backup system

[stokes79]

Have been searching on here for a while for a backup system. I just need it to run the boiler circulator in a power outage which happens frequently here.

Here is what I have a 008 Taco pump which is .87 amps so for easier math 1 amp which is 120Watts

If I were to load the boiler and leave to work I would like something that would keep the circulator running for up to eight hours. I am looking for an inverter/charger that I can hook up to batteries that would be available at lets say NAPA so probably not a true deep cycle battery and I would like to run 12 or 24V

So far the least expensive inverter/charger I have found is the Freedom HF 1800 by Xantrex @ 549 this appears to have battery sensors, smart charging, automatic transfer from utility power to DC backup (batteries)

How do I figure out amp hours @ 12Volts so I would know how many batteries I would need to get the 8 hours run time for my circ pump?

Does modified sine wave affect taco pumps? they are quite a bit cheaper than pure sine wave units and I am not wanting to run any equipment other than my boiler

and another thing, my plan is that I would never start a fire if my storage tank temps were high, so I planned on using the tank for a "dump zone". I am thinking that to overheat the boiler I would need the circ pump to fail or start a fire when I have no business starting a fire like loading the boiler when my storage is completely charged?? Does this sound like a safe assumption?

thanks for any help
casey

 

[Piker]

From Xantrex:

1. Converting AC amps to Watts: AC amps x 120 Volts = Watts

2. Convert Watts to Actual DC amps: (Watts / 12) x 1.1 = actual DC amps

3. amp hours consumed between charge cycles:

run-time of appliance (hours) X actual DC amps = amp hours consumed

I am not sure if this takes into consideration the efficiency of the inverter or not. I don't think so.

I would say probably a 100 or 115 A-hr battery should do the trick. A cranking battery will work, but they will eventually tank if completely discharged many times.

Modified sine wave is acceptable for induction motors. It's not the best thing in the world for them, but it should do the trick for a backup which will actually see very little use.

The tank will work as a dump zone, like you said, unless your pump fails. At that point, it would be nice to have a gravity fed loop... unless your normally open valve also fails, at which point you get steam. It's important to make sure that whatever you have installed for overheat protection is working properly. There's always a chance of muliple failures in a system.

cheers

 

[atlarge54]

I've got a Tripplite APS700HF and two Walmart (marine?) batteries. The inverter/trans switch/charger was about $225 inc shipping from Provantage. It's probably not as high a quality as the Xantrex, but then I've never seen a comparison just going by price. The batteries (125 amp/hr) were about $79 each, less tax and core at Walmart a few weeks ago.

 

[JSJAC]

I have a battery bank and an inverter setup for my boiler. I have a modifide sine wave inverter and it works ok . I woulsd suggest a full wave inverter. It cost more but the pumps and blowers will like it better. Also if your boiler uses solinoids they will not get as hot.
I have 320AH battery bank and would like to double it .The more batterys the better.