SPDT switch > 20A @ 32VDC?

[brulaz]

I'm seeing SPDT toggles that are 20A at 125VAC Ebay 20A 125VACand some that are simultaneously rated to 21A at 14VDC DelCity 20A 125VAC

But I want to switch a max of ~700W at ~30A, so maybe 23A?

What about doubling up on the contacts of DPDT to act like a SPDT?

And what about a "Motor Rated" DPDT toggle that's 20A at 277VAC (all the others are 10-15A at 277VAC)? DelCity Motor Rated toggle

Actually, doesn't have to be a toggle, only SPDT and cheaper and smaller than the big HD marine engine switches.

Thanks

[myredracer]

FWIW, a motor rated has much heavier contact surfaces so it can handle the arcing from high momentary inrush current (5-6 times FLA for AC motors) but doesn't mean it can handle continuous current higher than it's rating. You could always try going to a local electrical wholesaler and see what they have listed in their catalogs.

[brulaz]

CA Traveler wrote:

...
1. Turn off the AC and hence no Meanwell load.
2. With portable panels lay them face down or whatever so that there is no load.
...

Exactly. That's the reason for my face palm a few posts earlier.

The portable panels are only used when there's no 120VAC from any source. Otherwise they are unplugged and stored away.

The Meanwell is only used when travelling or on shorepower; the portable panels will not be connected in either case.

So I'll just parallel the two inputs and skip the switch for now.

[CA_Traveler]

So now that we know what you are doing - back to the switch.

A fully rated DC switch is nice but you could
1. Turn off the AC and hence no Meanwell load.
2. With portable panels lay them face down or whatever so that there is no load.

Hence no switch required. Or perhaps just use the SPST in your first post and watch your loads when switching.

[CA_Traveler]

OK With a 12V truck and a 24V rig your approach sounds reasonable. Provided the controller works OK with the Meanwell as input. You do have losses in the inverter, Meanwell and controller but your truck setup is adequate for the losses.

Temperature compensation is a benefit as is voltage sense.

[brulaz]

wa8yxm wrote:
I will say again. If you hook several different chargers to a battery system, be it 12 volt 24 volt or xx Volt. so long as all the charging systems are set to the same voltage.. IT IS NOT A PROBLEM. No switching needed, (NOTE This applies ONLY to DC systems) as the one with the highest output voltage wins and gets the job of charging while the others automatically idle or at the very least throttle back big time.

IF you are worried that multiple chargers might exceed the battery charge rate then (for a 24 volt system)

Run multiple charge controllers.. Stage one (All sources) set to like 30-40 volts, these the outputs go to the input of the 2nd stage. Set up for the battreies.. Or alternatevely you can get one that limits current only but .. While I know how to build one, I don't know where to buy one.

I agree, and routinely run two chargers together (2 solar, or 1 solar and the Meanwell PS).

But this discussion is about having two separate INPUTS to a solar charger: Solar panels versus the Meanwell PS.

[wa8yxm]

I will say again. If you hook several different chargers to a battery system, be it 12 volt 24 volt or xx Volt. so long as all the charging systems are set to the same voltage.. IT IS NOT A PROBLEM. No switching needed, (NOTE This applies ONLY to DC systems) as the one with the highest output voltage wins and gets the job of charging while the others automatically idle or at the very least throttle back big time.

IF you are worried that multiple chargers might exceed the battery charge rate then (for a 24 volt system)

Run multiple charge controllers.. Stage one (All sources) set to like 30-40 volts, these the outputs go to the input of the 2nd stage. Set up for the battreies.. Or alternatevely you can get one that limits current only but .. While I know how to build one, I don't know where to buy one.

[brulaz]

CA Traveler wrote:
So you want to use the truck inverter for 120VAC to the Meanwell in the rig to produce 32VDC which will be connected to the solar controller input to charge the 12V batteries while driving. At other times you'll have solar panels connected to the controller input. And at other times you'll have shore power for the Meanwell. Does that sum up what you want to do?

