Hey, late '90s Dodge Roadtrek owners... What's draining my engine battery?

VTPete · 06-14-2018, 11:57 AM

Yesterday I went to start my 1996 Dodge Roadtrek 190 popular.
The engine battery was almost completely dead. A few days earlier, I had ran the van fine.

I had left the headlight switched turned all the way to the left (counter clockwise) and that was the only thing different about how I had parked it.

The Roadtrek manual is notoriously confusing with regards to how that headlight switch operates. But, the overhead lights were definitely not left turned on. The manual makes reference to an "ignition light", but I don't know what that is! The clear plastic ring around my ignition key area does not light up under any condition. (Maybe it should?) It even references being careful about leaving the light switch in that position as it could drain the battery... but I didn't see anything on. Whatever it was took about 3 days to bring the voltage of my battery down to a point where it *tried* to turn over the engine, but couldn't quite do it. Charging the battery solved the problem.

Anyway, I could find nothing draining power... and I definitely did not leave the headlights on.

Any thoughts, guys?
By the way, I can NOT find a '96 Dodge RAM Van owner's manual anywhere.

-Pete

ericw · 06-29-2018, 05:35 PM

Pete, I've got a '95 Dodge Sportsmobile. Recently the battery isolator (SurePower 12023A) went bad, and I believe the engine battery was discharging into the house batteries over a period of time. I discovered this issue when my engine battery went dead and when the positive cable was disconnected and brushed against a chassis screw it sparked... I replaced mine with a Stinger S12023 isolator which was an exact fit replacement and that resolved the problem -- oh, and a new engine battery and house batteries as well :-/

If you have a similar setup in your Roadtrek you might want to test the isolator to see if it still operating correctly.

Good luck with tracking the issue down!

Eric W.

VTPete · 06-29-2018, 05:44 PM

Eric,
Thanks! I believe it had something to do with the light switch being left in the full counter-clockwise setting. That was the only that was different and I haven't had the issue since.

But, now is a good time to ask: What does the isolator look like and where do I find it! Not to mention, how would I test it?

-Pete

Quote:

Originally Posted by ericw

Pete, I've got a '95 Dodge Sportsmobile. Recently the battery isolator (SurePower 12023A) went bad, and I believe the engine battery was discharging into the house batteries over a period of time. I discovered this issue when my engine battery went dead and when the positive cable was disconnected and brushed against a chassis screw it sparked... I replaced mine with a Stinger S12023 isolator which was an exact fit replacement and that resolved the problem -- oh, and a new engine battery and house batteries as well :-/

If you have a similar setup in your Roadtrek you might want to test the isolator to see if it still operating correctly.

Good luck with tracking the issue down!

Eric W.

ericw · 06-29-2018, 05:52 PM

Quote:

Originally Posted by VTPete

Eric,
Thanks! I believe it had something to do with the light switch being left in the full counter-clockwise setting. That was the only that was different and I haven't had the issue since.

But, now is a good time to ask: What does the isolator look like and where do I find it! Not to mention, how would I test it?

-Pete

I hope it is as simple as the light switch being left in the counter-clockwise position -- that would be great.

Here's a link to the isolator I bought. Mine is mounted on the firewall more-or-less dead center in the engine compartment.

https://www.amazon.com/Stinger-S1202.../dp/B001TH8O8S

There's some good videos on YouTube showing how to test an isolator if you need some instruction.

Regards,
Eric W.

VTPete · 06-29-2018, 06:14 PM

Eric,
So, I found it... it's on the driver's side of the firewall, down by the bottom.
It's a Powerline PLI-130-2 by Hehr Power Systems.

I did a simple test when I removed the cabin battery. I checked the voltage at the disconnected cables and it read 3 volts! (Yes, with no cabin battery attached.) Then I flipped the big knife switch on the engine battery under the hood and it read zero volts back at the cabin cables. Shouldn't it be isolated!?!?!?

Thank you for the link and hint. I've suspected something is odd since I'm on my third cabin battery in one year now after "mysterious drains".

I'll look up those videos right away!
-Pete

ericw · 06-29-2018, 06:50 PM

Quote:

Originally Posted by VTPete

Eric,
So, I found it... it's on the driver's side of the firewall, down by the bottom.
It's a Powerline PLI-130-2 by Hehr Power Systems.

I did a simple test when I removed the cabin battery. I checked the voltage at the disconnected cables and it read 3 volts! (Yes, with no cabin battery attached.) Then I flipped the big knife switch on the engine battery under the hood and it read zero volts back at the cabin cables. Shouldn't it be isolated!?!?!?

Thank you for the link and hint. I've suspected something is odd since I'm on my third cabin battery in one year now after "mysterious drains".

