I have a set of huge deep cycle batts and I would like to have bat backup. Any cheap way to maintain charge and outo swith when power fails? This would be for wood-oil boilers and circ pumps.Thanks for any input.
Battery backup auto switching and charging
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ohbie1
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I have a deep cycle battery that backs up my storage tank to boiler circulator in case of power failure. You need an inverter $20 for 200W......more for more wattage.
You will need a trickle chgr. (not expensive) to keep batt. charged (I don't have one so I just charge mine every once in a while with a reg. car batt. chgr.).
Two time delay relays from a surplus store (a couple of bucks each). You need these to keep the inverter from trying to run your circs. while the house current is on; this would blow out your inverter. (I speak from experience) You need a little delay from the time the power fails 'till your backup comes on, especially those times when you have a quick off,on,off power failure.
Maybe a transformer, depending on the control voltage of the relays you are able to get.
You will need a trickle chgr. (not expensive) to keep batt. charged (I don't have one so I just charge mine every once in a while with a reg. car batt. chgr.).
Two time delay relays from a surplus store (a couple of bucks each). You need these to keep the inverter from trying to run your circs. while the house current is on; this would blow out your inverter. (I speak from experience) You need a little delay from the time the power fails 'till your backup comes on, especially those times when you have a quick off,on,off power failure.
Maybe a transformer, depending on the control voltage of the relays you are able to get.
I purchased on of these unit's it does it all http://www.theinverterstore.com/the-inverter-store-product.php?model=pwric150012s . I bought frpm e-bay for about $450 last spring. With one deep cell batt. I can run my system for +6 hrs.
Robby
Member
Used RV inverted/chargers. They are automatic. Grid power goes off, almost instantaneous inverter power. Grid power comes on, waits to make sure will stay on, trips back to grid and recharges batteries. I purchased a 2500 watt and six deep cycle's for $500. Looks after complete heating system and solar system. There seems to be quit a few around. You can install more or fewer batteries depending on how long and how many watts draw. I checked with Taco and Grundfos about pumps on non-sine wave inverters. The answer was not forever, but ok for a few days if necessary. I test my system weekly, transformers hum a little more, electronic boiler controls seem fine, pumps a little more hum, blowers and other controls no difference. Worth a look!
Gooserider
Mod Emeritus
You can sometimes get old / surplus computer UPS units and use the guts to build a system... Get a heavy duty "server grade" unit, not a cheapo home PC item. The really good units actually isolate the protected device completely from the power line by essentially running off the inverter all the time - good protection against surges...
The usual power supply in a computer UPS is one or more sealed gel-cel batteries, which wear out after a while, so many companies will replace their server UPS's every few years, and the old ones end up on the surplus market...
It is important to note that many of these units will run on multiple batteries, so you will need to come up with the right combination for your particular unit - I have a bunch of these (Actually I wouldn't mind selling a few) some use 4x12v batteries, and others use 4x6v, and I've also had smaller units that ran off one 12 volt battery, so you usually have to open them up to see what you've got...
Obviously you will want to put your deep cycle batteries in appropriate containers, with proper venting for fumes and all that. Keep them away from the UPS guts as acid fumes and electronic parts don't mix... In addition, I've heard some folks claim that oversizing the batteries can put a strain on the charging circuits if bringing the batteries up from a deep discharge state - might not be a bad idea to supplement with a backup charger in such cases...
Gooserider
The usual power supply in a computer UPS is one or more sealed gel-cel batteries, which wear out after a while, so many companies will replace their server UPS's every few years, and the old ones end up on the surplus market...
It is important to note that many of these units will run on multiple batteries, so you will need to come up with the right combination for your particular unit - I have a bunch of these (Actually I wouldn't mind selling a few) some use 4x12v batteries, and others use 4x6v, and I've also had smaller units that ran off one 12 volt battery, so you usually have to open them up to see what you've got...
Obviously you will want to put your deep cycle batteries in appropriate containers, with proper venting for fumes and all that. Keep them away from the UPS guts as acid fumes and electronic parts don't mix... In addition, I've heard some folks claim that oversizing the batteries can put a strain on the charging circuits if bringing the batteries up from a deep discharge state - might not be a bad idea to supplement with a backup charger in such cases...
Gooserider
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