Bob C Posted July 25, 2013 Share Posted July 25, 2013 I replace the original isolator with a solid state unit. That lasted 1 year before it stopped running power to my coach battery. I replaced the sold state unit with a relay type to made things easier. After only 3 days of use, the relay type stopped letting full voltage go through. I found out because my coach battery was not fully charge after driving and using my electric frig. I used my volt meter to determine that the alt is putting out 14.46 volts, the battery is getting 14.44 volts and the isolator is only reading 13.0 volts at the bolt where the coach battery hooks up. I thought it was due to my coach battery being drained so I unhooked the wire from the isolator to the coach battery. I checked the isolator terminal bolt and it still reads 13.0. I checked the voltage to the bolt that activates the coil and it reads 14.44 so I know that the isolator is getting a good voltage to engage. To get through the trip, I just hooked coach and truck battery cables to the same bolt and the coach battery charged very well. Any ideas on why I am toasting isolators or did I just get unlucyk and get a junk but new isolator. Quote Link to comment Share on other sites More sharing options...
Totem Posted July 25, 2013 Share Posted July 25, 2013 I installed two tiny LCD volt meters that i ran through the firewall to the isolator posts for just this reason. My isolator is solid state and is always in the 14's during a running vehicle mode even while idling. Something definitely wrong with your isolator. Quote Link to comment Share on other sites More sharing options...
waiter Posted July 25, 2013 Share Posted July 25, 2013 Looks like the Isolator failed. Make sure you are using an Isolator and not a starter relay. They look identical. ALSO - I highly recommend installing the isolator vertically, with the terminals near the top. Some cheap isolators the plunger can drag and bind internally, If it's vertical, the plunger can't bind or drag. JOhn Mc 88 Dolphn 4 Auto Quote Link to comment Share on other sites More sharing options...
Bob C Posted July 25, 2013 Author Share Posted July 25, 2013 I supposedly bought an isolator, but it may have been a starter relay which is not built for long term connection. I am finishing my voltmeter install for front and back very similar to Totem's setup. I had it installed but ender up removing it so that I could relocate it (wife not happy, nobody happy.) I also mounted the isolator verticlly. I guess I will buy another isolator and hope for service measured in years not hours. Quote Link to comment Share on other sites More sharing options...
zero Posted July 26, 2013 Share Posted July 26, 2013 I replace the original isolator with a solid state unit. That lasted 1 year before it stopped running power to my coach battery. I replaced the sold state unit with a relay type to made things easier. After only 3 days of use, the relay type stopped letting full voltage go through. I found out because my coach battery was not fully charge after driving and using my electric frig. I used my volt meter to determine that the alt is putting out 14.46 volts, the battery is getting 14.44 volts and the isolator is only reading 13.0 volts at the bolt where the coach battery hooks up. I thought it was due to my coach battery being drained so I unhooked the wire from the isolator to the coach battery. I checked the isolator terminal bolt and it still reads 13.0. I checked the voltage to the bolt that activates the coil and it reads 14.44 so I know that the isolator is getting a good voltage to engage. To get through the trip, I just hooked coach and truck battery cables to the same bolt and the coach battery charged very well. Any ideas on why I am toasting isolators or did I just get unlucyk and get a junk but new isolator. Get a "full-time" relay with a high amp rating an it's likely to last longer then you. Starter relays are only meant for intermittent duty and are often only rated around 80 amps for full time use. The first low-draw, full-time relay I bought for an RV was over 20 years ago and I'm still using it. Cole Hersee continous with silver contacts (not copper) and rated for 200 amps. Expensive though. They used to cost $35 just a few years ago but are not $65 to $75. http://www.fisheriessupply.com/cole-hersee-200-amp-continuous-duty-solenoids A few others if you want cheaper . . . $19 - full-time rated for 150 amps continous - http://www.surpluscenter.com/item.asp?item=11-3290&catname=electric $12 - full time rated for 80 amps continous - http://www.surpluscenter.com/item.asp?item=11-3278&catname=electric . Quote Link to comment Share on other sites More sharing options...
Totem Posted July 26, 2013 Share Posted July 26, 2013 http://toyotamotorhome.org/forums/index.php?app=gallery&image=2462 picture of where i located them and their size; it was like they were made to go there Quote Link to comment Share on other sites More sharing options...
