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brian_bp said:
A simpler low-voltage cutoff device in the control wire for my basic trailer power relay would suit me better, and make me more likely to use an accessory circuit (instead of ignition-switched circuit) for control.
Are you leaving the key in the ignition with it in "ACC" position for long periods of time? If not, then having an accessory switched circuit or a Ignition controlled circuit doesn't make lick of difference...other than the relay cycling twice during starting of the engine. Just change your setup to use the Power point fuse in the panel instead of the EFI. Playing with the EFI controller's power is a bad idea. Maybe I'm just dense (ask my wife, she'll let you know), but what's your need of a circuit that only powers when the engine is running? You're not going to draw enough out of the sienna battery during the moment you pass through the ACC point in turning the key to drain it to the point where it won't start.

I've got a relay setup similar to yours, but on a switched circuit in the network of wires under the glove compartment inside the vehicle. My "off" switch and relay are inside the engine bay by the windshield washer fluid tank. I also run a second fused wire to the rear and have a circuit that isolates the running lights/brake lights/signal lights. These get switched through a number of P-channel Mosfets to control the light action of the trailer. Completely isolates the sienna's lights from the trailers and has no moving parts. Works like a charm and can push 20 amps through each circuit, if required.
 

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tcp said:
brian_bp said:
A simpler low-voltage cutoff device in the control wire for my basic trailer power relay would suit me better, and make me more likely to use an accessory circuit (instead of ignition-switched circuit) for control.
Are you leaving the key in the ignition with it in "ACC" position for long periods of time? If not, then having an accessory switched circuit or a Ignition controlled circuit doesn't make lick of difference...
I agree that it's not a big deal of difference in normal use. If the trailer were powered in the ACC position, it would be tempting to use it... and then there's the potential problem. The more I think about this, the more I think it would be easiest to settle for ACC... there's the value of forum discussions!

tcp said:
Playing with the EFI controller's power is a bad idea.
I've only spent a couple of minutes today with the wiring diagrams, but so far it looks like this source is from the EFI relay, not an ECM, so it really shouldn't matter to the engine control system. In the end, all circuits get their power from the same source, and all see the same noise and voltage swings. I could have triggered the trouble indication by some action (such as probing other circuits) quite unrelated to the circuit which I actually installed.

tcp said:
I also run a second fused wire to the rear and have a circuit that isolates the running lights/brake lights/signal lights. These get switched through a number of P-channel Mosfets to control the light action of the trailer. Completely isolates the sienna's lights from the trailers and has no moving parts. Works like a charm and can push 20 amps through each circuit, if required.
That level of isolation for trailer lighting is great; unfortunately, the optional OEM lighting converter (although apparently well built and nicely installed) still draws its power from the van's lighting circuits. If I had to start again, I too would use a powered (and solid-state) converter.
 

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I just purchased a 2010 Sienna with Tow Package and am currently wiring it up for towing a popup (once I've reached my break-in period). I'm ready to wire the 12V charge line from the Sienna to the trailer. Does anyone know how much charge current will actually go to the battery in the popup when driving? Estimates are that a fridge will pull 10-12 amps while on battery driving down the road. If I drive for 8 hrs, I'll have a dead battery when I get to my destination if I don't pull more current than that to feed my trailer battery. I'm planning to make it simple to start with and just run a 10 guage wire through a circuit breaker off the Sienna battery to the trailer battery.
 

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Does anyone know how much charge current will actually go to the battery in the popup when driving? Estimates are that a fridge will pull 10-12 amps while on battery driving down the road.
In my old pop-up (2006 ROCKWOOD) The fridge will not operate while "in-tow" There was a switch on the sink(that poped up onto the fridge). So if the sink was down the fridge did not work. This will have to be over-ridden to operate while "in-tow"

Before I went away for the weekend I would set up my trailer 2 days before i went in the driveway and put whatever i needed for the weekend in the fridge the night before while plugged into the house. It kept cool for me but the max I drove was 3 hours.

