[font size="3"]For those considering installing a SeeLevel tank monitoring system I offer some recommendations from my experience.
First, since all three tanks are short and shallow, use the 710JS sensors vice the standard 710ES. They are the same price if ordered from RVupgrades.com and provide greater resolution and accuracy. Use them in their uncut 6" length.
Second, position the waste tank sensors as close as physically possible to the top tank edge. You're more interested in when the waste tanks are close to full. If you follow Garnet's recommended 0.5" spacing you end up with a premature 100% reading. My first installation of a 710ES on the gray tank down 0.5" from the top registered 100% at 22 gallons. This meant I really had 6-8 gallons available but no indication of exactly how much. That's the difference of a dish washing or a couple of showers.
Third, position the FW sensor close to the bottom of the tank. You don't really care when you just filled the tank, but you don't want to start a shower with one usable gallon left. I define the "bottom" of the FW tank as the residual water level when the pump stops pumping. Some experimentation of placement using duct tape is invaluable before permanently adhering the sensor. You only get one shot at this.
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The graphs show the present installation for Fresh and Gray tanks. The green curve shows the effect of replacing the original 710ES (centered) with the full length 710JS very close to the top. Positioning and trailer leveling is extremely critical. I could have moved the gray sensor even higher, but working with the adhesive backed circuit board in the tight place is not easy. There is a similar chart for the black tank, but that's a different story.
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I plan on doing this upgrade at some point. I'll be coming back to this for sure! Thank you for sharing the info...
Charlie - I've thought about getting a SeeLevel system but have one reservation. Perhaps you can address it from your experience.
My tank situation is not typical. I had the factory install a Thetford cassette toilet (their first) instead of the conventional toilet & waste tank. If I were to invest in a SeeLevel system I'd certainly want to install a sensor on the cassette tank. I'm pretty sure the 710JS sensor would work. The tank slides in & out on rail like sliders in the recessed housing. I could mount the sensor so it wouldn't be affected by the sliders. The reservation is only about the connections between the sensor and the rest of the wiring. I assume there is some form of quick-connect plug thingie you use to connect a sensor. When used with a cassette tank the implication is every time the tank is full I'd need to 'unplug' the sensor to allow the tank to be removed for dumping. That clearly would necessitate relatively frequent disconnect/reconnects compared with how the system is typically used. I wonder if the standard 'plugs' would stand up to that kind of use as they likely weren't designed for that many cycles. Any thoughts would be appreciated.
I suppose the connections could be swapped out for a suitable plug set designed for high frequency. I'd imagine there has to be some plug system out there that would be suitable -- I just don't know where to find such a thingie-ma-do.
Edit: I just thought of another thing that might dampen my potential application. When you first install the system does it have to discover the sensors and calibrate itself? If so then I suppose every time I unplug & replug in the cassette the system would need to do the setup all over again. Would that be a simple no-brainer kind of thing or a possible problemo?
[quote source="/post/20938/thread" timestamp="1462226537" author="@peislander"]Charlie - I've thought about getting a SeeLevel system but have one reservation. Perhaps you can address it from your experience.
My tank situation is not typical. I had the factory install a Thetford cassette toilet (their first) instead of the conventional toilet & waste tank. If I were to invest in a SeeLevel system I'd certainly want to install a sensor on the cassette tank. I'm pretty sure the 710JS sensor would work. The tank slides in & out on rail like sliders in the recessed housing. I could mount the sensor so it wouldn't be affected by the sliders. The reservation is only about the connections between the sensor and the rest of the wiring. I assume there is some form of quick-connect plug thingie you use to connect a sensor. When used with a cassette tank the implication is every time the tank is full I'd need to 'unplug' the sensor to allow the tank to be removed for dumping. That clearly would necessitate relatively frequent disconnect/reconnects compared with how the system is typically used. I wonder if the standard 'plugs' would stand up to that kind of use as they likely weren't designed for that many cycles. Any thoughts would be appreciated.
I suppose the connections could be swapped out for a suitable plug set designed for high frequency. I'd imagine there has to be some plug system out there that would be suitable -- I just don't know where to find such a thingie-ma-do.
Edit: I just thought of another thing that might dampen my potential application. When you first install the system does it have to discover the sensors and calibrate itself? If so then I suppose every time I unplug & replug in the cassette the system would need to do the setup all over again. Would that be a simple no-brainer kind of thing or a possible problemo?[/quote][font size="3"]PEI,
An interesting problem. My first concern would be whether the sensor would work properly on your tank. The sensors were designed for the standard RV Polyethylene or ABS tanks about 0.25" thick. I'm not familiar with your tanks, but I'd think if they're not too thick, and are non conductive with no metallic coating, they might just work. I'd call Garnet, either in Alberta or Texas, and ask. They've been pretty good at answering questions for me.
