automatic transfer switch debate

slyttle
slyttle Registered Users Posts: 9 ✭
in Off Grid Solar & Battery Systems #1
Well .. it is a debate in my mind at least ;) (also, my appologies if this isn't in the correct forum ... it is a question loosely about batteries charging and loads so I figured this was the best fit)

As I have mentioned in previous posts, I am slowly building up a battery backup system that will backup critical circuits.

I plan to have about 800 Ah of batteries and want to backup approximately 1000 Watts of load @120V (~150W continuous, spiking to 1000W intermittently .... (load include a network and 1 server for the continuous loads .... my gas furnace and a fridge would be intermittent)). Charging these batteries would be done primarily through an AC Plug-in charger (a big one ... maybe 100amps) ... I will probably have some solar charging as well at some point, but primarily it will be a plug-in charger.

I am wondering if it is worth putting an automatic transfer switch (ATS) between the inverter and the loads. Something fast that would be able to switch from grid power to battery power without interruption. (I believe Aims sells such an ATS)

My reasoning is:

1) if I hook the loads directly up to the batteries, when I get a spike on the load, I am worried it could damage the charger, or at the very least confuse it (it would be a 3 stage charger)

2) My primary goal is to have backup power during blackouts ... it seems inefficient to run the loads from the charger(s) when I don't have to (ie. why not just use grid power when available rather than converting from AC to DV in the charger, and then back to AC through the inverter)

3) With an ATS in the mix, I wouldn't really be using my batteries until I actually need them, thereby extending the life as long as possible.

Any opinions on this?


-Sheldon
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Comments

  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #2
    Re: automatic transfer switch debate

    What you need is a Inverter / Charger with a built in Automatic Transfer Switch ( 16 ms ). I'll charge your batteries when the grid is present and act like a large UPS during power failure. A small backup generator would be nice, like a Honda EU2000 and it can charge during a power outage. The MS-2000 might be a good size Inverter. I wouldn't make my battery bank to large, 800 is a little large and remember, anything you take out, you have to put back in.


    http://www.magnumenergy.com/Products/MSseries.htm
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  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    #3
    Re: automatic transfer switch debate

    Transfer switch is definitely a must.

    There are units on the market, such as Xantrex XW, which will combine the charger, inverter, and transfer switches. This will make setup easier and possibly save some money.
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