Lithium battery drain to TV

[rubicon327]

Originally Posted by TTMartin

You might want to contact ETI and ask them if the DC to DC charger was installed (I doubt it since you supplied the batteries) and if not, could they do a last minute install of one prior to shipping it out. I'm guessing they won't be able to, but, it never hurts to ask.

Exactly what I was going to suggest. I believe when Dream would have been contemplating lithium ETI was still developing what they would provide in their lithium packages if made an option. Otherwise Dream would just have presumably gotten the batteries through ETI as well.

[Dream]

ETI does not have the Victron Orion Smart TR 12/12-18 Victron chargers and will not have them until January. Amazon has them now. You guys were correct. Looks like I will need to install it myself. Anyone willing to help me think through this? My thought is cut into the 7 pin cable inside the trailer and isolate the #4 line. Route it to the Victron and split the ground wire? Then one of the two following options:
1. Attach both wires (hot and ground) through the correct input side of the Victron and two new output cables directly to one of the two Lithium batteries. Or
2. Victron output wires back to the existing #4 pin wire previously cut which continues into trailer? Which is better #1 or #2?
Also, it should not be mounted on a flammable surface. How hot does it actually get? Standoffs over metal under the dinning work? Thanks again

[TTMartin]

Originally Posted by Dream

ETI does not have the Victron Orion Smart TR 12/12-18 Victron chargers and will not have them until January. Amazon has them now. You guys were correct. Looks like I will need to install it myself. Anyone willing to help me think through this? My thought is cut into the 7 pin cable inside the trailer and isolate the #4 line. Route it to the Victron and split the ground wire? Then one of the two following options:
1. Attach both wires (hot and ground) through the correct input side of the Victron and two new output cables directly to one of the two Lithium batteries.
2. Victron output wires back to the existing #4 pin wire previously cut which continues into trailer? Which is better #1 or #2?
Also, it should not be mounted on a flammable surface. How hot does it actually get? Standoffs over metal under the dinning work? Thanks again

Neither the 7 pin connector comes into a junction box on the frame near the hitch similar to this one.




You can make your connections to the 7 pin connector there.

[Dream]

TTMartin, thanks that certainly makes it easier. Then I assume I just put the Victron ahead of the junction box, mount it exterior in a wet protected enclosure and attach the outputs back to the junction box. WOW don't know why I would even bother with ETI which would cost more anyway. I appreciate your help.

[Vermilye]

My Victron DC to DC converter is mounted under the driver's side rear bench seat. I have a switch so I can shut it off if the batteries are fully charged & I have a long drive ahead. It is set at 14.4V.

The existing charge line from the front of the truck (and the black pin in the 7 pin splicing box) goes through the switch, then to the input of the Victron. The output goes to the battery side of the battery disconnect switch. The grounds both go to the ground post on the back of the WFCO Distribution Panel (where all the Escape grounds are tied together).

To power the breakaway switch & power tongue jack I ran a second #6 wire from the battery side of the battery disconnect switch to the 7 pin splicing box. I used the unused yellow terminal to tie the new #6 wire to the breakaway switch & tongue jack by moving those wires & connectors from the black terminal to the yellow one. I disconnected the yellow wire coming from the 7 pin connector & taped it up since some vehicles use it for back up lights.

Hope this helps, but either PM me or post with questions.

Jpn

[Brian B-P]

Originally Posted by Vermilye

Depends on your tow vehicle. Most trucks that have a tow/haul switch will keep the voltage to pin 4 high enough, but lots of modern SUVs will drop the charging voltage as soon as possible after starting the vehicle in order to save fuel.

Yes, my car does that; it can drop as low as 13.2 V. Probably every non-commercial vehicle does that now.

Originally Posted by Vermilye

Assuming you have solar, when the alternator voltage drops below the typical 14.4 charging voltage of the trailer's solar system, it will be charging both the lithium batteries & the tow vehicle battery through the charge line.

Yes, however...

Originally Posted by TTMartin

The resting voltage of a fully charged Battle Born Battery is 13.5 to 13.6 volts.

With the resistance of typical tow wiring, and the internal resistance of the batteries (especially the one in the tow vehicle) and only 0.3 to 0.4 V between batteries, how much current will really flow from a lithium-ion trailer battery without a charging source active to the battery of a running tow vehicle? This is the "my tug won't charge my trailer" issue, with the roles reversed. It doesn't seem like something really worth worrying about.

Originally Posted by TTMartin

Yes, it can over charge the truck batteries.

With an active solar charging system the tow vehicle's battery could get charged. Since the solar system's output voltage is similar the tow vehicle's normal charging voltage, and there is still all of that wiring and internal battery resistance, it's hard to imagine the running tow vehicle's battery getting overcharged while driving. Of course, if the tow vehicle wiring system is deficient and doesn't disconnect when the engine is not running, it would be bad to leave the batteries connected.

[TTMartin]

Originally Posted by Brian B-P

Of course, if the tow vehicle wiring system is deficient and doesn't disconnect when the engine is not running, it would be bad to leave the batteries connected.

Many vehicles including my Mercedes Benz Sprinter van keep the power pin on the 7 pin connector hot even when the ignition is off. ISO specifications call for it to be permanent hot, so it's actually vehicles that don't keep it connected that don't meet the 'standards'.

Any vehicle that has it's converter and solar charger set up to charge lithium batteries could certainly over charge the tow vehicle's battery if left plugged in while not driving, which is what the OP's question was.

[Brian B-P]

Originally Posted by TTMartin

Many vehicles including my Mercedes Benz Sprinter van keep the power pin on the 7 pin connector hot even when the ignition is off. ISO specifications call for it to be permanent hot, so it's actually vehicles that don't keep it connected that don't meet the 'standards'.

