elchivodemontanas Posted June 1, 2018 Share Posted June 1, 2018 1986 Sunrader 22RE. This is the way my solenoid was wired up. Is this the correct wiring setup for the solenoid? "+" goes straight to engine battery, "A" is connected to 12v hot (constant) thick white wire spliced off bottom of alternator harness, "CB" runs to coach battery through 30A breaker. Also, top lug of Alternator has a wire that runs directly to positive terminal on engine battery. Thanks! Quote Link to comment Share on other sites More sharing options...
WME Posted June 1, 2018 Share Posted June 1, 2018 If your pic is labeled correctly, then the solenoid is wired WRONG. CB is correct. The large wire from the alternator should go to A, the large wire to the truck battery should ALSO go to A. You can also run the alternator wire to the battery, then a large wire from the battery + to A on the solenoid, electrically its the same. There should be a small wire to + that is a switched 12v source, IE when the ignition key is in the run position there should be 12v to +. With the key off there should be 0v to +. The deal is the 12v to + turns the solenoid on and the truck alternator charges the truck battery and the house battery. With the key off the solenoid is off and the house battery is isolated from the truck battery , so that if you run the house battery down the truck will still start. The ground for the solenoid is the mount bracket so it should be bolted to solid metal Quote Link to comment Share on other sites More sharing options...
Alvin Posted June 1, 2018 Share Posted June 1, 2018 (edited) So...that;s not a soleniod is it? Looks like the house/cab isolator. A back-to-back automotive diode. Edited June 1, 2018 by Alvin Quote Link to comment Share on other sites More sharing options...
Derek up North Posted June 1, 2018 Share Posted June 1, 2018 A 'Typical' Sunrader wiring diagram. Quote Link to comment Share on other sites More sharing options...
elchivodemontanas Posted June 1, 2018 Author Share Posted June 1, 2018 Thank you for your quick response! These are the wires off the bottom of the alternator. The thick white wire that is 12v constant (under my thumb) is the one that was connected to the "A" terminal on the solenoid. Should I probe the other 4 wires (yellow, red, black, and thinner white) to see which one is 12v source? Also, is it redundant to have both the 12v constant white wire and the wire directly to battery on the same post since they are both 12v constant? Thank you! Quote Link to comment Share on other sites More sharing options...
WME Posted June 1, 2018 Share Posted June 1, 2018 This is going to be a slow slog, but 1st question where is the large white wire spliced to. Is it spliced to a small wire some where or other wires spliced to it? Does it go to a plug on the back of the alternator? The large red wire at the top of the alternator goes to the battery. yea got one right, the CB terminal is to a C/B and then to the house battery, yea got 2 right. The problem is the control wire and the charge wire to the solenoid. You have a solenoid isolator. There is also a solid state diode isolator, many require 4 wires. If some time in your Toys past a PO converted from a solid state to a solenoid type it would explain the odd wiring Quote Link to comment Share on other sites More sharing options...
elchivodemontanas Posted June 1, 2018 Author Share Posted June 1, 2018 Ok did some digging, I apologize for the misinformation previously stated. The large white wire runs from the 80A engine fuse, around the front of the radiator and was connected to the terminal marked "A" on the isolator, no splicing. By the terminal "CB" I meant "Coach Battery" so I'm pretty sure that was wired right. The 3 wires coming off the plug on the alternator are unmolested and run to a factory loom. I'm just hung up on why there was a "bubba" run wire from the top nut of isolator to 12v positive. It should really be a switched 12v source , correct? So would the switched 12v source wire be one of the 3 wires coming out of the Alternator plug? Quote Link to comment Share on other sites More sharing options...
WME Posted June 1, 2018 Share Posted June 1, 2018 OK, there is light at the end of the tunnel and it aint a train.... Bubba wire OK Thick white wire OK CB wire OK Just remove the "the other white wire" and replace it with a 12v switched wire. I think some folks use the power wire for the wiper motor, just check first Quote Link to comment Share on other sites More sharing options...
Alvin Posted June 2, 2018 Share Posted June 2, 2018 The schematic Derick up North provided is correct. The idea is the alternator charges both the house and engine batteries when the vehicle engine is running...or when the alternator is turning. The back to back diodes in the “isolator” keep the two systems, engine and house battery, separate except for alternator charging. Quote Link to comment Share on other sites More sharing options...