I am not saying to override the switch, I am saying their IS a switch ;) (maybe)
 

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I see the pop up switch under the sink so you may be right about it killing the power anyway. This will be my first trip with Sienna and camper so I think I'll plug in and cool down the fridge at home also, then throw in a block of ice 'till I get to my destination. In my case, I'll probably be driving 6-8 hrs before I get to my destination and can turn on the propane.
 

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Why not just run it on propane on the trip there? Ours stays on propane from the minute we leave until we return from our trip. The longest has been 14 days straight and 1400miles.

boder said:
I see the pop up switch under the sink so you may be right about it killing the power anyway. This will be my first trip with Sienna and camper so I think I'll plug in and cool down the fridge at home also, then throw in a block of ice 'till I get to my destination. In my case, I'll probably be driving 6-8 hrs before I get to my destination and can turn on the propane.
 

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tcp said:
Why not just run it on propane on the trip there?

boder said:
...In my case, I'll probably be driving 6-8 hrs before I get to my destination and can turn on the propane.
Having a propane appliance burning - or even just having the propane tank valve open - can be a safety concern. In some specific circumstances - while in some tunnels and presumably while on a ferry - it may not be allowed.

Also, some RV refrigerators will not maintain the flame while moving on the road, as it gets blown out... although perhaps only in specific crosswind conditions.
 

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boder said:
... Does anyone know how much charge current will actually go to the battery in the popup when driving? Estimates are that a fridge will pull 10-12 amps while on battery driving down the road. If I drive for 8 hrs, I'll have a dead battery when I get to my destination if I don't pull more current than that to feed my trailer battery...
Current draw depends on refrigerator size, of course, but on the order of 10 to 12 amps sounds plausible. This will only be drawn when the refrigerator runs, and just like the refrigerator in a house it only runs part of the time, as much as necessary to maintain the set temperature (very approximately). In hot conditions it might run continuously, but in cool weather it will only run a small fraction of the time.

I would - and did - still hook up the power supply from the Sienna.
 

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boder said:
I see the pop up switch under the sink so you may be right about it killing the power anyway.
I'm not sure about other pop-up makers, but although our Fleetwood/Coleman does have a "kill switch" under the flip-over sink this switch only prevents the interior lights from working - the fridge will still run on DC while the camper is closed-up (and thus the sink is down). You don't want the interior lights on when closed to prevent their heat from damaging the canvas (I know, it's not really canvas anymore :)).
 

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brian_bp said:
This will only be drawn when the refrigerator runs, and just like the refrigerator in a house it only runs part of the time, as much as necessary to maintain the set temperature (very approximately). In hot conditions it might run continuously, but in cool weather it will only run a small fraction of the time.
I'm not sure this is entirely true for most RV refrigerators. An RV 3-way fridge has an ammonia-based cooling system that does not have a compressor but rather relies on a heating element to drive the ammonia cooling cycle. I'm not sure, but I think that the "temperature control" simply adjusts how hot the heating element gets (via a resistor?) - note that there is a separate "temperature control" for use when running on propane.

Regardless, the fridge is not as efficient when running on DC power (vs. AC power or propane), so we travel with ours on the max cool setting which basically maintains the pre-cooled temperature. Of course, we're in Florida 8), so YMMV.
 

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Zero260 said:
brian_bp said:
This will only be drawn when the refrigerator runs, and just like the refrigerator in a house it only runs part of the time, as much as necessary to maintain the set temperature (very approximately). In hot conditions it might run continuously, but in cool weather it will only run a small fraction of the time.
I'm not sure this is entirely true for most RV refrigerators. An RV 3-way fridge has an ammonia-based cooling system that does not have a compressor but rather relies on a heating element to drive the ammonia cooling cycle. I'm not sure, but I think that the "temperature control" simply adjusts how hot the heating element gets (via a resistor?) - note that there is a separate "temperature control" for use when running on propane....
Yes, these refrigerators are based on an ammonia/water absorption cooling systems; however, they are not continuously variable. They run on/off, just like a compressor-type refrigerator. Just like a furnace or water heater, in propane mode they either have either a pilot flame or a direct spark ignition, but either way the main burner switches on and off under the control of the thermostat.

