DC Switch Questions

[Xtremewave]

Good Day all.
I am just about ready to put in a pre-order in for the September delivery but have a few questions on the DC switches


Currently i have all my remote sites set up the following,

I have multiple - 72 volt solar arrays (3 - 24 volt solar panels tied together) supplying power (this ensures with the low sun light hours in Northern Canada i get the proper voltage while the sun is up in the winter) thought a MPPT Smart Controller to my (4 banks) of 48 volt battery bank.

Then i use another MPPT Controller with the supply coming from the 48 volt battery banks to drop the voltage to 12 volts to my 1 bank of 12 volt battery's (4 of them) to then supply my 12 volt inverter (120 volt AC) to power up all the devices.

This allows me to have a reserve bank of power at each site that i use a RMS-200 to monitor voltage on and get emails when the voltage drops/increases to a set power point on the RMS-200. And it also gives me time to get up to these remote sites if the power drops on the 48 volt battery banks and not have everything shut down.

Now with the DC switch i can now change things around as the power loss from 12 volt DC to 120 Volt AC is around 95% it's still a loss.

So my thoughts are to now install a 24 volt battery bank instead of the 12 volt battery bank and supply the DC switch with 24 volts. As i do not have any devices requiring 48 Volts.

Questions:

1. If i remember correctly from reading past form pages, the supply in to the switch is what the POE supply out is.

2. What is the current draw on 24 volt supply ~ 8 port DC switch with no POE turned on?

3. What is the current draw on 24 volt supply ~ 12 port DC switch with no POE turned on?


the reason i ask the current draw on these switches is looking in the future, I may require more ports and if the power drain is the same as either 8 port or 12 port, then i can go ahead and get the 12 ports for all the sites that could require more now instead of just getting what is required now to save on power consumption...

4. any chance in the near future to have the Mini switch turn on with 24 volts and supply POE out at 24 volts? the current configuration of the mini does not work well with me as powering up the switch to 48 volts only to have the switch supply power out on the POE side to 24 is to much of a loss in power consumption, that is with the guess that the mini switch is not MPPT smart in that it dissipates the extra voltage drop thought a heat sink.

[sirhc]

The WS-12-DC has no power supply and expects to be feed 48V +/-. It will keep running down to 37V and continue to power 24V devices but at 43V and below it turns OFF 48V POE as yes it just passes it through.

The WS-12-250-DC has a "smart" DC to DC power supply and will power both 24V and 48V devices with any DC input from 9-60V, it does not care. So you could hook this to a 48V battery bank and it would stay operational all the way down to 9V if you told it to.

The current draw on the 8 port and 12 port switch with no POE turned on is very close at 10 watts +/- max

The WS-12-250-DC (Smart DC to DC powers supply) will monitor DC volts in and current draw from your battery bank and will alert you to a power drop to a predefined value you set. It will also turn POE ports ON and OFF based on DC input voltages and also alert you when it does this.

[Xtremewave]

Thanks for the quick reply,
so based on what you just typed.

I require the WS-12-250-DC or the WS-8-250-DC, and I can supply power to it at 24 volts and it will not increase the internal voltage of the switch to 48 volts.

As all my radios only need is 24 volts to run.

As I do not need this switch to increase the voltage to 48 and then drop it to 24 volts to run the equipment, for this is a waste of power doing the voltage up and down on a total solar site.

[sirhc]

No, our switch boards are designed to accept 48V +/-

The switch boards then down converts this to 24V

So if you feed the WS-12-250-DC 24V the smart DC to DC power supply will have to up convert this to 48V to power the switch board and then the switch board will down convert to 24V.

The switch board in the WS-12-DC, WS-12-250-DC, and the WS-12-250-AC are all the same board minus some software changes. All of our switch boards expect 48V +/- as their input and then they down convert this to 24V, 3.3V, and other voltages they need but they all start with 48V +/-.

[Xtremewave]

Ok thanks for the clarification. will have to think more on our remote sites as I really like having the reserve power supply on the battery banks.

[sirhc]

Ok thanks for the clarification. will have to think more on our remote sites as I really like having the reserve power supply on the battery banks.

Well if you hook all the batteries together in one large bank the switch allows you to define the normal DOD with warnings so you get the same affect with a whole lot less confusion.

PM me your cell number and I can explain.