Measure water used

[Kwest364]

I bought a prebuilt skoolie. It's got 100gal fresh water, 55gal grey and 55gal black water.

What's an easy, cheap, and simple way to add a flow meter of sorts to my current water system? I'd like to measure:

1. How much water has left my 100 gal fresh water tank

2. How much water has gone into my black and grey tanks




-Is there a smart place to add such a meter? Ie. Just downstream of fresh water exit nozzle or after my shutoff valve would make sense I suppose

Recommended brand/type of meters?

Will it drop water pressure at all?

How do I install it? Cut pipes and glue it mid pipe I guess?

[Tejon7]

Interesting idea. I'd never considered trying to measure flow to and from the tanks. The conventional approach is to measure tank levels directly. If that is something you'd be into, the Seelevel system from Garnet seems to be the simplest retrofit solution. It has external tank level sensors that stick to the outside of your tanks, so no new plumbing required. The basic Seelevel kit is around $200, so it doesn't exactly fit your goal of a cheap solution.

[Kwest364]

I want to be accurate in knowing when the black/grey tanks are full, mostly. And knowing what my general water usage is like for things like showers and dishes. Easiest thing I'd do is look at the tanks, but the black and grey are colored black, unfortunately.

[rffffffff]

Depending on your technical aptitude they sell external water sensors on eBay for dirt cheap. Similar to the system described above just stick them on the outside of the tank at various levels, but you’ll have to design an led indicator system to make it work. Shouldn’t be too hard and it’ll save a ton.

Flowmeters typically are instant read but not cumulative and I would never put one in a drain line so the external level sensors make way more sense to me.

https://www.ebay.com/itm/1-2-5-10PCS...-127632-2357-0

[HamSkoolie]

There are also level metering systems that include the external sensors that use an inductive method of determining the level and are customizeable by just snipping tabs. The SYSTEMS come with the sensors AND the inside display units which will read in PERCENT. So a 100 gallon fresh tank at 50% means 50 gallons left. since your black and grey are 55 gal each percent is pretty darn close to 2 gallons.
You can find Juan on YouTube channel "beginning from this morning" discussing and installing them on his 1964 (non skoolie) bus.
They're THE way to go if you want accurate readings.

[Rucker]

Originally Posted by Kwest364

I bought a prebuilt skoolie. It's got 100gal fresh water, 55gal grey and 55gal black water.
What's an easy, cheap, and simple way to add a flow meter of sorts to my current water system? I'd like to measure:
1. How much water has left my 100 gal fresh water tank
2. How much water has gone into my black and grey tanks
-Is there a smart place to add such a meter? Ie. Just downstream of fresh water exit nozzle or after my shutoff valve would make sense I suppose
Recommended brand/type of meters?
Will it drop water pressure at all?
How do I install it? Cut pipes and glue it mid pipe I guess?

I have a vertical tube that is visible with a little floating ball. Low tech, but straight forward solution.
Google this topic and you'll find a couple of vendors with sensors that stick to the tank on the outside-those seem like the most robust solution, if you want an electronic solution.

[somewhereinusa]

I started designing a system that, using flow sensors, would measure the amount of water coming from the fresh tank then measuring the amount going to the toilet and calculating the difference to get amount going to the gray and black tanks. I had found a rough figure somewhere on how much extra volume would be needed to black figure because you are adding a small bit of volume to it. It should be pretty accurate as long as you reset when you dump. I have all of the needed sensors and micro computer but got side tracked as I often do.

[HamSkoolie]

Originally Posted by somewhereinusa

I started designing a system that, using flow sensors, would measure the amount of water coming from the fresh tank then measuring the amount going to the toilet and calculating the difference to get amount going to the gray and black tanks. I had found a rough figure somewhere on how much extra volume would be needed to black figure because you are adding a small bit of volume to it. It should be pretty accurate as long as you reset when you dump. I have all of the needed sensors and micro computer but got side tracked as I often do.

We have a concept in the business world.

"You need to track your costs to keep them under control but if you try to count every staple and paperclip your company will go bankrupt in short order."
The same applies to just about everything in life. For instance, look at skoolie solar systems. To get the most our of your panels they need to be kept pointed at the sun. Some people make elaborate tilting mechanisms to accommodate this. Others realize that they're probably not going to go up on the roof 4+ times a day to readjust the panel tilt and simply accept the loss of leaving them flat and instead adjust the size of the panel array(s) once, during planning, to account for the losses.
You need to know how much fresh water you have left and how much black and grey tankage but what level of accuracy is NECESSARY?

Are you in a skoolie to enjoy the trip and the scenery or to keep track of how many pints of black tankage remain?

[o1marc]

Having 2 tanks connected, one over the other, one inside, one outside. I know when the top one is empty, I still have 40 gallons left, time to refill.

[somewhereinusa]

Originally Posted by HamSkoolie

Are you in a skoolie to enjoy the trip and the scenery or to keep track of how many pints of black tankage remain?

