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Are there any solid-state battery or starter contactor?

AX-O

AX-O

Well Known Member
I was talking with Dayton yesterday regarding my FWF work and he asked me if I checked for solid-state battery or starter contactor. I told him no. It did not even cross my mind. So, do you guys know of anything out there?
 
AX-O said:
I was talking with Dayton yesterday regarding my FWF work and he asked me if I checked for solid-state battery or starter contactor. I told him no. It did not even cross my mind. So, do you guys know of anything out there?
Click to expand...

I could see it for the starter................. but the master is really basic and proven........:)
 
gasman said:
I could see it for the starter................. but the master is really basic and proven........:)
Click to expand...

Not to mention inexpensive. Solid state relays have very low current draw on the switched side, a good thing. But then you need a switch with gold contacts, or run a resistor in parallel to generate enough sparking current to keep your existing switch reliable. Which sorta defeats one of the benefits.
 
Lamar do a solid state contactor for battery and/or starting but they're not particularly cheap.

I have read that Lamar are a very reputable manufacturer of aircraft electrical gadgets.
 
There are no practical industrial SSRs sized large enough to withstand the 350A+ inrush current of the starter. That and there is a significant voltage drop. I have a couple here that I've used for various projects in the shop but they aren't practical for use in an aircraft.
 
Lamar

I installed the Lamar SS master relay. Until I get some flying hrs I can't chime in on the performance. The only negative point I found was the case/enclosure. I was not comfortable with the lack of weather seals. From the back the PCB is completely exposed! Made my own mounts and seal

nsvpt.jpg
 
Hi All,

Are we seeing common use yet of solid state battery contactors/relays? The reason I ask is that the 0.8 to 1A current draw of a typical battery contactor is not insignificant in the case of an alternator failure (for a single alternator VFR setup) and you are running on battery reserve. Since the semiconductor space seems to be moving quickly, I thought it may be worth asking before I go barreling down the path of a regular contactor. Perhaps JD has an update on his Lamar unit performance?

Tom.
 
Sort of. I was looking for a single solid state relay just for the battery contactor, as that is running continuously whereas the starter is only used once per flight. My aim was to reduce my continuous current draw without having to take out a mortgage. As much as I'd love one of those Vertical Power units, it's a little outside what I can justify right now.
Tom.
 
Nice solution Adrian. That is 1/7th of what the standard ones draw, so definitely a possible proposition. Last night I realized there was an alternate solution, and that was the use of Nuckolls' "E-bus". From what I gather, I could even have the E-bus just on a switch rather than a relay (because the current draw would be so low), reducing its parasitic draw to zero, and just shut down the battery contactor, given that I'll already have the engine started at this stage. The E-bus will still get power, since it is on the battery side of the contactor, and I just have the essential devices such as my GAD27 trim controller connected to this bus. Then again, your solution is far more simple, and negates this secondary wiring route. I'll send you my schematic before I pull the trigger on it.
I wonder how these guys are able to make their current draw so low, as it doesn't seem to be solid state. Perhaps they reduced the spring tension, which would bring into question it's ability to handle G loads. Things for me to look into I guess.
Tom.
 
I spent a lot of time looking at the best option to get rid of the parasite draw (alternative, electrically dependent engine). I wound up with a 'standard' master contactor and two alternators. But my critical engine bus is on a high current switch direct (through a fusable link) from the battery. Also have a switchable redundant path from the airframe bus.

The easiest way around parasite draw, especially if the battery is up front on the floor like a 4/6, is to use a manual battery disconnect. Blue Sea makes them, but so do many other vendors. Some are set up to use a push-pull cable for control, and most can be configured to use a shaft on a universal joint if needed. On a 4/6, just mount it near the battery within reach of the pilot. There are some older certified a/c that use a similar setup (disconnect on/near the panel), even with the battery mounted under or behind the seats. Not ideal in a crash, but the FAA did bless the idea.

Charlie
 
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