Current limiting on the rectifier is always a good thing. During recharge during deep discharge, hopefully the voltage did not go low enough to cause the system to fail. If it did, then perhaps you should have had a low voltage disconnect, back up generator or larger battery.
But having the batts pull down and starve the load will always happen to a certain extent. If the system is still up when that happens it will not go down, it will just be low voltage for a while. From: George Skorup Sent: Monday, March 20, 2017 7:27 PM To: [email protected] Subject: Re: [AFMUG] DC Power Site Yeah, I wouldn't do that. No charge current limiting means the batteries will likely pull down the supply and starve the load. Also pay attention to the initial current spec on the batteries. Smaller ~9-20Ah batteries call for 2A or so. The Mean Well DR-UPS40 is capable of 40A @ 27VDC and limits the charging current to 2 or 2.5A I believe. It's a decent cheap option. There's also the Mean Well DRC-100 A (12VDC) or B (24VDC). I wish they made a 48V version. 100W and 1.25A of charging current which is roughly 2X the AD-155B. But the 155B gets you a little more power at 150W. I might start using the DRC-100B for new stuff since it's smaller and natively DIN rail mountable unlike the AD-155. If you want fancy stuff like alarm contacts and temperature compensation, the Traco BCMU360 at about $170 + a Mean Well SDR240-24 or -48 isn't all that expensive. The BCMU is jumper selectable between 24 and 48VDC which is nice. Regulated output. Some folks don't like that it does the internal DC-DC conversion. Yes, it takes a 12VDC battery and converts to the selected output. I have up to 40AH on a few. The charging current is limited to 1A. If you want big boy stuff, buy a rectifier shelf for 500W, 1kW, 2kW, whatever, and 100+ Ah of batteries. You can get ICT's new 1U shelf in +12, +24, +48 and -48. On 3/20/2017 12:24 PM, Adam Moffett wrote: Qualifying info: If you don't want/need any features like temperature compensation or low voltage disconnect, then all you need is a power supply that can be adjusted to your float voltage, then you wire the batteries and load in parallel. ------ Original Message ------ From: "Chuck McCown" <[email protected]> To: [email protected] Sent: 3/20/2017 1:20:49 PM Subject: Re: [AFMUG] DC Power Site You don’t need two power supplies. Just pick the power supply that has enough current to both power the radios and supply a healthy recharge current right after a power outage to the radios. From: Darin Steffl Sent: Monday, March 20, 2017 11:11 AM To: [email protected] ; [email protected] Subject: [AFMUG] DC Power Site 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 507-634-WiFi Like us on Facebook