Maineah Posted June 2, 2018 Share Posted June 2, 2018 A common take off point is the wiper motor it's right there don't mess with the small alt wires they do different things, the small terminal on the isolator needs to be "keyed" on and off with the ign switch. The other two large lugs go to the engine battery and the coach battery it matters not either one. Don't know about the bubba wire it goes to the battery from the factory from the alt. "B" terminal and was white with a red tracer. Quote Link to comment Share on other sites More sharing options...
Maineah Posted June 2, 2018 Share Posted June 2, 2018 12 minutes ago, Alvin said: The schematic Derick up North provided is correct. The idea is the alternator charges both the house and engine batteries when the vehicle engine is running...or when the alternator is turning. The back to back diodes in the “isolator” keep the two systems, engine and house battery, separate except for alternator charging. The rely type isolator really is nothing more than and on and off switch. The solid state device requires some alternator rewiring and in MHO is less efficient due to the loss factor of the diodes. The diodes are configured in a Y and only pass current in one direction the tail of the "Y" being the Alt. "B"+ so once the alt. stops supplying current the flow can not pass backwards through the diodes to where they are joined at the "B" terminal. Quote Link to comment Share on other sites More sharing options...
linda s Posted June 2, 2018 Share Posted June 2, 2018 I don't know crap about all this electric talk but on my 86 Sunrader, wire from alternator goes directly to front terminal marked +. CB goes to coach and A goes to truck battery. Mine's been working fine with this hookup since 1986. I also have the original isolator instructions from Sunrader and that's what it says Linda S Quote Link to comment Share on other sites More sharing options...
Alvin Posted June 2, 2018 Share Posted June 2, 2018 Linda, that is exactly right. A diode is a semiconductor which only allows positive current flow in one direction. An isolator is a device with two back to back diodes built in, and the alternator is the source of this ‘positive’ current, supplying current when the engine runs. The alternator connects to the isolator junction of both diodes and supplies charging current through each diode, one to the house battery charging system and the other to the vehicle battery. When the alternator is not supplying current (when the vehicle engine is not running) then the house battery can’t short to the vehicle battery and visa-vera due to their respective one-way diodes in the isolator. It means you can turn off the engine safely with each system, vehicle and house, remaining separate. Quote Link to comment Share on other sites More sharing options...
Alvin Posted June 2, 2018 Share Posted June 2, 2018 I marked up your drawing. Get rid of the two wires with red zigzags over them. Connect, using one heavy peice of alternator grade audomotive wire, the connection shown in my drawing in blue. You don’t want any splices... it should be one heavy wire between alternator and isolator. If you splice thats a future breakdown due to corrosion. Quote Link to comment Share on other sites More sharing options...
DanAatTheCape Posted June 4, 2018 Share Posted June 4, 2018 (edited) I disagree with Alvin, E.Montana is right. I am assuming that I am seeing an older mechanical solenoid. Something that looked and function like these was used on Ford starters for decades; except one BIG difference - the ford starter is a heavy duty/ short cycle solenoid whereas the one's in our camper are light duty/ long cycle. As E.Montana explained, the little terminal is for control - on my camper it is connected to the hotwire on the wipers. That means whenever my ign switch is "on", the solenoid activates and the house battery and the coach battery are connected. The alternator output is connected to the + terminal on the engine battery. The 2 larger contacts connect to the 2 batteries. The wire running from solenoid to coach battery should have a circuit breaker, A solenoid is essentially an electric switch - a small bit of juice activates the solenoid (switch). The attached pic might give you the idea I also attached the instructions - I changed mine years ago. Note Alvin's diagram would work IF the blue wire is to the engine battery terminal (a large lug) Edited June 4, 2018 by DanAatTheCape Quote Link to comment Share on other sites More sharing options...
Alvin Posted June 4, 2018 Share Posted June 4, 2018 I still think I’m right...thought I’d add two more schematics I have on hand to add to the confusion. I think the part is an Isolator and not a solenoid. I have one in my 89 Odyssey. Quote Link to comment Share on other sites More sharing options...
linda s Posted June 4, 2018 Share Posted June 4, 2018 The original poster has a Sunrader. This is the isolator and nothing else. Alvin sketched it correctly the same as I described it. Linda S Quote Link to comment Share on other sites More sharing options...
