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We are planning on installing a couple of Netonix WS-12-DC switches (the 48V only version) at the top of a water tower soon. We are going to be running an APC UPS at the base of the tower because we don't have the experience or the time to engineer a full DC power rig, and are going to run DC and fiber up the tower. Does anybody have any recommendations for an AC to DC power supply to power the two switches? It can be one power supply for each Netonix, or one power supply that powers them both.

One thing you could consider is if you used the WS-12-250-DC units you could do the following.

Purchase 2 or 4 AGM batteries in series and use them as you backup as well as power source, if it is a heavy loaded tower I would use 4 batteries in series with 48V output.
I use Optima AGM batteries (Blue Top): https://www.optimabatteries.com/en-us

Then you would only need to purchase a charger unit as the WS-12-250-DC unit would compensate for any voltage drop lost going up the tower.

You would also need to use some decent wire to handle the amperage, at least 12AWG or 10AWG if using one wire for each polarity.

As far as chargers I use these: http://www.minnkotamotors.com/Battery-C ... -Chargers/

Optima also has chargers.

If you did it like this your tower would have easily 24 hours of backup.

As far as AC powered power supplies I would use a 10A 50-56V power supply for each switch.

ecommerce@qx.net wrote:We are planning on installing a couple of Netonix WS-12-DC switches (the 48V only version) at the top of a water tower soon. We are going to be running an APC UPS at the base of the tower because we don't have the experience or the time to engineer a full DC power rig, and are going to run DC and fiber up the tower. Does anybody have any recommendations for an AC to DC power supply to power the two switches? It can be one power supply for each Netonix, or one power supply that powers them both.

Hey, neighbor. We are using Traco TSP series power supplies (TSP-360-48) to do exactly what you are trying to do. We use these in our DC plants as well, but these particular sites are utilizing existing APC UPS solutions at the bottom of a tank just like you describe. Once the APC dies, all we have to do is add in a Traco Battery Charge controller (BCM) to convert the site to full DC.

sirhc wrote:As far as chargers I use these: http://www.minnkotamotors.com/Battery-C ... -Chargers/

Just to be clear, you are using AC -> Minnkotoa -> Battery -> WS-12-250-DC?

We have 4 AGM Batteries in series to produce 48V.

The AC powered MinnKota charger has 4 charging leads that hook to each battery and it charges each battery individually as needed.

The charge is a smart 3 stage charger and can charge each battery separately at the same time up to 10A each so it can recover completely discharged batteries.

That's what I thought, I just wanted to confirm since the MinnKota manual states

"It is not intended to supply power to low voltage electrical systems other than for charging and maintaining batteries."

and I have tried some other "smart" chargers which have problems when there is a load in addition to the battery.

I am going to order one to test out, thanks.

sirhc wrote:We have 4 AGM Batteries in series to produce 48V.

The AC powered MinnKota charger has 4 charging leads that hook to each battery and it charges each battery individually as needed.

The charge is a smart 3 stage charger and can charge each battery separately at the same time up to 10A each so it can recover completely discharged batteries.

Those look sweet. These guys have basically the same thing: http://www.dualpro.com/project/sportsman-series/

I was talking to an EE who was skeptical about the whole idea of charging batteries individually while they're connected together.. I explained the charger outputs were completely isolated..
Given Kirchoff's Current Law, I admit it's hard to visualize working but it should.. each battery might have a different overall current flowing through it depending on its state relative to the other battery. If you have a 2 amp load across 24v, it seems to me each channel of the charger will supply 2 amps @ 12v to the load, and there will be 8 amps of capacity in each channel left over to go into the battery
Dave?

sirhc wrote:One thing you could consider is if you used the WS-12-250-DC units you could do the following.

Purchase 2 or 4 AGM batteries in series and use them as you backup as well as power source, if it is a heavy loaded tower I would use 4 batteries in series with 48V output.
I use Optima AGM batteries (Blue Top): https://www.optimabatteries.com/en-us

Then you would only need to purchase a charger unit as the WS-12-250-DC unit would compensate for any voltage drop lost going up the tower.

You would also need to use some decent wire to handle the amperage, at least 12AWG or 10AWG if using one wire for each polarity.

As far as chargers I use these: http://www.minnkotamotors.com/Battery-C ... -Chargers/

Optima also has chargers.

If you did it like this your tower would have easily 24 hours of backup.

As far as AC powered power supplies I would use a 10A 50-56V power supply for each switch.

Sorry to double post. I've just spoken to another person, in my mission to get a quote for a multi-bank charger in Canada, who said that it was generally a bad idea to charge your batteries and pull a load on them at the same time.

I don't have a good enough understanding to really know, though I'm guessing it would depend on the design of charger. Don't you run the risk of boiling your batteries if your charger is constantly putting out 14.4v per battery because it thinks it should be in absorption mode, when really you're just pulling a small load?

Thanks if anyone has some insight.

Well chargers like the MinnKota mentioned above are smart chargers, they will not boil your batteries.

How else do you have a battery bank and use it if sometimes you are charging it when you are using it?

I guess one could have (2) Banks and rig up some type of switcher but that sounds expensive with twice the batteries and another device to switch things over?

Another solution would be both an AC-DC power supply to power equipment while there is grid power, the charger, and a transfer switch that switches over to using the batteries when the grid goes out. Otherwise the batteries are just sitting there being charged.

Can you tell me what kind of load you are running at one of your sites with a MinnKota charger? And does it permanently stay in float mode once the batteries are charged?

This person got back to me saying either DualPro or MinnKota chargers would be good for up to 2A per output, over that and the charger will reset itself requiring it to be rebooted.
Makes no sense to me really.
He's just trying to help me, but it's making the whole thing cost more.

EDIT: Just called DualPro: explanation: if there is a load accepting much more than 2 amp, it won't allow the charger's voltage to raise the way it would expect a battery to. It then presumes there's a battery fault, and sets a fault code, which kills the charger.
So yeah... calling MinnKota next :)