Truly automatic fat sac filling

Has anybody figured out how to TRULY make fat sac filling automatic? Meaning; no guages, no overflowing out the side etc. I want to fill my fat sacs so, that I just hit a button and the pump shuts off automatically when they're full.
I'm in the process of redesigning my pump system for my over the tank fat sacs and I want it automatic. Just hit the fill button and I don't have to think about it again, no monitoring, no waiting for the overflow out the side etc.

A couple of thoughts:
1.) In line Current sensor on pump power - when pump starts to get some resistance from the sac being full it'll draw more current, when the sensor senses the rise in current, it shuts off the pump.
2.) An inline switch with the pump. When the fat sac reached a certain fullness it would contact the switch and shut down the pump.
3.) An optical switch to view when the fat sac has reach a certain height and broken a beam, kinda like walking into Radio Shack.

All of these options would have to be incorporated into some sort of circuitry to trigger the shutdown of the pump.

Has anybody done something of this nature?

Thanks,

Chris
Get the Grip you Deserve
www.wakejunky.com

another way you could do it is have it set on a timer. fill it once manually and use a stopwatch to time it, then figure out something to make it stop when it runs for that amount of time after you hit the button

I thought about the timer option. Problem would be that it may fill at different rates if you're moving or stopped. Also, what if the sac is partially filled already?

Chris
Get the Grip you Deserve
www.wakejunky.com

Hey Chris,

You could try a 'Bilge Alert' High Water Alarm made by Johnson Pump www.johnson-pump.com

Your "A couple of thoughts: 1.) In line Current sensor on pump power - when pump starts to get some resistance from the sac being full it'll draw more current, when the sensor senses the rise in current, it shuts off the pump."
Idea reminds me of what Mastercraft has done with their ballast this year.

I've thought about using either ultrasonics to measure ballast level or a pressure sensor. Automatic ballast systems would be much easier with hard tanks than sacs just because most of the liquid level sensors are designed to be mounted in something like a gas tank.

You could also use infrafred sensing to make distance measurements between the top of your vdrive compartment and the the sac. As the sac fills up the distance between the top of the vdrive locker and the sac will decrease. When the sac reaches a certain distance then shut off the pumps. You could do the same using ultrasound.

I just had mine done, but its only an overflow from my stock hard tank and then fills a 750 lbs bag. When it spits out the side, it's full and then I turn it off. Takes 11 minutes to fill 2400 lbs.

It seems if you make it anymore complicated than that, you may end up having more headaches with mechanical/electrical issues. i.e., like having more links in the chain... That's my .02. If you get it figured out, let me know. I may wanna go that route.

A 2 switch system would work.:
fill switch and a flow switch on the over flow/vent line.
A Switch for the drain with a nother flow switch on the drain.

I would recomend a delay switch in there as well to insure total fill/empty

In hindsight, a timer will be the best bet. But, it will only work on one time set--starting empty to total fill. That's how the new MC timers work. I'd give up on the expense and maintenance of specialty sensors, InfraRed detection, etc.

MasterCraft has already done it for 2007.

Chris,

This is what I was planning before I sold my 1995. Probably the easiest way to do it is to use a washing maching sensor. They open a relay when the tub is full. The way they work is pressure. As the tub fills the pressure on the fill line goes up. All you need to do is to T it into the fill line. I have a couple you can try in a box in the garage. Do you want me to sent them to you?

Mike

Toyota did it in '99, with a flow switch. It must have proved to be problematic, as they changed the system to not have the switch soon after

Why not put a switch or sensor on the over flow tube and when its triggered it shuts the system down?

i like that idea ryan

To add to ryans idea, how about a hollow brass check ball in the over flow. It would allow air to pass but when water pushed it up it could connect two contacts closing a relay to shut off the pump.