Maineah Posted June 4, 2018 Share Posted June 4, 2018 In a stock application with a relay nothing is changed only parts added. With the solid state isolator the B+ alternator wire has to be disconnected from the truck battery and landed on the isolator B or "A" terminal or it will not charge either battery then a wire has to be added to the #1 terminal that goes to the truck battery. The #1 and 2 terminal can be interchanged it does not matter. The internal regulated Toyota alternator has to have 12 volt supplied from the exciter lead to the B+ (or A) this is why the isolator has a "E" terminal it too is a diode it supplies the 12 volts to the B terminal this wire has to be added also, spliced into the exciter alternator wire. This can not be done with a simple battery wire otherwise the electrical system system would be supplied with 12 via the B+ the the engine would not turn off because it would be backfeed power from the alternator. There is no magic inside a simple solid state isolator it consists of 3 diodes and a heat sink they are nothing more than a one way electrical valve it allows power into the batteries but not out. The "E" terminal allows power into the alternator B+ but not back out. The coach builders were the ones that added the isolator generally they used the relay type because they were cheaper simpler and more efficient. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted June 4, 2018 Share Posted June 4, 2018 9 hours ago, Alvin said: I think the part is an Isolator and not a solenoid. Yes, that's what it seems to represent. But I'm no electrical Wizard. I've taken the gross liberty of marking up the Odyssey wiring diagram. I think (hope?) it clarifies things. Quote Link to comment Share on other sites More sharing options...
WME Posted June 4, 2018 Share Posted June 4, 2018 Sigh.. Guys the OPs original post picture is a solenoid isolator, the OPs hand drawn diagram is a solenoid isolator. Moving 1 wire would make it work correctly. All the posts about a diode isolator are wasted bandwidth and a confusion factor. KISS If some Sunraders came with an alternator field wire providing a control voltage great. Which terminal??, the OP would still have to move a wire to make their isolator work Quote Link to comment Share on other sites More sharing options...
Terry406 Posted May 27, 2022 Share Posted May 27, 2022 On 6/3/2018 at 11:21 PM, DanAatTheCape said: I disagree with Alvin, E.Montana is right. I am assuming that I am seeing an older mechanical solenoid. Something that looked and function like these was used on Ford starters for decades; except one BIG difference - the ford starter is a heavy duty/ short cycle solenoid whereas the one's in our camper are light duty/ long cycle. As E.Montana explained, the little terminal is for control - on my camper it is connected to the hotwire on the wipers. That means whenever my ign switch is "on", the solenoid activates and the house battery and the coach battery are connected. The alternator output is connected to the + terminal on the engine battery. The 2 larger contacts connect to the 2 batteries. The wire running from solenoid to coach battery should have a circuit breaker, A solenoid is essentially an electric switch - a small bit of juice activates the solenoid (switch). The attached pic might give you the idea I also attached the instructions - I changed mine years ago. Note Alvin's diagram would work IF the blue wire is to the engine battery terminal (a large lug) I would think, and I actually did install 30 A auto-reset circuit breaker from the isolator to the coach battery. I personally think that's just as important as the 30 amp Auto reset breaker from the positive terminal of the primary battery to the isolator/solenoid. For only five or six bucks, it certainly worth having there, just use two sheet metal screws, or small bolts and nuts, if you're able to get to the backside and get them snug, and attach it anywhere on the firewall around where you installed your isolator/solenoid. You might have to use a punch, or even a strong nail, maybe even a drill with a small bit to create a small hole in your firewall/ inside fender, for it to attach to the automatic breaker. I had to also do that to install my isolator, which is more important because it needs to be bolted to ground. Quote Link to comment Share on other sites More sharing options...