Continuously variable operation may be possible, but I've never heard of a refrigerator which works that way.

Since switching the burner and switching an electric heating element are different, some have two thermostat dials, but both of my RV refrigerators do not - a single dial is commands either the electric (AC or DC) or propane control system, depending on the appliance's current operating mode.


Zero260 said:
Regardless, the fridge is not as efficient when running on DC power (vs. AC power or propane), so we travel with ours on the max cool setting which basically maintains the pre-cooled temperature
I think this is a comment on effectiveness, rather than efficiency, but it's still a good point. The cooling rate of a typical RV refrigerator is not as high on DC power as on propane (the DC heater just doesn't have as much heat output as the propane flame), so the fraction of the time that the heat must be on to keep the food cold will likely be higher on DC power than on propane... thus Brad's runs flat out all the time if running on DC, in Florida.
 

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They run on/off, just like a compressor-type refrigerator. Just like a furnace or water heater, in propane mode they either have either a pilot flame or a direct spark ignition, but either way the main burner switches on and off under the control of the thermostat.
I agree. If it has a thermostat it has to cycle on/off. I don't know IF this is with all 3 way fridges. When the trailer is plugged in and running on A/C the heater element is D/C 12 volt heater. This is done via the A/C, D/C converter.



Continuously variable operation may be possible, but I've never heard of a refrigerator which works that way.
I think this is only true in the 12 VOLT coolers that plug into the cig/power outlet. All the models I have seen do not have a thermostat so they are constant.
 

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tcp said:
Why not just run it on propane on the trip there? Ours stays on propane from the minute we leave until we return from our trip. The longest has been 14 days straight and 1400miles.

True it can run on propane as there is no switches to override when it is down. When I got my pop-up I asked the guy if I can run it while driving. Again it came down to a safety concern. BUT he did say that on your travels IF you stop to take a walk or stretch. Light it up for the time that you are stopped(15 minutes??) It will give you that little extra burst of cool. Just make sure you are away from any petro station @ the time. Use in a well ventilated area. ;D

"tcp" You must have a great memory to remember to turn off the propane before refuelling during your travels. All the people I see leave coffee cups ,purses,wallets,gas caps ETC on their vehicle because they do not pay attention :eek:
 

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Typical 3-way refrigerators have separate 120V AC and 12V DC elements, so the converter is not involved. That means they can have three different rates of cooling, with the DC mode usually being the least effective (because it is the lowest-power heater)... it is typically intended only for temporary use to keep the contents cold while driving, assuming the door is not being opened, with the lowest practical electrical power demand. It's still enough power that I agree that for a full day of driving, the 12V line from the Sienna is appropriate.

The all-electronic coolers are fundamentally low-voltage DC devices, so they do depend on an AC-to-DC converter when running on AC power.
 

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brian_bp said:
It's still enough power that I agree that for a full day of driving, the 12V line from the Sienna is appropriate.
So do you think that if the fridge uses 10-12 amps, that the charge line from the Sienna will supply that while driving? I just ran my 12V line from my Sienna battery through a 30-amp circuit breaker to the trailer battery.
 

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boder said:
So do you think that if the fridge uses 10-12 amps, that the charge line from the Sienna will supply that while driving? I just ran my 12V line from my Sienna battery through a 30-amp circuit breaker to the trailer battery.
Yes. The wire really doesn't limit current, it just adds resistance. The more current which flows, the less voltage there is at the refrigerator (and trailer battery), but to keep the trailer battery up to an adequate voltage (e.g. 12 V), with the Sienna's system supplying a significantly higher running voltage (e.g. 13.8 V), then the wire would have to lose more than the difference in voltage (1.8 V in this case) while carrying only the refrigerator current (12A in this case).

