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Startling behavior of a RAM 1500 HEMI 5.7 with e-Torque - TV parasitic draw from RV


GraniteStaters
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During our recent issue with our Oliver Batteries we observed that we were drawing from the RV batteries if we were connected and the engine was off.  This wasn't an insignificant draw either.  Our temporary solution was to either unplug the Oliver from the TV or keep the engine running.  We chose the former during our hastened trip home last fall because we were having enough battery issues already.  We got the offending batteries replaced, 2 of 4, with Oliver's help as they were delivered just barely over a year ago and their was evidence that we had some of the symptoms while under warranty.  After we installed the new batteries and did all of the testing that we could think of we are quite satisfied that our Oliver issue is behind us, but there was one more test to do with our 2019 RAM 1500 HEMI 5.7 e-Torque engine.  I finally got around to backing up the truck to the now winterized Ollie.  I simply connected the Oliver plug to the TV without the engine running and immediately observed the draw from the Oliver to the RAM.  I have visibility because I have installed a Victron Smart Battery Shunt inline on the negative side of the Oliver batteries and can monitor in realtime with my iPhone via Bluetooth.  Before I connected the tow plug to the TV, I had solar positive solar amperage and wattage.  Once I connected the RAM it immediately went negative until I either disconnected the TV or started the TV engine.  I also used an inductive meter to measure the battery positive cable and observed the same draw when the Oliver was plugged into the RV.  I find this behavior very concerning.  The RAM with e-Torque has more than just a starter battery as it is considered a mild hybrid.  I suspect that the starter battery is isolated to prevent significant parasitic draw from the e-Torque batteries, but believe that wouldn't necessarily prevent those batteries drawing from the RV batteries.  Thoughts? 

David Caswell and Paula Saltmarsh


Hull 509 "The Swallow"

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I think you need to research this on some Ram truck forums, if you do not see your answer, start a thread there. Maybe talk to your dealer’s service manager, so he can contact Ram Support to see if this is a known fault. This forum is much too small to expect to get helpful info. Other than: Good luck.

How many amps did you see leaking back to the truck?

John Davies

Spokane WA

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"Mouse":  2017 Legacy Elite II NARV (Not An RV) Two Beds, Hull Number 218, See my HOW TO threads: https://olivertraveltrailers.com/topic/john-e-davies-how-to-threads-and-tech-articles-links/

Tow Vehicle: 2013 Land Cruiser 200, 33" LT tires, airbags.

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It sounds like they’re using the hybrid battery to power the 12 volt system while the truck is off, rather than the start battery. That would be a sensible design in all cases except the one you’re describing. If that’s the case, then I doubt there’s a fix outside of some sort of smart relay to cut the trailer power, which would be more trouble to install than just remembering to unplug. FWIW, I always unplug for the opposite reason, to keep my trailer batteries from draining the truck’s. 

You might look through the Victron catalog - they make a number of products for interconnecting dual battery systems on ambulances and the like. Perhaps they make something with a diode or something similar that would only allow power to go one way. 

Thanks for bringing it up - I suspect we’ll see issues like these come up as more hybrid trucks come onto the market. 

Edited by Overland
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I suspect the Ram does not have a disconnect relay for the 12v battery line to the 7-way connector. As a result, the parasitic loads in the truck are also pulling current from the trailer connection. The trucks 12V systems battery is isolated from the 48V e-torque starter battery by a converter so this issue will be there whether e-torque equipped or not. You could add a Schottky diode isolator to the charge line in the trailer, but the expense may be hard to justify when just remembering to disconnect costs nothing.  

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David,

Our tow vehicle draws five to six amps from the trailer, to the vehicle, when the engine is not running.  It does this for five to ten minutes and then gradually diminishes.

I believe it is because we have LiFePO4 batteries in the trailer and they run at a higher resting voltage, than the vehicles AGM.  This causes power to be drawn for the higher voltage in the trailer to the lower voltage in the vehicle.  I suspect that would continue until the voltages are the same.  

If we stop for any extended period of time, I disconnect the 7-way.  I forgot once to plug it back in so be careful doing so.  I have also tracked down the fuse providing power to the and have seriously considered just pulling the fuse.  