Terry406 Posted May 27, 2022 Share Posted May 27, 2022 1 minute ago, Terry406 said: I would think, and I actually did install 30 A auto-reset circuit breaker from the isolator to the coach battery. I personally think that's just as important as the 30 amp Auto reset breaker from the positive terminal of the primary battery to the isolator/solenoid. For only five or six bucks, it certainly worth having there, just use two sheet metal screws, or small bolts and nuts, if you're able to get to the backside and get them snug, and attach it anywhere on the firewall around where you installed your isolator/solenoid. You might have to use a punch, or even a strong nail, maybe even a drill with a small bit to create a small hole in your firewall/ inside fender, for it to attach to the automatic breaker. I had to also do that to install my isolator, which is more important because it needs to be bolted to ground. I also wired the hot thick white (looks like 10 G) wire from the alternator connected with the primary engine positive battery wire to one side of the isolator/regulator. And the other side through a 30 amp automatic breaker to the coach battery positive. Also, the 2 large 🔩 bolts coming out of each side of the isolator we're too big for the ring connectors from the alternator wire and the positive battery wire to connect to. So I purchased a few inches of 8 gauge wire, and some gold-plated ( best conductor, not much more expensive) larger ring connectors, and crimped on the large ring connectors, then connected the positive battery and the alternator wires to those wires with the larger ring connectors that would fit on the isolator/ solenoid. I used some insulated wire connectors and crimped them together to prevent shorting to ground when I attach the additional wire which I needed to do anyway because where I put the isolator and the 30 amp breaker, the original battery positive wire and the original white alternator wire we're not quite long enough so the extra wire with the larger ring connectors helped that as well. Quote Link to comment Share on other sites More sharing options...
Terry406 Posted May 27, 2022 Share Posted May 27, 2022 3 minutes ago, Terry406 said: I also wired the hot thick white (looks like 10 G) wire from the alternator connected with the primary engine positive battery wire to one side of the isolator/regulator. And the other side through a 30 amp automatic breaker to the coach battery positive. Also, the 2 large 🔩 bolts coming out of each side of the isolator we're too big for the ring connectors from the alternator wire and the positive battery wire to connect to. So I purchased a few inches of 8 gauge wire, and some gold-plated ( best conductor, not much more expensive) larger ring connectors, and crimped on the large ring connectors, then connected the positive battery and the alternator wires to those wires with the larger ring connectors that would fit on the isolator/ solenoid. I used some insulated wire connectors and crimped them together to prevent shorting to ground when I attach the additional wire which I needed to do anyway because where I put the isolator and the 30 amp breaker, the original battery positive wire and the original white alternator wire we're not quite long enough so the extra wire with the larger ring connectors helped that as well. 3 minutes ago, Terry406 said: I also wired the hot thick white (looks like 10 G) wire from the alternator connected with the primary engine positive battery wire to one side of the isolator/regulator. And the other side through a 30 amp automatic breaker to the coach battery positive. Also, the 2 large 🔩 bolts coming out of each side of the isolator we're too big for the ring connectors from the alternator wire and the positive battery wire to connect to. So I purchased a few inches of 8 gauge wire, and some gold-plated ( best conductor, not much more expensive) larger ring connectors, and crimped on the large ring connectors, then connected the positive battery and the alternator wires to those wires with the larger ring connectors that would fit on the isolator/ solenoid. I used some insulated wire connectors and crimped them together to prevent shorting to ground when I attach the additional wire which I needed to do anyway because where I put the isolator and the 30 amp breaker, the original battery positive wire and the original white alternator wire we're not quite long enough so the extra wire with the larger ring connectors helped that as well. DON'T attach any ground wires to the isolator, as it's grounded when you bolt it to your firewall. Quote Link to comment Share on other sites More sharing options...
Maineah Posted May 27, 2022 Share Posted May 27, 2022 7 hours ago, Terry406 said: DON'T attach any ground wires to the isolator, as it's grounded when you bolt it to your firewall. Some are 4 terminal you will need a ground wire if so, but the relay frame will do as a ground provided it is. Quote Link to comment Share on other sites More sharing options...
linda s Posted May 28, 2022 Share Posted May 28, 2022 My Sunrader came from the factory with a 4 pole isolator and it has a ground to the chassis Linda S Quote Link to comment Share on other sites More sharing options...
