What do you think? DC 1A rating??

[cancatchfire]

I have been asked/invited to "post more", lol, so let me make another post right away.
I thought of sth worthy to post, of interest to many, I hope I found sth on the quick...

The photo is just to illustrate the switch I'll be talking about. What's visible, I did long ago, serves me well: power switching is reliable and safe, that's how I like it.
So, again, the relevant part of the photo is just the switch display: the first ... let me count ... 4 images, counted from top left.


On to the discussion point, if you like:
- I got another one of this "Heschen" switch (as I liked its solidity), regardless that most reviewers (amazon) complained: "far too tight space to wire anything!!!", like that, yeah, really, they post their reviews) But I can wire it of course, nimble fingers.

- Plan was, to use the new switch for a different purpose, obviously, namely: DC only, namely ONE IN, TWO OUT (contrary to the first switch, and which was AC only anyway)

- received it, opening the casing though, I see now (may have missed the sticker on the first switch), it's rated only Ie: 1A DC (240VDC rating of no concern)

Plan was, to use this second Heschen switch for:
--- Solar Charge Controller (is a variable voltage CC) > existing DC Breaker box > Heschen switch IN
--- Switch pos 1: Heschen switch OUT > House battery bank Ue 25.6VDC LiFePo4 (24S 150Ah 6x, if you understand DC batteries)
--- Switch pos 2: Heschen switch OUT > new e-motorbike battery bank Ue 76.8VDC LiFePo4 (also 24S 50Ah 2x)
--- Solar input MAX: 180VDC @7A > MPPT CC > ~28VDC @~42A OR ~85VDC @~14.7A MAX
--- The MAXes are theoretical maxes, never realized where I am currently. But the house battery bank charging might well get ~30A if we get good sun in the summer (expected).
--- The wiring is NOT to discuss, it's Silicone AWG10 which is plenty for this purpose.

Yes, since the (new also) CC has USER setting, I can have it charge EITHER house battery bank OR motorbike battery bank.
The 2nd Heschen switch was meant to switch between the two purposes. FYI: Most efficient is when you charge EVs straight from solar DC, if you can.

It's a very solid switch, hence why I got it again, I was suprised now to find its sticker saying Ue 1A DC.
Discussion points I see would be (at Uni ):

1) Would you put 30A through switch pos 1 at times when the sun radiation is high? Give reasoning either way.
2) Is switch palpation sufficient for you to determine that if switch gets warm, you discontinue your switch test?

 

[EddieB]

I'm no sure what to think but if the DC amperage exceeds the 1A DC that the switch states it's rated at then you'd be unwise not to take heed.

 

[Mixtel]

The contacts are pushed open by a cam as the shaft is turned so they operate quite slowly. That's fine on AC as any arc is self-extinguishing at the zero crossing point. However, they are poor at switching DC, which needs a snap action to open the contacts to extinguish the arc.

You can use these on DC, but you need to have several contacts in series so that any arc has to jump several clearance distances. Switching 240V DC at over 1A is not a good idea. The switch will carry 20A of DC, at that voltage but breaking that sort of load could be very bad,. At best you'll shorten the switch life appreciably.

At low voltage DC (less than 30V) the DC switching capability is the same as the AC rating for most of the smaller switches in the range IIRC. That's because any arcs are small.

Personally I wouldn't put 30A through this switch under any conditions. The current capability depends on the size of the contact area and the pressure of the contact spring, neither of which are designed for 30A.

As a matter of interest, I've used a larger version of these with all the poles in series to isolate 3.3kV AC. That was fun.