Monday, August 13, 2007

Reefer Madness

We are still at the Santa Fe Elks, for one final morning. Shortly, we will load up the bikes and hit the road.

As Louise has already mentioned, yesterday the lodge had its annual picnic. Since we've known about this since Wednesday, we knew that if we were still here Saturday night, then we would be here at least till today, since we would not be able to maneuver Odyssey through the picnic arrangements.

I spent all day Saturday wrestling with the fuel system, so we ended up staying the whole weekend. The fuel line, which had to come off first in order to get to the fittings I wanted to clean, tighten, or replace, was torqued on so tight that the two of us could not budge it with the pair of Crescent wrenches we had. So off I trudged to Lowe's (no dice) and Sears to get better tools. They were pricey, but I am now the proud owner of a Craftsman 1-1/4" combination wrench, which is too big to fit in my toolbox, but makes a handy self-defense item lying around in the cockpit. I also bought a Craftsman 1-1/16"\1-1/8" open-end, and, at Lowe's, a 6" turnbuckle. By aligning the two wrenches just right, I was able to use the turnbuckle as a come-along to loosen the fuel line. The mechanic who put it on, Vicente, is a huge, strong guy, I would guess weighing in at over 330. I couldn't just put my own weight into it, as that was just loosening the fitting next to it.

In any event, I managed to get the fuel line off, and remove all the supply fittings and the check valve from the water separator, as well as the drain fitting at the bottom. One of the fittings was damaged -- it had been tightened down to the point where the end of the fitting bottomed out, and on a pipe-taper fitting, that's sure to be leaky. I replaced it, re-doped and re-tightened everything, and cleaned and inspected the check valve. I also put an elbow in on the drain fitting, so it won't dump right onto the fan belt any longer. I'm hoping this has cured the fuel delivery problem, but we won't know until we get the coach out on the road today and back under load. A 20-minute static test at high-idle did not reveal any problems.

Yesterday we had lunch at the lodge picnic, where we both sampled local delicacy chicaronnes for the first time. They tasted great, but you can hear your arteries hardening as you swallow -- this is basically deep-fried pork fat, with just crumbs of meat involved. Fortunately, there was also some barbecued beef brisket, hamburgers, and several side dishes. Lunch was our main meal yesterday, and we just had a light snack at dinner time.

After lunch I was in the mood to tackle another project, and this time I dug into the fridge. Our refrigerator is a 12/24-volt (DC), high-efficiency electric model, targeted at the marine and alternative energy markets. We love it, and it has served us well, but it has had an annoying habit. In order to protect the battery bank, the fridge automatically shuts down at 22.8 volts, and won't come back on again until the battery voltage rises above 24.2 volts. While, on the surface, that seems reasonable, in practice it means we can not get all the energy we'd like out of our battery system. We've had to set the cut-out and charging parameters on our inverter/charger to ensure that the voltage can't really drop below 22.8 without the charger coming back on.

Nevertheless, there are times that this does happen, as voltage reaches the cusp. Specifically, when voltage is down around 24 volts, and the air compressor comes on, voltage drops below 22.8 momentarily. It rises very quickly to 23+ after the start-up surge passes, so the inverter doesn't think it needs to start the generator for charging (the voltage has to remain low for at least 15 seconds for this to happen), but, in this brief moment, the fridge has quit working. Since the voltage is below the fridge's cut-in setting, the fridge now remains off until either the batteries drop below 23 (and that can take a long time, if little else is running), or we happen to notice. And noticing is nearly impossible -- the fridge doesn't have any obvious indicator of being on or off (and the light that comes on when the door is opened works regardless).

Nothing in the documentation that came with the refrigerator, a NovaKool RF7500, indicated there was any way to change any of this. There certainly are no switches or settings, other than the thermostat. But the last time we had food spoil, I went on a witch hunt for ways to fix this, and discovered the manufacturer's documentation for the high-efficiency, low-voltage compressor, made by Danfoss. Lo and behold, the circuit board on the compressor has terminals where (1) a resistor can be attached to change the voltage cut-out/cut-in settings, and (2) an LED can be attached to indicate the circuit board has detected a problem, including low battery voltage.

So yesterday we yanked the fridge out of its cabinet, for the first time in three years. After spending a good five minutes vacuuming the dust bunnies out of the enclosure (and the condenser coils, which should improve the efficiency), I attached the appropriate resistor to drop the cut-out to 21.8 (which made the cut-in 23.2 -- they can't be adjusted independently), and also installed an LED in the front bezel of the fridge and ran wires back to the circuit board. Today I ran down to Radio Shack and picked up a rheostat to test the whole arrangement, and the indicator light works perfectly, although finding the exact low-voltage cut-out with this arrangement is tricky. We'll have to see how it works out as our actual battery voltage drops -- at least now we have an indicator so we can monitor the situation. I may need to get back in and change resistors one more time.

It's still a furnace east of here, so today's plan is to drive around town until we're comfortable that the fuel situation is resolved, then head north to Taos. It's just a couple degrees warmer there, but still acceptable during the day and wonderfully cool at night.

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