Terry406 Posted May 28, 2022 Share Posted May 28, 2022 Thanks, I didn't attach any ground to the isolator, as it does ground through the case to the body when I bolted it on. The new isolator has four bolts on it, the two large ones on each side and two smaller ones labeled I and s. I connected the alternator wire and the positive battery wire from the engine compartment to one of the large terminals on the side of the isolator. Then ran the other side of the isolator through a 30 amp automatic circuit breaker to the coach battery. I didn't use either of the I and S smaller terminals on the isolator, it's not sure what those two are for I think the S is for accessory, not sure about the connector labeled I. But I'm fairly certain neither one are ground, as it grounds to the chassis when I bolted it on. So the other large connector coming out of the other side of the isolator leads back to my coach battery box through a 30 amp automatic circuit breaker. Now, there are three other ring connectors that go to the coach battery, so in total, there are 4 positive and one ground wires with ring connectors in the coach battery compartment. Does that sound correct? I've crawled up underneath it trying to trace all five of the wires, they all disappear into a harness and for some unknown reason, come out of the harness a totally different color, like white changes to Black inside of the harness or vice versa. The only one I can see, attaches to the frame so I know it's ground, all of the other 4 certainly appear to be positive, to hook to the coach battery. Does that sound correct? Thanks so much for your responses. When I got this sunrader, it had no coach battery installed just the wiring in the coach battery box. Also had no isolator, just a wire coming from the coach battery box through the 30 amp automatic breaker, and the wire coming off the other side of the 30 amp automatic breaker cut. With no isolator at all. That's why I bought and installed the isolator, and I'm trying to get the coach battery wired up. Any help or ideas would be appreciated. Thank you... Quote Link to comment Share on other sites More sharing options...
extech Posted May 28, 2022 Share Posted May 28, 2022 the relay you have is likely a starter relay from a ford. i is for ignition, s is for start. if it is an automotive start relay it will burn out as it is not designed to stay engaged. the relay wont work at all unless it is actuated by putting power to the s terminal. Quote Link to comment Share on other sites More sharing options...
Maineah Posted May 28, 2022 Share Posted May 28, 2022 2 hours ago, Terry406 said: Thanks, I didn't attach any ground to the isolator, as it does ground through the case to the body when I bolted it on. The new isolator has four bolts on it, the two large ones on each side and two smaller ones labeled I and s. I connected the alternator wire and the positive battery wire from the engine compartment to one of the large terminals on the side of the isolator. Then ran the other side of the isolator through a 30 amp automatic circuit breaker to the coach battery. I didn't use either of the I and S smaller terminals on the isolator, it's not sure what those two are for I think the S is for accessory, not sure about the connector labeled I. But I'm fairly certain neither one are ground, as it grounds to the chassis when I bolted it on. So the other large connector coming out of the other side of the isolator leads back to my coach battery box through a 30 amp automatic circuit breaker. Now, there are three other ring connectors that go to the coach battery, so in total, there are 4 positive and one ground wires with ring connectors in the coach battery compartment. Does that sound correct? I've crawled up underneath it trying to trace all five of the wires, they all disappear into a harness and for some unknown reason, come out of the harness a totally different color, like white changes to Black inside of the harness or vice versa. The only one I can see, attaches to the frame so I know it's ground, all of the other 4 certainly appear to be positive, to hook to the coach battery. Does that sound correct? Thanks so much for your responses. When I got this sunrader, it had no coach battery installed just the wiring in the coach battery box. Also had no isolator, just a wire coming from the coach battery box through the 30 amp automatic breaker, and the wire coming off the other side of the 30 amp automatic breaker cut. With no isolator at all. That's why I bought and installed the isolator, and I'm trying to get the coach battery wired up. Any help or ideas would be appreciated. Thank you... Pictures would help. Quote Link to comment Share on other sites More sharing options...
Maineah Posted May 28, 2022 Share Posted May 28, 2022 The isolator is just that, it's purpose it to isolate the coach battery from truck battery the ideal is to not end with a dead truck battery, the next morning. So with the key off the batteries are separated once the truck is started the isolator turns on and charges both batteries. The small wire gets a signal from the truck turning the isolator on as soon as it is running. If you asked for an isolator relay that is most likely what you got not some they sell every day. Several heaver wires is not unusual on the truck side, the isolator it is a convenient spot to hook them up. Quote Link to comment Share on other sites More sharing options...
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