Low Fuel Level Sensor?

Ok guys, I searched through many posts, but can't find much. I am ready to put on tank baffles, and am thinking it might be nice to have a low fuel alerting system. Especially valuable if I don't go glass, and use Vans fuel gauges instead.

I have read about the optical unit from aircraft extras. I have also read about the micro switch on a float that Spruce sells. Have any of you used the latter? Does it work?

Now, I know there are those of you who will want to respond with "you don't need that" , and "manage your fuel and you won't have to worry about it"...
But please don't. I'm just curious as to what folks have successfully used.

For the record, I am using the standard Stewart Warner floats for fuel qty.

Thanks!

Gregg

I have one of the sensor kits from Aircraft Extras, never installed. If you go this way, I can sell you mine.

New In Box, instructions, etc.

I plan on installing 2 float switches and a Tri color LED as the only means of directly measuring fuel level in a aux tank. Green, yellow, red will tell me more than 5, less than 5, and empty, respectively. Anyway, I purchased some stainless duckbill float switches from Amazon for about $8 bucks. It's going to be a while before I do the install, but they seem to be a quality piece.

I owned a BD4 for about a year that had float switches in its sump tanks. Unfortunately, I can't swear about which switches were installed, but the previous owner said they came from Spruce. While I can't swear about them, I came pretty close to swearing AT them, before disconnecting them completely. The seller warned me about them before I departed in the plane, and sure enough, within 15 minutes, one of the indicators lit up with over 30 gallons still in the tank.

If you're going to use float sensors, try to find some with hermetically sealed magnetic reed switches, instead of regular microswitches.

If you're not in a time bind, watch ebay for deals on GEMS *optical* liquid level sensors. Very pricey from regular suppliers, but often under $30 on ebay. They make some that are fuel safe, and are completely solid state, using an optical sensor to detect presence/absence of liquid. The ones I have on the shelf are made with NPT threads, so installation/removal is simple. Here's what they look like:
http://www.ebay.com/itm/92C8743-Gems-Sensors-194471-Liquid-Level-Sensor-/261508177285?pt=LH_DefaultDomain_0&hash=item3ce31a1d85

They also make a less expensive all-plastic version that's fuel safe.

Charlie

PS: If you do install them, it's worth giving some thought to how you'll verify proper operation, and what design you'll use to know their failure mode. The accepted design is 'closed' (switch ON) with fuel present, and 'open' with fuel absent. That way a faulty indication is in the 'safe' direction; not the dangerous direction. That then raises the issue I had in the BD4: a flaky switch means 'land now' (safer), but also 'cries wolf'. You need reliable switches to make the idea worthwhile.

Aircraft Extras low fuel sensors

I have the Aircraft Extras low fuel sensors. I like them, they work perfectly. I have one set for 8.5 gallons remaining and the other set for 4.5 gallons remaining. Good peace of mind and gets your attention.

That is one of my tanks in the picture on the AE web site.

LeRoy Johnston RV-6A Esperanza 860 hrs.

I installed the low level warning system from aircraft extras and would not do it again because any sloshing causes false alarms even when the tanks are half full or more. I would put the money toward the EC-10 that Van sells as I have found mine to be great.