Andrew

Edited by AndrewK
typo
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Andrew, Carianne and Buffy | San Diego, CA


2019 Legacy Elite II Hull #468 "California Burrito" | 2018 BMW x5 35d 

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Folks-  we are picking up our Oliver in February and it will have the new lithium batteries.  We will be towing it with a 2021 Ram 1500 5.7l hemi with etorque.  As best as I can tell from the folks at Oliver, the Oliver Lithium system wIll not be charged by the tow vehicle electrical system, but it seems that it could be.  Anyone know anything about this?  We previously owned a Roadtrek class b with lithium and a second alternator kept the lithium batteries charged very nicely.

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4 hours ago, Ospreybob said:

Folks-  we are picking up our Oliver in February and it will have the new lithium batteries.  We will be towing it with a 2021 Ram 1500 5.7l hemi with etorque.  As best as I can tell from the folks at Oliver, the Oliver Lithium system wIll not be charged by the tow vehicle electrical system, but it seems that it could be.  Anyone know anything about this?  We previously owned a Roadtrek class b with lithium and a second alternator kept the lithium batteries charged very nicely.

I'd suggest you lean on Oliver for further clarification of their statement. The issue is charging the combination of Lithium trailer and lead acid truck batteries from a single charging source as AndrewK has described above. There are fairly easy solutions available but Oliver should be incorporating something as part of the Lithium Pro package.

Edited by bhncb
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I am not sure why Oliver believes this to be true as the generator on the etorque engine as opposed to a standard alternator can provide much more power.   Maybe it is the charging requirements for the Lithium.  I have been led to believe that Lithium batteries have an integrated BMS which seems like it would eliminate any issues with TV power.  

David Caswell and Paula Saltmarsh


Hull 509 "The Swallow"

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To get a charge from your tow vehicle, you’ll need heavy gauge wiring and a battery to battery charger.  The existing wiring is too small for the distance between the alternator and the trailer batteries, and modern truck electrical systems will not supply a continual voltage from the alternator high enough to charge a bank of batteries.  It’s a wiring/electronics issue and not a battery issue. 

Edited by Overland
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Overland, we are easily able to charge our AGM batteries using the generator on the Ram with e-torque.  We are also able to power the the refrigerator on DC when we travel between campsites without any issues.  The rating for the generator is quite high.  This isn't your father's alternator.

 

David Caswell and Paula Saltmarsh


Hull 509 "The Swallow"

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1 hour ago, GraniteStaters said:

Overland, we are easily able to charge our AGM batteries using the generator on the Ram with e-torque.  We are also able to power the the refrigerator on DC when we travel between campsites without any issues.  The rating for the generator is quite high.  This isn't your father's alternator.

 

“Can I recharge my lithium battery from my vehicle alternator? – Yes, but not necessarily to full charge, due to the fact that most Alternators are adjusted for the lower voltage requirements of the vehicle Lead/Acid Battery (approximately 13.9-Volts).  Lithium Batteries require 14.4 to 14.6-Volts to fully charge.  That being said, you can get up to approximately a 70% charge, depending on the depth of discharge and distance driven while recharging from your vehicle alternator.”

https://www.progressivedyn.com/frequently-asked-questions-on-converting-to-lithium-charging/

John Davies

Spokane WA

"Mouse":  2017 Legacy Elite II NARV (Not An RV) Two Beds, Hull Number 218, See my HOW TO threads: https://olivertraveltrailers.com/topic/john-e-davies-how-to-threads-and-tech-articles-links/

Tow Vehicle: 2013 Land Cruiser 200, 33" LT tires, airbags.

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Victron mentions that the combination of low internal battery resistance and low alternator RPMs as a potential issue for alternator overheating.  Their Orion 12 12 30 will address the parasitic issue between the tow vehicle and the trailer.  The feature is called input votlage lockout.  The adjustable Vout would address the Li battery charging since it can be setup to 15V.

Website
PDF
Video

 

Edited by mjrendon
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2 hours ago, mjrendon said:

  I have been looking to see if their  Orion 12 12 30 might will address the parasitic issue between the tow vehicle and the trailer.  

