. Inside I found a 3.0 amp diode. Pulled it and put it between the "E" terminal and "A" terminal. I used the WHITE band closest to the A terminal. (Don't know if 3.0 amp is enough between E & A terminals, but using it for test purposes. If I could draw it it would look like this E ---->|----- A The white band is the "|". Anyway here are my results with diode TEST 5 - Vehicle in the ACC position + Diode Battery 1 Connector - 12V+ A Connector - 0V E Connector - 0V Battery 2 connector - 12V+ TEST 6 - Vehicle in the ON position (not running) + Diode Battery 1 connector - 12V+ A Connector - 12V+ E Connector - 12V+ Battery 2 connector 12V+ TEST 7 - Vehicle Running + Diode Battery 1 Connector - 14.25V A Connector - 15.6 - 15.9V !!! E Connector - 15V+ Battery 2 Connector - 14.25V It looks like it's working, but I'm a bit concerned that my alternator seems to be putting out SO high. Is it supposed to be like that when hooked to an isolator? If so, I'm good to go!!!! (Finally). If not, I'm back to the drawing board. The diode that I used is a HER3003 - 3.0 amp. I'm not sure if this is large enough to go between the excitation & alternator. The small wire is pretty thin leading out of the harness though. I guess I could always go buy the rectifier from Radio Shack to save the confusion. Keeping my fingers crossed hoping for good feedback on that high alternator voltage. (One other thing, if I hook up the alternator wire to the battery directly, I get 14.25V) Thanks! -Chris R. Quote Link to comment Share on other sites More sharing options...
Maineah Posted February 26, 2011 Share Posted February 26, 2011 The voltage is probably fine with low batteries it will come down as they charge I don't think I would worry until it's run for awhile. The 3 amp would be enough to excite the alternator I personally would use some thing with a little more current rating. There will be a .7 volt drop across the diodes that's normal. Not sure why the "E" terminal is at 15 volts it should be close to battery voltage maybe it would be a good ideal to replace the E to A diode with some thing a little heaver the whole ideal is to keep it from trying to charge the battery through what ever it is wired to instead of the #1 or #2 terminal. The isolator has no regulating ability it's all up to the alternator. Quote Link to comment Share on other sites More sharing options...
crasster Posted March 5, 2011 Author Share Posted March 5, 2011 The voltage is probably fine with low batteries it will come down as they charge I don't think I would worry until it's run for awhile. The 3 amp would be enough to excite the alternator I personally would use some thing with a little more current rating. There will be a .7 volt drop across the diodes that's normal. Not sure why the "E" terminal is at 15 volts it should be close to battery voltage maybe it would be a good ideal to replace the E to A diode with some thing a little heaver the whole ideal is to keep it from trying to charge the battery through what ever it is wired to instead of the #1 or #2 terminal. The isolator has no regulating ability it's all up to the alternator. Sorry I was kind of being stupid. The E terminal is 15V but that is AFTER the diode I installed. Before the diode it's 13.5V. I think I fixed it. What's so strange about this is that 2 of the exact same isolators I bought from Oreilly auto had the exact same problem. No wonder I was completely confused. I was sitting here like "this is NOT that hard" and scratching my head.... I think the diode completely fixed the problem. (I just used the 25A bridge rectifier from Radio Shack) I'll get photos of all of this soon. I'm the type that snaps photos and sees something and starts working on something else & gets involved with a whole new project. Then when I am through I get hoarded by all the kids LOL. Thanks for the awesome suggestion of the diode Maineah. I really think it worked well. Isolator is nice & warm & both batteries at 13.5V when vehicle running. Quote Link to comment Share on other sites More sharing options...
Oldiesel Posted March 8, 2011 Share Posted March 8, 2011 Trying to understand this,my 86 has a3 wire isolator that is dead (diodes open) and has all three wires in the same post so no isolation.I have from a previous boat project a new 3 wire isolator so looking at the diagram posted here it looks like if i ran a wire from the ign switch to the alternator post the 3 wire one could work why would a diode be needed in that wire ? Easy enough tp put one in but i wonder what its purpose would be. Don Quote Link to comment Share on other sites More sharing options...
Rolling TMCI Posted March 9, 2011 Share Posted March 9, 2011 Oh great, I too have an 86 dolphin, and the brake, and battery light just came on the other day. Oh man now I'm scared....... Quote Link to comment Share on other sites More sharing options...
Maineah Posted March 14, 2011 Share Posted March 14, 2011 Trying to understand this,my 86 has a3 wire isolator that is dead (diodes open) and has all three wires in the same post so no isolation.I have from a previous boat project a new 3 wire isolator so looking at the diagram posted here it looks like if i ran a wire from the ign switch to the alternator post the 3 wire one could work why would a diode be needed in that wire ? Easy enough tp put one in but i wonder what its purpose would be. Don The diode is there to keep the alternator from back feeding in case you have problems with the isolator. In other words if you lose a blocking diode to the battery or just have a bad connection it will try to charge through added wire and this may cause some rather ugly smoke. Some alternators do not need the 4th wire (like GM) but it is alternator design and the Toyota's need it. Yes you could do this externally but you still would need a diode for protection so why not just use an isolator that has it. Quote Link to comment Share on other sites More sharing options...
Vanman Posted March 14, 2011 Share Posted March 14, 2011 <br />The diode is there to keep the alternator from back feeding in case you have problems with the isolator. In other words if you lose a blocking diode to the battery or just have a bad connection it will try to charge through added wire and this may cause some rather ugly smoke. Some alternators do not need the 4th wire (like GM) but it is alternator design and the Toyota's need it. Yes you could do this externally but you still would need a diode for protection so why not just use an isolator that has it.<br /><br /><br /><br /> Our 91 Dolphin and others I've seen came with a relay type 3 wire isolator, which I prefer to the diode type. In this set-up Toyota is feeding the truck battery to the alternator as per stock, the left side big wire runs to the truck battery, the right side big wire to the coach battery, the center small wire to truck battery thru ignition switch so when it;s hot it energises the relay coil to connect the 2 big wires together. If this is the way yours was set up stock why not simply replace like for like with no re-wiring ? Vanman Quote Link to comment Share on other sites More sharing options...
Oldiesel Posted March 18, 2011 Share Posted March 18, 2011 If you prefer the relay type you should have no problem if you use a Cole Hersee 24059 continous duty solenoid, any decent auto parts store or marine supply should be able to get you one.There is one in my boat that has been switching my house batterys (4 Golf Cart) to the 80 amp main engine alternator for going on 20 years and still works fine.In the boat i have it connected to an oil pressure switch so it only works when the engine is running,that way if the key switch was accidently left on the house and starting batterys would be separate. Don Quote Link to comment Share on other sites More sharing options...
Rolling TMCI Posted March 19, 2011 Share Posted March 19, 2011 So replaced the "Isolator" with a 3 prong silenoid from Oriellys. Not the problem, I need a new alternator!!!!!!!!!!! ¦} lol. Quote Link to comment Share on other sites More sharing options...
Rolling TMCI Posted March 19, 2011 Share Posted March 19, 2011 Great thread though... Quote Link to comment Share on other sites More sharing options...
Maineah Posted March 21, 2011 Share Posted March 21, 2011 A solenoid isolator has no diodes and it does only use 3 wires it's nothing more then a switch however if it is solid state (having diodes) it needs 4 wires to work on a Toyota, they are two different animals. The solenoid type is like a small can the solid state type is a box with little cooling fins. Quote Link to comment Share on other sites More sharing options...
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