That Meanwell sounds right.  I will have to see if they make a more powerful 
one?

 

From: Af [mailto:[email protected]] On Behalf Of Mathew Howard
Sent: Wednesday, March 09, 2016 11:39 AM
To: af
Subject: Re: [AFMUG] Small DC Site

 

Is there really any advantage to using something like an AD-155B with a UPS 
function over just connecting the batteries in parallel with the load to a 
normal DC power supply and setting the voltage properly? It seems like there 
would be less parts to fail and it'd be easier to add redundancy if the 
batteries were just connected in parallel.

 

On Wed, Mar 9, 2016 at 12:52 PM, Chuck McCown <[email protected]> wrote:

A pair of power supplies that are capable of pulling the load and charging the 
battery.

 

For example, if you needed 200 watts for your 24 volt loads, you need 8.3 amps. 
 Round that up to 10 amps.

Then you have to decide how long you want this thing to last without commercial 
power.  I would think 24 hours is a minimum.  So 10 amps x 24 hours is 240 amp 
hours of battery.

It is always a safe figure to charge a battery at .1C or 10% of its capacity or 
less.  That would be 24 amps to charge the batts after a power outage, plus 10 
for load = 34 amps of power supply.  You could get by with 20 amps, just will 
take a bit longer to charge.

 

Lots of 20 amp 28VDC power supplies out there.  

Rule of thumb double your load power or more to size the charger.  

 

From: SmarterBroadband <mailto:[email protected]>  

Sent: Wednesday, March 09, 2016 11:45 AM

To: [email protected] 

Subject: [AFMUG] Small DC Site

 

What are people using to power small DC sites.  Option 1 up to 150 - 200 Watts, 
option 2 up to 300 – 400 Watts.  I’m looking for a DC UPS that can charge 
attached batteries.  Need to have 24 and 48 volt.  

 

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