Gerald55
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Re: Fridge cooling: coils or fins?
Chris Bryant wrote: The top condensor fins are the most critical. The more liquid ammonia you can condense out the more cooling you will have. The absorber coils do reject some heat, but that is not their real function. The unit should be baffled so that all of the air must pass over the condensor. Thanks! My fridge does have baffling, but it is focused on the absorber and stops before the condenser fins, so air can indeed avoid the absorber unit. I'll fix that.464Views0likes0CommentsRe: Fridge cooling: coils or fins?
Right, I'm planning on using all four fans to promote a good bottom to top flow, two in-between the vents, and two on the top vent to expel the hot air. I still kind of need to know what need to be cooled though, since it affects fan placement and baffling. In particular, the condenser fins at the top are poorly barffled and tend to be hot because they are located right at the top of the top vent. Fixing that requires some work. Work I want to avoid if what needs to be cooled is the condenser coils.464Views0likes0CommentsFridge cooling: coils or fins?
I'm making an extended trip into a hot area, and often my Dometic fridge does not cool adequately. It has no fans at the back to help cooling, and so I'm adding 4 thermostat controlled fans, as well as some baffling, to help. What is unclear to me is exactly what needs to be cooled. Many posts simply refer to "the coils" - but there are at two things which seem like they could use additional cooling: 1) The condenser at the top of the fridge. This is a set of heatsink fits on the pipe right after it comes out of the boiler. 2) The absorber. This is a set of large turns of the pipe forming coils, lower down (just above the tank-like absorber vessel at the bottom of the fridge). The absorber better fits the definition of "coils", but the condenser obviously seems like it needs to be cooled as it is heavily finned and is the hottest part of the fridge based on my non scientific tests. I can't figure out how to attach pictures (from mobile), but I'm working on it.3.9KViews0likes11CommentsRe: Annoying PWM sound from Xantrex inverter
CJW8 wrote: Think of a battery sense line as the same as a meter lead. Meter leads are very small wire and yet the meter reads very accurately. This is because there is no current flow. Some better charge controllers use this to sense the realtime battery voltage rather than just pull the voltage reading off of the controller output. Right, that makes sense. In some respects thought the controller-battery system is self correcting when it comes to voltage readings: when the battery is approaching float, the current is slowing and so the readings become more accurate even when taken from the controller output (since the main distortion in the voltage at the controller output is current induced voltage drop, as far as I know). While not ideal, my MPPT controller is connected to the inverter input for convenience. I have the same inverter as you and there is no noise...ever, no matter what stage the controller is in. Thanks for the data point! My noise may be related more to my particular wiring setup, than the inverter. I do notice a small amount of noise from the same battery/inverter area when I have my LEDs on PWM, and the solar controller is off. I even bought an oscilloscope to help narrow this down (and, well, because it was an excuse to buy an oscillscope). Then, I put the bed back on - I had to remove the bed in the back of my van to get at the installation area - and that muffled the noise to the point where I just don't hear it. Occasially when I open the back doors, which have a direct line of sight to the inverter, I hear the noise and am reminded of this thread I started and the oscilloscope I haven't unboxed yet :) As a final note, I installed an toaster oven in my rig as well. When I leave the oven plugged in, I often hear a buzzing from it, even though it is off. That seems to happen even when my solar is off, so I guess there is yet another noise source on the 120V lines.697Views0likes0CommentsRe: Where to buy crimped battery cable
Almost! The ones I was thinking of weren't braided though. From the same site I found this: http://www.gacopper.com/images/Jumper-1x6-GC-txt2.jpg which is along the lines of what I was thinking about. They call them "jumpers" but of course googling that just results in a million jumper-cable related results. Part way down this page you can see also what I'm talking about: http://www.sbsbattery.com/products-services/by-product/batteries/batteries-flooded-wet-cell-batteries/flooded-wet-cell-batteries-stt-series-flooded-2v-cell.html They call them: "solid un-insulated intercell connectors".565Views0likes0CommentsRe: Where to buy crimped battery cable
Thanks for all the suggestions. I called a few places and ended up going with a battery supply shop near San Diego. They cut to length, crimped and used heat-shrink between the lug and the cable casing. No solder. One problem was that according to the guy who did them, it's tough to get the length exact (I had measurements down to 1/4 inch), so he erred on the side of slightly longer, so most of the cables ended up about 1/4 inch longer than I asked for. The most problematic cables were 4.25" cables for a direct connection between lugs which ended up at 4.75". To use up the extra space, I had to bend the cables at almost 90 degrees, which was just barely possible (they were welding cable). I'm not happy that the cables will be under nearly constant strain, but those are the breaks, I guess. I was able to get a much cleaner and safer system than what I had before (with 4 AWG cable). BTW, I've seen lead acid battery banks where the terminals were connected not with cables, but with flat metal links that simply go directly from one terminal to the next (they must be of exact length). I couldn't find out what they were called or even if they are made commercially - perhaps they are just a homemade thing. Anyone know?565Views0likes0CommentsRe: Annoying PWM sound from Xantrex inverter
CA Traveler wrote: Filters are worth a try. See if you can locate someone with some in is junk box that you could try out. Is that something I can buy off the shelf, or do I have to build it? I've been googling "DC filters" and "low pass filters" without seeing much available to buy beyond some audio centric stuff. Whatever I put inline with the inverter/battery connection would have to be able to handle 200A.698Views0likes0CommentsRe: Annoying PWM sound from Xantrex inverter
MEXICOWANDERER wrote: I just snapped a giant DC line filter around a controller to battery line plus connected a 5uf electrolytic cap right at the controller to battery line. Things got awful quiet. Done at a rancho with panels and batteries. Now the lady is off Ruben's case and my case and she can watch her soap operas. Ojala gracias a dios! Thanks! Did you have audible noise, or was it interference showing up on your TV or elsewhere?697Views0likes0Comments
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Prefer to camp in a travel trailer? You're not alone.Jan 13, 202544,029 Posts
