Hot solenoids Z14 architecture

[maniago]

I've put in Z14 as described by Nuckholls. I ordered then returned the speced B&C solenoids for the main, aux and cross feed duty and replaced with Cole Hersee 24213 200amp continuous solenoids w/ N5408 diodes because the B&Cs ran too hot to touch (120F) at 14.1V buss voltage.....and because they were obviously CH knock offs (and B&C wouldnt give me a techsheet on them). Sure enough the CHs run just as hot. Each is pulling spec 1.5amps.

Are these solenoids supposed to run that hot in regular duty? Theres little or no current going across the contacts as I'm still in panel build mode, so this is all coil heat.

Seems logical that the CHs should be able to take 14v since thats charging voltage, and I'd hate to replace these with Gigavacs if this is "normal". But too hot to touch doesnt seem normal....

Any help greatly appreciated.

[Bill Boyd]

At that voltage and current, it's dissipating 21 watts. Fair surface area with some "fins," but they bolt to a typically warm firewall which won't help much with moving heat out.

A typical night light bulb with what looks like a similar wattage to surface area ratio gets uncomfortably hot to touch, so this may be expected. Mine is far enough out of reach that I've never had occasion to gauge its operating temp with my fingers.

In the end, if the device wattage is within spec, the operating temp will be what it will be - because physics

[BillL]

I can not say it is normal, but a cousin comparison is the starter solenoid, the one on the starter. Although it does not get continuous power, it runs at 170-180F all the time. (recent measurement)This might be why the continuous solenoid is metal cased while the starter contactor is plastic.

I still have the thermocouple run to the FWF, so I'll tape it on the master contactor next time the cowl is off and post the results.

[vic syracuse]

The master and avionics solenoids will get hot to the touch.

Vic

[maniago]

Ok guys thanks. I guess its ok if youve seen it many times before (Vic). I couldnt find any one else on the search that call this out, so by rule of averages, seemed maybe I was off the bell curve in a bad way.

I did some more temp testing today and did indeed see a rise in temp with 8amps going thru the contacts, so there mustnt be zero ohms there....

All that said, some kind of wrap around heat sink (and paste) cant be a bad thing Id think....something like this in the right size....

https://www.amazon.com/Black-Type-Ar.../dp/B015YRY0LS
------------

I just ordered one of these. Prob need some work on the milling machine, but for $10 worth a shot. Fits a 4465 1/8 scale RC car motor, which is pretty close to the dia of the Col Hersees....
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[Mich48041]

A person might want to reduce the energy consumption for some reason, for instance: a very small alternator, or to reduce heat, or to conserve the battery when the alternator fails. There are ways to accomplish that goal. It takes more current to energize a contactor than to hold it closed. Once the contactor is pulled in, current can be reduced by using a series resistor or diode, or with PWM (Pulse Width Modulation). Another option is to install a relay in parallel with the contactor. After the engine is cranked, the contactor can be shut off and the relay energized.
I am not necessarily recommending that any of the above be done, just saying that it is possible. In most cases, it is not worth the trouble. And adding additional parts results in more parts to fail.

[Walt]

I installed a Gigavac MX11 some time ago just because I think it a better unit than the typical CH units. The 'S' models use less than 1 watt holding current and basically exceed the CH specs by a pretty good margin.

[maniago]

Originally Posted by Walt

I installed a Gigavac MX11 some time ago just because I think it a better unit than the typical CH units. The 'S' models use less than 1 watt holding current and basically exceed the CH specs by a pretty good margin.

I think theres no doubt that the Gigavacs are the gold standard for solenoids/contactors - I was looking at the GV200.

But they also exact a gold standard price, and with the Z14 design, thats 3 units......its a tough pill to swallow.

[rv7charlie]

Mani,

It's worthwhile to decide what your concerns really are. If it's mounted where it's burning your leg, then the heat is a concern. :-) Or if power consumption is
a major concern, then something like the Gigavac is an option (pricey, but an option).

But if your concern is component reliability, you can just relax & build on. As others have pointed out, the coil does consume quite a bit of energy, and a fair percentage gets converted to heat. The device is designed to survive the heat, just like Lyc cylinder heads are designed to survive ~400 degree heat.

[maniago]

Originally Posted by rv7charlie

Mani,

It's worthwhile to decide what your concerns really are. If it's mounted where it's burning your leg, then the heat is a concern. :-) Or if power consumption is
a major concern, then something like the Gigavac is an option (pricey, but an option).

But if your concern is component reliability, you can just relax & build on. As others have pointed out, the coil does consume quite a bit of energy, and a fair percentage gets converted to heat. The device is designed to survive the heat, just like Lyc cylinder heads are designed to survive ~400 degree heat.

No its reliability - dark and stormy night stuff. Just havent had to work with continuous solenoids before so didnt know if this was normal or an aberration on my part, and the tech documentation from CH doesnt discuss how the product should react.

I dont know what I dont know, so I asked. And yes I got my answer, thanks everyone.

But as an EE, in general, I dont like hot electrical components......as a gearhead, mechanical ones I give more latitude.....