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New Coach Battery Drained


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Hello-

Keep fixing problems, keep finding problems. :) But I am getting closer. 

Current problem- I bought a brand new marine battery for the coach, worked great but noticed the charge kept decreasing until now its dead (after spending two days at the mechanic getting some engine work done). So I figured the wires are connected properly to the engine battery but I don't know. Everything looks connected properly in the little battery box. I looked in the engine but I don't know what to look for or what should be connected to the battery. 

I noticed there is some device on the fire wall that has a wire coming out of it that goes nowhere. I've attached pics. I don't think this has to do with the coach battery but who know. Any insight on why my coach battery might now be holding its charge is greatly appreciated.

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8 hours ago, Thirsty Spirit said:

Hello-

Keep fixing problems, keep finding problems. :) But I am getting closer. 

Current problem- I bought a brand new marine battery for the coach, worked great but noticed the charge kept decreasing until now its dead (after spending two days at the mechanic getting some engine work done). So I figured the wires are connected properly to the engine battery but I don't know. Everything looks connected properly in the little battery box. I looked in the engine but I don't know what to look for or what should be connected to the battery. 

I noticed there is some device on the fire wall that has a wire coming out of it that goes nowhere. I've attached pics. I don't think this has to do with the coach battery but who know. Any insight on why my coach battery might now be holding its charge is greatly appreciated.

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That’s your wiper motor. In the first picture someone tapped into the power lead. Probably to power something that requires an “ignition on” power source (usually the isolator for duel batteries).

Second picture, not sure what the PO was doing. That’s not factory wire. If it’s going nowhere, just delete it.

As far as coach battery draining, you probably have a short somewhere in the system.

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Do your wipers work? If they don't that well could be your problem the extra wire energies the the isolator relay to connect your coach battery to the charging system.

 

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Thanks for all the info. Gonna start following wires. One more question. Since I drained my brand new battery can I jump it like I would my car battery or is it dead now and I need a new one. Seems like that is something I should know

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22 minutes ago, Thirsty Spirit said:

Thanks for all the info. Gonna start following wires. One more question. Since I drained my brand new battery can I jump it like I would my car battery or is it dead now and I need a new one. Seems like that is something I should know

Jumping it will not help unless you leave your running car hooked up for a few hours. In the meantime you can buy a fairly cheap battery maintainer to connect to it plug it in and leave it on for a day or two. Your converter charger in the camper should also charge the camper battery as long as it is plugged into the house.

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Adding on here. I took some pictureds and looked at the terminal switch diagram. So everything looks correct. Not sure what the little fuselike boxes are that the wires go to. Can you all take a look at the photos and see if something looks wrong. I followed the wires back to the terminal and on under the vehicle to the coach battery. The coach battery is grounded and everything looks attached in the right places. Could the rust on the terminal be causing a problem? Also checked the fuses, they seem to be intact.

Thanks for any help!

relay2.jpeg

Negative lead.jpeg

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Coach ground.jpeg

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Wow are you going to have fun.

A pure WAG is the white wire in the second photo of the first is the control wire for the isolator. Isolator is black cylinder in the first photo of your last post.

With the engine off you should have 0v on the white wire, with the engine running there should be 12-14v on the white wire. If this is correct then check the isolator terminals one side should be 12v and the otherside 0v with the house battery disconnected.

If both are so, then hook the white wire to the B terminal on the isolater. Start the engine and check the isolator for 12v on both sides. If thats good then hook up the battery + and check the house batter for voltage with the engine off. That should be less than 12v. Start the engine and the battery voltage should be 13.5v +. If that happen you good to go and as you drive around the engine will be charging the house battery. I can't tell is your isolator is a 3 post with a blob of rust or a 4 post with a broken terminal.

Finding the battery V drain with the engine off and the ignition key removed requires a mini amp meter and you have to check each wire to the + post on the battery.

Have fun

Edited by WME
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The little boxes are thermal cutouts they appear to be fairly new. The taped white wire is supposed to supply power to the big relay with the key on that's why the system does not work. 

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Thanks everyone for the info. I have my volt meter and am going to check everything. Hoping its that white wire that I just have to attach to the b terminal on the isolator. What does WAG stand for? Also, if the white wire does solve the problem will this be enough to recharge the house battery since it is drained if I drive around for a while or will I need to get a battery charger to recharge the house battery?

Thanks again cross your fingers.

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Btw WME- its a three post. 