Actually I enjoy tinkering and seeing if I can do/make things. I have tank monitors that work quite well and hardly ever look at it. In 10 years I hardly look at them and have never emptied the fresh tanks or come close to filling the gray/black.

[Rucker]

Originally Posted by o1marc

Having 2 tanks connected, one over the other, one inside, one outside. I know when the top one is empty, I still have 40 gallons left, time to refill.

Good point-I have a 25 gallon freshwater tank and a 40 gallon waste. I also have two 6 gallon jerrycans, so I know I'll be at capacity in the graywater when the second jerrycan goes in and I run out of freshwater.

[HamSkoolie]

Originally Posted by somewhereinusa

Actually I enjoy tinkering and seeing if I can do/make things. I have tank monitors that work quite well and hardly ever look at it. In 10 years I hardly look at them and have never emptied the fresh tanks or come close to filling the gray/black.

Well there's the answer....you enjoy it..... THAT's what life is about.
ME, I want to see things, but I'm definitely going to be fiddling with the onboard water reclamation system to maximize time between filling my fresh tank. If they can do it on the ISS, I should be able to do it in a bus....though the GF has said no to recycling all liquids....LOL

[CoffeeGuy]

The easiest solution for fresh and grey tanks (maybe black?) is a sight glass. It’s just a vertical tube that is connected to the side of the tank near the top and bottom. Whatever level the water is inside the tank, that’s what you will see in the sight glass, barring something clogging the ports.

The other thing you could do is a basic fuel sender unit like the ones used in gas tanks. It might take some rigging but I don’t see why it wouldn’t work.

The next idea that comes to mind is mounting load cells to each tank so that you can monitor the volume by weight. It would be more accurate when stationary than when moving, of course, and I don’t know how well they would hold up if they were constantly loaded.

Perhaps you could mount your tanks so that they are suspended at a high point when empty and lower progressively as they fill. It would be like a simple mechanical weight scale… sort of.

[Mr_Geenie]

This is the system I am using. The same one used in most RV and MH. RecPro sensors, probes and monitor panel.
The sensors go in 3/8" holes drilled into the tank. The waste tank probes stop working if they clog up with poo paper, so keep your black tank about 1/4 full with enzyme solution after every dump or you get the nasty job of changing black tank sensors or guessing when you are at capacity.

[HamSkoolie]

Use of inductive sensors eliminates the need to drill holes in your tanks, eliminates sensors being contaminated with tank contents, and can give much more accurate readings than the type of sensors that are installed through the tank wall and return readings typically of 1/4, 1/2, 3/4, full.
Check out "Beginning after tomorrow" YouTube building Juan and family. This is what they installed and it's far superior.

[Mr_Geenie]

Originally Posted by HamSkoolie

Use of inductive sensors eliminates the need to drill holes in your tanks, eliminates sensors being contaminated with tank contents, and can give much more accurate readings than the type of sensors that are installed through the tank wall and return readings typically of 1/4, 1/2, 3/4, full.
Check out "Beginning after tomorrow" YouTube building Juan and family. This is what they installed and it's far superior.

I work at an RV dealership, and my bus is being built with other people's warranty replacement parts.
A Jayco worker used 1.75" screws instead of 1.25" screws on the floor, so my new-to-me fresh water tank had a row if holes in the top. 20 minutes with a plastic welder and some PE rods got me a brand new tank. It already had the holes drilled for the monitoring system.

They shipped us a 40 gallon black tank instead of a 80 gallon on a warranty replacement. They told us to "dispose" of the wrong one because of the cost of shipping. It got strapped under my bus.
$640 tankless propane water heater had a copper line blow out. They shipped us a new one, the local AC teacher at the community college welded (brazed, I think is the correct term) the pipe for me at no charge.
A customer didnt like the color of his fold down stairs, and ordered a new one. Now my rear door has fold down stairs with adjustable length legs. A customer forgot his 35 foot long 50 amp power cord. Called us back and said he bought a new one, throw it away. So I decided to go with 50 amp power supply since I was given a $350 power cord.


Make friends with the lot porter and parts manager at your local RV dealership. A LOT of really expensive parts get theown away that are super easy to fix.

[bus-bro]

I guess someone has to deal with all the throw-aways, but why can't that someone be me.

[TheArgobus]

I built a flow meter on my bus that does exactly what you say, you really don't need to know any coding if you get the same components and copy/paste my code:

https://theargobus.blogspot.com/2020...flow-rate.html


I have a sensor in the vent line that, when water touches it, sets the gallons remaining variable to 40, and then simply measures how much water flows out of the tank and subtracts that from 40. I have a simple 7-segment display screen that tells me how much is remaining, what the flow rate is, and how full the tank is as a percentage.

[somewhereinusa]

Great, I'm working on some other projects just now but will take a look soon.