That raises a lot of questions for me about this working as you expect. But as an experiment go for it and let us know the results.

Yes. Currently the Meanwell output is directly connected to the 24V battery bank at ~28-29V. It works very well as a 500-700W bulk charger (either while travelling or on shorepower) but is not temperature compensated and requires manual over-sight.

I run it in parallel to the primary solar charger that handles the fixed panels on the roof. Have seen the it pump 700W into depleted batteries; about the same as my 690W permanent solar array on the trailer. On the truck, power comes from a 220A alternator via an old 1000W PSW inverter.

But if I can run the Meanwell's output through the unused (at the time) secondary solar charger (Epsolar Tracer with temp compensation for the portable panels) I will reduce the amount of fiddling, V adjustments, and attention that it requires. Whether this works has yet to be confirmed.

Initially I was thinking that the two inputs to this secondary solar charger should be "either/or" switched. But now I'll try permanently parallelling the Meanwell's output with the portable solar panel's wiring stub (thank you DrewE). There's no way the Meanwell will be fired up at the same time as the portable panels are plugged in, although even if it accidentally were I dunno if it would harm anything other than confuse the solar charger.

Pretty complicated, I know. But so far everything is working well.

[CA_Traveler]

So you want to use the truck inverter for 120VAC to the Meanwell in the rig to produce 32VDC which will be connected to the solar controller input to charge the 12V batteries while driving. At other times you'll have solar panels connected to the controller input. And at other times you'll have shore power for the Meanwell. Does that sum up what you want to do?

That raises a lot of questions for me about this working as you expect. But as an experiment go for it and let us know the results.

[wa8yxm]

A thought. This is for a solar charger system or something else?

On charger systems no switching is needed from one source to another. You can parallel half a dozen different battery chargers. Solar, Wind, Hydro, Shore power. ENgline alternator. Hand cranked charger.. Hook them all up at once.

The one with the most OOMPH charges the rest idle.

[CA_Traveler]

deleted

[brulaz]

DrewE wrote:
Thinking some more about this, is there any inherent reason why you couldn't simply connect the power supply and the solar panels in parallel, possibly with a blocking diode or two if you're feeling particularly paranoid? Why have a switch at all?

:S

Of course. They will not be powered up simultaneously anyway.

The solar panels are portable and only plugged in when boondocking.

The Meanwell is plugged into either the truck's 120VAC inverter when travelling or to shorepower when not boondocking. Noway will I have the portable solar setup at these times.

And I already have Schottky diodes on its output to keep it from sucking 50ma or so from the batteries when unpowered. Maybe these will do something when the solar panels are plugged in?

Sigh. I'm feeling old.

[DrewE]

Thinking some more about this, is there any inherent reason why you couldn't simply connect the power supply and the solar panels in parallel, possibly with a blocking diode or two if you're feeling particularly paranoid? Why have a switch at all?

[brulaz]

enblethen wrote:
Careful about using circuit breakers as switch as many are not rated to be used as a switch.
Langir specs says to use in conjunction with switch

Ouch.

Well, my other, spare DC breaker is Midnite Solar. And they're cheap and claim " breakers are rated to break the full rated load at the rated voltage repeatedly, with NO DAMAGE. Always use a properly sized breaker for disconnecting. "
Midnite Solar Breakers

So I'll get another one of those. I already have a one of their Baby Breaker boxes installed for the main solar system and it has two empty slots, but is a bit out of the way ...

We'll see once I get back to the trailer and get everything tested out.

Thanks everybody for all the great advice and suggestions ... as usual.

[CA_Traveler]

time2roll wrote:

I used this one from Home Depot but is not rated for DC. In actual practice of infrequent use it has been fine.

Home Depot EATON DP221NGB

I used this to switch both + - solar wires for 95VDC @ 8.1A.