More data re solar panels and running the fridge on 12V

[paulk]

Originally Posted by cpaharley2008

Welcome PaulK to our little world. You lost me above in your description other than it is a better controller than the stock one. What are the prices and installation procedures?

They're fairly expensive, which is why they seem to still be fairly niche.

The Ctek D250S DUAL, which I do not recommend unless you don't care too much about your solar input, is $239.97 on amazon

The much better Redarc BCDC1225-LV seems to not be sold in the USA, but you can import it easily. Redarc themselves will ship it to the USA, and they sell it for $659.93 Australian Dollars. I've seen it new on ebay for $390 Australian Dollars. That would make it $300 USD at today's exchange rate.

Installation should be fairly easy. It needs to be close to the battery, just like other chargers, so I'm putting it under the dinette seat. It should be secured to the floor or something else solid.

For the alternator only installation, just disconnect the +12 volt wire coming from the vehicle and attach it instead to the input on the DC-DC charger. Attach the output of the DC-DC charger to whatever the +12 volt line was attached to originally. Attach the DC to DC unit's ground to ground. Done.

Installation for solar requires an additional SPDT relay to switch between the solar input and the alternator input. Attach the relay's switch controlling terminal to the +12 volt wire from the vehicle, so that it selects the vehicle's alternator input whenever the vehicle is providing power. Attach the +12 volt line to input #1 on the relay. Attach the solar cable to input #2 on the relay. Connect the common output of the relay to the DC-DC charger. Remove the GoSolar charge controller since the solar cells attach directly to the DC-DC charger. Done

The Redarc manual accessible from their website has some visual diagrams showing various installations. I omitted a few minor details above for clarity, but those details are in the manual.

Redarc also sells a Relay that you can use, but these are commodity items and Redarc charges $100 for that component. I'd just get one from a hardware store.

In addition to the above, I'd recommend getting a Trimetric as neither the Redarc nor the Ctek has a display to show solar amps. A trimetric can show that after deducting the trailer loads, which you could argue is a better metric anyways.

So yes, in summary these are expensive units. They're still less expensive than a $800 Honda 1000 watt generator though for someone who is planning on only occasionally using one, and the 20% or more improvement in solar should be valued at about $170 considering a 160 watt solar panel is $850 when installed by ETI. I should mention though that a generator will charge you batteries a lot faster, so this only applies to very occasional users.

[paulk]

Originally Posted by yardsale

Escape recommended running #10 ground wire but my local installer said it wasn't possible--should have persisited. I think our fridge draws about 4 amps per hour as I was able to run the fridge on 12v during a sunny day when my 160w panel was producing that much power.

Not sure which fridge you have, but the 4.3 cubic foot fridge that ETI is currently installing in the 17 foot models as an upgrade is the Dometic RM2454, and Dometic's "DIAGNOSTIC SERVICE MANUAL" manual says on page 11 that it uses 15 amps

Source:
http://www.dometic.com/QBankFiles3/E...nual_17606.pdf

[paulk]

Originally Posted by yardsale

Escape recommended running #10 ground wire but my local installer said it wasn't possible--should have persisited. I think our fridge draws about 4 amps per hour as I was able to run the fridge on 12v during a sunny day when my 160w panel was producing that much power.

Not sure which fridge you have, but the 4.3 cubic foot fridge that ETI is currently installing in the 17 foot models as an upgrade is the Dometic RM2454, and Dometic's "DIAGNOSTIC SERVICE MANUAL" manual says on page 11 that it uses 15 amps. I'd post a link, but my posts with links seem to not be getting posted.

[Losangeles]

Originally Posted by paulk

Not sure which fridge you have, but the 4.3 cubic foot fridge that ETI is currently installing in the 17 foot models as an upgrade is the Dometic RM2454, and Dometic's "DIAGNOSTIC SERVICE MANUAL" manual says on page 11 that it uses 15 amps. I'd post a link, but my posts with links seem to not be getting posted.

if i recall Paul... you need to make about 15 posts without links before you can include links... to reduce the # of spammy posters.

[gbaglo]

Post the link anyway. A moderator will be alerted and will approve it when they notice it.

[paulk]

Originally Posted by Losangeles

I had my local (expert and trusted) trailer guy run #10 wire from the engine in our SUV to the power connection at the back of the tug.

(When I finally got ahold of the right tech at Acura, they admitted that the super thin wire they use to the hitch power connection is only sufficient for trailer brake lights)

Adding the #10 wire to the tug made a HUGE improvement. We run the medium sized Casita fridge freezer when towing on 12v, not propane (don't start that debate here)

and with the "factory tow" kit from Acura (before the $100 mod) we'd arrive after 1 day of towing with 2/3 depleted Casita battery.

after the #10 wire was in, we'd arrive with a FULL Casita battery. Makes a huge difference when boondocking!!!

It might be possible for a trailer with a battery in the front to not discharge while driving with #10, but from the above discussion it seems that a real world drop of 1.75 volts is occurring to a rear trailer battery, so even with #10 you should expect some drain on an Escape with the batteries in the rear. 13.2 volts at the alternator will get dropped to 11.5 which is going to cause the rear battery to kick in and provide some amps.


A quick calculation assuming 60 feet of round trip #10 -> 40 feet on the +12 volt wire and 20 feet on the ground wire (which is partly connected through the frame) leads me to a voltage drop of:


V=IR
V=15 amps * 0.06 ohm
V=0.9


Which is better than the real world figure above, so YMMV.

[Losangeles]

Originally Posted by paulk

It might be possible for a trailer with a battery in the front to not discharge while driving with #10, but from the above discussion it seems that a real world drop of 1.75 volts is occurring to a rear trailer battery, so even with #10 you should expect some drain on an Escape with the batteries in the rear. 13.2 volts at the alternator will get dropped to 11.5 which is going to cause the rear battery to kick in and provide some amps.

all i can say is our experience with before tug mod and after tug mod was night and day.

[Brian B-P]

Originally Posted by yardsale

I think our fridge draws about 4 amps per hour as I was able to run the fridge on 12v during a sunny day when my 160w panel was producing that much power.

It's not clear what "amps per hour" is intended to mean, but it could be:

• 4 amps - not likely, since that's only 48 watts (at 12 volts, a bit more at the actual operating voltage), which is not much for this type of refrigerator; the 15 amp value is more likely.
• 4 amp-hours per hour, or an average of four amps (and more than 48 watts, matching the panel output) while the heater cycles on and off - more likely, but the wiring needs to handle the actual current while the refrigerator is running, not just the average.