These guys have it for 10% off through 12/06/20.  Plus shipping. So it might be a wash compared to Amazon Prime unless you order other stuff. I just ordered $2500 of Victron goodies 😳 Merry Christmas to me. I was planning on waiting but the sale got me.

https://www.solar-electric.com/victron-energy-orion-tr-smart-12-12-30a-dc-dc-charger.html

I will be interested to learn more about this, though I am hoping my Land Cruiser won’t require it. I’m not sure where I would mount it, it can’t go in the engine compartment and under the chassis might not be so great. Maybe behind one of the interior panels behind the rear wheels. What is your tow vehicle?

For a bumper connection I strongly recommend an Anderson 120 amp Power Pole (AKA “winch quick disconnect”) bolted to a bracket in a protected spot. These are super tough and very high quality. They also look super cool with the red pull tee handle (it takes 15 pounds of force to unplug it.)
 

701A1712-F794-4D5A-89B8-FD733ACF7DB2.jpeg.26f5c5372d456eb91186e68ce73965c3.jpeg


https://powerwerx.com/anderson-sb-connectors-sb120-120amp

https://powerwerx.com/anderson-power-sb120-hdl-red-handle

Have you thought about how you would get the big cables into the Ollie? Maybe into the space under the bath vanity..... it sounds fun to me.

John Davies

Spokane WA


 

 

Edited by John E Davies

"Mouse":  2017 Legacy Elite II NARV (Not An RV) Two Beds, Hull Number 218, See my HOW TO threads: https://olivertraveltrailers.com/topic/john-e-davies-how-to-threads-and-tech-articles-links/

Tow Vehicle: 2013 Land Cruiser 200, 33" LT tires, airbags.

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Maybe in the trailer would be best. Should be able to pick up the charge lead (12 ga black) and ground (14ga white) from the 7 pin near the battery box.  The manual states that there is a 20 amp fuse on the charge wire.  So the 18 amp version of the Orion might be a better choice.

Edited by mjrendon
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1 hour ago, mjrendon said:

Maybe in the trailer would be best. Should be able to pick up the charge lead (12 ga black) and ground (14ga white) from the 7 pin near the battery box.  The manual states that there is a 20 amp fuse on the charge wire.  So the 18 amp version might be a better choice.

You need to consider more than the continuous amp rating, the 18 amp one puts out 25 amps for ten seconds, it would pop that 20 amp fuse immediately. 

How about this Redarc Trailer Charger, it could mount inside the Ollie near the batteries and connect to the 12 AWG factory charge wire, no worries. Plus it isolates, so no back feed of current.

“The BCDC1212T is specifically designed for, but not limited to, applications where the input current required to charge a trailer mounted auxiliary battery is drawn through the vehicle’s towing harnesses and connectors. It limits the input current drawn to 12A which provides for safe and reliable operation when using towing harnesses, fuses and connectors that are suitably rated without the need to install additional cables and connectors between the start battery/alternator and the BCDC1212T/auxiliary battery.
The BCDC1212T is a three-stage, 12V DC-DC battery charger that operates from an alternator input of 12V or 24V. The input voltage to the BCDC1212T can be above, below or equal to the output voltage making it ideal for charging an auxiliary 12V battery where the distance from the start battery or alternator may cause a significant voltage drop. When connected to a 12V alternator the BCDC1212T will typically provide peak boost currents of 11A, and 20A when connected to a 24V alternator (the peak boost current however also depends on alternator voltage and input cable voltage drop).
The BCDC1212T isolates the start battery from the auxiliary battery, to avoid over-discharging the start battery.“

 

91CE2904-B5C6-4623-989B-8512514C62A1.thumb.jpeg.b930cee0e2006ffc4b2a164ca038d35d.jpeg

https://redarcelectronics.com/products/trailer-battery-charger

Instruction Manual pdf
 


John Davies

Spokane WA

Edited by John E Davies

"Mouse":  2017 Legacy Elite II NARV (Not An RV) Two Beds, Hull Number 218, See my HOW TO threads: https://olivertraveltrailers.com/topic/john-e-davies-how-to-threads-and-tech-articles-links/

Tow Vehicle: 2013 Land Cruiser 200, 33" LT tires, airbags.

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There have been several threads in the recent past specifically dealing with this topic.  LifeBlue provided a design for charging the house batteries from the TV.  I decided long before I even picked up my Oliver that I was pulling the fuse that supplies direct battery power to the trailer harness.  Without this design, charging Lithium batteries from the TV is never going to be very efficient and it seems detrimental in some cases to the TV battery/alternator.

