gen2 tow package trailer power

I just got home from our maiden voyage with our new Casita...



we had a great time. the tacoma 4x4 access cab trd offroad hauled it very smoothly, using a weight distributing hitch.

The trailer electrics seem to be working perfectly, voltage monitor shows it at 12.7V when its running on battery (right after charging), and if I either connect it to 120VAC or my running tacoma, the voltage shows 13.8V if its fully charged (or charges til it gets there, hah!).

this trailer has a little dometic 3-way fridge. I prechilled it on 120VAC, for several days before we left, switched off the AC, unplugged the house power, plugged the trailer into the truck, started the tacoma, saw proper charging voltage on my monitor, and switched on the fridge to DC, and immediately the voltage dropped to like 12.7V. huh. we drove a few hours, stopped for gas, and I checked the voltage with the truck running, it was down to 12.1V, ouch!, thats dead battery land.

switched off the DC fridge, and drove the rest of the way, we had power at our site, so could use the AC fridge all weekend. (fridge works fine on propane too, now that I know how to light it, hahaha).

my question is, how much DC amps can the tacoma's trailer hitch output?

 

Are you taking about the 'wall outlet' in the truck bed?

 

no, I'm talking about the 12VDC jack output on the 7-blade trailer ... with my casita plugged into that, and the truck running, it couldn't keep the trailer battery charged when the fridge was running on DC.

 

ok, the fridge in DC mode is rated at 12V 15A... I guess thats just more current than the hitch plug and truck harness can deliver, but I do plan on poking around with my volt meter and determining where the voltage drop is.

 

Voltage drop is probably in the gauge wire (plus length) that is run back to the trailer connection.


A 15 amp load will see a voltage drop of 1.224 12 AWG (10 AWG will see a drop of 0.77 volts)

That would be using 25 ft run of wire.


You would probably need to run a 30 amp run to the trailer and then maybe get around 25 amps with the loss of the wire.

You might be better off to just run 2 batteries in the trailer for refrigerator use. Even two 6 volts in parallel to gain more reserve. You could just run it off the propane and not have to deal with it.

 

there's no room in the Casita for a second battery, its a tiny trailer, every cubic inch is carefully allocated. btw, if you used 6v batts, you'd have them in SERIES, not parallel

I need to figure out how I can measure the voltage at the trailer hitch connector when its plugged in, those blade connectors aren't very ammendable to snaking thin wires around pins to probe with the meter. unluckily, I can't readily access most of the wiring inside the trailer without ripping up the floor, and/or taking the a/c unit out. I did determine that with the tacoma engine running, I have 14.10V at the taco battery, and 13.8V at the trailer battery terminals on its power panel when the fridge is off. With the fridge on, the tacoma battery read 14.07V, and the trailer power panel battery termianls were 12.5V (and dropping), so now I want to see how much of this drop is on the tacoma side of the harness...

 

tacoma alternator->battery wiring
http://www.customtacos.com/tech.old...6toyewd/06toypdf/ewd/2006/tacoma/h/em01d2.pdf

tacoma factory trailer harness wiring
http://www.customtacos.com/tech.old...toyewd/06toypdf/ewd/2006/tacoma/h/em01d40.pdf

note the trailer power runs through a 30A fuse "BATT CHG" and a relay (also BATT CHG).

main fuse panel (in engine compartment just aft of the battery) layout:
http://www.customtacos.com/tech.old...6toypdf/ewd/2006/tacoma/f/em01d0up.pdf#page=5
(page 5, labeled page 24, if your PDF viewer doesn't take you there directly).

relay marked *15 and fuse marked *6

me, I just plug a battery monitor into the DC connector under the rear shelf unit in my Casita, start the truck, and verify I'm seeing charging voltage (typically ~ 13.8V if the battery is fully charged)

 

The trailer 7 pin connector only provides a trickle charge to maintain your battery.Not enough for running anything.Have to run it on propane or turn it off when driving.