So I checked all the volts. The car battery reads 12+ Volts, the terminal into the isolator reads about the same. I turned on the engine and the mystery white wire read 12+ volts. The terminal out of the isolator to the house battery reads 0v. I attached the white wire to the isolator and the terminal out of the isolator still read 0v. I attached the house battery and the reading out of the isolator read 456 volts and the house battery read the same. I'm gonna take a sunday drive and see if the volts go up but maybe my isolator is bad?

 

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43 minutes ago, Thirsty Spirit said:

Btw WME- its a three post. 

So I checked all the volts. The car battery reads 12+ Volts, the terminal into the isolator reads about the same. I turned on the engine and the mystery white wire read 12+ volts. The terminal out of the isolator to the house battery reads 0v. I attached the white wire to the isolator and the terminal out of the isolator still read 0v. I attached the house battery and the reading out of the isolator read 456 volts and the house battery read the same. I'm gonna take a sunday drive and see if the volts go up but maybe my isolator is bad?

 

Can you hear the solenoid click when you give it ignition power? If it does not click and you have 12v on the small terminal it is bad . If it does click and you only have 12 volts on one side of the large terminals it is bad. If it has 12 volts on both sides follow the wire testing as you go. I may have missed something but why did the previous owner cut the wire going to the windshield wiper motor. Were both add on white wires not connected to anything? Find any other wires that are not connected to anything? 

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1 hour ago, Thirsty Spirit said:

Are they all created equal?

No, not really. Similar (in looks) is a 'starter solenoid' meant only for short engagement (while your starter spins). You want a battery isolator designed for 'continuous duty' (hours on end while you travel).

An example:-

https://www.amazon.ca/Tow-Ready-118665-Isolation-Solenoid/dp/B004R36U8M/ref=asc_df_B004R36U8M/?tag=googleshopc0c-20&linkCode=df0&hvadid=292910228812&hvpos=1o2&hvnetw=g&hvrand=10837429675731225246&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9000625&hvtargid=pla-570056170279&psc=1

image.png.ac66b6b12b449a58132b782d10033582.png

 

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2 hours ago, Gulfstream Greg said:

Can you hear the solenoid click when you give it ignition power? If it does not click and you have 12v on the small terminal it is bad . If it does click and you only have 12 volts on one side of the large terminals it is bad. If it has 12 volts on both sides follow the wire testing as you go. I may have missed something but why did the previous owner cut the wire going to the windshield wiper motor. Were both add on white wires not connected to anything? Find any other wires that are not connected to anything? 

I’m with you Greg. A tap makes sense. Cutting the wire makes no sense.

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OK dead battery or not the terminal on the other side should have been pretty close to the other side. It kind of points to the isolator being toes up that could be why the control wire was disconnected. As been stated before do not use a starter solenoid it will cook in a matter of minutes and it's possible it killed the wiper fuse and that's why it was disconnected.. 

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Alright I got a new Isolator (switch interuptor - what it says on the box). Basically looks the same as the one that was there but has the two prongs on the front. According to the diagram up above the second prong needs to be grounded. I did all this. I grounded it to chassis. I hooked up the other wires turned the key and what do you know?! I have 12 volts coming out the other side of the Isolator and to the coach battery. So I loaded up the dog and we went for a Sunday drive. When I came home an turned off the vehicle the gauge in the coach said full charge of 12 volts. So I think this all worked. My only guess for why that white wire was disconnected from the isolator is that it wasn't actually connected to the wiper motor but it was the actual connection to the Ignition. Maybe it was disconnected for winterizing?? So no chance of the house battery getting any charge form the car battery? Who knows.

My only fear now is that the ground wire is attached to the wrong place or the wire isn't a heavy enough gage. I'll take a pic and post. 

Thank you a ton everyone for your input and helping me get this problem solved.

Edited by Thirsty Spirit
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OK good deal. Be advised you have shortened your house battery's life span, by how much is the question.

Let it rest over night and check the house battery with a digital meter. Here is  v vs charge % info

https://www.energymatters.com.au/components/battery-voltage-discharge/

If its still low a trickle charger should be used to top it off. Or plug it in and see if your converter works.

Check your battery water level

Edited by WME
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2 hours ago, Thirsty Spirit said:

Alright I got a new Isolator (switch interuptor - what it says on the box). Basically looks the same as the one that was there but has the two prongs on the front.