I don't know how much relevance ISO standards have to towing in North America, where the common "RV style" 7-pin connector doesn't even follow the SAE standards which are normally used here. What specific ISO standard applies to this? I might try to look it up, although without a corporate subscription that means a library visit which is currently not practical.

In any case, the towing connection standard used for caravans in Europe is very different from that used here, and includes two +12V circuits - and my understanding is that only one of them is live all of the time. An Escape (like other North American trailers) is designed with no restriction of what 12 V DC devices are used dependent on whether the tow vehicle is running, so it is at least questionable to leave a tow vehicle battery connected to the trailer.

Originally Posted by TTMartin

Any vehicle that has it's converter and solar charger set up to charge lithium batteries could certainly over charge the tow vehicle's battery if left plugged in while not driving, which is what the OP's question was.

But if that is true, and the charging voltage is about 14.4 volts, then the same is true without the lithium-ion battery (because that's also the highest charging voltage for lead-acid batteries, although for a limited time), and the tow vehicle's own charging system is a similar risk for overcharging (given the typical 14.2 V motor vehicle charging system).

I agree that ideally the tow vehicle should be protected from the trailer - an obvious way to at least limit the time of exposure to any such risk is to just configure the tow vehicle to disconnect the charge line when the engine isn't running, so the tow vehicle's battery isn't connected to the trailer in extended parking.

[Brian B-P]

I realize that the original question was about power flow from the trailer's lithium-ion battery through an always-on connection to the tow vehicle's (presumably lead-acid) battery while the vehicle is not running; however, if a DC-to-DC converter such as the Victron Orion-Tr Smart DC-DC is seen as the solution, it is important to ensure that the configuration is correct. Unless it knows to shut off, the Orion will continue to charge the trailer's battery from the tow vehicle's battery (the other direction of power flow) until the trailer battery is fully charged or the tow vehicle's battery is down to 7 volts (also known as dead and possibly damaged). The 12/12-18 will use more than 20 amps to do this as long as the trailer battery accepts the full 18-amp output, so if shut off is not properly set up the tow vehicle's battery will be dead in about the time specified by that battery's reserve capacity (which is the number of minutes for which it can supply 25 amps).

Of course the Victron people understand that, so they built in automatic engine-on detection, to shut the Orion DC-to-DC charge off unless the tow vehicle's engine (actually its charging system is running). They publish an explanation and setup guide for this feature; I would want to be careful to ensure that the setup is correct before leaving a vehicle lacking engine-off disconnect plugged into a trailer with the Orion.

Although this feature was intended to handle the situation in which the RV battery is in the same vehicle as the engine and starting battery (a motorhome or truck camper), rather than a trailer connection without a shutoff, it will work for the trailer scenario as well.

[tdf-texas]

Originally Posted by Vermilye

My Victron DC to DC converter is mounted under the driver's side rear bench seat. I have a switch so I can shut it off if the batteries are fully charged & I have a long drive ahead. It is set at 14.4V.

The existing charge line from the front of the truck (and the black pin in the 7 pin splicing box) goes through the switch, then to the input of the Victron. The output goes to the battery side of the battery disconnect switch. The grounds both go to the ground post on the back of the WFCO Distribution Panel (where all the Escape grounds are tied together).

To power the breakaway switch & power tongue jack I ran a second #6 wire from the battery side of the battery disconnect switch to the 7 pin splicing box. I used the unused yellow terminal to tie the new #6 wire to the breakaway switch & tongue jack by moving those wires & connectors from the black terminal to the yellow one. I disconnected the yellow wire coming from the 7 pin connector & taped it up since some vehicles use it for back up lights.

Hope this helps, but either PM me or post with questions.

Jpn

I updated the electrical drawing for my trailer to show the Victron 12-12/18 in the circuit.

Is this close to what you did to your trailer and is this the correct way to wire it?

The negative return is through the trailer frame ground. Should a separate ground wire be run to reduce voltage drop?

[Vermilye]

Originally Posted by tdf-texas

I updated the electrical drawing for my trailer to show the Victron 12-12/18 in the circuit.

Is this close to what you did to your trailer and is this the correct way to wire it?

Close. The difference is both the tongue jack & the breakaway switch are wired with a #6 wire to the battery side of the disconnect switch. I disconnected the 7 pin connector to the 7 pin junction box & used the yellow terminal to connect the #6 wire to the tongue & breakaway connections.

Other difference is the solar controller goes directly (through a 30 amp breaker) to the battery rather than through the Escape installed in line 60 amp fuse (which, as installed in my trailer was a 40 amp fuse). While unlikely, I could have as much as 30 amps from the solar controller & 35 amps from the converter at the same time, stressing the 60 amp fuse.

[gklott]

Originally Posted by Vermilye

My solution to this problem (and to get a higher voltage from the tow vehicle to the lithium batteries) was to install an inexpensive DC to DC converter in the trailer's tow vehicle charge line.

We installed a Sterling Power Battery-to-Battery Charger, 12V input to 12V output 30amp, model BB1230. When powered by our Infiniti QX80 or Mercedes Sprinter tow vehicles, BB1230 provides the proper charging profile for our four Battle Born GC2 batteries. We wired the 7-pin connector 12V Aux power line straight to the Sterling via a 30A Maxifuse. This is a correct-profile charging solution rather than the normal DC-to-DC converters described.

We also replaced the ETI supplied WFCO converter with the Sterling Power- ProCharge Ultra : 12 Volt, 40 Amp Marine Battery Charger, model PCU1240. You will find the Sterling chargers on many larger boats, yachts, custom coaches, etc. It is extremely well built.

We've used Sterling chargers on many projects, and we have them on both our trailers. We can highly recommend them as an option to WFCO, Victron, Blue Sea, etc.

73/gus