 

um, on my gen2, BATT CHG is fused at 30A, thats way more than a trickle charge. it will take my Casita's group 29(?) from 80% discharged to 100% charged in a few hours of driving. there's just too much voltage drop in the wiring to do that while running the fridge on DC...

 

Just because the circuit is fused at that doesn't mean it will supply that.The salesman told me when I bought my trailer that if I ran the batteries dead in the bush I could close the slide or the awning by pluging in to the truck and running it while packing up the rig.Doesn't work.The supply from the truck won't run anything worth a damn and certainly not the fridge.but if you figure out how to do it ,let me know.
As an aside,I asked these questions specifically of the salesman and the orientation rep at the dealer when I bought the trailer.Both quite simply lied for the sale.In three years no one has told me how to get more power from the truck.

 

what probably is needed for the tacoma is heavier gauge BATT CHG wire from the under-the-hood relay/fuse panel to the trailer connector, like 10 gauge. the wiring in the trailer is a big issue, too. OTOH, you don't want TOO much current flow, or you could drag the tow vehicle's system voltage down lower than its happy with.

but, with a nearly dead trailer battery, whats going to happen is that battery is going to suck up every amp it can, until its charged, so the trailer system voltage will be dragged way down until that battery recovers.

I'm surprised those trailer slideouts don't have a manual backup system where you connect a crank to them, and hand crank them in, albeit slowly. I've noted that all my various european cars with sunroofs provide that, usually in the trunk, sharing the scissors jack handle as the crank.

 

The manual cranking on the slideout is pretty straight-forward.but the power awning you have to dis-assembly a portion of the motor.my generator cost less than the dealer cost to re-assemble the awning.generator on the plug-in runs the slides easy.

 

reminds me why when we spend the last year looking at small campers I was pretty much dead set against slideouts just seemed like one more expensive thing to break, or to leak, or whatever.

 

btw, re: my earlier question to myself abou tthe voltage drop in the tacoma vs the voltage drop in the casita trailer... its split just about 50-50 as I got into the back of the trailer connector on the tacoma, and measured the voltage, with the truck idling, and the fridge on DC... I had 14.1 at the truck battery even when the tacoma is idling, so the truck alternator and battery is fine, I had low 13V at the trailer connector, and mid 12V (and dropping) at the casita battery connector, so I'm losing some in the truck, and some in the casita wiring, between the two, the voltage drop is bad enough that the fridge is running down the casita battery.

I probably should do that test again, and do it for an hour, taking voltage readings every so often at both places, and write them down, so i can graph it. I do have two DVMs that read quite close, so with clip leads I could probably leave them both connected, which would make recording their values easier.

meanwhile, I've given up entirely on using the fridge on DC. it stayed lit for 1000 miles of driving last week, and I ran it on AC when I had generator power during the heat of the day (we shut off the generators at night)

 

I know what you mean about the slide-outs.I like the fiberglass egg-trailers but I couldn't swing the cost.the trailer I got was a little bigger but was still only 2/3 the price.Wanted an Escape 19 but with options was over 30000. Canadian.wasn't impressed with the small water tanks either.everyone that has one raves about them.On the fridge issue I tend to run it for a day before leaving and load it with frozen water bottles when I go to help keep it cool longer.happy camping.

 

yeah, I prechilled for several days, but it was full of pellegrino water, lemonata soda, beer, and hard cider, along with some food, when I left, and I had a 7 hour drive the first day. propane kept it cold enough.

i got my casita 16' for $12000, a few years old and like new. its cozy for two, not suited for kidlets, of course.

 

how big are your holding tanks?the older escapes only had 5 gallon black and grey tanks and a six gallon fresh water tank?they are larger on the newer trailers but I was worried the smaller tanks would be a problem for us on an older trailer.wetry to camp a week at a time .weekends are too short.

 

the casita 16 deluxe has a 15g black tank, and 13g grey holding, with a 16g water tank. the Casita 17 deluxe optionally gets (HIGHLY recommended for boondockers), 32g grey and 25g water.