1.8V for 12A is 0.15 ohms, which may not sound like much but is a lot of resistance for a few metres (about 15 m or 50 ft, round trip, with detours) of reasonable (e.g. 10 ga) wire... it would take about 400 m (1500 ft) of 10 ga wire to have this much resistance. Of course there are imperfect connections along the way, which add resistance, but the point is that at the level of current demand we're talking about here, I don't think that the circuit from the Sienna should have any problem keeping up.

Other people with travel trailers have reported that this sort of common power setup at least maintains the trailer's battery charge level while driving with a refrigerator on, although it may not charge the battery very quickly. I have not monitored my trailer battery charge level closely enough to really say.
 

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robo5 said:
Continuously variable operation may be possible, but I've never heard of a refrigerator which works that way.
I think this is only true in the 12 VOLT coolers that plug into the cig/power outlet. All the models I have seen do not have a thermostat so they are constant.
Many thermoelectric coolers (based on the Peltier effect) don't have any control at all, so they run constantly (I have one). Some do have a thermostat, and switch on and off for control just like other refrigeration appliances (I have one of those, too). While I'm not aware of any reason that such a design wouldn't work well with a continuously variable level of power (adjustable heat flow rate and thus power consumption, which is what I mean by "continuously variable"), these are usually relatively cheap appliances which are not that sophisticated.

A possibly helpful analogy: the headlight switch is an on/off control (it's all or nothing), while the dash light dimmer is a continuously variable control (it can be adjusted to any desired level over some range).

Thermoelectric coolers sound promising, if only because the "electronic" label makes them sound efficient, but in fact they are neither very effective (most can't get really cold in warm surroundings) nor very efficient (they use much more power than the same size of compressor-type refrigerator). I flattened the Sienna's battery in one cool night of running a thermoelectric cooler from the Sienna's battery while camping. Ever looked for a battery boost in a campground in summer? :-[
 

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I am wiring up my 7 blade and looking for the where tap in for the ACC and Reverse lights. I haven't pulled the driver side panel yet to look for where the harnesses all run. I was assuming the ACC tap would be easy but then remembered my XLE has a 120V plug (not 12v round "cigarette lighter) style and therefore I can't just put a t-tap on it.

Anyone recall their installation and what colour of wire (or even what harness) they tapped into? I can put a tester on the harness until I find a 12V acc only line.

I also am looking for where to tap in the Reverse lights. Since I don't need to open the hatch up, would prefer to tap into the harness somewhere inside the cabin. I heard that above the third row seating the harness for the hatch runs... anyone have any advice on what to look for when I open that up? remember the reverse lights wire colour?

Removing ceiling panels could have a low WAF (Wife Acceptance Factor) so I am trying to minimize time in the cabin and go at it with a plan.
 

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Most trailer wiring doesn't have a reverse. It is sometimes used to lockout the surge brakes while backing up, but a trailer with electric brakes often doesn't have a reverse. Mine doesn't.

I would run a dedicated wire from the battery for the ACC to the trailer. Run it through a relay that uses the ACC to activate the coil of the relay, but not to supply the actual current to the trailer. If your trailer has a dead battery and you're hooked up to the ACC directly, you MAY blow the fuse. It is rated for 15amps maximum off the cigarette outlets.

robaer said:
I am wiring up my 7 blade and looking for the where tap in for the ACC and Reverse lights. I haven't pulled the driver side panel yet to look for where the harnesses all run. I was assuming the ACC tap would be easy but then remembered my XLE has a 120V plug (not 12v round "cigarette lighter) style and therefore I can't just put a t-tap on it.

Anyone recall their installation and what colour of wire (or even what harness) they tapped into? I can put a tester on the harness until I find a 12V acc only line.

I also am looking for where to tap in the Reverse lights. Since I don't need to open the hatch up, would prefer to tap into the harness somewhere inside the cabin. I heard that above the third row seating the harness for the hatch runs... anyone have any advice on what to look for when I open that up? remember the reverse lights wire colour?

Removing ceiling panels could have a low WAF (Wife Acceptance Factor) so I am trying to minimize time in the cabin and go at it with a plan.
 
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