SPDT switch > 20A @ 32VDC?

AMPS: Switch amps are like FUSE amps.. You put a 20 amp switch in a 30 amp circuit and it's a fuse. only it may not blow fast enough to avoid starting a fire.

Volts .. Well in a Resistive circuit volts need to be equal or greater than supply voltage. A 12 volt switch may arc over if hooked to say a 120 volt line.. and again. FIRE is possible.

MOTOR RATED.
A motor starting draws way more than it does running, I will use a 1HP 120 volt motor as my example.

Let's say that it draws 10 amps (Should be less but we will make it a non-eficient motor) running.

May draw 50 or more starting (For a very short time) Switch has to be "Slow blow" as it were. (So should the fuse)

And when you shut it off the inductive "kick" can easily break 1000 volts.

MrWizard wrote:
Double throw
Is this an either/or situation
Meanwell or solar, only one or the other?

Yes, Either/or.
The Meanwell might be used when 120VAC (shorepower or truck's inverter) is available.
The solar panels are portable only. So just when boondocking.

Pollak has spst switches rated to as high as 50 amps.

To suppress arcing a special switch is used.

The moniker is SNAP ACTION SWITCH.

Either rotary or on/off toggle, when the lever is moved it moves against a very noticeable springing action that resists the movement.

When the "over-center" point is reached, the switch makes a CLACK noise and pressure on the knob or toggle is relaxed.

Inside the switch the contacts move with blinding speed. Far faster than what fingers could accomplish.

Mercury is also used where arcing is a problem but the EPA goes into "nuclear attack mode" when the word "mercury" is seen. Ford, perhaps saw the light and dropped the "Mercury" model. Just kidding.

One note about solid-state DC relays -- good relays are NOT cheap. They have to have elaborate transient voltage spike protection built-in or they WILL fail in a short amount of time when operated at or near near maximum rating. They also demand a proper size heat sink and added together a solid state/relay and heat sink is quite a bit larger than a standard Bosch/Tyco relay.

EATON DH221NGK on eBay

Might be a bit bulky but has the rating to switch all day long.

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

It is a bit more difficult to switch off DC but you are just 32 volts so not a huge deal IMO.

theoldwizard1 wrote:
Amps is amps. The voltage does not matter much unless you are taking about over 250V. A relay would be safer.

While amps are amps in DC vs AC the thing that one must be careful of is suppressing or quenching the arc during switching of DC voltages/current.

Not all AC switches do a very good job of handling arc suppression under high current DC loads.

Some but not all AC switches have a DC voltage/current rating which is typically lower than the AC ratings.

I would agree that a DC rated relay is most likely the better choice, however, one must account for the current drawn through the relay in their battery usage which will eat some of their capacity.

There are purpose made latching solenoids which only use coil current during the switching period that might work well with this configuration..

I know of no "standard" size toggle that would be reliable.

Bosch style relays would work. Is there a "fitment" problem?

I would as for experiment only, use two 35 amp switches. Wire the outputs together as common point. Inputs would come from the two devices.
You could then operate them independently or together.

brulaz wrote:
I have an extra DC breaker but it's not double throw.
A relay sounds like a better idea.
But one with double throw and centre off?
Could use the DC breaker to provide the Off function I suppose.

Double throw switch plus 2 relays.

Double throw
Is this an either/or situation
Meanwell or solar, only one or the other?