I'll look up those videos right away!
-Pete

That sure sounds suspicious to me. The isolator should prevent current draw-down from the engine battery, but if you are seeing 3 volts on the disconnected house battery positive wire then something is putting voltage on the line. The fact that a hard disconnect with the switch on the engine battery removes the 3 volts would indicate that somehow the engine battery voltage is leaking to the house battery.

Testing the isolator is quite simple as long as you have a digital volt meter. The videos should be very clear. I will be interested to hear your results!
Eric W.

VTPete · 06-29-2018, 07:15 PM

When it gets cooler, I'll try some more things.
I just did another interesting test: I have a 400 watt inverter I use to charge my laptop with in the RV.

With the cabin battery installed, I can plug the inverter into an RV 12V socket, but it will NOT run my battery charger. The inverter tells me the voltage goes from 12.4 without any load down below 11.0 under load.

When I remove the cabin battery entirely from the RV, it has no problem running the same inverter. Something is causing a huge voltage drop under load. Perhaps there is some wire going to the outlet that was way too small a gauge, but I somehow doubt that. This voltage drop effect happens regardless of whether the engine battery is connected or not, by the way.

When I have more time, I'm going to remove the isolator entirely to see if it is the limiter. I have a brother who's an electrician specializing in low-voltage DC, so he might be able to help me. Either way, I think the new isolator is a no-brainer.

-Pete

Quote:

Originally Posted by ericw

That sure sounds suspicious to me. The isolator should prevent current draw-down from the engine battery, but if you are seeing 3 volts on the disconnected house battery positive wire then something is putting voltage on the line. The fact that a hard disconnect with the switch on the engine battery removes the 3 volts would indicate that somehow the engine battery voltage is leaking to the house battery.

Testing the isolator is quite simple as long as you have a digital volt meter. The videos should be very clear. I will be interested to hear your results!
Eric W.

ericw · 06-29-2018, 07:33 PM

So if I understand correctly, when you remove the house battery entirely from the circuit (in fact taking it outside of the RV) then the inverter is able to run the laptop charger from the house battery?

With the house battery removed have you measured the engine battery voltage? If the house battery voltage is OK, and the engine battery voltage is low this is another indication of the isolator being faulty. I would agree -- it seems like a no-brainer that the isolator should be replaced.

Eric W.

VTPete · 06-30-2018, 12:08 AM

Hi Eric (and everyone else),
This afternoon after the sun was behind the trees (it's hot!), I removed the isolator. This was quite a job because to get to the screws, you have to remove the engine battery and the windshield and antifreeze reservoirs. It took me far too long and my forearms are pretty scratched up!

Regardless, it removed it and tested it. Unfortunately, it tests on the bench perfectly with my voltmeter.

Tomorrow I have a new one arriving and I need to decide if I return it or use it. Hummm....

-Pete

Quote:

Originally Posted by ericw

So if I understand correctly, when you remove the house battery entirely from the circuit (in fact taking it outside of the RV) then the inverter is able to run the laptop charger from the house battery?

With the house battery removed have you measured the engine battery voltage? If the house battery voltage is OK, and the engine battery voltage is low this is another indication of the isolator being faulty. I would agree -- it seems like a no-brainer that the isolator should be replaced.

Eric W.

ericw · 06-30-2018, 12:11 AM

Quote:

Originally Posted by VTPete

Hi Eric (and everyone else),
This afternoon after the sun was behind the trees (it's hot!), I removed the isolator. This was quite a job because to get to the screws, you have to remove the engine battery and the windshield and antifreeze reservoirs. It took me far too long and my forearms are pretty scratched up!

Regardless, it removed it and tested it. Unfortunately, it tests on the bench perfectly with my voltmeter.

Tomorrow I have a new one arriving and I need to decide if I return it or use it. Hummm....

-Pete

Bummer. That's all I've got, I'm afraid. Sounds like time to bring your brother on board for some more advanced trouble-shooting. I wish you rapid success!

Eric W.

VTPete · 07-01-2018, 02:12 AM

Today I installed the new isolator. The voltage "bleed" that was three volts read back at the wires connecting to the cabin battery has now dropped to less than .2 volts! YAY!

My brother the electrician explained how old diodes can start to fail under load. Something about substrates...

ericw · 07-02-2018, 05:25 PM

Well, that's good news! Hopefully all your charging issues will be resolved with this relatively simple fix.

Eric W.

Sehc · 07-04-2018, 12:40 PM

Could your battery be old and failing? Once Pb battery go dead once or twice, they are likely to be not much good.

Doneworking · 07-04-2018, 03:47 PM

Glad all that work helped your problem. For the last several RVs we have owned, I installed these on the coach batteries and the chassis battery on two units because of discharge problems. It is not a perfect solution but I only use the rv every few weeks so really not a problem for me. Most Walmarts sell these as well.

https://www.amazon.com/NOCO-ID220S-6...70_&dpSrc=srch

Paul

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