Meanwhile, I'm trying to get some sort of electrical diagram from Oliver for the 2020 model.  It's missing entirely from the owners manual!  Hard to do much with the electrical without a basic understanding of the electrical layout.  I was looking for the DC fused connection for the TV charge line (shown in the 2019 electrical diagram) and it's not there in the 2020.  I'm hoping Oliver didn't just connect that TV hot wire directly to the batteries

Alternator Charge Circuit copy.pdf

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Here is a description of the etorque system on the Ram 1500.  My question is can the 48volt lithium battery in the tow vehicle be used to charge the lithium batteries in the Oliver without damaging the trailer or truck?  And who could do the work necessary to set up the electronics?  

The eTorque system includes a battery pack with 12 pouch-format nickel manganese cobalt lithium-ion cells from LG Chem, supplied by the battery giant’s Holland, Michigan, facility (which also supplies the Chevy Bolt EV, Volt, and others). The modular power-pack unit, from Continental, includes an inverter and DC-DC converter. 

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4 hours ago, NCeagle said:

I was looking for the DC fused connection for the TV charge line (shown in the 2019 electrical diagram) and it's not there in the 2020. 

It would be interesting to know if the breakaway switch for the electric brakes is still being fed by the now lithium batteries. And, is the 12 volt 7-way charge line connected to anything at all like maybe a dedicated breakaway battery/charger. Just removing your vehicle fuse may not be necessary or desirable.

 

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The RAM 1500 eTorque battery is only 430wH which is not much when compared to the 2400 to 4800 wH in the Oliver LE2.  There is a 12V DC to DC converter in this truck since it uses this same battery for the traditional electronics.  I have not found any specifics on the trucks ability to charge the batteries in the tow trailer, but it seems likely. 

 

Edited by mjrendon
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1 hour ago, Ospreybob said:

My question is can the 48volt lithium battery in the tow vehicle be used to charge the lithium batteries in the Oliver without damaging the trailer or truck?  And who could do the work necessary to set up the electronics?

Practicalities and pitfalls aside, there would be no need to tie into the e-torque 48V  because a highly  efficient conversion to 12v  has already been done by the system with more than ample capacity available.  The primary issue of getting amperage to the trailer batteries via the 7-way would still exist.

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10 hours ago, John E Davies said:

You need to consider more than the continuous amp rating, the 18 amp one puts out 25 amps for ten seconds, it would pop that 20 amp fuse immediately. 

How about this Redarc Trailer Charger, it could mount inside the Ollie near the batteries and connect to the 12 AWG factory charge wire, no worries. Plus it isolates, so no back feed of current.

John, 

These are great points. 

I lean towards placing the 12 12 DC converter in the trailer and a new power line from the truck to the trailer for charging, however, the potential for parasitic discharging remains via the 7 way connector.  I guess a proper low Vf Schottky diode could be placed inline to address this issue.

I need to think about this for awhile. 

Maybe others have already solved these issues?

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Keep in mind that a simple converter is not a “smart” charger, it relies on a battery’s built in BMS to prevent cell damage. I would be happier with the more precise control of a real charger.


I peeled off the Redarc charger info onto a brand new thread since it addresses more than just isolation. Let’s add comments specific to that particular unit here:

https://olivertraveltrailers.com/forums/topic/4759-redarc-trailer-charger-mounted-inside-the-ollie-for-100-lithium-charge/

Thanks.

John Davies

Spokane WA

 

Edited by John E Davies
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"Mouse":  2017 Legacy Elite II NARV (Not An RV) Two Beds, Hull Number 218, See my HOW TO threads: https://olivertraveltrailers.com/topic/john-e-davies-how-to-threads-and-tech-articles-links/

Tow Vehicle: 2013 Land Cruiser 200, 33" LT tires, airbags.

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2 hours ago, bhncb said:

It would be interesting to know if the breakaway switch for the electric brakes is still being fed by the now lithium batteries. And, is the 12 volt 7-way charge line connected to anything at all like maybe a dedicated breakaway battery/charger. Just removing your vehicle fuse may not be necessary or desirable.

 

I've already inquired about getting a copy of the 2020 electrical diagrams - which I need for other things as well.  Can other 2020 owners ask as well?  The more that ask the more likely we will get something sooner.

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