Equis
Premium
join:2005-03-18
Australia
| Battery Chargers
Hello
I am going to use battery's and chargers instead of UPS on my sites
I found a charger that is 1.25 amp at 12v and my radios will draw about 1 amp under load max.
That's cutting it pretty fine and charging time will be about 2 years j/k but is that enough overhead (.25 amp)
I like the charger because its meant to make batteries last longer but I hope it will cope at 1mp 24/7
Any thoughts?
Thanks |
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40883644
Premium
join:2003-06-05
Parker, CO
| Not a good idea....
Battery chargers are not clean (well rectified)and will have a substantial amount of AC left over. Your radios will not be happy with that as they are designed to run off of a clean DC supply. UPS's are well rectified and filtered.
I could get into great detail, but the simple suggestion would be DON'T.
--
Rich
»www.highgainantennas.com |
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brucenolan
Premium
join:2002-06-19
Ramona, CA
2 edits | reply to Equis
I went thru two 1.5 amp "smart" chargers on an AP drawing 1 amp, then upgraded to a 6 amp (same brand). it still didn't like the ambient temperature and would go to error mode (not charging) so I finally just put a dumb 6 amp charger with a 24 hour timer and adjusted the on time to suit the load,works great! two 90 ah batteries give about 4-5 days run time at 50% discharge without charging and I try to get up there once a week to check voltage
--
main access:5.8ghz@16Mbs and backup 900mhz@2.2 Mbs 6 mi to town-fixed wireless rocks! |
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Equis
Premium
join:2005-03-18
Australia
| reply to Equis
Interesting points..
Can anyone give an educated guess on how long a 500va UPS would power a 12v 1.5 amp plugpack?
I liked the battery idea because I though it would give prolonged uptime, but not worth it if its going to blow my gear up
Thanks Again |
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Equis
Premium
join:2005-03-18
Australia | reply to Equis
»www.batterydoctor.ashop.com.au/p···tep.html
Is what I was thinking of BTW |
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public
join:2002-01-19
Santa Clara, CA
 ·DSL EXTREME
| reply to Equis
said by Equis  :Interesting points.. Can anyone give an educated guess on how long a 500va UPS would power a 12v 1.5 amp plugpack? I liked the battery idea because I though it would give prolonged uptime, but not worth it if its going to blow my gear up You can use a UPS as a charger. Take the output from the battery, not from the AC out.
Cheap chargers usually overcharge batteries. Flooded cells can be refilled, but gel cells are quickly destroyed.
Off the shelf UPS usually contains microscopic batteries. External battery is needed for any serious backup use.
Also get a ups with an ethernet card so that you can remotely monitor the status. |
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brucenolan
Premium
join:2002-06-19
Ramona, CA
| reply to Equis
I also liked the battery set up because it gave me days-- instead of hours of up time. took some experimenting but has been up over 6 months without problems, running 1 rb532 w/cm9 and sr5 + tr6000 and trango M900s ap. seems like most UPS will run down after a short time even without a load
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main access:5.8ghz@16 Mbs and backup 900mhz@2.2 Mbs 6 mi to town-fixed wireless rocks! |
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kf6ytc
join:2002-03-26
Turlock, CA
| reply to Equis
I use old commercial ups batteries that are taken out of use due to a maintaince agreement, These are deka 110ah sealed lead acid batteries.... they have a 7 year life per deka, and i get them after 1 year....
High end batteries will have a charge voltage, ie. 12.9 volts....... If you get a good power supply, $50 for a switching one, about 10amps, just adjust the power supply to the charge voltage (12.9) and the powersupply will charge the battery, but once the voltage of the battery is also 12.9 the battery will draw virtually no current from the supply, so you can leave the power supply on the batteries without having to turn it off, or overcharging.
I know some places sell charge controllers, i would be interested in others feedback on them........
TJ |
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public
join:2002-01-19
Santa Clara, CA
·DSL EXTREME
| said by kf6ytc :High end batteries will have a charge voltage, ie. 12.9 volts....... If you get a good power supply, $50 for a switching one, about 10amps, just adjust the power supply to the charge voltage (12.9) and the powersupply will charge the battery, but once the voltage of the battery is also 12.9 the battery will draw virtually no current from the supply, so you can leave the power supply on the batteries without having to turn it off, or overcharging. The float voltage depends on the battery construction AND on temperature. A long life charger must be temperature compensated.
A pulse charging method is believed to reduce sulfation and extend battery life. Steady charging is simple, but does not give the longest battery life. |
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lutful
Premium
join:2005-06-16
Ottawa, ON
| reply to Equis
said by Equis :Can anyone give an educated guess on how long a 500va UPS would power a 12v 1.5 amp plugpack? The "VA" rating of SoHo UPS only indicate how much power UPS can supply to PC.
The runtime in minutes will be mentioned in small text - only that number will give you an indication of the battery Amp-hour rating.
said by Equis :I liked the battery idea because I though it would give prolonged uptime, but not worth it if its going to blow my gear up I am confused by this statement. You always need more batteries for prolonged uptime. Is there another way? |
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Equis
Premium
join:2005-03-18
Australia | Hello
I was meaning not using a UPS (ac-dc-ac-dc)
Just use a charger and SLA (ac - dc) |
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jrmcdaniel
Premium
join:2006-12-12
Grantsville, MD
| reply to Equis
Marine stores have the best chargers since boats sit at the dock for weeks with chargers connected to the battery. Same for batteries -- the marine battery is designed for deep discharge rather than cranking an engine (car battery). The battery will act as a huge capacitor and the ac from the charger will be gone (enough, anyway) for powering most dc gear (especially if your gear has voltage control as does virtually all).
COnditions on a boat are pretty wet sometimes so the gear tends to be rugged, too. |
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macyh
Ex-Isp
Premium,MVM
join:2001-04-24
Medina, OH
 ·Armstrong Zoom In..
2 edits | reply to Equis
I've done quite a bit of work over the past 30 years setting up standby power for alarm systems, phone systems, ham radio and even remote POP's back when I owned an ISP.
First, keep in mind that every time you do a power conversion, you add complexity (more chance for failure) and lose energy (means less standby time). So if you can operate your equipment directly from DC, you should do so. Many wireless devices I have seen will operate at 12vdc. The only downside of 12vdc operation I can think of is that you cannot have the battery pack more than 100 feet or so away from the load without using heavier (more expensive) power cables.
From what I've seen, the low power levels that wireless systems run at means your actual DC power consumption is typically 1 or 2 amps. That's well within the range of off the shelf alarm industry standby power equipment. You can use the larger capacity gel cell batteries, but I'd suggest using sealed type golf cart or trolling batteries from WalMart.
Here are two commonly used 12vdc standby power controller/chargers:
ELK PS-624 1 AMP Power Unit, Card Only
Altronix AL400ULB 4 AMP Power Unit, Card Only
This should get you started, as these manufacturers make a variety of sizes and products. You can buy these from any alarm equipment distributor, check this list.
You can also build you own supply/charger using off the shelf parts.
And if you're really cheap, you can buy these units used. I've purchased quite a few at hamfests for a couple bucks each, along with the necessary plug in power transformers. (Yeah, I'm a ham and small biz owner, cheap is my middle name...)
Another comment: Both batteries and radios don't work well in extreme heat or cold. If you are in an area with cold winters, it is wise to provide a heat source. I have found than a thermostatically controlled 25 or 40 watt incandescent lamp is useful. And be sure to furnish a sun shield and perhaps a small vent fan for heat control.
--
Macy Hallock, Medina, OH and Lutz, FL
Ex-telco tech, network engineer and former ISP Owner |
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