As shipped the sensors have ~8" pigtails with no connectors. The display is similar so wiring is up to the installer. I wired using crimp automotive connectors, leaving enough slack to permit removal and replacement if necessary. Your application would require a two conductor polarized connector that can withstand repeated engagements. A Molex or Anderson connector or some quality audio connector like a 3.5mm headphone connector might work, depending on the environmental exposure. If the connector can be located where it isn't exposed to rain, salt, rocks, etc. it should be easy. The sensor itself gets protected by applying a spray coating of rubber automotive undercoating material. Works great.
Each sensor is coded as to where it will be located by cutting off corners of the circuit board. Once done the sensor can be disconnected and reconnected without calibration. I purposely tried this while replacing one sensor just to see. It worked. There are error indications and diagnostics to warn of open, short, or high resistance connections. Seems well thought out. The only additional calibration I did was a one time graph of indicated percentages vs real world. Handy for us techies.
Let me know what you're thinking and if I can add anything more.
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Thanks Charlie!
One thing the cassette toilet system has going for it is the tank fits into a dry enclosed compartment. (It is relatively civilized arrangement - you don't need gloves and the hands don't get dirty). The dry compartment would mean that any wiring connectors would not need to be waterproof. I like the idea of using a connector like a male/female headphone jack.
If I proceed I will confirm the suitability of the sensor to the relatively thin walled tank. A couple of years ago when I priced the SeeLevel model that displays the levels continuously, it was very expensive. Too expensive to justify then - especially with my concerns that it might not work. Now with greater confidence that it will work I might be tempted to look into the system again.
[quote source="/post/20945/thread" author="@peislander" timestamp="1462271037"]Thanks Charlie!
One thing the cassette toilet .............................
A couple of years ago when I priced the SeeLevel model that displays the levels continuously, it was very expensive.
[/quote][font size="3"]It sounds like you were looking at the 714 system, which is more expensive. The more common and less expensive system is the 709 series. It's 1/2 or less the 714 price. It requires a button push for each reading, but does go off automatically. Saves the battery when off the grid.
Don't pass up the chance to buy a rare "designed and manufactured in Canada" product. You can probably buy it north of the boarder to escape outrages prices you guys pay for "imports". And check with the factory: they may have a sensor you could mount on the outside wall to measure snow depth around the mighty 11.
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I'd recommend this type of connector. This has 16 gauge wire, which is more than is needed, but it's rugged, easy to use, and should take years of plugging and unplugging.
http://www.amazon.com/Hopkins-47965-2-Pole-Flat-Extension/dp/B0002Q80RW
[font size="3"]Merlin's Hopkins connector will work fine, a[/font][font size="3"]nd the price is within my range![/font][font size="3"] Be sure to polarize it such that it cannot short the hot side of the display harness to ground when disconnected.
That said, I like the idea of the headphone jack, either 1/8" or 1/4". They are designed for years of in/out cycles. Just ask any kid with an iPhone. And, if layout permits, the female jack could be mounted in a wall allowing one handed connection.
FEDERAL WARNING: Do not plug cassette into iPhone. Androids? maybe OK.
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Gives a whole new meaning to iTunes. :-X
Same caveats apply; put the female connector of the headphone jack on the display side so nothing gets shorted when unplugged.
Quote from: @sandroad" source="/post/20953/thread" timestamp="1462298868Gives a whole new meaning to iTunes. :-X
Same caveats apply; put the female connector of the headphone jack on the display side so nothing gets shorted when unplugged.
You guys are great! The tips about polarity and using the male connector for the sensor make so much sense yet I know I would never have thought of either.
The tips may also come in handy with another project I'm planning to do soon. --- I have one of those little made-in-Canada 'Koolatron' 12v thermoelectric coolers that heats or cools. It is the 29qt size. It sucks as a cooler but I had what I hope will be a great idea. I'm going to turn it into a temperature-controlled environment for making yogurt, cheese, tempeh, or kimchi! Those processes ideally require a environment within a few degree temperature range. On amazon I ordered a 12v digital thermostatic controller. It was like $6 shipping included -- from China! It includes a temperature probe that I'll put in the cooler. I will use controller to control power to the koolatron's thermoelectric 'heater' to keep the 'box' at the desired temperature for fermentation etc. Homemade Cheddar is within the realm of possibilities! (Gouda is good-a but chedd-a is bett-a). Cured sausage is another possibility! There are online retailers of all kinds of starter cultures. I'm hoping it will prove to be a great culinary adventure!
I may need to get a 710js for my GW tank, because it reads 100 too early. My FW is fine, it shows a reading of 19 at empty, a bit high but better to have a reading I can work with than to hit 0 too early.
