That's what I'm talking about, except we like twice the off grid
capacity... When the shit hits the fan, don't like to be adding
recharging duty to the recovery cycle... So we look for 24V PS's that
can do at least 28 amps...
On 3/20/17 8:08 AM, Chuck McCown wrote:
Yeah, I would go 10% of the capacity of the batts being the additional
current your PS needs to be able to make over and above the load
current. Figure out all the loads and get something that can do at least
twice the current you need minimum.
Say you have 70 watts of load. 24 volt system will be about 3 amps of
load.
On a grid powered system I want at least two days of battery. So
3*48=144 amp hours.
I will want to charge them at 15 amps. I would want a 20 amp power
supply minimum.
-----Original Message----- From: Robert
Sent: Monday, March 20, 2017 12:01 PM
To: [email protected]
Subject: Re: [AFMUG] DC Power Site
And those batteries would be toast at 11V... But more importantly pick
a charger that will recharge your batteries in a reasonable time when
power returns. More than once we have seen power problems return in
bad weather and if your system takes two weeks to recharge the batteries
fully you are going to sweat it if power is bouncing up and down while
the lines are being repaired...
On 3/20/17 7:34 AM, Adam Moffett wrote:
Good point.
------ Original Message ------
From: "Chuck McCown" <[email protected] <mailto:[email protected]>>
To: [email protected] <mailto:[email protected]>
Sent: 3/20/2017 1:32:33 PM
Subject: Re: [AFMUG] DC Power Site
The issues is not current as much a voltage headroom. If you are
running a 12 volt system which quickly drops to 12 volts when the
power quits, and your radios quit working at 11 volts, you will not
have as much time as if you were running a 24 volt system and the
radios quit working at 11 volts.
*From:* Adam Moffett
*Sent:* Monday, March 20, 2017 11:25 AM
*To:* [email protected]
*Cc:* [email protected]
*Subject:* Re: [AFMUG] DC Power Site
If you had a couple of < 10 watt devices, I don't see how you'd have
an issue with too much current.
------ Original Message ------
From: "Chuck McCown" <[email protected]>
To: [email protected]
Cc: [email protected]
Sent: 3/20/2017 1:23:42 PM
Subject: Re: [AFMUG] DC Power Site
I would never build a 12 volt site if there was any way to avoid it.
*From:* Justin Wilson
*Sent:* Monday, March 20, 2017 11:21 AM
*To:* [email protected]
*Cc:* [email protected]
*Subject:* Re: [AFMUG] DC Power Site
Don’t skimp by going with the lower voltage. You will run into an
amperage issues pretty quickly. Seen a 12-13 volt site with 1
backhaul and an omni run into amperage issues within a week. Voltage
is fine, just way too much amperage. It’s not worth the headache.
Justin Wilson
[email protected]
---
http://www.mtin.net Owner/CEO
xISP Solutions- Consulting – Data Centers - Bandwidth
http://www.midwest-ix.com COO/Chairman
Internet Exchange - Peering - Distributed Fabric
On Mar 20, 2017, at 1:11 PM, Darin Steffl <[email protected]>
wrote:
Hello all,
We're looking to build our first DC power site for small MicroPops
and I see two options after reviewing the WISPA archives.
The first option would be the the SDR-240-24 and DR-UPS40 with Two
12v batteries powering a Netonix DC switch.
The second option we were looking at is just doing the AD-155A with
one 12v battery but I see the charging current is only 0.5 amps and
voltage is only 13.3V which is not an optimal float voltage.
My question is, to keep cost down, would we be OK going the AD-155A
route with the slightly lower float voltage with a 35ah battery?
We're ok with the battery taking longer to charge but I'm just most
worried if the 13.3V will wreck the battery or not.
Thanks all
--
Darin Steffl
Minnesota WiFi
www.mnwifi.com <http://www.mnwifi.com/>
507-634-WiFi
<http://www.facebook.com/minnesotawifi> Like us on Facebook
<http://www.facebook.com/minnesotawifi>