Some of those with two prongs on the front operate differently than a solenoid isolator. Like this one which is the wrong type. Notice that when power is applied it switches on or off.  https://www.intellitec.com/wp-content/uploads/2019/04/53-00066-100.pdf 

And no matter what, the wiper wire should not have been cut like that. And your solenoid should have been getting 12v ignition from somewhere else, not the wiper circuit.

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The 4 wire isolator could be controlled by interrupting the ground with the other terminal connected to the + truck battery terminal basically just an option to do so. 

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Continuing to learn. I think I do have the wrong isolator. even with the engine off I have a charge coming out of the opposite side of the isolator. And my coach battery charge after a night of sitting is at 11.40. 

With engine ignition off :  Battery (12.40)--->Isolator input(12.40)--->isolator output to coach battery(11.4)---->coach battery (11.40). With the engine ignition off shouldn't the isolator output to coach battery read 0v?

Can I revive my coach battery with a plug in battery charger?

Edited by Thirsty Spirit
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Your OK. Just a little fine tuning. With the Engine off the the isolator is disconnected. Your not reading voltage out of isolator, your reading your house battery voltage.

You need to start the engine and report back with the voltages.

Another WAG your battery was severely discharged and you drive wasn't long enough to fully charge the battery. So what to do?, your RV should have a power cord that plugs into your house AND if everything is right😜 there is a converter that will charge the house battery. If things aren't right then a regular car battery charger will do.

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You may have bought a switching disconnect solenoid. Switching solenoids switch from off to on or on to off. They operate by using a momentary on push button switch that supplies power to the trigger terminal (ign) to trigger them from on to off or off to on. The momentary push button switch sends power temporarily to the solenoid, switching its direction. The solenoid locks itself on or off. Like a toggle switch. 

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7 hours ago, Thirsty Spirit said:

Continuing to learn. I think I do have the wrong isolator. even with the engine off I have a charge coming out of the opposite side of the isolator. And my coach battery charge after a night of sitting is at 11.40. 

With engine ignition off :  Battery (12.40)--->Isolator input(12.40)--->isolator output to coach battery(11.4)---->coach battery (11.40). With the engine ignition off shouldn't the isolator output to coach battery read 0v?

Can I revive my coach battery with a plug in battery charger?

No you are reading the coach battery voltage that is correct what you should see is something close to the the truck battery with the truck is running only. The isolator is connected to both batteries on or off but it only connects them both together when the engine is running. Judging from your coach battery voltage I'm going to say your coach battery has a bad cell even a weak battery will be something in the low 12 volt range.

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  • 2 weeks later...

Hey everyone who chimed in on this thread, Thank you! Looks like everything is running as it should, Battery is charging when we drive, coach battery got recharged up to 12.7ish. Thanks for the all the help. Now how do I improve the gas milage to over 12mpg? :) Took our inaugural overnight out to the Oregon coast last weekend. So great to have a vehicle to camp in, such a great upgrade from being in a tent. Best purchase I've made in a while.

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4 hours ago, Thirsty Spirit said:

Hey everyone who chimed in on this thread, Thank you! Looks like everything is running as it should, Battery is charging when we drive, coach battery got recharged up to 12.7ish. Thanks for the all the help. Now how do I improve the gas milage to over 12mpg? :) Took our inaugural overnight out to the Oregon coast last weekend. So great to have a vehicle to camp in, such a great upgrade from being in a tent. Best purchase I've made in a while.

I have noticed the best way for impressive MPG is to lie about what you get.  Be careful if you go over 15 mpg with a V6,  no one that has been around long  will believe you. 

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Your converter has a relay that switches from battery 12v to  converter 12v. It when the converter 12v is on the battery should be charging. Open up the case and clean the relay contacts and recheck the battery voltage when the converter is plugged in.

P.S. this is very common on relay equipped converters. Also the battery charger is only 3 amps.

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11.7 volts is a dead battery and probably indicates a bad cell. If it is the original converter it is a poor battery charger. Here is what happens when you plug in, the battery is disconnected from the coach the converter has two circuits one to supply power to the lights etc the other to charge the battery. The house power is pretty hefty in the 30 amp range it is the battery that suffers. The second half of the system (battery charging) is only in the 3 amp range it is a poor charger with basically no regulation. Eventually it will charge the battery and if left on will continue to until it has boiled the water out. Driving is another story the truck will charge the battery but short trips will not help much. Be careful of the changeover relay inside of the converter the relay is for the 12 volt system but the relay coil is 120 volts AC there is lethal voltage inside when it is plugged in. One of the very best upgrades hands down to an old MH is a modern converter charger.

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