[font size="3"]The early 100% reading on the gray tank is more an issue of placement than sensor type. You have to get the sensor as high as possible, even higher than the recommended 1/2" from top. While you're at it you might as well get the 710JS for the added resolution, but placement is key. Try using the duct tape trick before you install it permanently.
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[quote source="/post/21758/thread" author="@charliem" timestamp="1464633879"][font size="3"]The early 100% reading on the gray tank is more an issue of placement than sensor type. You have to get the sensor as high as possible, even higher than the recommended 1/2" from top. While you're at it you might as well get the 710JS for the added resolution, but placement is key. Try using the duct tape trick before you install it permanently.
[/font][/quote]I've been calibrating the SeeLevel sensors in prep for our trip west next month. So far in our shorter trips, actual tank numbers didn't matter, but in a longer trip we want to know what's going on. Grey and fresh tank sensors are working ok and calibrated fine.
I've discovered our black tank is only 22 gallons to full (instead of the advertised 28) and the 710ES sensor that I originally installed at the very top of the tank with 3 pads active reads 67% when the tank is full. I'm not sure why that is; it seems like the sensor should read 100% when full. There is, however, about a 1 inch gap between the bottom of the sensor and the bottom of the tank. That didn't matter, since I don't care about the first few gallons in the black tank. I have the sensor installed on the road side of the tank because that's the only side that doesn't have a 1 inch thick lip at the top. On that side, the tank is pretty short; only 5.5 inches high.
My first question is whether the 710JS is simply shorter (fewer sensor pads), or if it's made differently than the 710ES and would read more accurately when the tank is full.
My second question is whether that 1 inch thick lip around 3 sides of the black tank top makes it so the SeeLevel sensors can't read "full" accurately. Does anyone have a SeeLevel sensor installed so that black tank reads 100% when it's actually full?
[font size="3"]The definition of full on the black tank is a bit problematicl. On mine the apparent full point reads 88% on the SeeLevel. My 710JS is on the end away from the drain. I guess that's the curb side on the 21RBS. On that side I could get it close to the top. That's also the shortest side of the tank so the 710JS works nicely. Due to the slope and shape of the tank there is a considerable dead zone from empty, but as you say, you really don't care about that end of the range. The 710ES is longer, but the sensors are further apart so the resolution is not as fine.
At 88% the toilet begins to burp when flushed. This is due to air and gasses becoming trapped in the toilet throat and the vent has become submerged in fluid. I think this is similar to the gray tank problem we've had. I have seen the SeeLevel go to 100% without overflowing so I know the gauge is sensing the full tank, but by that time the burping can get messy. When backflushing the black tank I close the drain and watch the SeeLevel until it hits 82%. That's time to head out and open the drain. I have a label next to the monitor panel reminding me of the 88% limit. Someday, with a clean tank, I may rerun the calibration and really see what it does at 90-100%, but for now it's OK. The black tank being what it is I need to start paying attention when it gets close to 90% anyway. A full gray tank is manageable; a full+ black tank is not (puke) .
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Thanks, that helps a lot. I'm going to order a 710JS sensor strip from RVUpgrades and do a better job of placement. Hopefully I can get a more accurate reading when close to full.
[font size="3"]Merlin,
Attach the sensor with two strips of duct tape to try out placement. You'll learn a lot. You only get one shot with the supplied 3M super adhesive.
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Yup, I learned it cost $51 for a new sensor each time I screw up. I paid some "tuition" on this by not taking the "tape first" advice.
As a relevant aside, in my calibration of the fresh tank, I'm sorry I put the sensor strip all the way to the bottom of the tank. I should have accounted for the fact the pump pick-up leaves an inch of water in the tank. As a result, the sensor reads 19% when the pump will no longer hold a prime. I wish I had mounted that sensor with the pump pick-up point as the "bottom" of the tank.
[quote timestamp="1465503067" source="/post/22034/thread" author="@sandroad"]As a relevant aside, in my calibration of the fresh tank, I'm sorry I put the sensor strip all the way to the bottom of the tank. I should have accounted for the fact the pump pick-up leaves an inch of water in the tank. As a result, the sensor reads 19% when the pump will no longer hold a prime. I wish I had mounted that sensor with the pump pick-up point as the "bottom" of the tank. [/quote][font size="3"]Yep. In an unusual flash of brilliance I let the pump run dry, then positioned the sensor just a bit higher. But I did pay some dues on the gray tank. Education is always expensive. I just try not to pay twice for the same lesson ;) [/font]
My fresh also reads 19% at the point where it starts sucking air. I don't see any need to fix that. That's a known read point I can work with.