Controlling 24v Contactor w/ 12v...?

[bigjoncoop]

I've got a TE LEV200A5NAA High Voltage DC Contractor, that's rated at 900v / 500a with a 24v coil. (Datasheet Attached)

I'm using it to remotely contol the output of a large 12v lithium battery bank. (the battery bank already has the necessary management system, I'm just using this to wirelessly control the output)

I've tested the coil using 12v  and it seems to close the contacts just fine... Now I know that the magnetic field that closes the contacts will be weaker by using a lower coil voltage.
Now I know that I could easily just use a small step up / boost converter (which I have tons of 😜), but that would just add another point of failure which I'm really trying to avoid in this situation.

I'm assuming that the only inherent risk is that the contacts may open inadvertently due to the lower voltage. Correct? I don't see how the lower coil voltage, could make them get stuck closed...

I'm basically asking a question that I already know the answer to, but I'd rather double check then have a catastrophic issue!

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Oh, as I mentioned the contactor is rated at 900v @ 500a and I'm only using it with 12v and a maximum of 100a continuous for no more then 30-45 minutes at a clip.
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[AVGresponding]

Given it lists the dropout voltage as 1-5VDC for the 24V coil I suspect you'll be fine

[bdunham7]

Once the contactor is activated, it won't let go until the voltage drops a lot.  The only risk I see is that even though it is operating at 12V or 12.6V now, it may not always operate at that voltage since it is far below the spec.  Also, it may not operate when the battery bank is not fully charged and you have less than 12V.  You could characterize it by trying to actuate it with a power supply at various voltages to see where the minimum is.

[tom66]

Given it lists the dropout voltage as 1-5VDC for the 24V coil I suspect you'll be fine

Agreed.  The biggest risk is that the coil doesn't activate in the first place.  Once it is activated, it will be fine. 

Over time, you might find that wear causes the required activation voltage to increase but I would expect most of the time you will get away with it.