Maineah Posted July 26, 2013 Share Posted July 26, 2013 The starter type relays will cook the windings if left on for extended time it may have even melted the plastic inside and bound up the plunger. It is a super simple device and should deliver full voltage it is my preference for an isolator. What year is your camper? If it had a solid state isolator and does not have an external regulator you will need to make changes to your alternator wiring if you want to use the relay type. Did the solid state one have 4 posts? Quote Link to comment Share on other sites More sharing options...
Vanman Posted July 27, 2013 Share Posted July 27, 2013 Totemhttp://toyotamotorhome.org/forums/index.php?app=gallery&image=2462picture of where i located them and their size; it was like they were made to go there.Looks great, that's my next project so where did you get those??? I looked online and there are lots but not sure of quality, many have no reviews and some bad.TIA vanman Quote Link to comment Share on other sites More sharing options...
DanAatTheCape Posted July 28, 2013 Share Posted July 28, 2013 I will add you probably have some circuit breakers in that circuit - use your multi meter & step through the circuit - you should get a very small voltage drop at each connection - wold not be surprised if you find a bad connection. I had a similar problem - replaced the solenoid (got one at an RV place for less than $20), got CB;s at napa autoparts (cost a lot less) and doubled up some wiring including adding a ground wire from the solenoid (it grounded on the chassis) Quote Link to comment Share on other sites More sharing options...
Bob C Posted July 29, 2013 Author Share Posted July 29, 2013 I replaced most of the circuit breakers and the cables in the entire system. I think that when I bought my relay style isolator, the guy sent me a starter relay. I will make certain that I get a continuous duty relay next time. I keep finding new problems but luckily I have been able to get things running again. 25 year old RV's need a lot of TLC. Quote Link to comment Share on other sites More sharing options...
Vanman Posted July 31, 2013 Share Posted July 31, 2013 Just replaced my isolator and ckt. breaker yesterday. It's been OK but it suddenly developed a 3V drop across the contacts. Not charging the RV battery well. But from the looks of it I guess they are both original as well as the crimp lugs. I also added a 2A fuse in the line from the wiring harness to the ioslator coil. I neated everything up and re-insulated all the hot leads. vanman Quote Link to comment Share on other sites More sharing options...
Bob C Posted August 6, 2013 Author Share Posted August 6, 2013 I have got a new relay style isolator on order. The local parts shop had to order it. I ordered the one from Cole Hersee with the silver contacts. It is rated for 150 amps constant/300 amps surge. I sure hope that htis one last. At least it has a 1 yr warranty. I have replaced all of the wires, end terminals, and circuit breakers. I thought that I had my electric problems beat but came up with this recuring isolator. I love the electric refrigerator when everything is working. According to my wife, I drink too much soda but really enjoy an ice cold can a couple times a day. I also enjoy having my food cold without it swimming in ice water in the bottom of a cooler. The 12 volt compressor style frig is nice because I don't have to worry about being level, it can run up to 30 degrees off level without harm. Quote Link to comment Share on other sites More sharing options...
Bob C Posted August 13, 2013 Author Share Posted August 13, 2013 I just got back from a nice couple of days camping with the grandkids. The new isolator worked great and kept everything very nicely charged. The voltmeter that I installed for the rear battery definitely gives piece of mind after having 2 new isolators fail. I hope this last one gives me many years of service. Quote Link to comment Share on other sites More sharing options...
Oldiesel Posted August 21, 2013 Share Posted August 21, 2013 For years i have used the Cole Hersee 24059 solenoid as an isolator in marine applications,its rated for 80amps continous duty and is for 12v systems on my own boat there were three of them that lasted the twenty odd years that i owned the boat and have installed many in customer boats and i cannot recall a single failure. Any NAPA store can order them and might even have them on stock. Quote Link to comment Share on other sites More sharing options...
Bob C Posted August 22, 2013 Author Share Posted August 22, 2013 I bought mine at NAPA and they had to order it from their warehouse. It got here overnight. It looked just like the last junk one that I bought but it has the company name on it. At least they have enough faith in their product that they put their name on it. Quote Link to comment Share on other sites More sharing options...
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